Download Immune system

Semiology
of immune
system
Department of pediatrics
Notion
Immune system
reunites the organs, tissues and
cells, which ensure the defense of
human organism against the
genetically strange substances
(antigens) by exogenous and
endogenous origin.
Immune system
Two possibilities of IS response manifesting
were distinguished for to understand how the
organism succeeds to put up resistance to the
external medium factors (infectious agents) :
elimination of pathogenic agents with the
nonspecific means of IS response or
producing of some cellular and molecular
components for adopting the pathogenic agent
(specific means).
Physiologic importance
The function of IS consists in the Ag
identifying and generation of specific
response –
synthesis of antibodies,
accumulation of sensibilized
lymphocytes, which will
neutralized,
destroyed and
eliminated the Ag from organism.
Components of immune
system
1. Lymphoid organs:
a) Central
b) Peripheral
2. Humoral components
a) Nonspecific
b) Specific
3. Cellular components
a) Nonspecific
b) Specific
Immune system
Central lymphoid organs
The central lymphoid organs
(primary) are represented by:
hematogene marrow
thymus
Central lymphoid organs
The central lymphoid organs have a major
significance in immunity because they
represent the place of lymphopoiesis.
At their level, the cellular components of
IS: B lymphocytes and T lymphocytes, are
differentiating from derived precursors
originated from stem cell, proliferating and
se maturating in functional cells.
Hematogene marrow
Hematogene marrow is localizing in the
trabeculae of osseos spongious tissue
from long bones epiphyses, from flat
bones and from short bones. From the
histologic point of view, it is formed from
stroma, blood, lymphatic vessels and
nerves. The stroma is formed from
conjunctive reticular cells, forming a
network where are sitting the stem cells.
Here the B lymphocytes are
differentiating.
Thymus
The thymus is sitting retrosternally.
From the anatomic point of view, the thymus
is formed from two lobes connected by
isthmus.
Each lobe is formed from lobules delimited
by conjunctive septa which proceed from the
capsula covering the entire organ.
Two zones are described in the thymic
lobule: cortical and medullar.
The thymic cells are lymphocytes, epithelial
and non-epithelial cells.
The process of differentiation is developing
under the influence of local hormones
(thymosine, thymopoietine, thymuline)
secreted especially by subcapsular and
subtrabecular epithelium.
Thymus
Thymus
The thymus is forming at the end of first
month of intrauterine development.
It is positioned retrosternally.
It is covered by conjunctive tissue
capsula which separates the organ in
lobules.
Each lobule has cortical and medullar
layer. The cortical layer contains Tlymphocytes, and epithelial cells of
medullar layer form the Gassale
corpuscles.
Thymus
The thymus releases in the systemic circulation
T-lymphocytes,
hormones (thymosine, thymopoietine, thymic
factor etc.) which regulates the proliferation
and differentiation of lymphocytes.
The thymus achieves the maximal degree of
development in early childhood.
In the period of 3 – 13-15 yrs the stabilization
of gland mass has place, and ulterior it
involutes.
The cortical layer becomes more poor in Tlymphocytes, the Gassale corpuscles from
medullar layer disappear, these structures
being replaced with conjunctive and adipose
tissue.
Thymus
In rare cases the physiologic
involution is not producing.
These clinical situations usually are
associated with diminishing of GCS
secretion by cortical layer of
suprarenal glands. Such patients are
more receptive to intercurrent
infections, have increased risc for
neoplastic processes appearance.
Peripheral lymphoid organs
Peripheral (secondary) lymphoid organs
are represented by:
Spleen
Lymph nodes
Lymphoid tissue from mucosae
Spleen
The spleen is situated in the left superior part
of abdomen.
It has exterior capsula from conjunctive tissue
which sends in parenchyma prolongations
forming trabeculae. These together with the
reticular cells network form a support for a
great lot of cells.
Two types of tissue enter in the spleen
structure : the tissue responsible for grown
old blood cells destruction and urgent
generation of new erythrocytes, platelets and
granulocytes (red pulp) and tissue populated
by immune competent cells (white pulp).
Spleen
Spleen white pulp is a lymphoid tissue
situated in two zones:
T-dependent zone, situated around central
arteriola and
B-dependent zone, which surrounds the Tzone, as a muff.
In B-zone the cells are organized in primary
follicles (non stimulated) and in secondary
follicles (stimulated).
At the periphery of B-zone, to the exterior,
the splenic macrophages are sitting.
Lymph nodes
The lymph nodes are oval
formations by different dimensions,
situated in the confluence place of
great lymph vessels.
Lymph nodes
The forming of LN begins in the 2-nd month of
intrauterine development and is finishing in the
postnatal period.
In new-born the LN capsula is very thin and
fine, the trabeculae are weakly differentiated, and
their palpation is difficult. LN are soft and they
are included in good developed adipose tissue at
this age.
At 1 year age the LN can be palpated at the
majority of children.
Parallel with their growing their differentiation has
place.
Lymph nodes
In the 3 yrs age the capsula is good
formed.
At 7-8 yrs the forming of trabeculae in the
interior of LN begins.
At 12-13 yrs the structure of LN is
definitized, being good differentiated all their
structures:
capsula, trabeculae, follicles, sinuses.
Lymph nodes
In the puberty period the LN growing
is finishing, and sometime even partially
regresses.
The maximal number of LN is achieved
around10 years age.
The mature has approximatively
460 LN, having total mass by1%
from corporal mass (500 – 1000g).
Lymph nodes
Each lymph node (LN) is covered at surface with
conjunctive tissue capsule, and in interior contains
lymphoid tissue.
The lymphoid tissue of LN is separated in two
layers:
cortical and medullar.
Cortical layer is formed from follicles–
conglomerates of B lymphocytes.
In paracortical layer the T-lymphocytes are placed
In medullar layer the plasmocytes, secreting
immunoglobulins are placed.
Lymph nodes
LN are placed in groups, through them the lymph
drainage from distinct anatomic zones has place.
Due to their structure and localization the LN
have a role of barrier in the pathway of infection
spreading, preventing its generalization.
LN filter the particles with antigenic properties,
and the lymphocytes and plasmocytes from
LN ensure the synthesis of antibodies.
The lymphoid system of respiratory and digestive
tract ensures the good functioning of local
immunity at the level of their mucosa.
Lymph nodes
The reaction of LN at different stimuli, especially
infectious can be observed from 3 months age.
In 1-2 yrs age children the barrier function of LN
is not good expressed, therefore in this age the
infections easily are generalized (septicemia,
meningitis, generalized forms of TBC).
Immaturity of lymphoid system at the level of
digestive tube predisposes the suckling babies at
intestinal infections and allergization of organism on
enteral pathway.
Lymph nodes
In the antepreschool age the LN are still
good structured and can serve as
mechanical barrier against the infection
spreading.
In this age the lymphadenites, including
these purulent and caseous (TBC) are
frequent.
In the age of 7-8 years the LN become
functional and can suppress the infection
through immunologic mechanisms.
Lymph nodes
Occipital – placed on occipital tuberozities – they
collect the lymph from the scalp skin and cervical
posterior region.
Mastoidian – placed in region of mastoid apophises,
retroauricular – placed postrior from ears pavilion –
both groups collect the lymph from medium ear,
external auditive conduct, ears pavilion, paraauricular
teguments.
Submandibular – placed under inferior bundles of
mandiba – collect the lymph from face skin and gums
mucosa.
Mentoniar – placed one self bilaterally in the region of
chin – collect the lymph from the inferior lip skin,
mucosa of gums and from inferior incissives.
Lymph nodes
Anterior cervical and tonsilar – placed
anterior from the sternocleidomastoidian
muscle, in superior cervical triangle– collect
the lymph from face teguments, from
parathyroid gland, nasal, faringeal and
buccal mucosa.
Posterior cervical – placed posterior from the
sternocleidomastoidian muscle, anterior from
trapezium muscle, in cervical superior
triangle – collect the lymph from cervical
region and partially from larynx.
The LN from above mentioned groups are
frequently catalogued as a unique group –
cervical LN.
Lymph nodes
Supraclavicular – placed in supraclavicular
fossa – collect the lymph from superior part
of thorax, pleural domes and pulmonary
apexes.
Subclavicular – placed in infraclavicular
fossa – collect the lymph from the thoracic
wall and pleura.
Axillary – placed în axillary fossa – collect
the lymph from superior members (exception
fingers V, IV, III and palm).
Thoracic – placed on the inferior margin of
big pectoral muscle – collect the lymph from
thoracic wall teguments, parietal pleura,
partially from lungs and mammal glands.
Lymph nodes
Cubital – placed in the cubital region
at the level of biceps tendon – collect
the lymph from V, IV, III fingers and
palm.
Inguinal – placed on line of inguinal
ligament– collect the lymph from the
teguments of inferior member,
hypogastrium, buttocks, anal region,
perineum, genital organs.
Popliteal – placed in the popliteal
fossa – collect the lymph from the
teguments of leg.
Lymph nodes
The knowledge of LN localization
and of their draining zones has a
major role in the identifying of
infection gateway, especially in the
case when the modifications of
infection gateway are minimal or
even absent, but regional LN will
react in the all cases.
The semeiology of LN
affection
Complaints.
In the case of LN marked
enlargement, the child or the
parents can remark this modification
and can present the respective
complaints.
In the case of lymphadenitis the child
can accuse pain, tumefaction and
hyperemia at the level of affected
LN.
Semeiology of LN affection
Inspection.
Only LN which are placed
superficially and are very enlarged in
volume (lymphogranulomatosis,
infectious mononucleosis) can be
observed.
In lymphadenitis the hyperemia of
teguments covering the involved LN,
which usually is tumefied and painful
at palpation can be observed.
Semeiology of LN affection
Palpation. At palpation the LN the following
Characteristics are appreciated:
Dimension – usually the LN have a diameter
around 0,3-0,5 cm (pea seed).
The dimension of LN is gradated as the
following:
I degree – dimension of millet seed
II grad – dimension of lentil seed
III grad – dimension of pea seed
IV grad – dimension of horse bean
V grad – dimension of peanut
VI grad – dimension of pigeon egg.
Increasing of LN dimension poate can be
isolated or in group, symmetrical or unilateral.
Semeiology of LN affection
Number
If in each group 3 or less LN are
palpable – they are considered
solitary,
If in some group more than 3 LN are
palpated – they are considered
multiple.
Semeiology of LN affection
Consistence
Can be soft, elastic, hard.
It depends from the oldness and nature
of process:
in chronic pathology the LN are hard,
in the case of recent affection they
have soft consistence.
Physiologically the consistence of LN is
elastic.
Semeiology of LN affection
Mobility – usually the LN are mobile.
Report with teguments, adipose
subcutaneous tissue, other LN.
Physiologically the LN don’t connect
with adiacent tissues and not
between them.
Sensibility.
LN are painless at palpation.
The presence of pain at palpation
indicates an acute inflammatory
process at the level of LN.
Semeiology of LN affection
The palpation of symmetrical LN is
performing with both hands
concomitantly.
(exception – cubital LN).
In healthy children until 3 groups of LN
are palpable.
In physiological conditions the
The chin, supra- and subclavicular,
thoracal, cubital and popliteal LN
are not palpating.
Semeiology of LN affection
The LN can be considered normal, if:
their dimension does not exceed the
dimension of pea seed,
are solitary,
by elastic consistence,
mobile,
don’t adhere between them and
adjacent tissues,
are not painful.
Semeiology of LN affection
For the performing of certain
diagnosis, the clinical examination of
LN is supplemented at necessity with
special paraclinical examinations:
puncture of LN,
biopsy of LN,
lymphography.
Semeiology of LN affection
In children the modifications of LN
both local and generalized are
frequently observed.
Local/regional enlargement of LN
accompanies the suppurative
processes at the level of teguments:
folliculites, pioderma, furunculosis,
miliary multiple abscesses , infected
sores, hydroadenitis etc.
Semeiology of LN affection
Lymphadenopathy – enlargement of
LN in dimensions, sometimes with
modification of their consistence.
Polyadenia – increasing of number of
palpable LN.
Semeiology of LN affection
In diphtheria, scarlet fever,
tonsillitis the cervical LN react.
În felinosis the cubital and/or
axillary LN are modified.
Semeiology of LN affection
TBC of peripheral LN usually is limiting at
the affection of one group of LN, most often
cervical.
The LN represent a voluminous, hard,
painless conglomerate (packet).
They are adherent between them and
adjacent tissues.
They have tendency of evolution to the
caseous necrosis, with forming of
local fistula, after that the „ stellated
scars” remain.
Semeiology of LN affection
In the infectious mononucleosis all
groups of peripheral LN are affected,
but the affection of cervical posterior
LN predominates.
In rujeola the occipital LN are
affected.
For rubeola the diffuse LN
affection, more pronounced in cervical,
occipital and axillar LN groups is
characteristic.
Semeiology of LN affection
In adenoviral and paragrippal infection
the anterior and posterior cervical and occipital
LN are predominantly involved.
In mumps the auricular LN are palpating as
firm formations which are placed
superiorly to parotidian tumefiated glands.
In toxoplasmosis most frequently
the groups of cervical,
axillary, inguinal LN are affected. The LN
have the dimensions of a nut, sometimes can
have a form of pockets, but each node can be
palpated separately.
Semeiology of LN affection
In HIV/AIDS the generalized
lymphadenopathy is a precocious
and constant symptom.
The diameter of LN is 2-3 cm, the
contur net delimitated, hard at
palpation, not adhere between them
and not to adjacent tissues, usually
are sensible at palpation, sometimes
painful.
Semeiology of LN affection
Lymphosarcoma is manifesting by
affection of isolated LN group,
usually cervical or supraclavicular.
LN are very hard, painless at palpation,
the local signs of inflammation are
absent.
The generalized lymphadenopathy can
be present in a lot of acute or chronic
infectious pathologies and in
noninfectious pathologies.
Semeiology of LN affection
The diffuse diseases of conjunctive tissue can
be around the noninfectious causes of
generalized lymphadenopathy.
Lymphogranulomatosis as a rule begins with
peripheral LN affection, more frequently
cervical or/and mandibular. In the same time with
disease evolution the LN grow in conglomerates.
LN are painless, at palpation creates a sensation
of „sack of potatoes”. The diagnosis is confirmed
by the hystologic examination of LN (BerezovskiSternberg cells).
In ALL (acute lymphoblastic leukaemia) all
groups of LN are rapidly growing in
dimensions. They are soft and painless at
palpation.
Lymphoid tissues
associated to mucosae
The lymphoid tissues associated to
mucosae also enter in the category of
secondary lymphoid organs.
These can be:
good individualized anatomically
structures
or
lympho-epithelial diffuse structures.
Lymphoid tissues
associated to mucosae
The individualized anatomically structures
are:
1. Componentele of Valdayer lymphatic
ring
a) lingual tonsils
b) palatine tonsils
c) tubar tonsils
d) faringean tonsils
2. Payer’s patches
3. Vermiform appendix
Lymphoid tissues
associated to mucosae
The diffuse lympho-epithelial tissues
Are localized at the level of digestive,
respiratory, genito-urinary tracts etc.
After their localization these tissues were
named:
MALT – mucosae associated lymphoid
tissue
SALT – skin associated lymphoid tissue
BALT – bronchia associated lymphoid
tissue
GALT – gut associated lymphoid tissue
IS. Nonspecific immunity
The factors of nonspecific protection have
a large spectrum of action, that is possess
a high specificity.
The nonspecific forces of protection are
sufficient for to combat the majority of
pathogen agents.
Nonspecific reactions are at the basis of
natural immunity and offer to organism the
immunity even against the pathogen
agents which the organism didn’t
anteriorly met.
IS. Nonspecific immunity
These factors being phylogenetically
older have a decisive role
In the protection of nevborns
until the maturation of specific
immune mechanisms.
IS. Nonspecific immunity
Nonspecific protection
is ensured by the
physiologic barriers and
humoral nonspecific factors.
IS. Nonspecific immunity
In the physiologic barriers enter:
teguments and intact mucosae,
LN,
ciliary epithelium,
acid gastric medium,
Hematoencephalic barrier,
kidneys (which excrete some
microorganisms, especially viruses).
IS. Nonspecific immunity
Nonspecific humoral protection is ensured
by:
lysozyme,
properdin, present in blood and other
BL,
interferon,
complement system ,
phagocytosis.
The last two components have special
status being mechanisms of nonspecific
and specific protection in the same time.
IS. Nonspecific immunity
Lysozyme– a protein which
possesses enzymatic qualities. It
destroy the structure of
mucopolysacharides of cellular
bacterial membranes. It is very active
on Gramm “-” bacterias.
Secretory Ig A potentiates the action
of lysozyme. The most high level of
lysozyme is in newborns, and further
decreases gradually.
IS. Nonspecific immunity
Properdin – a plasmatic globulin,
which activates alternatively the
complement and together ensure the
elimination of viruses and bacterias
from organism.
The contain de properdin in children
is low, at the 1-3 weeks its level
rapidly increases and remains high
during all childhood.
IS. Nonspecific immunity
Interferon – a protein with antiviral
action, which is manifesting in the
phase of de intracellular virus
replication.
It can be synthesized by each cell of
human organism, but especially by
leucocytes.
IS. Nonspecific immunity
Interferon also:
blocks the multiplication of chlamidias,
plasmodium malariae, ricketsies,
increases the organism cells resistance to
the action of exo- and endo
toxins,
stimulates the phagocytosis,
increases the cytotoxicity of lymphocytes,
blocks the cangerogenesis,
Influences the antibodies forming
(small doses – stimulates it, and
high doses – inhibates it).
IS. Nonspecific immunity
In newborns the capacity of
interferon synthesis is low,
increases gradually and achieves the
maximum at the age of 12-16 years.
IS. Nonspecific immunity
The complement (C) – enzymatic
system, formed from plasmatic
globulins, the biologic role of al which
is the cellular antigens lysis (viruses,
virus infected cells, bacterias,
mycoplasmas, protozoa, tumoral
cells) fixed by Ab.
It includes 11 complement fractions
and 3 inhibitors.
IS. Nonspecific immunity
All components of complement system
circulate in blood under the form of
precursors which can be activated on 2
pathways:
classic or
properdinic.
The trigger of classic activation pathway is
the Ag-Ab complex.
In the absence of Ab the complement system
can be activated through alternative pathway
– properdinic.
IS. Nonspecific immunity
Phagocytosis – a process of capture
and digestion of Ag by tissular
macrophages (monocytes) and
circulant macrophages (neutrophils
and monocytes). The phagocytes are
the first cells which enter in contact
with exo- or endogenous Ag.
IS. Nonspecific immunity
The immune protection is ensured by
2 specific mechanisms :
cellular and
humoral,
which are differing from one another
by the mechanisms of
neutralization and
Ag elimination.
Cellular immunity.
The immune response is ensured by
T-lymphocytes (thymodependent) and
B-lymphocytes (bursodependent).
The both cellular lines have a common
predecessor –stem cell, which migrates from
bone marrow in thymus and in analog of
Fabricius burse, when the differentiation and
their maturation have place.
Then these cells populate the T şi B zones
of LN. Here, at the first meeting with Ag their
sensibilization and ulterior differentiation in
another 2 subpopulations have place:
effector cells and
memory cells.
Cellular immunity
Effector cells – participate directly in
the „liquidation” of antigenic
aggressor. In the cell immunity there
are cytotoxic T-lymphocytes (Tkiller). They neutralize the antigen
directly or through some special
biologic active substances –
lymphokines.
Cellular immunity
The memory cells are the lymphocytes
which are transforming in the inactive
form, but preserve the information
about the Ag. These cells are going in
again in the sanguine and lymphatic
circulation and „patrol” the organism.
Humoral immunity
The humoral immunity is ensured by
B-lymphocytes.
Initially theT-lymphocytes are stimulated,
And they will be transforming in T-helpers.
These through interleukins will stimulating the
transforming of B-lymphocytes in plasmocytes,
which will synthesize the specific antibodies.
So, the effector cells of humoral immunity are
plasmocytes.
B-lymphocytes receive also information about
the nature of Ag and from macrophages which
captivate these antigens and remake them
primarly.
IS. Specific immunity
In this way for good functioning of IS an
harmonious collaboration between these
three types of immunocompetent cells is
necessary:
T-, B-lymphocytes and macrophages.
In the same time during antigenic stimulation
the T-suppressors are forming. They block Thelperis, in this way blocking the Ab
synthesis by B-lymphocytes.
This capacity of the organism is the basis of
immunotolerance.
Cytokines
There are the soluble molecules,
synthesized by a great variety of
cells, inclusively by lymphocytes,
with the role of humoral messengers,
which realize the communication
between different cells, controlling
their growing, differentiation,
maturation, division, metabolism,
functions.
T lymphocyte
B lymphocyte
Macrophage
IS. Specific immunity
T- and B-lymphocytes can be found from
the age of 10-12 weeks of intrauterine
development.
T-lymphocytes become functionally after
the age of 14-15 weeks of intrauterine
development.
The newborns have a more number of
T- and B-lymphocytes comparatively with
another age and adults, but these cells
are not completely functional.
IS. Specific immunity
B-lymphocytes synthesize more
classes of Ig: G, M, A, D, E.
In each antigenic aggression a lot of
Ig classes are synthesized
As a response to primary contact
with Ag the Ig M, after that IgG,
ulterior IgA are synthesized.
At repeated contact with Ag the IgG
from start is synthesized.
Humoral immunity
IgG constituies 70-80% from the totality
of plasmatic Ig.
It is the self Ig which passes the
placentar barrier, ensuring the passive
immunity of the new-born.
Transmission of IgG from mother to
fetus has place more actively in the last
weeks of pregnancy, thus the level of
IgG in premature babies is less than in
term born baby.
Humoral immunity
During the time the level of maternal
IgG in blood plasma of suckling baby
decreases, and achieves the
minimum at 6-9 months.
At the age of one year the intensity
of proper IgG synthesis constitutes
50% from that of adult.
At 4-6 years the level of IgG in
children achieves the IgG level at
adult.
Humoral immunity
IgM constitutes 5-10% from total
plasmatic Ig. They constitute the first
line of defensive taking part in the
complement activation on classic
pathway, agglutination and
opsonization of Ag, lysis of alien
cells.
In plasma of newborns the level of
IgM is low, but increases quickly,
achieving the adult level at the1-2
years age.
Humoral immunity
IgA constitute 10-15% from total plasmatic Ig.
They are synthesized by plasmocytes, which
are localized at the level of mucosa and
submucosa of digestive tube and respiratory
pathways.
The most part of IgA remains in the place of
synthesis(secretory IgA), ensuring the local
immunity.
Secretory IgA is finding in tears, saliva, nasal
and bronchial secretions, secretions of
digestive tube, colostrum.
The level of secretory IgA in children is low. It
increases with age and achieves the most high
level at 5 years.
Humoral immunity
Seric IgA in children is less active.
In usual newborn is absent. It
appears after first week of life.
At 1 year age the IgA level
constitutes 20% from that of adult,
which is achieved only at 10-12
years age.
Humoral immunity
IgD and IgE are containing in în non
significant quantities(each - 0,2%).
IgD is a globulin by embryonic type.
It is enable to activate the
complement on alternative pathway,
to neutralize some viruses.
Humoral immunity
IgE constitutes the most part of reagines
– antibodies responsible by allergic
reaction releasing.
They are synthesized as response to
primary contact with Ag.
IgE are fixed on the mastocytes and
basophils surface, realizing therefore the
state of sensibilization.
Humoral immunity
At the repeated contact with Ag the IgE
provokes the degranlation of these cells
with elimination from them of different
BAS, their biologic effect being at the
basis of pathological modifications in
allergic reactions.
IgE is practically absent in the plasma
Of newborns.
During the time their concentration
increases achieving the adult level at
10-12 years age.
IS. Specific immunity
Therefore, the IS development is an
ontogenetic process genetically programmed.
The forming process is initiating intrauterine.
The most important stimulus the IS receives
after birth, when the exo- and endogenous
antigenic aggression, determined especially
by digestive tube, superior respiratory
pathways and teguments microbial population
by conditioned-pathogene microflora,
increases considerably.
IS. Specific immunity
Immaturity of IS in children makes them
More sensible to intercurrent infections,
favour the generalization of infectious
process with the development of
septicemia and septicopiemia,
favour the more severe evolution of
infectious pathologies.
Semeiology of IS affections
Three types of this system functions
affection are possible:
Defect of one link of IS
(primary and secondary
immunodefficiencies)
Autoaggression against the normal
structures of human organism
(auoimmune diseases and diseases due to
immunocomplexes)
Dysfunctions when some functions of IS
are exagerrated in the detriment of another
(lymphoproliferative syndromes)
Semeiology of IS affections
The states of immunodeficiency appear
as a result of one or more links of IS
function abolition.
The states of immunodeficiency are:
primary (inborn) and
secondary (acquired).
Semeiology of IS affections
The states of primary immunodeficiency are
determined by:
primary affection of T-lymphocytes;
primary affection of B-lymphocytes;
combined affection of T- and Blymphocytes;
the summary incidence of primary
immunodeficiency states is by 2:1000,
50-70% being primary defects of
B-lymphocytar system, and
5-10% of T-lymphocytar system.
Suggestive signs for a
primary immunodeficiency
are:
The child supports frequently infectious
recurrent diseases especially of respiratory
pathways, digestive tube, reno-urinary
system, teguments, frequently complicated
with otitis, purulent sinusitis and septicemia.
They manifest unusual reactions at banal
infections (ex. pneumonia at varicella).
The suffering is determined by unusual
causal agents (ex. Pneumocystus Carinii)
Suggestive signs for a primary
immunodeficiency are:
Presence of some systemic reactions
after vaccination with live viral
attenuated vaccines or BCG
Bizarre hematologic deficit
(anemia, thrombocytopenia,
leucopenia)
Disorder of digestion with the
development of malabsorption
syndrome.
Secondary
immunodeficiencies
Secondary immunodeficiencies are determined by a
lot of pathological states which lead to the involution
of lymphoid tissue, lymphopenia,
hipogammaglobulinemia.
They are the following:
pathologic states associated with loss of proteins:
nephrotic syndrome, combustions, exsudative
enteropathy
dystrophias, avitaminoses
Viral (flu), bacterial (holera),
micotic (candidosis) infections, helminthiases
Massive surgical interventions and/or
postoperatory yatrogenic complications
(irradiation, imunosuppressives: GCS, CS)
Lymphoreticular tumors(lymphogranulomatosis,etc.)
Semeiology of IS affections
In children first 3 yrs of life the state of
immunodeficiency can be determined by
thymomegaly, which is induced by
hypothalamo – hypophysar - suprarenal axe
affection.
In stress situations an rapid accidental
involution of thymus can be developing, in
which a massive releasing of T-lymphocytes
in blood has place, their massive death in
thymus with their phagocytosis by
macrophages has place .
Transitory deficit of humoral immunity is
characteristic for first year age children,
between 6 – 9 months.
Semeiology of IS affection
Primary affection of nonspecific factors
of protection includes
disorders in Complement System
disorder of phagocytosis.
Semeiology of IS affection
The genetic deficit can involve each
component of Complement System,
which shell alter their cascade
activation.
It is clinically manifesting through
decreased resistance at bacterial
infections (C1, C2, C3, C5), increased
incidence of hipersensibility diseases
(C1, C2, C4). Deficit of C1 leads to
development of angioneurotic recurrent
edema.
Semeiology of IS affection
Patients with disordered phagocytosis
support frequent infections caused by
microorganisms usually non pathogene.
In chronic granulomatosis (syndrome of
paradoxes) the patients are resistant to
infections with high virulence
microorganiss (streptococci,
meningococci, pneumococci), but are
sensible to conditioned pathogene
microorganisms (Escherihia coli,
staphylococci).
Semeiology of IS affection
A global affection of all components of
Immune System
And of humoral nonspecific iactors
Is characteristic for
HIV/AIDS
Critical periods in the Immune
System development
Tere are a periods, when the organism immune
system in growing and development
Generates paradoxal or unadequate responses
to antigenic stimuli.
I-st critical period – first month of life.
II-nd critical period – from 3 to 6 month of life.
III-rd critical period – second year of life.
IV-th critical period – from 4 to 6 yrs of life.
V-th critical period – period of adolescence.
Critical periods in the Immune
System development
First critical period–
first month of life.
A decreased activity of phagocytes
is observing.
Lymphocytes are capable to react
at antigenic stimuli and mitogenic
actions.
Humoral immunity is ensured by
maternal IgG.
Critical periods in the Immune
System development
The second critical period–
from 3 to 6 months of life.
Maternal antibodies disappear from child’s
plasma,
the proper IgM is synthesizing as a
response to antigenic stimuli.
Deficit of IgA predisposes to frequent
infections of respiratory pathways (viral).
Immunocompetent cells have a diminished
activity.
In this period the primary
immunodeficiences are manifesting.
Critical periods in the Immune
System development
The third critical period–
the second year of life.
Immune system is completely functional.
The capacity of IgG synthesis increases,
but the mechanisms of local protection
remain insufficient developed.
This maintains a high receptivity of the
child’s organism to different
pathogene agents.
Critical periods in the Immune
System development
The fourth critical period–
from 4 to 6 years of life.
The antibodies synthesis, excepting IgA,
achieves the level of adult.
Concomitantly the titre of IgE increases.
The activity of local protection factors
remains diminished.
In this age the tardive congenital immune
defficiencies are clinically manifesting.
Critical periods in the Immune
System development
The fifth critical period–
the period of adolescence.
The gonadian hormones secreted in this
period inhibate the immune reactions.
As a result the autoimmune and
lymphoproliferative pathologies can
develop.
The increased receptivity
to diverse micobial agents is observing.
A nice day!