Download Antinuclear antibody test

Anti-nuclear antibodies
Significance and limitations of test
By Hatem H. Eleishi
Consultant Rheumatologist
In this mini-lecture:
What are ANAs
How useful they are
How unuseful they can be
Conclusion
What are antinuclear antibodies?
Antibodies to nuclear proteins
What are nuclear proteins?
Nucleolar proteins
Ro
La
dsDNA
Smith
Proteins that have
been synthesized in
the nucleus and
thereafter where
distributed to their
respective sites in the
cell
RNP
Jo-1
Scl-70
Ro
Nucleosomes
Nucleolar proteins
Nucleolar
Ro
La
dsDNA
Smith
Rim
RNP
Jo-1
Speckled
Scl-70
Ro
Homogenous
Nucleosomes
Importance of ANAs
One:
Serologic hallmarks of patients with systemic
autoimmune disease (ANA diseases).
Serologic hallmarks of patients with
systemic autoimmune disease:
•
•
•
•
•
•
•
•
•
•
SLE – sensitivity, 99 percent
Scleroderma – 97 percent
Mixed connective tissue disease – 93 percent
Polymyositis/dermatomyositis – 61 percent
Rheumatoid arthritis – 52 percent
Rheumatoid vasculitis – 33 percent
Sjögren's syndrome – 90 percent
Drug-induced lupus –100 percent
Discoid lupus – 15 percent
Pauciarticular juvenile chronic arthritis – 71 percent
Two
Can provide further diagnostic and
prognostic data concerning patients who
have minimal symptoms or who have
clinical features of more than one
autoimmune disease.
Examples
A young female with:
Polyarthralgias
Fatigue
Malar rash
Positive ANA
A lupus patient with:
Anti-Ro antibodies
Limitations of
utility and reliability
of ANA
in diagnosis
of systemic autoimmune diseases
One:
Can also be found in association with:
Many autoimmune disorders that are not
defined by these antibodies
In
In
Autoimmune disorders that are not
defined
by and
these
certain
infections
otherantibodies:
disorders
Hashimoto's thyroiditis – 46 percent
Chronic
infectious
diseases:
Graves' disease
– 50 percent
Mononucleosis
Autoimmune
hepatitis
– 71 percent
patients
receiving
certain
drugs too.
Primary autoimmune
cholangitis – 100
Subacute
bacterial endocarditis
In up
to 50 percent of patients taking certain
percent
Tuberculosis
drugs;
however,
mosthypertension
of these patients
do
Primary
pulmonary
– 40
Other disorders:
not percent
develop drug-induced lupus.
Some lymphoproliferative diseases.
Two:
Their presence does not mandate the
presence of illness, since they can
also be found in otherwise normal
individuals.
False positive ANAs (ie, ANAs in the absence
of autoimmune disease or known antigenic
stimuli) are more commonly seen in women
and in elderly patients. They are invariably in
low titer.
Three:
Accurate interpretation of different nuclear
patterns is confounded several difficulties
as:
• The recognition of specific patterns is operatordependent, and does not produce a permanent
record. The fluorescence fades in one to two
days, so that one cannot compare a result with
other samples without photographing each test
result.
• One nuclear pattern may obscure and prevent
the recognition of another pattern if several
antibodies are present simultaneously.
As a result,
A positive ANA, although useful and
important, yet should be interpreted
with
caution
and
within
the
appropriate clinical setting
As a result,
A good history compounded with a
thorough clinical examination remain
to be the mainstay of diagnosis
Thank you