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New Hepatitis Virus Discovered
Researchers recently discovered a virus that is highly
associated with acute and chronic hepatitis of
unknown origin. The SEN-V virus was discovered
by Daniele Primi, PhD, and his research team at the
DiaSorin Biomolecular Research Center in Brescia,
Italy. DiaSorin is the Medical Systems Division of
American Standard Companies (Piscataway, NJ).
The name of the virus comes from the initials
of the patient in whom the virus was first discovered; the patient was a person with HIV.
The newly discovered virus is bloodborne, so
patients who undergo transfusions and intravenous drug users are at risk. While no blood
screening system for the new virus exists, appropriate screening of blood and blood products may
control its spread in the future. The virus appears
capable of co-infecting patients who have other
types of viral liver disease, raising the possibility
that it may aggravate their clinical course, their
response to treatment, or both.
The SEN-V virus may account for a majority of
cases of viral hepatitis of unknown origin. As many
as 5.2 million people in the United States are
infected with acute or chronic viral hepatitis. Five
viruses (A, B, C, D, E) are known to cause 80% to
90% of the hepatitis cases worldwide, but 10% to
20% of cases are of unknown origin (non-A/non-E
[NANE] hepatitis).
Based on test data from carefully controlled
samples, the SEN-V virus may account for
approximately 68% of all chronic NANE viral
hepatitis cases.
Researchers analyzed nearly 600 sera. In 31
cases of NANE hepatitis, the virus was found in
68% of chronic cases and 83% of posttransfusion
cases. The prevalence of the virus in the general
population is less than 1%, according to the
researchers.
"These data suggest that this new virus
accounts for a significant proportion of transfusion-associated hepatitis of unknown origin," says
Harvey Alter, MD, chief of the Infectious Diseases
Section, Department of Transfusion Medicine at
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November Is...
the Clinical Center, National Institutes of Health
(NIH), Bethesda, Md. "Though the data are preliminary, it is striking that such a high percentage
of cases demonstrated new SEN-V infection in
association with transfusion and that the incidence of infection in various control populations
was very low. A great deal of work remains to be
done to confirm and expand these findings, but
this is the best candidate virus to account for previously unexplained hepatitis that I have
observed."
Primi and his team have characterized the
genomic sequences of the new virus and developed prototype assays. The team is conducting
additional research to isolate and characterize the
viral particle. Expanded clinical studies are also
being conducted in collaboration with the NIH to
understand further the dynamics of immune
response and the clinical implications of the
virus. Initial studies reveal that approximately
30% of patients with HIV are also infected with
the new virus.©
Diabetic Eye
Disease Month —
Contact Nancy Antol,
Prevent Blindness
America,
(800) 331-2020.
National
Alzheimer's
Awareness
Month —
Contact Alzheimer's
Disease and Related
Disorders Assoc,
(800) 272-3900.
National Diabetes
MonthContact American
Diabetes Assoc,
(800) 232-3472.
National Epilepsy
Month —
Contact Epilepsy
Foundation of
America,
(800) EFA-1000.
Schematic drawing of a damaged liver (lower left) shows a variety of viral cells,
including nonspecific enveloped and non-enveloped hepatitis cells. Worldwide
10% to 20% of hepatitis cases are of unknown origin (non-A/non-E) hepatitis.
Image courtesy DiaSorin (Stillwater, Minn).
NOVEMBER 1999
VOLUME 30. NUMBER 11
LABORATORY MEDICINE
703
Cervical Cancer Update
aMtaf
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H u m a n papillomavirus, which researchers believe causes more than
9 0 % of cervical cancer cases, is characterized by koilocytes, mature
s q u a m o u s cells w i t h nuclear dysplasia and cytoplasmic halos.
Illustration 35 f r o m DeMay RM. Practical Principles of
Cytopathology.
Chicago, III: ASCP Press; 1999:12.
Electron p h o t o m i c r o g r a p h of h u m a n papillomavirus (HPV) virions in
the nucleus of a koilocyte. HPV is an icosahedral non-enveloped
virus w i t h a capsid diameter of 55 n m .
Using molecular
technology, the
Digene Hybrid
Capture II HPV DNA
Test (Digene,
Beltsville, Md)
detects the DNA of
high-risk h u m a n
p a p i l l o m a v i r u s in
cervical cells.The
test was recently
approved by the
Food and Drug
Administration.
HPV Testing
Women with abnormal Papanicolaou (Pap) smear results may
not have to wait the traditional 6 months for a repeat Pap test
and possible colposcopy procedure now that the Food and
Drug Administration has approved a new test for human papillomavirus (HPV).
The Hybrid Capture II HPV Test (Digene, Beltsville, Md) is
a DNA-based technology for the detection of HPV, a family of
viruses that can produce genetic damage in cells of the cervix.
After HPV enters the body, some strains—including HPV-16
and HPV-18—can, over time, trigger cancers of the cervix.
Researchers believe HPV causes more than 90% of cervical cancer cases. HPV testing for women with abnormal Pap results
accurately identifies women with severe, precancerous cell
growth in their cervix.
Only 15% to 20% of women with mildly abnormal Pap
smears actually have underlying disease requiring treatment,
however. Today, these women are subjected to invasive medical
procedures and repeat Pap tests even though they may not be at
risk for cervical cancer. HPV testing can identify which women
are truly at risk, eliminating the need for repeat Pap tests and
colposcopy procedures for those who are not high risk.
With the HPV test, a swab is used to take a sample specimen
from a woman's cervix. This sample can be taken when a Pap
smear specimen is taken. The specimen is placed in a transport
tube and sent to a laboratory. The HPV test uses molecular technology to detect the DNA of high-risk HPV in cervical cells.
The test detects DNA from 13 different types of HPV virus
that are most commonly associated with cervical cancer. Cervical cancer is completely treatable if detected early. Nearly 5,000
people die from the disease in the United States each year.
Vaccine for Cervical Cancer
Several different treatment vaccines for cervical cancer are
under development at centers around the world. The National
Cancer Institute (NCI) is planning an institute-sponsored,
multicenter trial to test a vaccine as adjuvant treatment after
radiation therapy or surgery.
At least six preventive vaccines are also in development
worldwide. One of these, developed at NCI, has succeeded in
stimulating the body to produce antibodies to HPV, according
to early data. NCI is testing a viruslike particle from HPV-16 in
a phase I/II study in people at The Johns Hopkins University,
Baltimore. Preliminary results indicate that a low-dose injection of the vaccine induces high levels of protective antibodies
against HPV. If further follow-up and analysis confirm these
findings, the vaccine will be tested in larger numbers of women,
including those at risk for developing HPV infection.©
Reported by Terri Yablomky Stat.
704
LABORATORY MEDICINE
VOLUME 30, NUMBER 11
NOVEMBER 1999