Date: Fri, 8 Mar 1996 12:47:43 +0500
From: ghmcleaf{CONTRACTOR/ASPEN/ghmcleaf}%NAC-GATEWAY.ASPEN@ace.aspensys.com
Subject: MMWR 03/08/96


MORBIDITY AND MORTALITY WEEKLY REPORT
******************************************
Centers for Disease Control and Prevention
March 8, 1996
Vol. 45, No. 9

*  Persistent Lack of Detectable HIV-1 Antibody In a Person
   With HIV Infection --- Utah, 1995

Persistent Lack of Detectable HIV-1 Antibody In a Person With HIV
Infection -- Utah, 1995
     Infection with human immunodeficiency virus (HIV) is diagnosed
routinely by the enzyme immunoassay (EIA) for HIV-1 antibody; a
nonreactive blood sample is designated as negative without further
testing. However, one limitation of this screening algorithm is
that a blood sample may be obtained from a patient with recent HIV
infection before detectable HIV antibody is present ("window
period"). This report describes a patient with confirmed HIV
infection in whom EIAs for HIV antibody (HIV-EIAs) were
persistently negative beyond the expected "window period."*
Case Investigation
     In October 1995, the Utah Department of Health referred to CDC
blood samples obtained from a man who had had onset of persistent
fatigue and malaise during January 1995. During January-June 1995,
he had sought medical care at several clinics. When he was admitted
to a hospital in June because of respiratory illness and recent
weight loss of 27 lbs, HIV-EIA was negative. In August, he was
admitted with lung-biopsy-confirmed Pneumocystis carinii pneumonia
(PCP) and a CD4+ count of 129 cells/uL; an HIV-EIA again was
negative. The patient reported frequently donating plasma at a
plasmapheresis center from August 1990 through April 1994. Review
of records at the plasmapheresis center identified 33 donations by
the patient. At the time of each donation, testing on an aliquot of
the donated plasma was negative by HIV-EIA (Table 1).
     The patient was married and reported sexual contact without
condom use with his wife during 1989-1993; the couple separated in
1993 and had no further sexual contact. The wife was interviewed
and reported sexual contact during 1985-1989 with a bisexual man
who had died of acquired immunodeficiency syndrome (AIDS) in 1994.
In January 1994, she was diagnosed with PCP and HIV infection
(HIV-EIA positive). When the patient became aware of his wife's HIV
infection in May 1994, he was tested and was HIV-EIA negative
(Table 1). The patient denied male-to-male sexual contact or
receipt of a transfusion. He had used multiple nonparenteral
illicit drugs, but denied injecting-drug use.
Laboratory Investigation
     Two blood samples obtained in October and in December 1995
were analyzed by CDC and the Food and Drug Administration (FDA).
Both samples were weakly reactive for antibody (signal/cutoff ratio
less than 2.2) when tested by the HIV-EIA kit from manufacturer A,
but were negative by kits from manufacturers B and C.
     Because antibody detection assays were negative or weakly
positive, additional assays were conducted. Assays for HIV-1 p24
antigen using the kit from manufacturer D on both samples were so
weakly reactive that neutralization assays were invalid; however,
after the samples were subjected to base dissociation to disrupt
immune complexes, the p24-antigen results became strongly reactive
and neutralizable. Antigen results also were positive using EIA
kits from manufacturers E and F without immune complex disruption,
including a positive neutralization test (kit E). HIV infection was
diagnosed based on the positive p24-antigen test results.
     Testing also was conducted to evaluate whether the persistent
seronegativity was attributable to infection with an atypical virus
or to lack of immune competence. HIV proviral DNA present in the
peripheral blood mononuclear cells from the patient and his wife
was amplified by a nested polymerase chain reaction (PCR) and
sequenced directly. The results indicated that the HIV sequences
from the patient and his wife were closely related**, and that
these HIV strains were subtype B viruses, the HIV subtype
predominant in the United States. Immunologic evaluation of
specimens obtained from the patient in August 1995 detected normal
levels of serum immunoglobulin G, immunoglobulin M, and
immunoglobulin A and a positive immunoglobulin G titer to
Epstein-Barr virus and cytomegalovirus.
Reported by: L Reimer, MD, Veterans Affairs Medical Center and Univ
of Utah; C Brokopp, DrPH, S Mottice, PhD, R Den, C Nichols, MPA,
State Epidemiologist, Utah Dept of Health. Salt Lake City Resident
Post and Office of Blood Research and Review, Food and Drug
Administration. Div of HIV/AIDS Prevention, National Center for
Prevention Svcs; Div of AIDS, STD, and TB Laboratory Research,
National Center for Infectious Diseases, CDC.
Editorial Note: This report documents persistently negative HIV
test results from an HIV-infected man. HIV-infected blood may test
EIA negative for HIV antibody for at least three reasons. First,
infectious blood may be tested during the "window period." Second,
infections with divergent HIV strains (e.g., group O viruses) may
not be detected by EIAs designed to detect antibody to HIV-1 and
HIV-2 (1). However, a recently completed retrospective study in the
United States did not document any serum samples with peptide
reactivity consistent with HIV-1 group O infection (2). In the case
described in this report, genetic analysis indicated that the
husband and wife were infected with similar subtype B strains,
typical of HIV-1 strains found in the United States. Third,
although HIV-infected patients who are initially HIV seropositive
have been reported to become seronegative (serorevert) (3), this
phenomenon is rare when current HIV-EIAs are used (4).
     The persistently seronegative status of the patient described
in this report was not associated with one of the previously
recognized reasons. Based on the similarity of the genetic
sequences between the patient and his wife and results of the
epidemiologic investigation, the most likely mode of HIV
transmission to the case-patient was by heterosexual contact with
his HIV-infected wife; the persistent seronegativity probably
resulted from an atypical host response and not from infection with
an atypical viral strain. A small number of such patients have been
reported previously (5,6); in these cases, disease progression has
been rapid, and diagnostic specimens were collected and analyzed
only after the patient became ill.
     Plasma obtained by plasmapheresis (source plasma) is either
heat-treated or treated by a solvent/detergent process to
inactivate HIV. Because the products derived from pools containing
these donations were treated, no recall of plasma derivatives was
initiated. CDC has not received reports of instances of HIV
transmission by plasma products processed according to recommended
procedures to inactivate HIV. In comparison, whole-blood donations
are not treated, and failure to detect HIV antibody in an infected
person is a safety concern for whole-blood donations. The blood
supply in the United States is screened through predonation donor
deferral based on history of exposure risks and postdonation
laboratory testing (7). Of the 12 million units of blood donated in
the United States annually, an estimated 32-49 blood components are
potentially infectious for HIV and available for distribution by
blood banks for infusion into patients--primarily because of
"window period" donations (8). Since screening of donated blood
began in 1985, a total of 35 cases of AIDS have been associated
with receipt of "window period" donations; the sensitivity of the
screening test has improved during this period.
     FDA recently issued guidelines to blood and plasma
establishments (e.g., plasmapheresis centers) and recommends that
all blood and plasma donations be screened for HIV-1 p24 antigen
beginning within 3 months of the licensing of a test kit for
screening use (9). Although this recommendation was promulgated
primarily to decrease the number of "window period"
HIV-seronegative blood donations, p24-antigen testing may have an
additional benefit of identifying blood from the rare HIV-infected
donor with persistently undetectable HIV antibody. Kits to detect
HIV-1 p24 antigen have not yet been licensed for screening purposes
by FDA, but one or more such tests are expected to be licensed
soon. The Public Health Service has issued guidelines for testing
and counseling blood and plasma donors with HIV-1 p24 antigen (10).
     Although the conditions characterizing the case described in
this report are rare, such cases must be diagnosed correctly.
Physicians who treat patients with AIDS-defining conditions--but
for whom EIAs fail to detect HIV antibody--should seek specialized
laboratory assistance from their state or local health departments.
Laboratory procedures such as antigen testing, antigen testing
after immune complex disruption, DNA-PCR, and reverse-transcriptase
PCR can assist in defining the HIV-infection status of such
persons.
References
1. Schable C, Zekeng L, Pau CP, et al. Sensitivity of United States
HIV antibody tests for detection of HIV-1 group O infections.
Lancet 1994;344:1333-4.
2. Pau CP, Hu DJ, Spurill C, et al. Surveillance for HIV-1 group O
infections in the United States. Transfusion 1996 (in press).
3. Farzadegan H, Polis MA, Wolinsky SM, et al. Loss of human
immunodeficiency virus type 1 (HIV-1) antibodies with evidence of
viral infection in asymptomatic homosexual men: a report from the
Multicenter AIDS Cohort Study. Ann Intern Med 1988;108:785-90.
4. Roy MJ, Damato JJ, Burke DS. Absence of true seroreversion of
HIV-1 antibody in seroreactive individuals. JAMA 1993;269:2786-9.
5. Martin-Rico P, Pedersen C, Skinhoj P, Nielsen C, Lindhardt B.
Rapid development of AIDS in an HIV-1-antibody-negative homosexual
man. AIDS 1995;9:95-6.
6. Soriano V, Dronda F, Gonzalex-Lopez A, Chaves F, Bravo R,
Gutierrez M. HIV-1 causing AIDS and death in a seronegative
individual. Vox Sang 1994;67:410-1.
7. Food and Drug Administration. Revised recommendations for the
prevention of human immunodeficiency virus transmission blood and
blood products [Memorandum to all registered blood and plasma
establishments]. Rockville, Maryland: US Department of Health and
Human Services, Public Health Service, Food and Drug
Administration, Center for Biologics Evaluation and Research, 1992.
8. Lackritz EM, Satten GA, Aberle-Grasse J, et al. Estimated risk
of transmission of the human immunodeficiency virus by screened
blood in the United States. N Engl J Med 1995;333:1721-5.
9. Food and Drug Administration. Recommendations for donor
screening with a licensed test for HIV-1 antigen [Memorandum to all
registered blood and plasma establishments]. Rockville, Maryland:
US Department of Health and Human Services, Public Health Service,
Food and Drug Administration, Center for Biologics Evaluation and
Research, 1995.
10. CDC. U.S. Public Health Service guidelines for testing and
counseling blood and plasma donors for human immunodeficiency virus
type 1 antigen. MMWR 1996;45(no. RR-2).

* Single copies of this report will be available until March 8,
1997, from the CDC National AIDS Clearinghouse, P.O. Box 6003,
Rockville, MD 20849-6003; telephone (800) 458-5231 or (301)
217-0023.
** DNA sequence analysis determined that sequences from the patient
and his wife differed by 7.4% over 345 nucleotides of the C2V3
region of the env gene, and 3.1% over 393 nucleotides of the p17
region of gag. Phylogenetic tree constructions demonstrated the
close relation between the HIV sequences from the patient and his
wife, with a bootstrap support of 98% and 100%, respectively, for
each gene region.