Antibodies to HIV in Israeli hemophiliacs: relationship between serological profile and disease development

We studied 66 Israeli hemophiliacs for antibodies to HIV in blood samples collected between 1978 and 1985. By May 1985, 2 had AIDS, 2 had ARC, 4 had lymphadenopathy with some immunologic dysfunction, and 58 were asymptomatic. Antibodies to HIV were detected in 40 (60.6%) patients, including all 8 with disease. Presence of HIV antibodies was significantly associated with receipt of non-heat-treated commercial factor VIII concentrates (NHT fac VIII) between 1980 and 1983. Thirty-eight of 45 (84.44%) patients treated with NHT fac VIII developed antibodies to HIV, compared to 1 of 16 (6.25%) treated with cryoprecipitates and fresh plasma only. Of 40 seropositive patients, 1 (2.5%) had antibodies by 1980, 4 (10%) by 1982, 14 (35%) by 1983, 10 (25.0%) by 1984, and 11 (27.5%) by May 1985. The decline in the rate of seroconversion can be attributed to the replacement of NHT fac VIII concentrate with heat-inactivated factor VIII (HT fac VIII) concentrate by November 1983. As of January 1984 only HT fac VIII was administered. Twenty-nine multitransfused thalassemia patients as well as 20 healthy Israeli blood donors were seronegative to HIV. All 40 (100%) seropositive hemophiliacs had antibodies to viral env gene encoded gp120/gp160 antigens. Twenty-four (60.05%) also had antibodies to viral gag gene encoded p24 and/or p55 antigens. While antibodies to gp120/160 persisted during the follow-up time, a loss of antibodies to p24/55 was observed in 5 of 16 (31.25%) seropositive patients from whom multiple samples were available. gp120/160 positive, p24/55 negative hemophiliacs had significantly lower absolute T-helper cell counts and reversed Th/Ts ratios when compared to gp120/160 p24/55 seropositive patients. Four of the 16 (25.0%) asymptomatic gp120/160 positive, p24/55 negative patients developed overt disease within 15 months of the last blood collection. The data suggest that exposure to HIV antigens is widespread among hemophiliacs in Israel, and can be attributed to receipt of NHT fac VIII concentrates prior to 1984. Antibodies to gp120/160 are of the most important diagnostic value while loss of antibodies to p24/p55 may be of prognostic value.     

Detection of HIV antigen and specific antibodies to HIV core and envelope proteins in sera of patients with HIV infection

The sera of well-characterized populations were examined for three markers of human immunodeficiency virus (HIV) infection; HIV antigen (HIV Ag), and antibodies to HIV envelope (gp41) and core (p24) proteins. Of 563 serum samples tested, 251 were from HIV-infected patients diagnosed as having AIDS manifested by opportunistic infections (AIDS-OI), AIDS-associated Kaposi's sarcoma (AIDS-KS), or AIDS-related complex (ARC). One hundred seventy-six specimens tested were from asymptomatic high-risk individuals, and 136 were from heterosexual control subjects or patients with non-AIDS-related disease. None of the 136 control individuals tested had HIV Ag or HIV antibodies to either p24 or gp41. Of the 427 HIV-seropositive individuals, 99% to 100% were positive for gp41 antibodies to HIV. In contrast, the seroprevalence of p24 antibodies to HIV varied from 23% to 83% and appeared to be inversely associated with the severity of the patients' clinical symptoms. When specimens were analyzed for the presence of HIV Ag, in seropositive individuals the prevalence rate for this marker was lowest (1.4%) in asymptomatic individuals and highest (50%) in the AIDS-OI diagnosed group. Also, 240 cases with AIDS-KS, AIDS-OI, and ARC and the group of asymptomatic high-risk individuals were analyzed for T helper/T lymphocytes (T4) cell number and T4/T8 ratio; only one (2.0%) HIV Ag-positive case showed a T4 cell number greater than 400 and a normal T4/T8 ratio. These studies appear to demonstrate a direct correlation between the presence of HIV Ag and the severity of clinical complications of HIV infection.     

Stages in the progression of HIV infection in chimpanzees

Circulating HIV antigens and HIV specific antibodies in sera of experimentally infected chimpanzees were monitored by ELISA immunoassay, Western blot, and radioimmunoprecipitation procedures. Three of three chimpanzees given plasma from patients with AIDS or ARC tested positive for HIV antigens beginning six to ten weeks after transfusion. Antigen production rose sharply but was of short duration. Despite their proven infectivity and the presence of anti-HIV antibody, all donors to these chimpanzees tested negative for the HIV antigen. Of the three animals that developed HIV antigen one animal did not produce any HIV antibodies or evidence of disease. A second produced antibodies to only the p24 and p18 antigens and remained clinically well. The third produced antibodies beginning with anti-p24, to all the major HIV proteins except gp120, and then developed marked lymphadenopathy which persisted for 32 weeks. Antibody persistence after the disappearance of clinical disease was variable and was greatest for gp41 and least for p24. These data may be of value in the interpretation of human serological testing for HIV and in further studies of the sequence of events leading to the pathological effects of HIV infection. A significant value of the chimpanzee model is the capacity of this animal to respond in a variety of ways to HIV infection, suggesting the existence of successive or alternate states of early HIV infection, and may have implications in the design of early interventions.     

Prognostic significance of quantitative levels of HIV p24 binding capacity in HIV infection

Human immunodeficiency virus, type 1 (HIV-1), produces a chronic infection with a long latency before clinical disease. We followed 214 untreated subjects for 12-42 months to study the natural history of HIV infection: 110 were classified as asymptomatic, 11 as AIDS-related complex (ARC), 15 as AIDS with Kaposi's sarcoma (KS), 31 as AIDS with opportunistic infections (AIDS/OI), and 47 were HIV-seronegative controls. The quantitative capacity of serum to complex HIV p24 antigen, termed the p24 binding capacity (p24 BC), and quantitative levels of HIV p24 antigen in serum were determined at regular intervals. For people in all diagnostic groups, a p24 BC below 31 ng/ml was more closely associated with progression to AIDS/OI than was p24 antigen positivity; 94% of AIDS/OI, 86% of ARC, 56% of AIDS/KS, and 19% of asymptomatic subjects had p24 BC less than 31 ng/ml during the study period, while 67% of AIDS/OI, 27% of ARC, 61% of AIDS/KS, and 20% of asymptomatic subjects were p24 antigenemic. Prospective analysis of 47 asymptomatic seropositive men followed for 3 years, who showed actuarial progression rates to ARC at 4%, 13%, and 23% and to AIDS at 5%, 8%, and 8% at 1, 2, and 3 years, indicated that entry levels of p24 BC below 31 ng/ml were as strongly associated with progression to ARC/AIDS as was p24 antigenemia (p = 0.0003 vs. p = 0.008). The p24 binding capacity assay is a new and convenient methodology to measure immunocomplexing antibody to HIV p24 and is a powerful indicator of progressive HIV disease.     

Additional evidence for lack of transmission of HIV infection by close interpersonal (casual) contact

To further study the possibility of transmission of HIV infection by close personal but non-sexual, non-parenteral contact we have continued to enroll and evaluate household contacts of adult patients with AIDS. Two hundred and six household contacts of 90 patients with AIDS were evaluated with detailed interviews, physical examinations, and detection of HIV antibodies and p24 antigen from 1984 to 1987; 118 of these contacts were re-evaluated 6-12 months after cessation of household contact or death of the patient. The median duration of household contact from 18 months prior to symptoms in the AIDS patients to last contact was 23 months (range 3-101 months). The median time elapsed from first contact during this period to the last evaluation was 38 months (range 13-66 months). No household contact had signs or symptoms suggesting HIV infection. All 206 were negative for serum antibodies to HIV and HIV p24 antigen, despite extensive sharing of household facilities and items and personal interactions with AIDS patients. This study continues to show that household members without other risks remain at minimal to no risk for HIV transmission (95% confidence interval, 0-1.44) despite prolonged and substantial close non-sexual contact with AIDS patients, and after re-evaluation at a median of 10.9 months after initial evaluation.     

艾滋病患者的肝脏病理学研究

目的 观察艾滋病(AIDS)患者肝组织的病理改变。方法 对11例无症状人类免疫缺陷病毒 (HIV)感染者和3例 AIDS 患者肝活体组织检查(肝活检)以及12例尸体解剖肝脏进行组织学观察，采用 免疫组织化学对肝活检组织及尸体解剖肝组织中的HIV-1外膜蛋白 gp120和衣壳蛋门 p24抗原进行检测。结 果 14例肝活检组织中检测出巨细胞病毒感染1例，11例肝脏库普弗细胞和部分淋巴细胞中有 HIV-1外 膜蛋白 gp120或(和)衣壳蛋白 p24抗原表达，肝细胞呈阴性。尸体解剖肝组织中检出巨细胞病毒感染5例， 分枝杆菌及弓形虫感染各3例，HIV 1衣壳蛋白 p24抗原阳性5例。结论 AIDS 患者肝组织中存在 HIV 1 感染，活检肝组织病例中机会性感染的几率较低。在尸体解剖肝组织中，机会性感染较为多见，并常为全身 机会性感染的局部表现。     

Variation of secretory antibodies in parotid saliva to human immunodeficiency virus type 1 with HIV-1 disease stage

The secretory immune response to pathogens of the gut-associated lymphoid tissue is often independent of the systemic response. We investigated and compared the presence of antibodies to human immunodeficiency virus type 1 (HIV-1) antigens in parotid saliva and serum by Western blotting in 22 HIV-1-infected individuals. Antibodies to the HIV-1 envelope antigen gp160 were detected in saliva samples from 21 of 22 individuals and in serum from all individuals who were classified as CDC Group II, III, or IV. Antibody titers to gp160 were approximately 3000 times higher in serum than in saliva. Antibodies to viral core antigen p24 were detected in 6 of 7 Group II individuals in saliva and in 7 of 7 in serum. Antibodies to p24 were not found in the parotid saliva, but were detected in the sera of 3 of 3 Group III and 11 of 12 Group IV patients. The absence of secretory antibodies to HIV-1 core antigen p24 was correlated with CD4+ cell counts of less than 200/mm3. The results suggest that loss of secretory anti-p24 antibodies may be an early sign of progression to higher CDC clinical stages in HIV-1-infected individuals.     

Long-term immunogenicity of a plasma-derived hepatitis B vaccine in HIV seropositive and HIV seronegative hemophiliacs

Short-term studies indicate that hepatitis B vaccines are safe and satisfactorily immunogenic in hemophiliacs. The duration of immunity in these immunocompromised patients, however, is not known. To determine this, we studied 78 hemophiliacs prospectively 2, 3, and 4 years after the initial vaccination with a plasma-derived vaccine given as three monthly injections followed by a fourth booster injection at month 14. The duration of immunity clearly depended on whether the patients were infected with the human immunodeficiency virus (HIV). In HIV seronegative hemophiliacs (n = 67), there was a progressive decline in titers of antibody to the hepatitis B surface antigen (anti-HBs), but antibody was still detectable 4 years later in all of them. From the curves of decline of antibody titers, it appears that there is no need to revaccinate patients for at least 5 to 6 years. The HIV seropositive hemophiliacs (n = 11) not only started from much lower anti-HBs titers, but 5 of 11 lost anti-HBs. None of the 45 patients treated with concentrates during the postvaccination period developed serologic signs of hepatitis B, even though 6 of them had come into contact with live or inactivated hepatitis B virus as shown by the occurrence of spontaneous anamnestic antibody responses. This vaccine and schedule of vaccination afford a prolonged duration of immunity in HIV seronegative hemophiliacs, but HIV seropositive hemophiliacs have a risk of losing immunity early.     

Predictive markers for the acquired immunodeficiency syndrome (AIDS) in hemophiliacs: persistence of p24 antigen and low T4 cell count

STUDY OBJECTIVE: To investigate the predictive value of assays for human immunodeficiency virus (HIV) p24 antigen, p24 antibody, and gp120 antibody compared with T4 cell counts. DESIGN: Prospective cohort selected from persons who had HIV-antibody seroconversion. PATIENTS: Eighty-seven persons with hemophilia with an actuarial cumulative acquired immunodeficiency syndrome (AIDS) incidence of 26% (CI, 12% to 40%), 8 years after HIV-antibody seroconversion. INTERVENTION: None. MEASUREMENTS AND MAIN RESULTS: Human immunodeficiency virus p24 antigen was detected in 8 of 74 (11%) of the patients without AIDS and 7 of 13 (54%) of the patients with AIDS. The 2-year actuarial incidence of AIDS was 24% (CI, 0% to 48%) after detection of p24 antigen, 16% (CI, 0% to 34%) after loss of p24 antibody, 20% (CI, 0% to 45%) after loss of gp120 antibody, 31% (CI, 15% to 47%) after a T4 count of less than 200 cells/microL, and 67% (CI, 31% to 100%) after a T4 count of less than 200 cells/microL among those patients positive for p24 antigen. Very low numbers of T4 and T8 lymphocytes, presence of p24 antigen in serum, and absence of p24 antibody all had some predictive value. However, only p24 antigen (relative hazard 6.0, P = 0.008) and T4 counts (relative hazard 5.3, P = 0.002 with T4 count less than 200 cells/microL) independently predicted AIDS up to 12 months before diagnosis. CONCLUSIONS: Strong predictors of AIDS are p24 antigenemia or low T4 counts. Detection of p24 antigen is highly specific and complementary to the greater sensitivity of low T4 counts. These findings have important implications regarding prognosis, counseling, and the planning of clinical trials.     

Presence of antibodies to a putatively immunosuppressive part of human immunodeficiency virus (HIV) envelope glycoprotein gp41 is strongly associated with health among HIV-positive subjects.

The IgG response to gp41 (envelope glycoprotein of Mr 41,000) of the human immunodeficiency virus (HIV) was studied with eight synthetic peptides derived from three different regions of the protein. We tested sera from 17 HIV-seronegative and 68 HIV-seropositive subjects in an enzyme immunoassay. No HIV antibody-negative serum reacted with any of the peptides. The peptide HIV-env 583-599 has a sequence similarity with immunosuppressive peptides derived from the transmembrane proteins of other retroviruses. Antibodies to this 17-mer (HIV-env 583-599; hereafter also referred to as pHIVIS, putative HIV immunosuppressive sequence) were detected in 27 of the 35 sera from healthy HIV-positive persons but only in 1 of the 33 sera from patients with HIV-related disease. Another 17-mer, displaced four amino acids N-terminally from pHIVIS, reacted with fewer of the sera from healthy seropositive subjects than pHIVIS but with no serum from ill seropositive patients. HIV-env 586-603, which shares two-thirds of its sequence with pHIVIS, reacted with the sera from nearly all subjects, regardless of clinical status. The remaining five peptides did not discriminate between healthy and ill seropositive subjects either but gave lower reactivity rates. HIV-positive sera thus exhibited distinct patterns of reactivity with subsequences of gp41. We have mapped two overlapping epitopes within a narrow part of gp41; antibodies to the most N-terminally located of the two--i.e., the pHIVIS-reactive antibodies--might counteract a possible immunosuppressive effect of gp41.     

Human immunodeficiency virus (HIV) circulating immune complexes in infected children

Circulating immune complexes (CIC) were studied for the presence of human immunodeficiency virus (HIV) antigens (HIV-Ag) in 55 children infected by the human immunodeficiency virus type 1 (HIV-1). CIC were elevated in 85% of patients. In 33 of 55 patients CIC included at least one HIV-Ag (HIV-Ag-CIC). Sixty percent of patients had p17 antigen, 50% had p24 antigen, and 16% had gp120 associated with CIC. Levels of HIV-Ag-CIC did not correlate with free serum HIV antigens. Patients with high HIV-Ag-CIC had a more severe clinical course and 90% of those with markedly elevated HIV-Ag-CIC (greater than 3+) have died within 6 to 24 months. HIV-Ag-CIC were also present in some patients including neonates and young infants in whom free HIV-Ag was undetectable. Monitoring of HIV-Ag in isolated CIC may be of value for early detection of HIV infection and for monitoring of disease outcome.     

Natural history of human immunodeficiency virus infections in hemophiliacs: effects of T-cell subsets, platelet counts, and age

Serial T-cell subsets and platelet counts were determined in a cohort of 84 hemophiliacs in whom time of seroconversion for human immunodeficiency virus (HIV) antibody could be ascertained. An abrupt decrease in the number of T-helper (T4) cells was seen in 9 patients 12 to 24 months before the acquired immunodeficiency syndrome (AIDS) was diagnosed (p = 0.0007 compared with those who did not develop AIDS). Thrombocytopenia also was associated with an increased risk for AIDS (p = 0.02), as was older age at the time of seroconversion (p = 0.03). Ten patients developed AIDS at 24 to 95 months after seroconversion, for a cumulative incidence (+/- SE) of 18.0% +/- 7.1% at 6 years. Hemophiliacs who had T4 cell counts of less than 200 cells/microL had a 50% +/- 16% cumulative incidence of AIDS within 2 years, indicating that decreasing or very low T4 cell counts have predictive value for the development of AIDS. Furthermore, the data suggest that thrombocytopenia and older age may be markers for a cofactor that increases the risk for AIDS in hemophiliacs.     

Progression to AIDS in patients with lymphadenopathy or AIDS-related complex: reappraisal of risk and predictive factors

PURPOSE: In 1985, we reported that acquired immunodeficiency syndrome (AIDS) developed in 14 of 81 (17%) men with generalized lymphadenopathy followed prospectively for an average of 13 months. The presence of oral thrush or constitutional symptoms, or both, or severely impaired T4+ cell responses to specific antigen (interferon-gamma production) accurately identified patients at immediate risk for AIDS. The purpose of the current report is to describe the progress of these 81 patients during the three and a half years since enrollment and to include new data on initial serum levels of beta 2 microglobulin and human immunodeficiency virus (HIV) p24 antigen. PATIENTS AND METHODS: The mean age of the 81 patients was 35.4 years; 79 were homosexuals and two were drug abusers. Immunologic testing was performed once at the time of enrollment in all patients. Seventy-seven of the 81 patients were seropositive for HIV antibody. Frozen samples of serum, also obtained at initial study, were assayed in 1988 for beta 2 microglobulin and HIV p24 antigen. The clinical status of patients was determined six, 14, and 36 months after enrollment was closed (June 1984) by either interview and examination or telephone contact with private physicians. RESULTS: After three and a half years of follow-up, 42 patients have developed AIDS, including (1) 77% who had had thrush or symptoms, or both, (2) 80% to 88% of those who originally demonstrated marked immunologic abnormalities (skin test anergy, less than 200 T4+ cells/mm3, T4/T8 cell ratio of less than 0.5, severely impaired interferon-gamma production [less than 25 U/mL], or elevated serum beta 2 microglobulin level [greater than 3.0 mg/L], and (3) 95% of patients with HIV p24 antigenemia. However, AIDS also developed in 51% of patients who had had more apparently benign initial manifestations (lymphadenopathy alone, herpes zoster), in 41% to 54% despite normal initial results for either T4+ cell number, interferon-gamma secretion, beta 2 microglobulin, or skin testing, and in 44% of those whose sera did not contain HIV antigen. CONCLUSION: These updated results demonstrate the remarkably poor prognosis of patients with generalized lymphadenopathy or AIDS-related complex irrespective of initial clinical, immunologic, and serologic findings, and suggest that essentially all such persons may be candidates for antiviral therapy.     

Detection of Early Anti-p24 HIV Responses in EIA- and Immunoblot-Negative Individuals

A sensitive and specific radioimmunoprecipitation assay was developed for the detection and analysis of anti-HIV antibody response in human sera with the use of 125I-labelled purified HIV proteins with subsequent sodium-dodecylsulfate gel electrophoresis (125I-RIPA). The 125I-RIPA was shown to be as specific but at least 1 log more sensitive with respect to the detection of gp41env and p24gag than the immunoblot analysis as tested in serum samples from several risk groups. Sequential sera were obtained from 9 individuals who seroconverted for HIV antibodies. In 4 individuals, antibody to p24gag was detected in earlier serum samples by the 125I-RIPA than by EIA or immunoblot; in the other 5 individuals, the detection of p24gag concorded in enzyme-linked immunosorbent assay (EIA), immunoblot and 125I-RIPA. Moreover, in one of 78 randomly chosen EIA-negative sera from individuals at high risk, antibodies to p24gag could be detected by the 125I-RIPA. This early seroconversion was confirmed 3 months later by means of immunoblotting and EIA. The specificity of the 125I-RIPA was further demonstrated by analyzing sequential EIA-negative serum samples from 10 individuals at risk for AIDS, collected during 2 years at 3-monthly intervals. All 80 serum samples were found to be negative in the 125I-RIPA and the individuals revealed no signs of HIV infection. The 125I-RIPA technique may be a valuable confirmatory assay in the serology of HIV infections. The sensitivity of this test provides a reliable measure of effective sensitivity when new-generation screening tests are evaluated.(ABSTRACT TRUNCATED AT 250 WORDS)     

Interactive laser cytometric analysis of retroviral protein expression in HIV-infected lymphocytic cell lines

We have used interactive laser cytometry to investigate the expression of human immunodeficiency virus (HIV) envelope glycoproteins gp160, gp41, gp120, and the core protein p24 in the HIV-infected human lymphocyte cell lines H-9, CEM-SS, and C8166. This method allowed for the ultrasensitive detection of fluorescence signals at the single cell level and, when combined with specific anti-HIV antibodies, permitted unique quantitative detection of HIV antigens. Indirect immunofluorescence assays with monoclonal antibodies directed against gp120 revealed that a large proportion of lymphocytic cells expressed increased gp120-associated fluorescence consistent with HTLV-IIIRF infection. Certain monoclonal and polyclonal antibodies were also effective in quantifying gp160, gp41, and p24 expression. Expression of these antigens was found to vary significantly within 48 h. Significant loss (greater than or equal to 50%) of gp120 expression was observed when cells were treated with 1.0 microM AZT. The expression of the HIV-associated protein markers gp160, gp41, and p24 was detectable 24 h after infection of C8166, a cord blood lymphocytic cell line. C8166 cells expressed an additional 6- to 10-fold increase in gp120 in 48 h as well as a 3- to 4-fold increase in gp160, gp41, and p24. AZT (0.01 and 0.1 microM) decreased the expression of gp120, gp160, and p24 in a dose-dependent fashion. This new application of interactive laser cytometry permits early, sensitive, and statistically based distinctions in the expression of HIV-associated antigens in infected target cells at the single-cell level, and allows detection of important changes in HIV-associated antigen expression and the kinectics thereof.(ABSTRACT TRUNCATED AT 250 WORDS)     

Decline in CTL and antibody responses to HIV-1 p17 and p24 antigens in HIV-1-infected hemophiliacs irrespective of disease progression. A 5-year follow-up study.

CTL and antibody responses to HIV-1 p17 and p24 antigens were monitored from 1986-1991, in 4 hemophiliacs. The patients had been infected with HIV-1 between 1980 and 1984. Two patients have remained asymptomatic while two progressed to AIDS in 1990. CTL were boosted by culturing with peptides from p17 aa 86-115, or p24 aa 265-279; and aa 270-373 or PHA. Lysis was measured on autologous or allogeneic targets pulsed with peptides or infected with recombinant vaccinia virus carrying HIV-1 gag or influenza A matrix genes. Antibodies to p17 and p24 were tested by ELISA using peptides and by Western blotting. High levels of CTL activity to p17 and p24 antigens could be generated only with lymphocytes from the two asymptomatic patients between 1986 and 1989, but these responses were absent in 1990 and 1991. Antibodies to p17 peptides disappeared in parallel with CTL activity. Antibodies to some p24 peptides also declined but most patients retained activity to others. In all patients a > or = 3-fold increase in CD8+ cell numbers occurred over time and accompanied the decline of CTL and antibody responses. The loss of CTL and p17 antibodies occurred irrespective of whether patients remained asymptomatic or progressed to AIDS in the intervening two years.     

Antibodies reactive with human T cell leukemia viruses in the serum of hemophiliacs receiving factor VIII concentrate

The third member of the family of T cell leukemia viruses (HTLV III) has been proposed as the primary etiologic agent of the acquired immunodeficiency syndrome (AIDS). A high risk of AIDS has been reported among patients with hemophilia, particularly those with factor VIII deficiency who receive commercial clotting factor concentrates. In a prevalence survey conducted between September 1982 and April 1984, initial serum samples from 74% of hemophiliacs who had ever been treated with commercial factor VIII concentrate, 90% of those frequently treated with factor VIII concentrate, and 50% of those treated with both factor VIII and factor IX concentrates had antibodies reactive against antigens of HTLV III, compared with none of the hemophiliacs treated only with factor IX concentrate or volunteer donor plasma or cryoprecipitate. Two of the seropositive patients have developed AIDS-related illnesses, and a third patient died of bacterial pneumonia. One initially seronegative patient developed antibodies against HTLV III during the study and is currently well. The predominant antibody specificities appear directed against p24 and p41, the presumed core and envelope antigens of HTLV III, suggesting that factor VIII concentrate may transmit the p24 and p41 antigens of HTLV III. However, the presence of infectious retroviruses in clotting factor concentrates and the effectiveness of screening and viral neutralization procedures remain to be determined.     

Development and characterization of a bead-based, multiplex assay for estimation of recent HIV type 1 infection

Estimation of HIV-1 incidence is an important public health tool for understanding the status of the epidemic, identifying high-risk populations, and assessing various intervention strategies. Several laboratory-based methods have been developed for distinguishing recent from long-term HIV-1 infection; however, each exhibits some degree of misclassification, particularly among AIDS patients and those taking antiretroviral therapy (ART). To improve upon the limitations associated with measuring responses to a single analyte, we have developed a bead-based, multiplex assay for determination of HIV recent infection based on total antibody binding and antibody avidity to multiple analytes. An HIV-specific, multiplex panel was created by coupling the recombinant HIV-1 proteins p66, gp120, gp160, and gp41 to Bio-Plex COOH microspheres. Longitudinal plasma specimens from recent seroconverters were tested for reactivity to the coupled microspheres using the Bio-Plex 200 System. For each analyte, HIV-specific antibody binding and avidity increased for 1-2 years post-seroconversion, leading to a significant difference in reactivity between recent and long-term specimens. While the potential for misclassification of individuals diagnosed with AIDS or receiving ART appears to be minimal with avidity measures, the impact on total antibody binding was variable, depending on the individual analyte. This bead-based, HIV-specific multiplex assay measures several distinct immune responses in a single assay plate, allowing for sampling of multiple analytes in the determination of recent infection, which could aid in the development of improved statistical methods or algorithms that will more accurately estimate HIV incidence.