Immunoglobulin level in donor blood reactive for antibodies to human immunodeficiency virus.

Blood samples from 98 asymptomatic volunteer blood donors, including 55 that were reactive for antibodies to human immunodeficiency virus (HIV) in Western blot (WB) assay, were tested for levels of immunoglobulin G (IgG), IgM, and titer of antibodies to HIV, cytomegalovirus, and herpes simplex virus. Levels of IgG were significantly elevated (P less than or equal to 0.001) in donors with specific anti-HIV reactivity. A total of 69% of donors with anti-HIV had IgG levels of greater than or equal to 12 mg/ml, and 44% had IgG levels of greater than or equal to 14.5 mg/ml. Levels of IgM were not significantly different among WB-reactive and nonreactive donors. The titer of anti-HIV was significantly (P less than 0.02) correlated with IgG levels among donors reactive in the WB assay. Elevation of IgG, however, was not significantly associated with the presence of anticytomegalovirus or anti-herpes simplex virus antibodies. The data show that elevation of IgG may represent an early manifestation of HIV infection before the development of clinical symptoms of acquired immunodeficiency syndrome.     

A high proportion of sera of heroin addicts possesses anti-HLA class I and class II reactivity

The anti-HLA reactivity of sera from 210 heroin addicts was tested by the direct binding with 125I-labeled preparations of HLA class I and class II molecules purified from human B-cell lines of various HLA haplotypes. A high proportion (81.7%) of the sera tested possessed anti-HLA class I and II reactivity. The reactivity did not show any allospecificity and was apparently mediated by antibodies. The control included 100 healthy blood donors, 25 male homosexuals positive for anti-HIV (human immunodeficiency virus) antibodies, and 25 patients positive for HBsAg (hepatitis B surface antigen). Of these controls, only one of the healthy blood donors was positive for anti-HLA reactivity (P much less than 0.001). Among heroin addicts, the reactivity was independent of the presence of either HBsAg or anti-HIV antibodies in the serum.     

Development and studies of the anti-R7V neutralizing antibody ELISA test: a new serological test for HIV seropositive patients

A new peptide-based ELISA test developed for the detection of anti-R7V specific antibodies in the sera of HIV seropositive patients is described. HIV virus acquires a cellular antigen at the moment the virus is released by budding, the R7V epitope. Certain patients produce anti-R7V Ab which are described as having the capacity to neutralize in vitro cell infection by HIV. Anti-R7V Ab are also detected in asymptomatic patients who have a lower likelihood of progressing to AIDS. Tested with 449 serum samples, the prevalence of anti-R7V Ab was 53.2% in HIV positive patients and 5.5% in HIV negative subjects. According to the duration of infection, the seroprevalence reaches almost 80% of non-treated long-term infected patients. Other retrospective studies were conducted on 308 HIV positive samples; the presence of anti-R7V Ab was significantly higher for 177 asymptomatic patients (64.4%) compared to the 131 symptomatic patients (35.1%). Regarding their neutralizing ability, anti-R7V antibodies were detected at the highest percentage in asymptomatic HIV-infected patients naive of treatment. Besides conventional biological parameters (CD4 and viral load), the detection of anti-R7V antibodies could be proposed to clinicians as an additional tool to manage treatment initiation and to improve the psychological state of their asymptomatic patients.     

Accentuated antibody response to paramyxoviruses in individuals infected with human immunodeficiency virus

Sera from 31 human immunodeficiency virus (HIV)-infected patients, representing different clinical stages of HIV infection, were assayed for antibodies against measles and mumps viruses by various serological tests and compared to 23 healthy controls. Sera from four patients (two primary, one asymptomatic, and one acquired immunodeficiency syndrome) exhibited a pronounced antibody response to measles as detected by haemagglutination inhibition and radioimmuno-precipitation assay. The RIPA-positive sera showed increased reactivity to all the viral components and in particular to the haemagglutinin (HA) protein of the virus (Fig. 1). Three of these positive patients also showed a similar response to mumps virus. One of the control sera also showed an increase in antibody titre in measles serological tests. The measles antibodies were shown not be anti-HIV antibodies crossreacting with paramyxoviruses. The reactivity to haemagglutinin was still present when using nonglycosylated measles virus antigen grown in the presence of tunicamycin. Whether the accentuated antibody response is due to polyclonal activation mediated by HIV or to reactivation of the viruses remains to be answered.     

Human immunodeficiency virus type II (HIV-2) testing: a perspective.

Testing of blood for antibodies to the human immunodeficiency virus type 2 (HIV2) has begun. A major benefit of this testing will be the elimination of the exclusion of blood donors on the basis of geographic origin. Will this test be helpful? Present anti-HIV1 testing detects between 60 to 90 percent of those samples containing the HIV2 antibody. A Food and Drug Administration (FDA) licensed enzyme immunoassay for HIV1/HIV2 antibodies became available for clinical use in March of 1992. (There is an FDA unlicensed HIV-2 Western Blot (WB) Test). The specificity and sensitivity of either the HIV2 EIA or HIV2 WB are not well defined. In a survey of 24 million U.S. donors, no antibodies to HIV2 were detected. With the incidence of HIV2 infection being so small, it is probable that the majority of positive tests will be false-positives causing needles concern for the blood donor who must be counseled. The benefits to the blood supply remain to be evaluated.     

Sensitivity of HIV infection screening assays in 2001

Early detection of human immunodeficiency virus (HIV) infection is critical for clinical diagnosis and treatment of patients, as well as for ensuring the safety of blood products. Recently, fourth-generation HIV screening assays have been developed with the objective to offer an increased sensitivity by combining detection of anti-HIV antibodies (Ab) with detection of the p24 viral antigen (Ag). Eight different HIV assays commercially available in France (five fourth-generation HIV screening assays and three third-generation HIV Ab-only assays) were compared in a broad number of seroconversion panels (n = 27). This extensive analysis highlights: 1) the importance of p24 Ag detection for early diagnosis; 2) the improved sensitivity of fourth-generation assays over Ab-only tests. In conclusion, these results emphasize the detection limitations of the different assays and suggest improvements for future HIV screening assays.     

High prevalence of hepatitis B,C, and E markers in young sexually active adults from The Central African Republic

The Central African Republic is located in tropical Africa, where both the human immunodeficiency virus (HIV) and hepatitis B virus (HBV) are highly endemic. The exact prevalence of hepatitis C virus (HCV) and hepatitis E virus (HEVI markers in this country is unknown. The aim of the study was to determine, according to HlV and HBV serostatus, the prevalence of these markers in young sexually active adults in the Central African Republic. One hundred and fifty-seven consecutive patients attending the National Centre for Sexually Transmitted Diseases in Bangui were included. The following serological markers were examined: (i) anti-HIV1 and anti-HIV2 antibodies; (ii) markers of HBV infection; (iii) anti-HCV antibodies; (iv) anti-HEV antibodies. Anti-HIV1 antibodies were found in 31 of the 157 patients (20%). The prevalence of anti-HBc antibodies, reflecting exposure to HBV, was 140/157 (89%) and 45 had detectable anti-HBs antibodies. Twenty-two patients (14%) were chronic carriers of hepatitis B surface antigen (HBsAg), but only one was HBe antigen-positive. Anti-HCV antibodies were found in 8 persons (5%) and antiHEV antibodies in 38 (24%). No difference was found in the prevalence of these markers according to the presence or absence of anti-HIV antibodies. This study confirms the high rate of HIV infection, HBV exposure and chronic carriage of HBsAg in sexually active young adults in the Central African Republic. A high prevalence of HCV markers was found in this population, similar to that reported in neighbouring countries, together with a high rate of HEV markers, suggesting that HEV is endemic in this region. © 1995 Wiley-Liss, Inc.     

Flow cytometric indirect immunofluorescence assay with high sensitivity and specificity for detection of antibodies to human immunodeficiency virus (HIV)

A flow cytometric immunofluorescence assay (FIFA) was developed to detect antibodies to human immunodeficiency virus (HIV) using live cell indirect immunofluorescence and analysis by flow cytometry. A panel of 107 sera, previously tested for anti-HIV antibody with the Abbott Enzyme-Linked Immunosorbent Assay test and Western blot (WB), was rescreened by FIFA. Antibodies were tested on HIV-infected and uninfected H9 cells in the FIFA. Although ELISA results indicated seven false positive results by comparison with the WB, 46 of 46 FIFA positive results tested WB positive and 61 of 61 FIFA negative results were WB negative. The results of FIFA showed 100% sensitivity and 100% specificity compared with WB. This rapid, quantitative, relatively easy assay makes FIFA an alternate confirmatory test for the presence of HIV antibodies.     

Multicenter evaluation of a new, automated enzyme-linked immunoassay for detection of human immunodeficiency virus-specific antibodies and antigen

A collaborative multicenter study was conducted to evaluate the sensitivity, specificity, and precision of a three-step, fully automated, qualitative microparticle-based enzyme-linked immunoassay (AxSYM HIV Ag/Ab Combo; Abbott Laboratories), designed to simultaneously detect (i). antibodies against human immunodeficiency virus type 1 (HIV-1) and/or type 2 (HIV-2) and (ii). HIV p24 antigen. A significant reduction in the HIV seroconversion window was achieved by combining detection of HIV antibodies and antigen into a single assay format. For 22 selected, commercial HIV seroconversion panels, the mean time of detection with the combined-format HIV antigen-antibody assay was reduced by 6.15 days compared to that with a similar third-generation single-format HIV antibody assay. The quantitative sensitivity of the combination assay for the p24 antigen (17.5 pg/ml by use of the p24 quantitative panel VIH SFTS96') was nearly equivalent to that of single-format antigen tests. The combination assay demonstrated sensitive (100%) detection of anti-HIV immunoglobulin in specimens from individuals in CDC stages A, B, and C and from individuals infected with different HIV-1 group M subtypes, group O, or HIV-2. The apparent specificity for hospitalized patients (n = 1938) was 99.90%. In a random population of 7900 volunteer blood donors, the specificity (99.87%) was comparable to that of a third-generation single-format HIV antibody assay (99.92%) on the same donor specimens. In addition, the combination assay was robust to potential interfering specimens. The precision of the combination was high, with intra- and interrun variances of 相似文献   

Antigen-antibody reaction in solution in capture competition immunoassay for human immunodeficiency virus antibodies.

In the capture competition immunoassay, undiluted serum was reacted in solution with purified human immunodeficiency virus (HIV) antigen in wells of microtest plates coated with anti-HIV immunoglobulin G antibodies (HIV capture antibodies). HIV antibodies present in the serum being tested combined with the HIV antigen and thus blocked (completely or partially) the fixation of the antigen to the capture layer. Unblocked antigenic activity was measured in subsequent steps by the use of biotinylated anti-HIV immunoglobulin G and peroxidase-conjugated avidin. The assay was evaluated in comparison with indirect enzyme-linked immunosorbent assay and Western (immuno-) blot (WB). A total of 180 serum samples which reacted repeatedly as positive in indirect enzyme-linked immunosorbent assay but negative in WB were found to be negative by the capture competition assay. Of 54 serum samples showing dubious reactions (single p24 bands in WB), 53 were clearly separated into positive or negative reactions, whereas 1 serum sample gave a borderline reaction. It was concluded that a characteristic feature of this kind of inhibition assay is a very low frequency of equivocal results.     

Coxsackie B virus infections in women with miscarriage

Serum samples from 1,765 consecutive Sardinian blood donors, negative for hepatitis B surface antigen (HBsAg) and for antibodies to human immunodeficiency virus (HIV) (anti-HIV), were evaluated for the presence of antibodies to hepatitis C virus (anti-HCV) by second-generation ELISA. Anti-HCV was detected in 25 (1.45%) of the 1,765 donors examined. Anti-HCV was found in 15 of the 1,690 (0.9%) donors with normal alanine aminotransferase (ALT) and in 10 of the 75 (13%) donors with elevated ALT (P < 0.0001). Of the 15 anti-HCV-positive donors with normal ALT, only five (33%) were confirmed to be positive by second-generation RIBA, six (40%) were indeterminate, while four (27%) were RIBA negative. HCV RNA, as detected by polymerase chain reaction (PCR) using a set of primers from the 5′-noncoding region, was found in six of the 15 (40%) donors with normal ALT, including five RIBA, positive and one indeterminant. Of the 10 anti-HCV-positive donors with elevated ALT, all were RIBA positive and eight (80%) had detectable HCV RNA. Thus, among ELISA-reactive donors, those with elevated ALT had a significantly higher probability of being positive for secondgeneration RIBA and HCV RNA compared to those with normal ALT levels (P = 0.028). None of the 65 donors with elevated ALT but negative for anti-HCV by ELISA had detectable serum HCV RNA, as compared to eight of 10 anti-HCV ELISApositive donors (P < 0.0001). However, although negative for HBsAg, 12 of the 65 (18%) had serum HBV DNA by PCR. This study demonstrates that the combined use of second-generation ELISA and RIBA anti-HCV assays is highly effective in identifying HCV infection, whereas the specificity of ELISA alone for the screening of blood donors with normal ALT values appears to be limited. In contrast, in donors with elevated ALT levels, there is a positive correlation between second-generation assays (ELISA and RIBA) and HCV viremia. The high proportion of inapparent HBV infection in blood donors with elevated ALT levels underlines the importance of this test for the prevention of transfusion-associated viral hepatitis.     

Evaluation of a simultaneous HIV antigen and antibody detection test in Korean population

Current diagnosis of human immunodeficiency virus (HIV) infection relies on the detection of anti-HIV antibodies by enzyme-linked immunosorbent assay (ELISA). Recently, kits detecting both p24 antigenemia and anti-HIV/anti-HIV2 antibodies have been developed. Thus, it is necessary to compare those kits developed as such. The aim of this study was to evaluate the diagnostic efficiency of a simultaneous detection test of p24 antigen and anti-HIV1/2 antibodies in a low prevalence area. Eight hundred and four randomly selected sera proven negative for HIV infection and 110 sera from 54 patients diagnosed as HIV infected, obtained between 1999 and 2000, were used for this study. One commercial lot of panels composed of consecutive sera obtained from known HIV-infected patient was included. Anti-HIV1/2 antibodies were detected by two different commercial ELISA kits, one from Korean and the other from German manufacturer. P24 antigen test was performed by ELISA. The simultaneous HIV antigen and antibody detection test was carried out. In the meantime, HIV RNA PCR and anti-HIV and anti-HIV2 western blot assays were also performed to confirm the test results in cases the test results didn't agree. The simultaneous detection kit showed 100% sensitivity and 99.6% specificity. Furthermore, the test displayed the possibility of earlier diagnosis than conventional anti-HIV1/2 ELISA with the results obtained from a group of consecutive panel sera infected with HIV. From these results, we concluded that the simultaneous HIV antigen and antibody detection test can be applied as a substitute clinical screening test in the place of conventional anti-HIV1/2 ELISA, and there is the probable benefit of early diagnosis.     

B cell-mediated infection of stimulated and unstimulated autologous T lymphocytes with HIV-1: role of complement

In vivo, human immunodeficiency virus type 1 (HIV-1) is opsonized with complement fragments and virus-specific antibodies (Ab). Thus, HIV is able to interact with complement receptor (CR) - and Fc receptor (FcR) - positive cells such as B cells, follicular dendritic cells or macrophages. In this study we demonstrate that the interaction between B cells and HIV has an impact on autologous primary T cell infection in vitro. We confirmed the presence of complement-fragments and virus-specific Ab on serum-treated HIV using a virus-capture assay. In experiments with CR2-specific Ab we showed that the virus/B cell interaction was mainly dependent on CR2. In infection experiments immobilisation of HIV on stimulated tonsil B cells greatly enhanced the infection of interleukin (IL)-2-activated autologous tonsil T cells. Surprisingly, enhancement of T cell infection by B cell-HIV complexes was observed even in the absence of mitogenic stimuli such as PMA and was independent of the addition of exogenous IL-2. Taken together, these results indicate that primary B cells are able to efficiently transmit opsonised HIV to autologous primary T cells and induce a massive enhancement of infection. These in vitro experiments mimic the in vivo situation in the lymphoid tissue and suggest an alternative mechanism for the infection of primary T cells.     

Carriers of HBs antigen, anti-HIV antibodies and their association with blood donors in Brazzaville

Serum samples taken from 6,624 blood donors since 1984 to 1987, were tested for Hepatitis B virus surface antigen (HBs Ag) using a microhemagglutination assay and for anti-HIV antibodies by ELISA test. The mean carrier state of HBs Ag was 10.68% and that of anti-HIV antibodies was 6.99%. The association of HBs Ag and anti-HIV antibodies was discovered in 4.84% donors but without correlation for the period of the study.     

Comparison of human immunodeficiency virus (HIV)-specific infection-enhancing and -inhibiting antibodies in AIDS patients

The humoral immune response of the human host against the human immunodeficiency virus (HIV) type 1 (HIV-1) envelope glycoproteins comprises virus-neutralizing antibodies (NAs), antibody-dependent cellular cytotoxicity-mediating (ADCC) antibodies, and infection-enhancing antibodies (IEAs). Because of their potential significance for the outcome of infection with this virus, we have studied the relative prevalence of NAs, ADCC antibodies, and IEAs in the sera of patients infected with HIV. Our results demonstrate that while >or=60% of serum samples are positive for NAs or ADCC antibodies, 72% of these serum samples mediate the enhancement of infection in the presence of complement. In patients with low CD4 counts, NA and ADCC antibody levels tend to decrease, while IEA levels increase. A significant positive correlation was found only between the presence of ADCC antibodies and the presence of antibodies that neutralized HIV-1 in the presence of complement. These results show that the anti-HIV-1 humoral immune response consists of a mixture of antibodies that may inhibit or enhance HIV infection and whose ratios may vary in different stages of the infection.     

Incidence of retroviruses in some Brazilian groups

The prevalence of human T lymphotropic virus type I (HTLV-I) and human immunodeficiency virus (HIV) antibodies was evaluated in Brazil among 116 aboriginal Indians living in a pre-Amazonian region, and in 44 patients with haematological malignant disorders being treated in Rio de Janeiro. Screening for the presence of antibodies to HIV was performed routinely for 17224 blood donors at the National Cancer Institute, Rio de Janeiro, from January 1986 to May 1987. The results demonstrated that HIV infection was not endemic among Brazilian Indians, as none of them had antibodies to HIV, in contrast with the population of Rio de Janeiro, which showed a high prevalence (0.34%) of positivity among normal individuals. In a small group of patients with haematological disease only one with acute lymphoblastic leukaemia proved to be HIV-positive, the infection having been acquired through previous blood transfusion. None of the serum samples reacted with HTLV-I, including those of 17 non-Hodgkin's lymphoma patients. HTLV-I infection does not seem to be endemic in this country, but further large scale studies are necessary, especially in patients with haematological disorders, homosexual individuals and drug users.     

Evaluation of the analytic performance of blood collection tubes (BD Vacutainer SST) for the screening of anti-HIV, anti-HTLV, anti-HCV, anti-HBc, anti-CMV antibodies, and of HBs, P24 HIV antigens, and of alanine aminotransferase]

The Laboratory of Viral Diseases Immunology (Laboratoire d'Immunologie des Maladies Virales) of the Northern Region Blood Bank (Etablissement Fran?ais du Sang Nord de France) performs between 180.000 and 200.000 viral blood qualifications per year. The use of a serum gel separator evacuated tube should contribute to improve the quality of the pre-analytical phase. However, it must not impact negatively the analytical performances. We evaluated such tube within our specific environment and with the various reagents used in routine. The open study compared the BD Vacutainer plain tube (7 mL, non siliconised) with the BD Vacutainer SST tube (6 mL siliconised with serum gel separator) against the anti-HIV, anti-HTLV, anti-HCV, anti-HBc, anti-HBs, anti-CMV antibodies, the HBs, HIV P24 antigen and the alanine aminotransferase. The study objectives were to find potential gel interference; to verify the diagnostic sensitivity, reagents specificity, and reproducibility. The results analysis show: equivalent performances with the anti-HIV Ab (Anti HIV 1/2 recombinant--Biotest et Genscreen HIV 1/2--Sanofi), anti HIV WB Ab (New Lav Blot 1--Sanofi), anti-HBs Ab (Enzygnost anti-HBs micro--Behring), anti-HBc Ab (HBc Elisa Test System--Ortho), anti-CMV Ab (Enzygnost anti-CMV IgG + M--Behring) kits; lower performances with: The Vironostika HIV Uni Form II plus 0--Organon kit with a -3.5% signal decrease around the ratio R = 2.7 for positive anti-HIV Ab. The Elisa test System 3 Ag HBs-Ortho kit with an increase of the mean ratio of the negative Ag HBs samples; better performances with: the Vironostika HIV 1 Antigen--Organon kit with a +10% signal increase around the threshold ratio R = 1 for positive Ag HIV samples. This deserves further study to verify that the specificity is maintained. The HTLV Type 1 et 2 EIA--Ortho kit with +8% signal increase around the ratio R = 2 for positive anti-HTLV Ab samples without change of the specificity. The Ortho HCV 3.0 Elisa Test System and HTLV Type 1 et 2 EIA kits with a clear and significant improvement of the reproducibility of the anti-HCV and anti-HTLV Ab screenings. The results of this evaluation, together with the intrinsic BD SST tube characteristics, lead to the conclusion that its use would contribute to improve the quality. Because of the specificities of each laboratory, a change of tube type, as with any other material or reagent, request a close monitoring of the first results to confirm the absence of negative effects.     

Prevalence of HIV antibodies among prostitutes in Zürich,Switzerland

Summary The prevalence of antibodies to the human immune deficiency virus was determined in 123 prostitutes. Of 18 intravenous drug abusers 14 were anti-HIV positive, all others, with one exception, were seronegative. Neither race, nor number of clients, nor sexual practices correlated with seropositivity.Abkürzungsverzeichnis HIV Human immune deficiency virus - HTLV III Humans T-cell lymphotropic virus type III - LAV Lymphadenopathy-associated virus     

IgG subclass response to HIV in relation to antibody-dependent cellular cytotoxicity at different clinical stages

The anti-HIV IgG subclass response was analysed in sera from different clinical stages and related to virus specific antibody-dependent cellular cytotoxicity (ADCC). IgG1 was found to be the dominant subclass, present in all sera and with similar mean titres at different stages. The number of anti-HIV IgG3 positive sera, measured on whole viral lysate antigen plates, decreased during disease progression from 38% in symptom-free to 7% in AIDS patients. IgG2 and IgG4 subclasses were less prevalent although a slight increase of IgG4 frequency was found in AIDS patients. High IgG1 titres correlated with a positive ADCC reaction but there was no correlation between anti-HIV IgG1 and ADCC titres. Some sera which contained HIV IgG1 as the only subclass were able to mediate an ADCC reaction. In addition, when anti-HIV IgG3 was isolated, by protein A chromatography, no ADCC killing was induced by these antibodies. It is concluded that IgG1 is the major ADCC-active IgG subclass in HIV infected individuals. The lack of correlation between IgG1 and ADCC titres may be explained by a relatively small fraction of IgG1 antibodies mediating ADCC.