Plasma viraemia in seronegative HIV-1-infected individuals.

It has been reported that the period of latency between HIV-1 infection and the production of antibodies against the virus is sometimes prolonged for greater than 6 months. However, the data supporting this are still controversial and it is not known whether these individuals are actually infectious, especially through body fluids. We have performed a prospective study of 65 high-risk HIV-1-antibody-negative individuals who were followed-up for a period of at least 1 year. Twelve of these individuals were shown by polymerase chain reaction (PCR) to be carriers of HIV-1 proviral sequences. The virus was isolated from lymphocytes in five out of 10 PCR-positive subjects and from cell-free plasma in two. Our data indicate that in some cases delayed seroconversions may be associated with productive infection, suggesting that mechanism(s) other than viral latency may be responsible for the absence of antibody responses to HIV-1 proteins.     

Absence of HIV-1 DNA in high-risk seronegative individuals using high-input polymerase chain reaction.

Evidence of frequent HIV-1 infections in antibody-negative, high-risk individuals (so-called 'silent' infections) remains controversial. To evaluate whether these discrepant results may be the consequence of intermittent detection of rare infected cells (low viral load) preceding seroconversion, we developed a modification of the polymerase chain reaction (PCR) technique which enabled analysis of 10-fold greater amounts of cellular DNA per reaction than standard PCR (2 x 10(6) rather than 0.2 x 10(6) input cells). This technique allowed consistent detection of HIV-1 provirus in two seropositive individuals who had repeatedly tested negative by standard-input PCR. However, results were negative when high-input PCR was applied to 51 specimens from 39 selected high-risk seronegative individuals. These results suggest that variations in viral load preceding or in the absence of seroconversion probably do not explain discrepant evidence regarding silent HIV-1 infection.     

PCR analysis of HIV-1 sequences and differential immunological features in seronegative and seropositive haemophiliacs

We have compared the immunological features of two matched groups of seronegative and seropositive haemophilia A individuals. Both groups were exposed from 1981 to 1985 to comparable amounts and batches of FVIII concentrates not subjected to virus inactivation procedures, and had therefore a 100% probability of receiving HIV-contaminated material. The presence of proviral HIV-1 sequences was evaluated by PCR in the DNA from peripheral blood lymphocytes and/or monocytes. After hybridization with specific probes, DNA from all seropositive haemophiliacs revealed HIV sequences; no HIV sequences were observed from the DNA of seronegative patients, even after two rounds of amplification, thus suggesting that these patients were not affected by a latent HIV infection. Seronegative/PCR- and seropositive/PCR+ patients showed a normal and reduced number of CD4+ lymphocytes, and a slight and marked increase of CD8+ cells respectively. Activated T cells expressing the HLA-DR antigen were elevated in both groups. Interestingly, a significant reduction of circulating CD56+/CD3- NK lymphocytes was observed only in seropositive haemophiliacs, whereas NK lymphocytes with CD56+/CD3+ phenotype were within normal levels in both groups. In seropositive patients no correlation was found between the number of CD4+ and CD56+/CD3- lymphocytes. The marked reduction of CD56+/CD3- lymphocytes observed in seropositive haemophiliacs in addition to the CD4+ cell depletion may represent a key pathogenetic factor which facilitates the onset and/or the progression of HIV-1 infection in haemophiliacs, and is related to the capacity of HIV to infect NK cells.     

The immune response to parvovirus B19 exposure in previously seronegative and seropositive individuals

Little information is available on the immune response to parvovirus B19 after the administration of contaminated blood products. In the present study, we found that levels of B19 IgG in B19-seropositive recipients protect against reinfection and, after transfusion with pooled plasma containing B19 DNA (1.6 x 10(8) IU/mL), increase from 19-39 IU/mL to 50-100 IU/mL. We found that, in the presence of 1.6-2.2 x 10(8) IU of B19 DNA/mL in B19-seronegative recipients, a pooled-plasma B19 IgG level of 59.5 IU/mL is insufficient to prevent B19 transmission and subsequent seroconversion. These data should lead to improvements in the assessment of blood-product safety.     

Antibodies to the nef protein and to nef peptides in HIV-1-infected seronegative individuals

The silent period that follows infection by the human immunodeficiency virus (HIV-1) and precedes seroconversion remains a problem for the screening of blood supply, and knowledge about the mechanism involved in the maintenance of latency is only fragmentary. Using purified nef recombinant protein and six synthetic nef peptides, antibodies to the product of an HIV-1 regulatory gene, the negative regulatory factor (nef) involved in maintenance of proviral latency, were detected by Western blot and radioimmunoassay techniques in HIV-1-seronegative, viral antigen-negative, and virus culture-negative individuals at risk for HIV infection. This antibody response to nef was correlated in eight individuals with the detection of HIV-1 proviral DNA by oligonucleotide hybridization, following enzymatic amplification of HIV DNA in peripheral blood mononuclear cells. Such latent HIV infections have now been followed for up to 6 or 10 months in five individuals. In addition, retrospective and prospective analysis of HIV-1-seropositive individuals have shown (1) antibodies to nef preceding seroconversion, and (2) the persistence of antibodies to nef and of HIV-1 proviral DNA in a case of spontaneous complete HIV-1 seronegativation. Since DNA amplification cannot be currently considered for routine use, screening for anti-nef antibodies followed by confirmation by DNA amplification could represent a basis for new diagnostic strategies. Beyond their diagnostic implications, these findings, suggesting that regulatory genes of the HIV-1 provirus can be expressed prior to the initiation of virion synthesis, may also be applicable in the design of alternative vaccines against the acquired immunodeficiency syndrome.     

Lack of detectable HIV-1-specific CD8(+) T cell responses in Zambian HIV-1-exposed seronegative partners of HIV-1-positive individuals

Human immunodeficiency virus type 1 (HIV-1)-specific T cell responses were characterized in a blinded study involving infected individuals and their seronegative exposed uninfected (EU) partners from Lusaka, Zambia. HIV-1-specific T cell responses were detected ex vivo in all infected individuals and amplified, on average, 27-fold following in vitro expansion. In contrast, no HIV-1-specific T cell responses were detected in any of the EU partners ex vivo or following in vitro expansion. These data demonstrate that the detection of HIV-1-specific T cell immunity in EU individuals is not universal and that alternative mechanisms may account for protection in these individuals.     

Two-year evaluation of clinical and laboratory variables of immune function in 117 hemophiliacs seropositive or seronegative for HIV-1

Fifty-nine HIV-1 antibody positive and 58 antibody negative hemophiliacs were evaluated over a 2 year study period to gain insight into the natural history and prognosis of HIV-1 disease in members of this risk group. Mean CD4 (Leu 3+) cell counts calculated at 6 month intervals decreased gradually in seropositive patients (from 403 to 311/microliters) whereas CD8 (Leu 2+) counts remained stable but above the normal range. CD4 cell counts correlated closely with advancing CDC clinical stage; CD8 numbers showed no such association, but were markedly lower in the six patients with overt AIDS. Serum P24 antigenemia was associated with low CD4 cell counts and with advanced clinical stage (58% of antigenemic and 14% of non-antigenemic seropositive patients were in stage IV). In addition to CD4 cell counts, significant reductions in Leu 11+ natural killer cell (NK) subsets and in Leu 3 + 8 - cells occurred in seropositive patients over the study period; Leu 2 + DR + cells increased significantly. When expressed as a percentage of lymphocytes, the reduction in Leu 19 + NK cells was also significant, as were the increases in Leu 4 + DR + cells and Leu 12 + 8 + B cells. In summary, declining CD4 cell numbers and percentages are valuable markers of progressive HIV-1 disease in hemophiliacs, but may not always accurately reflect the degree of disease activity. Progressive changes in additional variables such as serum P24 antigen, and numbers and percentages of NK cell subsets and (as AIDS supervenes) CD8 cell numbers, may allow more precise monitoring of HIV-1 disease. This will, in turn, facilitate the design of optimal individualized strategies for therapeutic intervention.     

Mucosal and plasma IgA from HIV-exposed seronegative individuals neutralize a primary HIV-1 isolate

OBJECTIVE: To characterize functional properties of HIV-specific IgA in samples representing both systemic and mucosal compartments of HIV-1 highly exposed persistently seronegative (HEPS) individuals. METHODS: IgA was purified from plasma and mucosal samples from HEPS individuals and tested for the ability to neutralize infection of peripheral blood mononuclear cells (PBMC) by a non-syncytium inducing HIV-1 (clade B) primary isolate. None of these individuals had measurable HIV-1-specific IgG. RESULTS: HIV-1-specific neutralizing activity of the purified IgA from plasma (n = 15), saliva (n = 15) and cervicovaginal fluid (CVF) (n = 14) were found in the majority of samples (73, 73 and 79%, respectively). In contrast, plasma, saliva and CVF samples of low-risk, uninfected HIV-seronegative individuals lacked neutralizing IgA, with the exception of two out of 34 (6%) saliva samples. CONCLUSION: Mucosal and plasma IgA from HEPS individuals can neutralize HIV-1 infection.     

Low HIV-1 proviral DNA burden detected by negative polymerase chain reaction in seropositive individuals correlates with slower disease progression.

During 1989, 316 members of a cohort of homosexual men were tested for HIV-specific DNA by the polymerase chain reaction (PCR) using a pair of gag-region primers. Of 125 HIV-seronegative subjects, 123 (98.4%) were PCR-negative while 158 (82.7%) of 191 HIV-seropositive subjects were PCR-positive. Fewer of the 33 subjects who were seropositive and PCR-negative were at Centers for Disease Control (CDC) stage IV than the seropositive, PCR-positive subjects (6 versus 25%; P = 0.030). The seropositive, PCR-negative group had higher mean CD4 counts (640 versus 490 x 10(6) cells/l; P = 0.006), higher CD4: CD8 ratios (0.92 versus 0.64; P = 0.004), lower immunoglobulin (Ig) G levels (1290 versus 1645 mg/dl; P = 0.002), lower IgA levels (168 versus 251 mg/dl; P less than 0.001), and lower C1q binding activity (8 versus 14%; P = 0.010) than the seropositive, PCR-positive subjects. The median rate of CD4 cell decline in the 3 years preceding the PCR sample was less marked in the seropositive, PCR-negative group than the seropositive, PCR-positive group (-58 versus -77 x 10(6) cells/l per year; P = 0.028). To control for duration of infection, we restricted the analysis to the subgroups of 11 seropositive, PCR-negative subjects and 34 seropositive, PCR-positive subjects who had seroconverted earlier in the cohort study. Both subgroups had similar durations of infection, yet the same pattern of differences persisted.(ABSTRACT TRUNCATED AT 250 WORDS)     

DDI and liver tests in HIV-1 seropositive haemophiliacs

Many patients with haemophilia who are HIV-1 seropositive are co-infected with the hepatitis C virus with variable degrees of underlying liver disease. To evaluate whether the use of the antiretroviral agent Dideoxyinosine (DDI) causes worsening of hepatic dysfunction as measured by liver enzyme tests, we reviewed our cohort of patients previously treated with monotherapy with Zidovudine (AZT) and subsequently changed to DDI. Seventeen patients (median age: 34 years, median absolute CD4 lymphocyte cell count: 86 cells μL⁻¹) were included in this study. None had coincident use of other hepatotoxic agents. The median duration of treatment with AZT and DDI was 18 and 15 months, respectively. There was no significant change in liver function tests with the use of DDI and no development of clinical signs of hepatotoxicity. Neither duration of treatment, absolute CD4 lymphocyte cell count, pre-existing elevation of baseline aminotransferase levels nor the use of Pneumocystis carinii prophylaxis therapy resulted in further elevation of liver function tests. Monotherapy with DDI was well tolerated in this cohort of HIV-1-seropositive haemophiliacs with coincident hepatitis C infection.     

Synovial fluid acid phosphatase in seropositive and seronegative arthritides

Synovial fluid acid phosphatase was investigated in 82 arthritic patients with hydropsy in a knee joint. 39 of the patients were seropositive and 43 seronegative. 36 of the seropositive group had erosive rheumatoid arthritis. The mean synovial fluid acid phosphatase in the seropositive group, 11.6 U/l (SD +/- 8.4), was significantly higher (p less than 0.001) than in the seronegative group, 6.5 U/l (SD +/- 4.8).     

Differing X-ray patterns in seronegative and seropositive rheumatoid arthritis

Clinical Rheumatology - Anti-citrullinated protein antibody (ACPA) and rheumatoid factor (RF) status are important predictors for rheumatoid arthritis (RA) erosivity. Qualitative differences on...     

DNA amplification of HIV genome in hemophiliacs and in newborns from seropositive mothers

Summary We evaluated the validity of DNA enzymatic amplification (PCR) in a population at risk for HIV-1 infection, consisting of hemophiliacs and children born to seropositive mothers. All but one of the seropositive hemophiliacs and controls were found positive with the three sets of primers. All the seronegative patients and controls were found negative in PCR. No correlation with the anti-nef serology was found, one seropositive being anti-nef negative and three seronegative anti-nef positive. The results obtained with PCR are in good agreement with classical serology, and this would suggest that the possible period of latency may not be as long as suspected. No seroconversion has been described in hemophiliacs since solvent-detergent inactivated blood products have been in use, and seronegative hemophiliacs no longer constitute a population at risk. Studies on seronegative sexual partners of seropositive patients would be of great interest. For newborns from seropositive mothers, PCR is the only possible technique in early age before seronegativation of the healthy children. Further studies will be required to determine the fiability and sensitivity of the test.The study was supported by a grant from CNAMTS-INSERM (Biologie moléculaire des maladies hémorragiques et thrombotiques héréditaires).     

HIV-1 infection in HIV-1 enzyme-linked immunoassay seronegative patients in Kinshasa, Zaire

Serum samples of 62 African patients who had clinical manifestations of HIV-1 infection but were seronegative for HIV-1 by ELISA (Organon) were subsequently further tested by another HIV-1 ELISA test (Wellcozyme), HIV-1 IgG Western blot, HIV-1 antigen detection and HIV-2 ELISA. Patients' lymphocytes were cultured for HIV-1 and 2. Because of limited quantities of serum available all tests were not performed on all samples. Seven (26%) of 27 sera of patients meeting the WHO clinical case definition of AIDS were Western-blot-positive. In contrast, of 35 patients' sera with possible HIV related disease, only one (3%) was Western blot positive (P = 0.02) and none of 75 sera from HIV-1 ELISA (Organon) seronegative blood donors (P less than 0.01) were Western blot positive. Of 30 HIV-1 ELISA (Organon) seronegative patients tested with the HIV-1 ELISA Wellcozyme assay only one was seropositive (this patient's serum was also Western blot positive). Of 17 HIV-1 ELISA (Organon) seronegative patients tested, HIV-1 antigen was found in 1 case (6%) (this patient's serum was Western blot negative). None of the 34 patients tested by HIV-2 serology was HIV-2 seropositive. HIV-1 was isolated by culture in 3 (21%) of 14 HIV-1 ELISA seronegative patients (sera of the 3 patients were Western blot negative). In total, 12 (19%) of 62 HIV-1 ELISA (Organon) seronegative patients were found to be positive for HIV, either by Western blot HIV antigen testing or viral culture.(ABSTRACT TRUNCATED AT 250 WORDS)     

HIV-1 seropositive women in the Philippines: pregnancy outcome and perinatal transmission of HIV-1.

Annual surveillance studies were initiated in 1985 to determine the incidence and prevalence of HIV-1 infection in female prostitutes registered through the Social Hygiene Clinic System of the Philippine Department of Health. All of the confirmed HIV-1 seropositive women detected in the above surveys who could be contacted were followed up about every three months to monitor their clinical and immunological status. Since we regularly interviewed and examined these HIV-1 seropositive women, we were able to note the occurrence of pregnancies following HIV diagnosis. By September 1990, 54 HIV-1 seropositive women (aged 18-35) detected from the above surveys had been interviewed and examined. Twenty-six of these HIV-1 positive women had a total of 37 pregnancies. Eight were pregnant at the time of HIV diagnosis: three term deliveries, one premature delivery (PD) at eight months, three abortions, and one lost to follow-up while still pregnant. Five of these eight had repeat pregnancies: two term deliveries, two abortions, and one lost to follow-up while pregnant. Eighteen other women became pregnant one or more times after HIV diagnosis: seven term deliveries, 13 abortions, two PDs, one ectopic pregnancy terminated, one currently pregnant, and one lost to follow-up during pregnancy. There was no clear indication from clinical examinations and CD4+ cell counts that pregnancy exacerbated the course of HIV-1 related disease in these women. One of the 12 term infants has died and eight have developed non-specific findings that are suggestive but not diagnostic of HIV infection.2+ strongly seropositive by both ELISA and Western blot assay at 16 months.     

Detection, quantification and sequencing of HIV-1 from the plasma of seropositive individuals and from factor VIII concentrates.

A highly sensitive and reliable RNA polymerase chain reaction method has been developed which has been used to detect, quantify and sequence cell-free HIV RNA directly from the plasma of seropositive individuals. Plasma from 10 out of 12 haemophiliacs tested was found to contain detectable levels of HIV-1 RNA [log mean value: 1.2 x 10(3) copies for Centers for Disease Control (CDC) group II patients, 5.5 x 10(3) copies for CDC group IV patients]. The presence of cell-free circulating virus in both symptomatic and asymptomatic individuals suggests that viral replication continues throughout the course of infection. The same procedure has been used to detect and sequence HIV-1 RNA in two batches of unheated commercial factor VIII concentrate distributed in 1981 and 1983. The sequences obtained revealed a closer relationship to North American than to African strains of HIV-1.     

A comparison of patients with seropositive and seronegative rheumatoid arthritis

Summary It has recently been suggested that a subpopulation of patients with rheumatoid arthritis, diagnosed on clinical, radiologic and pragmatic grounds, but with negative rheumatoid factor tests, represents a clinical entity quite distinct from that of seropositve rheumatoid arthritis. We have studied 60 sequentially presenting patients, 30 of whom were selected because they were seronegative, and 30 selected because they were seropositive in regard to IGM rheumatoid factor. The only major differences detected between the two groups on blind assessment were a greater tendency to deformity, a greater degree of erosion and the presence of subcutaneous nodules in the seropositive group. Seronegative and seropositive rheumatoid arthritis appear to have very similar clinical features, but differing degrees of severity.