Risk of non-AIDS-defining events among HIV-infected patients not yet on antiretroviral therapy.

OBJECTIVES: Certain non-AIDS-related diseases have been associated with immunodeficiency and HIV RNA levels in HIV-infected patients on combination antiretroviral therapy (cART). We aimed to investigate these associations in patients not yet on cART, when potential antiretroviral-drug-related effects are absent and variation in RNA levels is greater. METHODS: Associations between, on the one hand, time-updated CD4 counts and plasma HIV RNA and, on the other hand, a composite non-AIDS-related endpoint, including major cardiovascular diseases, liver fibrosis/cirrhosis, and non-AIDS-related malignancies, were studied with multivariate Poisson regression models in 12 800 patients diagnosed with HIV infection from 1998 onwards while not yet treated with cART. RESULTS: During 18 646 person-years of follow-up, 203 non-AIDS-related events occurred. Compared with a CD4 count ≥ 500 cells/µL, adjusted relative risks (RRs) for the composite endpoint were 4.71 [95% confidence interval (CI) 2.98-7.45] for a CD4 count < 200 cells/µL, 2.06 (95% CI 1.38-3.06) for a CD4 count of 200-349 cells/µL, and 1.19 (95% CI 0.82-1.74) for a CD4 count of 350-499 cells/µL. There was no evidence for an independent association with HIV RNA. Other important covariates were age [RR 1.40 (95% CI 1.31-1.49) per 5 years older], hepatitis B virus coinfection [RR 5.66 (95% CI 3.87-8.28)] and hepatitis C virus coinfection [RR 9.26 (95% CI 6.04-14.2)]. CONCLUSIONS: In persons not yet receiving cART, a more severe degree of immunodeficiency rather than higher HIV RNA levels appears to be associated with an increased risk of our composite non-AIDS-related endpoint. Larger studies are needed to address these associations for individual non-AIDS-related events.

Delayed linkage to care in one-third of HIV-positive individuals in the Netherlands.

OBJECTIVES: To determine time to linkage to HIV care following diagnosis and to identify risk factors for delayed linkage. METHODS: Patients newly diagnosed with HIV at sexually transmitted infections (STI) clinics in the Netherlands were followed until linkage to care. Data were collected at the time of diagnosis and at first consultation in care, including demographics, behavioural information, CD4+ counts and HIV viral load (VL) measurements. Delayed linkage to care was defined as >4 weeks between HIV diagnosis and first consultation. RESULTS: 310 participants were included; the majority (90%) being men who have sex with men (MSM). For 259 participants (84%), a date of first consultation in care was known; median time to linkage was 9 days (range 0-435). Overall, 95 (31%) of the participants were not linked within 4 weeks of diagnosis; among them, 44 were linked late, and 51 were not linked at all by the end of study follow-up. Being young (<25 years), having non-Western ethnicity or lacking health insurance were independently associated with delayed linkage to care as well as being referred to care indirectly. Baseline CD4+ count, VL, perceived social support and stigma at diagnosis were not associated with delayed linkage. Risk behaviour and CD4+ counts declined between diagnosis and linkage to care. CONCLUSIONS: Although most newly diagnosed patients with HIV were linked to care within 4 weeks, delay was observed for one-third, with over half of them not yet linked at the end of follow-up. Vulnerable subpopulations (young, uninsured, ethnic minority) were at risk for delayed linkage. Testing those at risk is not sufficient, timely linkage to care needs to be better assured as well.

High incidence of intermittent care in HIV-1-infected patients in Curaçao before and after starting cART.

Retention in care is one of the major challenges to scaling up and maximizing the effectiveness of combination antiretroviral therapy (cART). High attrition rates have been reported in the Caribbean region, varying from 6% to 23%. We studied the incidence of and risk factors for intermittent care in a cohort of adult HIV-1-positive patients, who entered into care in Curaçao between January 2005 and July 2009. A total of 214 therapy-naïve HIV-1-infected patients aged 15 years or older, entered HIV care between January 2005 and July 2009. Intermittent care was defined as at least one period of 365 days or longer in which there was no HIV care contact in Curaçao. Cox regression models were used to identify characteristics associated with time to intermittent care. In all, 203 (95%) patients could be classified as having intermittent or continuous care. The incidence of intermittent care before starting cART was 25.4 per 100 person years observation (PYO), whilst it was 6.1 per 100 PYO after starting cART. Being born outside Curaçao was associated with intermittent care before and after starting cART. Time from diagnosis to entry into care was an independent predictor for intermittent care before starting cART. Younger age was independently associated with intermittent care after starting cART. Half of the patients returned to care after intermitting care. Upon returning to care, median CD4 count was 264 cells/mm(3) (IQR, 189-401) for those who intermitted care before starting cART, and 146 cells/mm(3) (IQR, 73-436) in those who intermitted care after starting cART. In conclusion, the incidence of intermitting care is high in Curaçao, especially before starting cART, and intermitting care before starting cART is an independent predictor for starting cART late.

Temporary antiretroviral treatment during primary HIV-1 infection has a positive impact on health-related quality of life: data from the Primo-SHM cohort study.

OBJECTIVES: The aim of the study was to compare health-related quality of life (HRQL) over 96 weeks in patients receiving no treatment or 24 or 60 weeks of combination antiretroviral therapy (cART) during primary HIV-1 infection (PHI). METHODS: A multicentre prospective cohort study of PHI patients, with an embedded randomized trial, was carried out. HRQL was assessed with the Medical Outcomes Study Health Survey for HIV (MOS-HIV) and a symptom checklist administered at weeks 0, 8, 24, 36, 48, 60, 72, 84 and 96. Mixed linear models were used for the analysis of differences in HRQL among the three groups. RESULTS: A total of 112 patients were included in the study: 28 received no treatment, 45 received 24 weeks of cART and 39 received 60 weeks of cART. Over 96 weeks of follow-up, the groups receiving 24 and 60 weeks of cART had better cognitive functioning than the no-treatment group (P = 0.005). Patients receiving 60 weeks of cART had less pain (P = 0.004), better role functioning (P = 0.001), better physical functioning (P = 0.02) and a better physical health summary score (P = 0.006) than the groups receiving no treatment or 24 weeks of cART. Mental health was better in patients receiving 24 weeks of cART than in patients in the no-treatment group or the group receiving 60 weeks of cART (P = 0.02). At week 8, patients in the groups receiving 24 and 60 weeks of cART reported more nausea (P = 0.002), diarrhoea (P < 0.001), abdominal pain (P = 0.02), stomach pain (P = 0.049) and dizziness (P = 0.01) than those in the no-treatment group. These differences had disappeared by week 24. CONCLUSIONS: Temporary cART during PHI had a significant positive impact on patients' HRQL as compared with no treatment, despite the initial, short-term occurrence of more physical symptoms, probably related to drug toxicity.

Late presentation of HIV infection: a consensus definition.

OBJECTIVES: Across Europe, almost a third of individuals infected with HIV do not enter health care until late in the course of their infection. Surveillance to identify the extent to which late presentation occurs remains inadequate across Europe and is further complicated by the lack of a common clinical definition of late presentation. The objective of this article is to present a consensus definition of late presentation of HIV infection. METHODS: Over the past year, two initiatives have moved towards a harmonized definition. In spring 2009, they joined efforts to identify a common definition of what is meant by a 'late-presenting' patient. RESULTS: Two definitions were agreed upon, as follows. Late presentation: persons presenting for care with a CD4 count below 350 cells/µL or presenting with an AIDS-defining event, regardless of the CD4 cell count. Presentation with advanced HIV disease: persons presenting for care with a CD4 count below 200 cells/µL or presenting with an AIDS-defining event, regardless of the CD4 cell count. CONCLUSION: The European Late Presenter Consensus working group believe it would be beneficial if all national health agencies, institutions, and researchers were able to implement this definition (either on its own or alongside their own preferred definition) when reporting surveillance or research data relating to late presentation of HIV infection.

Biphasic kinetics of peripheral blood T cells after triple combination therapy in HIV-1 infection: a composite of redistribution and proliferation.

The origin of CD4+ T cells reappearing in the blood following antiretroviral therapy in human immunodeficiency virus type-1 (HIV-1) infection is still controversial. Here we show, using mathematical modeling, that redistribution of T cells to the blood can explain the striking correlation between the initial CD4+ and CD8+ memory T-cell repopulation and the observation that 3 weeks after the start of treatment memory CD4+ T-cell numbers reach a plateau. The increase in CD4+ T cells following therapy most likely is a composite of initial redistribution, accompanied by a continuous slow repopulation with newly produced naive T cells.

Baseline lipid levels rather than the presence of reported body shape changes determine the degree of improvement in lipid levels after switching to atazanavir.

PURPOSE: To study factors influencing lipid changes after switching to atazanavir (ATV) and the effectiveness of ATV in maintaining virus suppression. METHODS: Retrospective cohort study in patients with viral suppression, comparing patients switching to ATV with those continuing combination antiretroviral therapy (cART). Outcome measures were 48-week total (TC), high-density (HDL) and low-density lipoprotein (LDL) cholesterol, and triglycerides (TG) changes, stratified for dyslipidemia and lipodystrophy and virological failure (time to first of two consecutive detectable HIV RNA). RESULTS: 225 patients switched to ATV (193 [85.8%] RTV boosted), and 3120 continued cART. In patients with baseline TC >6.2 mmol/L, those switching had greater mean (95% CI) TC decreases compared to those continuing cART (-1.26 [-1.63 to -0.89] and -0.54 [-0.64 to -0.44] mmol/L, p = .002). Likewise greater TG changes were observed in patients with high (>2.3 mmol/L) baseline TG (-1.44 [-2.05 to -0.83] and -0.54 [-0.70 to -0.38] mmol/L, p = .002). Effects were seen irrespective of presence of lipodystrophy. Patients switching to ATV had virological failure more often (17/224 [7.8%]) than those continuing cART (73/3100 [2.4%], p < .0001). CONCLUSIONS: Patients with virological suppression, including those with lipodystrophy, may benefit from switching to ATV with lipid profile improvement, especially if baseline lipid levels are high. This should be balanced against a possible higher virological failure risk.

T cell telomere length in HIV-1 infection: no evidence for increased CD4+ T cell turnover.

Progression to acquired immunodeficiency syndrome (AIDS) has been related to exhaustion of the regenerative capacity of the immune system resulting from high T cell turnover. Analysis of telomeric terminal restriction fragment (TRF) length, a marker for cellular replicative history, showed that CD8(+) T cell TRF length decreased but CD4(+) T cell TRF length was stable during the course of human immunodeficiency virus type-1 (HIV-1) infection, which was not explained by differential telomerase activity. This observation provides evidence that turnover in the course of HIV-1 infection can be increased considerably in CD8(+) T cells, but not in CD4(+) T cells. These results are compatible with CD4(+) T cell decline in HIV-1 infection caused by interference with cell renewal.

Combining hippocampal volume metrics to better understand Alzheimer's disease progression in at-risk individuals.

To date nearly all clinical trials of Alzheimer's disease (AD) therapies have failed. These failures are, at least in part, attributable to poor endpoint choice and to inadequate recruitment criteria. Recently, focus has shifted to targeting at-risk populations in the preclinical stages of AD thus improved predictive markers for identifying individuals likely to progress to AD are crucial to help inform the sample of individuals to be recruited into clinical trials. We focus on hippocampal volume (HV) and assess the added benefit of combining HV and rate of hippocampal atrophy over time in relation to disease progression. Following the cross-validation of previously published estimates of the predictive value of HV, we consider a series of combinations of HV metrics and show that a combination of HV and rate of hippocampal atrophy characterises disease progression better than either measure individually. Furthermore, we demonstrate that the risk of disease progression associated with HV metrics does not differ significantly between clinical states. HV and rate of hippocampal atrophy should therefore be used in tandem when describing AD progression in at-risk individuals. Analyses also suggest that the effects of HV metrics are constant across the continuum of the early stages of the disease.

Immunological abnormalities in human immunodeficiency virus (HIV)-infected asymptomatic homosexual men. HIV affects the immune system before CD4+ T helper cell depletion occurs.

To investigate the effect of persistent HIV infection on the immune system, we studied leukocyte functions in 14 asymptomatic homosexual men (CDC group II/III) who were at least two years seropositive, but who still had normal numbers of circulating CD4+ T cells. Compared with age-matched heterosexual men and HIV-negative homosexual men, the CD4+ and CD8+ T cells from seropositive men showed decreased proliferation to anti-CD3 monoclonal antibody and decreased CD4+ T-helper activity on PWM-driven differentiation of normal donor B cells. Monocytes of HIV-infected homosexual men showed decreased accessory function on normal T cell proliferation induced by CD3 monoclonal antibody. The most striking defect in leukocyte functional activities was observed in the B cells of HIV-infected men. B cells of 13 out of 14 seropositive men failed to produce Ig in response to PWM in the presence of adequate allogeneic T-helper activity. These findings suggest that HIV induces severe immunological abnormalities in T cells, B cells, and antigen-presenting cells early in infection before CD4+ T cell numbers start to decline. Impaired immunological function in subclinically HIV-infected patients may have clinical implications for vaccination strategies, in particular the use of live vaccines in groups with a high prevalence of HIV seropositivity.

Selective inhibition of syncytium-inducing and nonsyncytium-inducing HIV-1 variants in individuals receiving didanosine or zidovudine, respectively.

By studying changes in the clonal composition of HIV-1 populations during the first weeks of zidovudine (ZDV) treatment before the development of ZDV resistance-conferring mutations, we demonstrated previously a selective inhibition of nonsyncytium-inducing (NSI) HIV-1, even when present as coexisting population in individuals also harboring syncytium-inducing (SI) HIV-1. In this study, we observed the opposite in individuals receiving didanosine (ddI) treatment. In these individuals (n = 7) a median -0.98 log change (range -1.55-0.08) in infectious cellular SI load was observed, whereas the coexisting NSI load was only minimally affected (median -0.15 log, range -1.27-0.50; P = 0.03). The virus phenotype-dependent treatment responses were independent of the clonal composition of HIV-1 populations at baseline. Individuals treated with a combination of ZDV and ddI revealed an equal decline of both NSI and SI infectious cellular load (n = 4; NSI: median -1.55 log, range -2.19 to -1.45; SI: median -1.47 log, range -1.81 to -0.86; P = 0.56). To test the hypothesis that the previously reported optimal activation of ZDV and ddI in activated and resting T cells, respectively, in combination with the differential T cell tropism of NSI and SI HIV-1 is the basis for the observed virus phenotype specific efficacy of nucleoside analogs, we studied the effect of treatment with a protease inhibitor that does not require intracellular activation. Individuals receiving ritonavir (n = 4) indeed showed equal declines in NSI and SI infectious cellular load (NSI: median -2.37 log, range -2.59 to -2.16; SI: median -2.82 log, range -3.14 to -2.50; P = 0.25). Our data suggest HIV-1 phenotype as an additional parameter in the design of optimal treatment regimens.

Verapamil competes with doxorubicin for binding to anionic phospholipids resulting in increased internal concentrations and rates of passive transport of doxorubicin.

It is well documented that the Ca2+ channel antagonist verapamil can reverse multidrug resistance in cancer cells by decreasing P-glycoprotein mediated drug efflux. However, less information is available about effects of verapamil on drug-phospholipid interactions and on passive diffusion of drugs across the membrane, which both may play an important role in resensitizing cells to anti-cancer drugs. Therefore we studied the binding of verapamil to model membranes (large unilamellar vesicles) composed of various phospholipids and biological membranes. An increase of the amount of anionic phospholipids resulted in an enhanced binding of verapamil. Competition between verapamil and the anti-cancer drug and P-glycoprotein substrate doxorubicin for binding to anionic phospholipids was observed in model membranes composed of synthetic lipids, or composed of native Escherichia coli phospholipid mixtures, and in cytoplasmic membrane vesicles of this organism. Furthermore, verapamil specifically increased the rate of passive diffusion of doxorubicin across model membranes containing anionic phospholipids. It can be concluded that besides the decrease of P-glycoprotein mediated efflux at least two other effects may account for an increase of the internal (free and DNA-bound) doxorubicin concentration in the presence of verapamil; (i) a decrease of binding to anionic phospholipids in plasma-and intracellular membranes and (ii) an increase of the rate of passive import of doxorubicin across the plasma membrane.

Comparable interaction of doxorubicin with various acidic phospholipids results in changes of lipid order and dynamics.

We have characterized the interaction of the antitumor drug doxorubicin with model membranes of the anionic phospholipids dioleoylphosphatidic acid (DOPA), dioleoylphosphatidylserine (DOPS), cardiolipin and dioleoylphosphatidylglycerol (DOPG) as compared to the zwitterionic dioleoylphosphatidylcholine (DOPC) or dioleoylphosphatidylethanolamine (DOPE). The saturating binding levels were: 2.4 (DOPA), 1.3 (cardiolipin), 1.5 (DOPS, DOPG) and 0.02 (DOPC) doxorubicin per lipid phosphorus (mol/mol). The half-saturating free drug concentrations were comparable for DOPA, cardiolipin, DOPS and DOPG: 20, 16, 35 and 18 microM, respectively. Doxorubicin fluorescence revealed the simultaneous existence of at least two populations of bound drug in the various anionic phospholipids: (1) fluorescent molecules with chromophores that reside between the lipid molecules and (2) above 0.01-0.02 doxorubicin bound per lipid phosphorus: non-fluorescent drug-stacks that are closer to the aqueous phase than the fluorescent molecules. Small-angle X-ray scattering indicated that doxorubicin can reorganize anionic phospholipid dispersions into closely-packed multilamellar structures. Addition of the drug caused leakage of entrapped 6-carboxyfluorescein. Neither 2H-NMR on [2-2H]serine-labelled DOPS nor 31P-NMR revealed any significant effect of doxorubicin on headgroup conformation, but 2H-NMR on di[11,11-2H2]oleoyl-labelled phospholipids showed that the drug had a strong acyl chain-disordering effect on anionic phospholipids. 2H-NMR relaxation measurements indicated that the drug immobilized the headgroups and acyl chains of anionic phospholipids. The implications of these observations for the cellular activity of the drug are indicated.

Prognostic importance of initial response in HIV-1 infected patients starting potent antiretroviral therapy: analysis of prospective studies.

BACKGROUND: We examined whether the initial virological and immunological response to highly active antiretroviral treatment (HAART) is prognostic in patients with HIV-1 who start HAART. METHODS: We analysed 13 cohort studies from Europe and North America including 9323 adult treatment-naive patients who were starting HAART with a combination of at least three drugs. We modelled clinical progression from month 6 after starting HAART, taking into account CD4 count and HIV-1 RNA measured at baseline and 6 months. FINDINGS: During 13408 years of follow-up 152 patients died and 874 developed AIDS or died. Compared with patients who had a 6-month CD4 count of fewer than 25 cells/microL, adjusted hazard ratios for AIDS or death were 0.55 (95%CI 0.32-0.96) for 25-49 cells/microL, 0.62 (0.40-0.96) for 50-99 cells/microL, 0.42 (0.28-0.64) for 100-199 cells/microL, 0.25 (0.16-0.38) for 200-349 cells/microL, and 0.18 (0.11-0.29) for 350 or more cells/microL at 6 months. Compared with patients who had a 6-month HIV-1 RNA of 100000 copies/mL or greater, adjusted hazard ratios for AIDS or death were 0.59 (0.41-0.86) for 10000-99999 copies/mL, 0.42 (0.29-0.61) for 500-9999 copies/mL, and 0.29 (0.21-0.39) for 6-month HIV-1 RNA of 500 copies/mL or fewer. Baseline CD4 and HIV-1 RNA were not associated with progression after controlling for 6-month concentrations. The probability of progression at 3 years ranged from 2.4% in the patients in the lowest-risk stratum to 83% in patients in the highest-risk stratum. INTERPRETATION: At 6 months after starting HAART, the current CD4 cell count and viral load, but not values at baseline, are strongly associated with subsequent disease progression. Our findings should inform guidelines on when to modify HAART.

Limited patient adherence to highly active antiretroviral therapy for HIV-1 infection in an observational cohort study.

BACKGROUND: Adherence to highly active antiretroviral therapy (HAART) for human immunodeficiency syndrome type 1 (HIV-1) infection is essential to sustain viral suppression and prevent drug resistance. We investigated adherence to HAART among patients in a clinical cohort study. METHODS: Patients receiving HAART had their plasma concentrations of protease inhibitors or nevirapine measured and completed a questionnaire on adherence. We determined the percentage of patients who reported taking all antiretroviral medication on time and according to dietary instructions in the past week. Drug exposure was compared between patients reporting deviation from their regimen and fully adherent patients. Among patients who received HAART for at least 24 weeks, we assessed the association between adherence and virologic outcome. RESULTS: A total of 224 of 261 eligible patients completed a questionnaire. Forty-seven percent reported taking all antiretroviral medication on time and according to dietary instructions. Patients who reported deviation from their regimen showed lower drug exposure compared with fully adherent patients (median concentration ratio, 0.81 vs 1.07; P =.001). Among those receiving HAART for at least 24 weeks, patients reporting deviation from their regimen were less likely to have plasma HIV-1 RNA levels below 500 copies/mL (adjusted odds ratio, 4.0; 95% confidence interval, 1.4-11.6) compared with fully adherent patients. CONCLUSIONS: Only half of the patients took all antiretroviral medication in accordance with time and dietary instructions in the preceding week. Deviation from the antiretroviral regimen was associated with decreased drug exposure and a decreased likelihood of having suppressed plasma HIV-1 RNA loads. Patient adherence should remain a prime concern in the management of HIV-1 infection.

Neutralizing antibodies are positively associated with CD4+ T-cell counts and T-cell function in long-term AIDS-free infection.

OBJECTIVES: To assess the dynamics of neutralizing antibodies (NAb) in long-term AIDS-free HIV-1-infected subjects and establish correlations with known markers of disease progression. DESIGN: Cross-sectional study using sera collected from long-term non-progressors (LTNP) 8 years after seroconversion or study entry. Longitudinal study using sera collected from LTNP at 0, 0.5, 1, 2, 4, 6, 8 and 10 years after seroconversion and, as controls, from rapid progressors. METHODS: Individuals with documented AIDS-free HIV-1 infection for at least 8 years were evaluated for NAb against five heterologous HIV-1 primary isolates. In the cross-sectional study, serum viral RNA levels, CD4+ T-cell numbers and T-cell function were determined on samples collected during the eighth year of follow-up. For the longitudinal study, NAb were assessed in sequential sera taken from LTNP and rapid progressors. RESULTS: Serum neutralization titres found in individual sera differed from one HIV-1 isolate to another, were detected in 49-76% of LTNP, without correlation with the coreceptor usage of the isolate, and were positively associated with CD4+ T-lymphocyte counts (P = 0.0041) and T-cell function (P = 0.04). No correlation was found between NAb and the level of viral RNA in serum or the rate of CD4+ T-cell decline. Longitudinal analysis of sera from LTNP and rapid progressors showed that although several subjects in both groups had neutralizing activity at seroconversion, it thereafter became lower or no longer detectable. NAb were again found 1-4 years later and stably persisted in LTNP, but remained undetectable or at low levels in rapid progressors. CONCLUSIONS: NAb were preferentially found in subjects with relatively preserved T-cell function and CD4+ T-cell numbers. In these individuals, neutralizing activity against heterologous isolates increased with time. These data suggest that the capacity to produce broadly NAb is a function of the integrity of the immune system.

Rate of HIV-1 decline following antiretroviral therapy is related to viral load at baseline and drug regimen.

OBJECTIVES AND DESIGN: The dynamics uf viral decline following the initiation of antiretroviral treatment were studied in 29 HIV-1-infected patients participating in a two-arm trial comparing immediate (group A: ritonavir, zidovudine and lamivudine) and delayed (group B: ritonavir supplemented by zidovudine and lamivudine on day 21) triple therapy. Parameters underlying viral dynamics were estimated using mathematical models tailored to these treatment protocols. RESULTS: The decline in plasma HIV-1 density between day 0 and 21 was steeper in group A (-2.27+/- 0.46 log10) than group B (-1.87+/-0.56 log10). In a subset of patients amenable to full mathematical analysis, a short-lived productively infected cell compartment (producing approximately 97% of total virions) decayed with a half-life of 1.0-2.5 days, whereas a long-lived infected cell compartment decayed with a half-life of 18.8-32.8 days. Estimates for the time for the elimination of virus from these two cell populations ranged from 474 to 802 days. The rate of loss of productively infected CD4+ T cells was positively correlated with baseline viral load in group A and in the combined dataset. CONCLUSIONS: These results suggest that HIV-infected cell populations may have a faster turnover in patients with higher viral loads due to higher infection rate parameters, higher rates of virus production, or lower virus clearance rates.

Diagnostic value of specific IgM antibodies in primary HIV infection.

Sequential serum samples from 55 homosexual men with primary HIV infection were tested for IgM anti-HIV. An early IgM response was found in 27 out of 55 (49%). In five cases IgM anti-HIV was detected 1-3 1/4 months prior to IgG anti-HIV seroconversion, as detected by a commercially available ELISA, but in no case was IgM detected prior to IgG anti-HIV seroconversion, as detected by the more sensitive GACRIA (IgG antibody captive radio-immunoassay, see Subjects and methods) and immunoblot assays. In 22 out of 23 men (96%) the primary IgM response did not persist beyond 3 months. HIV antigenaemia was found before HIV antibody seroconversion in 6 out of 55 (11%) and concomitant with HIV antibody seroconversion in 8 out of 55 (15%) subjects. A 'flu-like' illness that might be ascribed to primary HIV infection was found in 37 out of 50 men (74%). A blood sample was taken from 11 men during or within 2 weeks of the illness: no serological markers of HIV infection were detected in four subjects, HIV antigen, IgM and IgG anti-HIV were detected in another four, HIV antigen was the only marker of HIV infection in two subjects, and in one subject, IgM and IgG anti-HIV were detected but not HIV antigen. These results indicate that no conclusive value can be attached to a negative IgM test in suspected primary HIV infection, and that any role for IgM anti-HIV testing in blood donor screening is highly questionable.

Viral gene expression, antibody production and immune complex formation in human immunodeficiency virus infection.

Human immunodeficiency virus (HIV) antigen (HIV-Ag) in polyethylene glycol (PEG) precipitates and supernatants and HIV antibodies (HIV-Ab) to core and envelope antigens were studied in serial serum samples of three HIV-Ab seroconverters and 11 HIV-Ab seropositive men with a mean follow-up time of 16.1 months. In five men not progressing beyond persistent generalized lymphadenopathy (PGL) and two progressing to AIDS, HIV-Ag was detected once in 'free' configuration before HIV-Ab seroconversion and persistently or intermittently 'complexed' thereafter; in six of these men HIV core antibodies were continuously present with a declining level in one. In two men not progressing beyond PGL and five progressing to AIDS HIV-Ag was detected 'complexed' before HIV-Ab seroconversion once and persisted predominantly in 'free' configuration thereafter, while no HIV core antibody was detected in six of these men and a declining level in one. HIV-Ag was detected in 37% (14 out of 38) of HIV core antibody seropositive samples, mostly in 'complexed' form, while HIV-Ag was detected in 86% (43 out of 50) of HIV core antibody seronegative samples, mostly in both 'complexed' and 'free' configuration. Antibodies to HIV envelope antigen were detected in all HIV-Ab seropositive samples. These results indicate that the level of HIV-Ag expression is the primary determinant of detectability of HIV core antigens as well as antibodies. Enhancement of HIV-Ag expression, in a significant number of cases associated with clinical deterioration, appears to lead to clearance of HIV core antibodies in immune complexes, while HIV envelope antibody levels remain relatively unaffected.