Decay of HIV-1 DNA in patients receiving suppressive antiretroviral therapy

HLA-B27 is associated with the etiology of ankylosing spondylitis (AS) and acute anterior uveitis (AAU). Transporter associated with antigen processing (TAP) 1 and TAP2 polymorphism influences the range of peptide presented by HLA class I molecules. In this report, contribution of TAP polymorphism to the susceptibility to AS and AAU was studied in HLA-B27-positive Japanese individuals. Patients were classified into three groups: 16 AS patients, 14 AAU patients and 22 patients with both AS and AAU. Twelve HLA-B27-positive healthy individuals were included as a control. TAP polymorphism was detected by PCR-RFLP methods. Significant differences in frequencies of TAP1 alleles were not found between patient groups. None of the TAP2 frequencies showed increased or decreased frequencies compared with HLA-B27-positive healthy controls. In comparison with a random Japanese control, TAP2D allele frequency was significantly increased in the AAU group, but failed to reach a significant level in a group consisting of the AAU-only patients and the patients with both AS and AAU. All of the patient groups were noted to have a significantly increased prevalence of the TAP2H allele as compared to random controls; however, the higher frequency of this allele was detected in HLA-B27 healthy controls as well. These observations suggest a linkage disequilibrium between TAP2D, TAP2H and HLA-B27 in Japanese.     

Improvement of chronic diarrhoea in patients with advanced HIV-1 infection during potent antiretroviral therapy

The functional projection of the medial perforant path (MPP) to different CA3 subfields was studied in urethan-anesthetized rats using current source density analysis. MPP stimulation resulted in an early-latency (presumed monosynaptic) sink with onset of 2-3 ms at the distal apical dendritic layer of CA3 (stratum lacunosum molecule) and a long-latency (presumed disynaptic, >7 ms) sink at stratum lucidum and radiatum of CA3. The population spike (onset 5. 3-6.1 ms), a sink at CA3 pyramidal cell layer, was observed 67% of the time (12 of 18 rats) in CA3a, 44% (8 of 18) in CA3b and 58% (7 of 12 rats) in CA3c following MPP stimulation. Population spike was not observed during presumed disynaptic excitation of CA3. Both early-latency sink (excitatory postsynaptic potential) and population spike in CA3 revealed robust paired-pulse facilitation (PPF). In contrast, little PPF was found for the MPP-evoked excitatory sink at the middle molecular layer of the dentate gyrus. The data suggested that the entorhinal cortex provides a strong monosynaptic excitation of different subfields of CA3. A direct entorhinal to CA3 input bypasses the dentate gyrus and may play a role in normal hippocampal signal processing and neural plasticity.     

Identification of a reservoir for HIV-1 in patients on highly active antiretroviral therapy

The hypothesis that quiescent CD4+ T lymphocytes carrying proviral DNA provide a reservoir for human immunodeficiency virus-type 1 (HIV-1) in patients on highly active antiretroviral therapy (HAART) was examined. In a study of 22 patients successfully treated with HAART for up to 30 months, replication-competent virus was routinely recovered from resting CD4+ T lymphocytes. The frequency of resting CD4+ T cells harboring latent HIV-1 was low, 0.2 to 16.4 per 10(6) cells, and, in cross-sectional analysis, did not decrease with increasing time on therapy. The recovered viruses generally did not show mutations associated with resistance to the relevant antiretroviral drugs. This reservoir of nonevolving latent virus in resting CD4+ T cells should be considered in deciding whether to terminate treatment in patients who respond to HAART.     

Discontinuation of prophylaxis for Pneumocystis carinii pneumonia in HIV-1-infected patients treated with highly active antiretroviral therapy

BACKGROUND: Prophylactic drugs for Pneumocystis carinii pneumonia (PCP) are strongly recommended for HIV-1-infected patients with CD4 cell counts of less than 200 cells/microL. Because of the highly active antiretroviral therapy (HAART) currently available, we speculated that prophylaxis can be discontinued in patients with CD4 cell counts of more than 200 cells/microL. METHODS: In this prospective observational study, PCP prophylaxis (primary or secondary) was discontinued in HIV-1-infected patients whose CD4 cell count had increased above 200 cells/microL (documented twice with an interval of at least 1 month) as a result of HAART. Patients and their CD4 cell counts were monitored every 3 months. The primary endpoint of the study was the occurrence or reoccurrence of PCP. FINDINGS: 78 patients were enrolled: 62 patients were receiving prophylaxis for primary prevention of PCP and 16 patients for secondary prevention of PCP. At the time of discontinuation of prophylaxis, the mean CD4 cell count was 347 cells/microL, and HIV-1-RNA was not detectable in 61 patients. The lowest mean CD4 cell count during prophylaxis was 79 cells/microL. Patients stopped prophylaxis 9.8 (SD 6.4) months after they started HAART. The mean follow-up after discontinuation of prophylaxis was 12.7 (SD 7.6) months, and none of the patients developed PCP (97.5% one-sided CI 0-4.4%). INTERPRETATION: The preliminary results of this study indicate that PCP prophylaxis can be stopped safely in HIV-1-infected patients whose CD4 cell counts have increased above 200 cells/microL after treatment with HAART.     

HLA antigens associated with susceptibility/resistance to HIV-1 infection

We studied the distribution of HLA-A, B, C, DR and DQ antigens in a cohort of HIV-1+ individuals and their heterosexual HIV seropositive (concordant) or seronegative (discordant) partners of Black non-Hispanic, Hispanic or Caucasian non-Hispanic ethnicity. The prevalence of DQ7 and Cw7 was significantly higher in the HIV-1+ compared to seronegative Black and Hispanic individuals, respectively. The frequency of DQ4 was significantly elevated in the Black seronegatives, whereas B53 was increased in the Hispanic seronegatives in comparison to the seropositives. No significant differences were observed between the Caucasian HIV infected and non-infected individuals. Analysis of the primary concordant HIV+ and discordant HIV+ individuals showed a marked increase in the prevalence of B44 in the Hispanic discordant seropositives, whereas the Caucasian primary concordants had a marked increase in the prevalence of A26. The prevalence of DQ7 and Cw7 was significantly increased in the Black and Hispanic secondary concordant seropositives, respectively in comparison to the seronegatives. The proportion of couples with matching HLA antigens was similar among the HIV-1+ concordant and discordant groups. These results provide additional evidence that HLA polymorphism may confer a genetic risk or protection for HIV-1 infection in individuals of various ethnic backgrounds.     

Oligonucleotide ligation assay for detecting mutations in the human immunodeficiency virus type 1 pol gene that are associated with resistance to zidovudine, didanosine, and lamivudine

Nonpregnant adults with group B streptococcus bacteremia were identified by active surveillance in three hospitals. Serum samples collected within 2 days of the time of blood culture were assayed for IgG antibodies to the capsular polysaccharide of the infecting strain: serotype Ia (3 isolates), III (5 isolates), or V (4 isolates). In 7 of 12 bacteremia episodes, the serum level of IgG to the infecting isolate was > or = 3.5 microg/mL, higher than the 1-2 microg/mL level thought to be protective in neonates. Among selected acute-phase sera, 4 of 5 that contained > or = 3.5 microg/mL specific IgG mediated efficient opsonophagocytic killing of the corresponding group B streptococcus isolate in vitro. High levels of specific antibodies during the acute phase of invasive group B streptococcus infection in nonpregnant adults may reflect a rapid antibody response to infection or, in some cases, may indicate that susceptibility is due to defects in other immune effectors.     

Expression of pro- and anti-apoptosis gene products in brains from paediatric patients with HIV-1 encephalitis

We have previously demonstrated the presence of DNA fragmentation in neurons, macrophages and microglia consistent with apoptosis, but not in reactive astrocytes in brain tissue from paediatric patients with HIV-1 encephalitis (HIVE). To further understand the underlying mechanism(s) for these findings as they relate to gene-directed neural cell death, we studied the in-situ expression of the Bcl-2 family of proteins, including the pro-apoptosis gene product Bax, the anti-apoptosis gene product Bcl-2, and Bcl-x. We demonstrate significantly elevated numbers of Bax-positive microglia and macrophages immunoreactive in basal ganglia and cerebral cortex of children who had HIVE, in comparison to HIV-1 infected children without encephalitis or children who were seronegative for HIV-1. In contrast, patients with HIVE, but not HIV-1 without encephalitis, or seronegative controls, had increased expression of Bcl-2 and Bcl-x in reactive astrocytes in cortex and basal ganglia. In vitro studies using Western blot analysis demonstrated an up-regulation in the levels of Bax, and phosphorylated (i.e. inactive) Bcl-2 in HIV-1 infected macrophages, and in LPS-activated macrophages, relative to levels in virus-negative unstimulated macrophages. These results suggest that productive HIV-1 infection, or cellular activation, renders macrophages more vulnerable to apoptosis. Taken together, these findings suggest that brain-resident macrophages and microglia in patients with HIV-1 encephalitis are more prone to undergo apoptosis and that astrocytes in contrast may be resistant to apoptosis. This may represent a mechanism to limit microglial activation and the spread of productive HIV-1 infection in the CNS of children with HIV-1 encephalitis.     

Treatment with protease inhibitors associated with peripheral insulin resistance and impaired oral glucose tolerance in HIV-1-infected patients

BACKGROUND: The use of protease inhibitors in the treatment of HIV-1 infection is associated with the new onset of diabetes mellitus, hyperlipidaemia and lipodystrophy. It is unclear whether these findings are coincidental or whether they reflect a causative effect of protease inhibitors. OBJECTIVE: To evaluate the effect of treatment with protease inhibitors on insulin sensitivity, oral glucose tolerance and serum lipids in HIV-infected patients in order to determine whether treatment with protease inhibitors can cause peripheral insulin resistance. DESIGN: Cross-sectional controlled study in HIV-infected patients treated with protease inhibitors to assess insulin sensitivity, oral glucose tolerance and changes in serum lipids. METHODS: Sixty-seven patients treated with protease inhibitors, 13 therapy-naive patients and 18 HIV-negative control subjects were tested for insulin sensitivity (intravenous insulin tolerance test). In a subgroup of 24 treated patients, oral glucose tolerance was determined. Serum lipids prior to and under treatment with protease inhibitors were compared. RESULTS: Patients on protease inhibitors had a significantly decreased insulin sensitivity when compared with therapy-naive patients (median, 75 and 156 micromol/l/min, respectively; P < 0.001). All treated patients with impaired (n=4) or diabetic (n=9) oral glucose tolerance, and four out of 11 patients with normal glucose tolerance showed peripheral insulin resistance; all therapy-naive patients had normal insulin sensitivity. Treatment with protease inhibitors led to a significant increase in total triglycerides and cholesterol in the 67 treated patients (median increase, 113 and 37 mg/ml, respectively). CONCLUSION: Treatment with protease inhibitors is associated with peripheral insulin resistance, leading to impaired or diabetic oral glucose tolerance in some of the patients, and with hyperlipidaemia. Overall, there is a large variation in the severity and clinical presentation of protease inhibitor-associated metabolic side-effects.     

Persistently biased T-cell receptor repertoires in HIV-1-infected combination antiretroviral therapy-treated patients despite sustained suppression of viral replication

In most HIV-1-infected patients, highly active antiretroviral therapy (HAART) reduces plasma viral load to <50 copies/mL and increases CD4+ T-cell number and function. However, it is still unclear whether alterations of T-cell receptor (TCR) beta-chain variable region (BV) repertoire, tightly related to disease progression, can be fully recovered by long-term treatment with HAART. This study analyzed the evolution of both T-cell subset composition and TCRBV perturbations in chronically HIV-1-infected patients with moderate immunodeficiency during 36 months of HAART. Despite persistently suppressed HIV replication, the rate of CD4+ T-cell repopulation, after an initial burst, progressively declined throughout the study period, resulting in a mean CD4+ T-cell count at the end of follow-up that was still significantly lower in HIV patients than in HIV-seronegative controls. This was seen in association with an incomplete restitution of both CD4 and CD8 TCRBV repertoire disruptions and was also demonstrated by the appearance of new TCRBV oligoclonal expansions occurring during HAART. In conclusion, these data indicate that 3 years of fully suppressive HAART may be not adequate to normalize CD4 counts and TCRBV repertoires in patients starting HAART with moderately advanced disease.     

Serum concentrations of nitrite in patients with HIV-1 infection

AIMS: To measure circulating concentrations of nitrite in patients with HIV-1 infection. METHODS: Nitrite concentrations were measured using the Griess reaction adapted to microtitre plates in the serum of 10 asymptomatic HIV-1 positive patients, 33 patients with AIDS with cerebral disorders, 17 patients with AIDS with pulmonary involvement, and in eight patients with AIDS with other disorders. Nitrite concentrations were also measured in bronchoalveolar lavage (BAL) fluid and cerebrospinal fluid (CSF) of patients with AIDS with pulmonary involvement and cerebral disorders, respectively. RESULTS: Increased serum concentrations of nitrite were observed in patients with pulmonary involvement, and in particular in serum and in BAL samples of patients with interstitial pneumonia (36.2 (26.2) mumol/l and 0.3 (0.4) mumol/l, respectively). Increased serum concentrations of nitrite were also noted in patients with retinitis caused by infection with cytomegalovirus. Serum nitrite concentrations were also raised in patients with cerebral toxoplasmosis, whereas normal serum concentrations were found in patients with HIV-1 encephalopathy and cryptococcal meningitis. Nitrite concentrations in CSF were not raised in patients with cerebral disorders. CONCLUSIONS: These results suggest that production of nitrite in patients with AIDS with concomitant opportunistic infections may be part of the host defense against opportunistic organisms.