Impact of highly active antiretroviral therapy on the maturation of anti-HIV-1 antibodies during primary HIV-1 infection.

OBJECTIVES: To study the impact of highly active antiretroviral therapy (HAART) on isotype switching and avidity maturation of HIV-1-specific immunoglobulin G (IgG) in patients with primary HIV-1 infection (PHI). METHODS: We studied the emergence and the evolution of anti-HIV IgG antibodies by quantitative immunoblotting to analyse IgG subclasses and IgG avidity. Serum samples were obtained from 16 PHI patients from the French PRIMO Cohort Study at various points in the first year of infection: eight patients received no treatment (group I), and eight patients received efficient HAART (group II) during the study period. RESULTS: Early initiation of HAART in PHI patients partially prevented an increase in anti-HIV-1 IgG levels. Within IgG subclasses, the amount of anti-HIV-1 IgG1 gradually increased with time in both groups, although levels remained lower in treated patients. The anti-p24 IgG2 level was always lower in group II. We observed a decrease in anti-p24 IgG3 over time in both groups. Treatment did not affect the maturation of HIV-1 IgG avidity, which increased in both groups until month 3 and then remained high until the end of the 12-month follow-up period. CONCLUSIONS: HAART in PHI partially prevents the emergence of HIV-1 IgG antibodies, but does not affect the quality of these antibodies, as reflected in their isotype and avidity.

A serological testing algorithm for the diagnosis of primary CMV infection in pregnant women.

OBJECTIVES: Serological diagnosis of CMV primary infection is usually based on the detection of specific IgM antibody. However, as the presence of IgM antibody is not always correlated with primary infection, measurement of IgG avidity must be performed. The aim of our study was to evaluate the best procedure for serological diagnosis of CMV primary infection. In other words, is it better to first search for IgM antibody, and, if positive, then measure IgG avidity, or first measure IgG avidity without the detection of IgM antibody? MATERIALS: CMV-IgM detection and CMV-IgG avidity measurement were performed on 310 IgG positive sera from pregnant women. RESULTS: CMV-IgM antibody was detected positive for 9 of 310 sera. Using CMV-IgG avidity index (AI), dating of infection was difficult in 81/310 cases (26%), while it failed in only 3/310 cases using CMV-IgM plus CMV-IgG AI. CONCLUSION: The diagnosis of primary CMV infection can be based on the detection of CMV-IgM antibody first and then on the measurement of CMV-IgG AI.

Preferential and persistent depletion of CCR5+ T-helper lymphocytes with nonlymphoid homing potential despite early treatment of primary HIV infection.

Strains of human immunodeficiency virus (HIV) transmitted between individuals use the CCR5 coreceptor, but no preferential depletion of particular Th-lymphocyte subpopulations has been reported during primary HIV infection (PHI). In contrast, gut-associated Th lymphocytes are preferentially depleted in macaques recently infected by simian immunodeficiency virus. The expression of CCR5 and the intestinal homing receptor integrin alpha4beta7 on subpopulations of Th lymphocytes was studied in 12 patients with PHI. There was a profound decrease of circulating alpha4beta7+ Th lymphocytes and CCR5+ memory Th lymphocytes with nonlymphoid homing potential (CD62L-CD45RO+). Unlike other Th lymphocytes, this cell population remained depleted despite early control of viral replication under antiretroviral treatment. Therefore, HIV preferentially targets a specific CCR5+ subpopulation of Th lymphocytes early during infection, inducing its persistent depletion despite treatment. Protective immunity in vivo depends on Th lymphocytes carrying homing capacity to nonlymphoid tissue, and therefore these data may explain the persistent abnormalities of immune functions in patients infected with HIV.

Early control of HIV replication in primary HIV-1 infection treated with antiretroviral drugs and pegylated IFN alpha: results from the Primoferon A (ANRS 086) Study.

IFN alpha has both antiviral and immunostimulating properties. The ANRS086 Primoferon A Study evaluated in 12 patients with primary HIV infection the tolerance and efficacy of an early and transient administration of pegylated IFN alpha, in addition to highly active antiretroviral therapy. Tolerance was good, and this regimen allowed the early control of HIV replication and rapid decay of the viral reservoir. These results support the initiation of comparative studies with pegylated INF alpha in primary HIV infection.

[Incidence and evaluation of viral retinitis in patients infected with the HIV virus and treated with HIV protease inhibitors]. / Etude de l'incidence et de l'évolution des rétinites virales chez les patients infectés par le VIH et traités par les inhibiteurs de protéase du VIH.

BACKGROUND: Since the beginning of the use of HIV-Protease Inhibitors (PI) to treat HIV-infected patients, a decrease of the incidence of extraocular opportunistic infections has been observed. We studied the incidence of CMV-retinitis in patients treated with a highly active antitetroviral therapy (HAART) containing PI over a mean follow-up of 12 months. METHODS: Ninety-three HIV-infected patients treated with HAART containing PI were included. The mean initial CD4+ cell-count was 54/microliter (median: 22/microliter), and the mean plasma HIV-load was 5.46 log 10 RNA-copies/ml. Fundus examination was performed each month in case of a previously treated and controlled CMV-retinitis or if initial CD4 cells were below 50/microliter. In other patients, fundus examination was performed every 3 months. The mean follow-up was 362 days. RESULTS: Among the 7 patients with a previously treated and controlled CMV-retinitis, one experienced a progression during the study (after 163 days of PI). Among the 59 patients with CD4 cells below 50/microliter and without previous CMV-retinitis before the beginning of PI, 5 experienced a CMV-retinitis (mean delay after the onset of HAART: 141 days), including 2 with relapse. When retinitis occurred, CD4 cells were below 32/microliter except in one case (147/microliter). CONCLUSIONS: Compared to previously published reports, this study showed an increase of the time to progression of previously treated and controlled CMV-retinitis in patients treated with PI. Considering deeply immunocompromised patients (less than 50 CD4-cells/microliter), the risk of suffering from CMV-retinitis was 8.5% after 12 months of PI treatment. Longer follow-up remains necessary to confirm these results.

Fatal intravascular autoimmune hemolytic anemia after fludarabine treatment for chronic lymphocytic leukemia.

We report the case of a patient with chronic lymphocytic leukemia (CLL) who developed fatal intravascular autoimmune hemolytic anemia (AIHA) after fludarabine treatment. He had previously received several treatments including two courses of fludarabine. The direct antiglobulin test (DAT) was negative at diagnosis but was found to be positive with anti-IgG after the first fludarabine treatment. When the patient was treated again with fludarabine nine months later, the DAT became positive with anti-IgG and anti-C3d antiglobulins after the second course of treatment. Abrupt, fatal intravascular hemolysis occurred after the third course. The occurrence of severe AIHA in CLL patients treated with fludarabine has been reported by several authors. Physicians should be aware of the risk of severe AIHA in CLL patients with a history of AIHA or positivation of the DAT during previous fludarabine administration, or in case of secondary fixation of complement to the red cell membrane occurring during fludarabine treatment.

Interleukin-13 inhibits interleukin-2-induced proliferation and protects chronic lymphocytic leukemia B cells from in vitro apoptosis.

Human interleukin-13 (IL-13) acts at different stages of the normal B-cell maturation pathway with a spectrum of biologic activities overlapping those of IL-4. B chronic lymphocytic leukemia (B-CLL) is characterized by the accumulation of slow-dividing and long-lived monoclonal B cells, arrested at the intermediate stage of their differentiation. In vitro, B-CLL cells exhibit a spontaneous apoptosis regulated by different cytokines. In this report, we show that IL-13 (10 to 200 ng/mL) acts directly on monoclonal B-CLL cells from 12 patients. (1) IL-13 enhances CD23 expression and induces soluble CD23 secretion by B-CLL cells but does not exhibit a growth factor activity. (2) IL-13 inhibits IL-2 responsiveness of B-CLL cells, activated either with IL-2 alone or through crosslinking of lgs or ligation of CD40 antigen. (3) IL-13 protects B-CLL cells from in vitro spontaneous apoptosis. The effects of IL-13 on neoplasic B cells were slightly less than those of IL-4 and occurred independently of the presence of IL-4. The present observations show that IL-13 may exhibit a negative regulatory effect on neoplasic B cells in contrast with that observed in normal B cells, and suggest that IL-13 could be an important factor in the pathogenesis of CLL by preventing the death of monoclonal B cells. Moreover, B-CLL may be an interesting model to study the regulation of the expression of IL-13 receptor and/or signal transduction pathways.

Staphylococcal superantigens activate HIV-1 replication in naturally infected monocytes.

OBJECTIVES: To study the effects of microbial superantigens, Staphylococcal exotoxins (SE), on HIV replication in monocytes following binding to and signalling through major histocompatibility complex (MHC) class II molecules. METHODS: We investigated the effects of SE on HIV replication and monokine production in three different in vitro models of monocyte culture: chronically infected monocytic cell line U1, acute infection of normal monocytes by different HIV-1 strains, and naturally-infected monocytes from seropositive patients. p24 antigen, interleukin (IL)-6 and tumour necrosis factor (TNF)-alpha production was measured by specific enzyme-linked immunosorbent assay (ELISA). RESULTS: Staphylococcal enterotoxin B and toxic shock syndrome toxin-1 (1-1000 ng/ml) are powerful inducers of HIV-1 expression in U1 cells pretreated with granulocyte macrophage colony stimulating factor. SE induce viral replication in short-term cultures (days 6-21) of monocytes infected in vitro by HIVBa-L, HIVLAI, or naturally infected in vivo. Induction of HIV expression requires direct interactions of SE with MHC class II molecules but not T-cell receptor binding and T-cell-monocyte contact. Anti-TNF-alpha and anti-IL-6 neutralizing monoclonal antibodies inhibit by over 61% SE-induced HIV replication. CONCLUSIONS: Using SE we have linked two important pathways for the regulation of HIV replication in monocytes, namely signalling through MHC class II molecules and monokine production potentially mediated by induction of the pleiotropic cellular transcription factor NF-kappa B. In HIV-infected patients bacterial infections are common and could be an important cofactor in the immunopathogenesis of AIDS by inducing HIV replication in latently infected monocytes. Their prevention might emerge as beneficial in these patients.

Production of interleukin 1 and tumour necrosis factor activities in bronchoalveolar washings following infection of mice by influenza virus.

Mice were infected with influenza A virus by aerosol. Bronchoalveolar washings obtained from infected mice contained interleukin 1 (IL-1) and tumour necrosis factor (TNF) activities. IL-1 was present at day 4 post-infection but not at day 7. TNF activity was present at day 4 and day 7 post-infection. The presence of both these monokines was coincident with increased cell populations in the lungs. In vitro studies demonstrated that macrophages from non-infected mice produce IL-1 and TNF activities in response to live influenza A virus stimulation. These results suggest that a direct interaction between virus and alveolar macrophages leads to IL-1 and TNF production during the course of infection and could account for both the immune responses and the pathology that occur during influenza A virus infection.

Enhancement of bronchoalveolar cell recovery and stimulation of alveolar macrophage chemiluminescence and resistance to influenza virus after treatment with RU 41821 aerosol.

Aerosol treatment with RU 41821, a glycoprotein extract from Klebsiella pneumoniae, was tested in mice for its effect on the kinetics of the induction of bronchoalveolar cells (i.e., alveolar macrophages, monocytes, lymphocytes, and polymorphonuclear leukocytes). RU 41821 led to an increase in the total number of bronchoalveolar cells. The largest increase was observed for polymorphonuclear leukocytes, and more moderate increases occurred in the numbers of alveolar macrophages, monocytes, and lymphocytes. The alveolar macrophages recruited in response to RU 41821 were activated, as indicated by luminol-dependent chemiluminescence in response to stimulation by opsonized zymosan. The effects of five RU 41821 aerosol treatments and those of a single treatment were further examined in vivo by aerosol infection of mice inoculated with a mouse-pathogenic influenza virus. The maximum protective effect was obtained after five once-a-day treatments and was correlated with the largest increase in the total number of bronchoalveolar cells.

Effects of RU 41740 aerosol treatment on mouse bronchoalveolar cells, and protection afforded against influenza virus infection.

RU 41740, an immunomodulating compound extracted from Klebsiella pneumoniae, was previously shown to enhance mice resistance to bacterial and viral lung infections. To explore lung defense mechanisms, we studied the influence of RU 41740 aerosol treatment on the bronchoalveolar cell populations. Five successive daily RU 41740 aerosol treatments induced a large accumulation of leukocytes in the lungs 4h after the last treatment. Polymorphonuclear leukocytes predominated. The numbers of lymphocytes and monocytes rose significantly. A single RU 41740 aerosol treatment significantly raised the number of polymorphonuclears only. A luminol-dependent chemiluminescence assay was used to test the effect of RU 41740 on the opsonized zymosan induced response of alveolar macrophages. In vitro, addition of RU 41740 enhanced this chemiluminescence. After a single RU 41740 aerosol treatment of mice, the chemiluminescence of purified alveolar macrophages from these mice increased significantly. The protective effect of five daily RU 41740 aerosol treatments against influenza virus infection was believed to be due to the great intensity of the cellular response and the polymorphonuclear influx. The alveolar macrophage activation observed might also explain the enhanced resistance of mice to influenza virus infection.

Enhanced resistance of mice against influenza virus infection after local administration of glycoprotein extracts from Klebsiella pneumoniae.

RU. 41 740, a glycoprotein extract from Klebsiella pneumoniae O1K2 strain was tested for its ability to enhance resistance of mice against influenza virus infection. Local (aerosol) and systemic (IP) routes of RU. 41 740 administration were compared for their effectiveness in protecting mice. When RU. 41 740 was administered prophylactically (10 mg/kg) via aerosol route (5 consecutive days before challenge), significant protection (P less than 0.0001) was conferred against lethal aerosol inoculation of influenza virus. Treated mice exhibited a reduced mortality, a decreased lung-to-body weight ratio and lower intrapulmonary virus titers. The main glycoprotein soluble fraction (RU. 41 821) was as active as the total glycoprotein extract (P less than 0.0001). Whereas the local (aerosol) route of administration was effective, the systemic (intraperitoneal) route of administration did not confer significant protection against an aerosol inoculum of virus. This finding suggests the important role of local immunity. The levels of interferon in the lavage fluids of immunized and infected mice suggest that interferon is not the main protective mechanism. The enhanced protection observed could be related to an augmented humoral or cell-mediated response within the lung.