Human immunodeficiency virus gp120 inhibits interleukin-12 secretion by human monocytes: an indirect interleukin-10-mediated effect

Interleukin-12 (IL-12), a cytokine with in vitro and in vivo immunomodulatory effects, is produced mostly by activated monocytes and macrophages. To study the effect of human immunodeficiency virus (HIV) infection on IL-12 production, we investigated the expression of IL-12 at mRNA and protein levels by human monocytes preincubated with HIV-gp120. In these conditions, we show that monocytes have a decreased ability to express IL-12 mRNA subunits and to produce IL-12 p40 and bioactive p70 proteins in response to Staphylococcus aureus strain cowan I (SAC). We showed that in human monocyte cultures, HIV-gp120 induces a significant IL-10 synthesis, which in turn inhibits IL-12 subunits mRNA accumulation and protein secretion after SAC-activation. Similar data were obtained with human macrophages. These results suggest that, during HIV infection, gp120 induces in uninfected monocytes and macrophages IL-10/IL-12 disregulation, which can alter immune response.

Maternal virus load during pregnancy and mother-to-child transmission of human immunodeficiency virus type 1: the French perinatal cohort studies. SEROGEST Cohort Group

Virus load in pregnancy and its relation to mother-to-child human immunodeficiency virus (HIV) transmission were studied prospectively. From 1989 to 1994, 320 HIV-infected women from 18 centers had plasma samples stored. Among women not receiving antiretroviral therapy, the polymerase chain reaction RNA level was 3.6 log at delivery, and 15% of women had levels below the detection limit. There was no variation during pregnancy. Women born in sub-Saharan Africa had lower RNA levels, although their CD4 cell distribution did not differ from that in other women. Among 236 evaluable children, 19% +/- 5% were infected. Transmission occurred in 12% of cases (confidence interval, 5%-22%) with <1000 copies/mL versus 29% +/- 10% of those with >10,000 copies/mL (P < .02). Maternal virus load appears strongly related to HIV transmission to the child.

The course of the SAPHO syndrome during pregnancy

In this report, we describe a case of a pregnancy in a 29 year old patient suffering from a new syndrome, the SAPHO syndrome (synovitis, acne, pustulosis, hyperostosis, osteitis). The SAPHO syndrome improved considerably during the course of this pregnancy and treatment with indomethacin ceased during gestation.

Obstetric factors and mother-to-child transmission of human immunodeficiency virus type 1: the French perinatal cohorts. SEROGEST French Pediatric HIV Infection Study Group

OBJECTIVE

We attempted to determine whether the risk of mother-to-child transmission of human immunodeficiency virus type 1 is related to events in pregnancy, labor, and delivery.

STUDY DESIGN

In a prospective multicenter cohort study of human immunodeficiency virus type 1-infected mothers and their children, we studied pregnancy histories, labor (including gestational age, induction, membrane rupture, length of labor, intrapartum procedures, bleeding, infection, antiseptic technique, and antiretroviral therapy), and conditions of delivery.

RESULTS

Among 1632 singleton infants, 310 were confirmed infected with human immunodeficiency virus type 1 at age 18 months (19.0% +/- 1.9%). Procedures (in particular, amniocentesis and amnioscopy) and sexually transmitted diseases during pregnancy, preterm delivery, premature membrane rupture, hemorrhage in labor, and bloody amniotic fluid were associated with increased transmission. Transmission was not related to mode of delivery or to the conditions of labor and delivery.

CONCLUSIONS

Transmission was not decreased after emergency or elective cesarean section. Most risk factors either were rare or appeared poorly amenable to obstetric management, with the exception of invasive procedures, which should be avoided.

Interleukin-13 and interleukin-4 act as interleukin-6 inducers in human microglial cells

The effect of interleukin 4 (IL-4) and IL-13 on IL-6 and IL-1 beta production by human embryonic microglial cells and human peripheral blood monocyte cells (PBMC) was compared. IL-4 or IL-13 increase intra-cellular IL-6 mRNA and IL-6 titres in supernatants of microglial cells whereas they decreased IL-6 production by PBMC tested in the same conditions. IL-4 and IL-13 increased also IL-1 beta production by human microglial cells. Stimulations associating IL-4 or IL-13 and IL-1 beta had an additive effect on IL-6 production by microglial cells, whereas, in the same conditions, an inhibitory effect was observed in PBMC. In contrast, dexamethasone downregulated IL-6 production by microglial cells and PBMC. Finally, IL-1 receptor (IL-1r) type 1 and IL-1r type 2 were detected on human microglial cells but it was demonstrated that IL-13 and IL-4 acted as IL-6 inducers in human microglial cells independently of the IL-1/IL-1r pathway.

Triggering of CD23b antigen by anti-CD23 monoclonal antibodies induces interleukin-10 production by human macrophages

The aim of this study was to evaluate the capacity of human macrophages to produce interleukin (IL)-10 upon stimulation of membrane CD23. An anti-CD23 monoclonal antibody (mAb) was found to elicit the expression of the specific mRNA for IL-10 in CD23-bearing macrophages, and to induce a time-dependent production of this cytokine with a maximal effect reached after 12 h. Inasmuch as we previously reported that CD23 ligation evoked the generation of nitric oxide and of cAMP, the effect of the Rp diastereoisomer of adenosine 3', 5'-cyclic phosphorothioate (Rp-cAMP, an inhibitor of the cAMP pathway) and of NG-monomethyl-L-arginine (L-NMMA, an inhibitor of the nitric oxide pathway) were evaluated on CD23-induced IL-10 production. In the presence of Rp-cAMP, the CD23-induced production of IL-10 and of the pro-inflammatory cytokine tumor necrosis factor-alpha (TNF-alpha) was totally abrogated, whereas, in the presence of L-NMMA, IL-10 production was enhanced and TNF-alpha production was suppressed. In addition, neutralization of IL-10 with an anti-IL-10 mAb increased both the magnitude and duration of CD23-driven TNF-alpha production. Such an inducing effect was observed with different anti-CD23 mAb (clone 135, MHM6 and 25), indicating that the triggering of the CD23 molecule at the surface of human macrophages induced the generation of IL-10 through a cAMP-dependent mechanism. Concomitantly this generation of IL-10 was down-regulated by nitric oxide, which was also produced after triggering of the CD23 antigen. Taken together these data indicated that human macrophages produced IL-10 after triggering of the CD23 molecule and that this production could regulate the inflammatory state of these cells.

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.

Lack of evidence of HTLV-I/II infection in T CD8 malignant or reactive lymphoproliferative disorders in France: a serological and/or molecular study of 169 cases

Human T lymphotropic virus type II (HTLV-II), originally isolated in 1982 from a patient with a "T hairy cell leukemia", has not yet been proven to be the causative agent of any specific hematological disease. In order to screen for such an event, and because HTLV-II has a preferential tropism for OKT8 (CD8) T cells (both in vivo and in vitro), we searched for the presence of HTLV-II in lymphoproliferative diseases (LP) of CD8+ T cells. We report a serological and/or molecular study of 169 patients with a T CD8 LP, including 76 patients with malignant or reactive T CD8 LP (34 lymphomas, 27 large granular leukemias, three prolymphocytic leukemias, one hairy cell leukemia, 11 reactive T CD8 LP) and 93 HIV-1+ patients with a T CD8 peripheral lymphocytosis ( > 1500/mm3) from a prospective HIV cohort involving 1264 individuals. In the first series, the 40 sera available were all HTLV-I/II negative, except a 67-year-old French Guyanan man, with a cutaneous large T CD8 cell lymphoma, HTLV-I+. Furthermore, the molecular analysis of the 69 available DNA samples by PCR failed to detect any proviral HTLV-I/II sequences, except for the HTLV-I+ patient. The serological study of the 93 HIV-1+ individuals with CD8 lymphocytosis, showed that three patients were HTLV-I+, but none was HTLV-II+. Thus, in contrast to HTLV-I, whose etiological role in adult T cell leukemia is now well established, there is neither epidemiological nor molecular evidence that prototypic HTLV-II may be etiologically associated specifically with any of the CD8+ T cell LP investigated in this report.

[Prescription of antiretroviral and prophylactic drugs in HIV diseases: reality of medical practices]

Antiretroviral and prophylactic therapy given to HIV-infected patients attending hospital (DMI 2 data base) was analyzed according to TCD4+ cell count; 19,020 patients were included in the study. Under 200 TCD4+/mm3, more than 80% of the patients received antiviral therapy, most often AZT (45.3%) or ddI (27.2%). Combined treatment was quite low, less than 8%. Although above 500 TCD4+/mm3, 11.6% of patients received AZT, this study showed that antiretroviral therapy followed French recommendations. This was not the case for prophylaxis: a large proportion of patients under 200 TCD4+/mm3 did not received pentamidine aerosol, or cotrimoxazole, or dapsone.

Pharmacokinetics of interferon-alpha in pregnant women and fetoplacental passage

Interferon (IFN) therapy is currently not approved for use during pregnancy. Two HIV-seropositive pregnant women, who were due to undergo abortion in the second trimester of pregnancy, were given a single intramuscular dose of IFN-alpha, with their informed consent. Blood samples were taken simultaneously from the mothers and fetuses, together with amniotic fluid. IFN was undetectable in the fetal blood and amniotic fluid in both cases. Pharmacokinetic parameters were similar to those in nonpregnant women. We conclude that maternal IFN-alpha during pregnancy should be safe for the fetus. The indications for IFN therapy in pregnancy could therefore be the same as those in the non-pregnant state.

Rapid and constant detection of HIV antibody response in saliva of HIV-infected patients; selective distribution of anti-HIV activity in the IgG isotype

Anti-HIV antibodies can be specifically detected with a sensitivity and a specificity of 100% in the saliva of all HIV-infected patients. A saliva collection device facilitates the sampling procedure, and if a rapid test is used, the diagnosis of infection can be established in as little as 10 min. The analysis of a group of CDC stage IV AIDS patients showed a decrease in lactoferrin (produced by the oral mucosa) in comparison with HIV-negative controls, associated with an increase in albumin (filtering from plasma), indicating an alteration of the mucosal barrier. The salivary anti-HIV-gp160 activity was largely carried by the IgG isotype whereas the salivary antibacterial activity (anti-Streptococcus sobrinus; anti-LPS from Escherichia coli) remained located in the IgA isotype as usually observed with all infectious agents. Salivary IgG carried a specific anti-gp160 activity 25-fold higher than that of serum IgG. Thus, significant local synthesis of specific IgG by oral mucosa was revealed as a characteristic of HIV infection.

Interferon-alpha-mediated prevention of in vitro apoptosis of chronic lymphocytic leukemia B cells: role of bcl-2 and c-myc

Chronic B lymphocytic leukemia cells (B-CLL), characterized by the accumulation in vivo of long-life span B cells, exhibit spontaneous programmed cell death or apoptosis when cultured in vitro. We show that interferon-alpha (IFN-alpha), although able to decrease in vivo the number of leukemic cells, protects chronic B lymphocytic leukemia cells from in vitro programmed cell death or apoptosis. This inhibition of spontaneous in vitro apoptosis of leukemic B cells was observed after 24-48 hr of culture with 100-1000 U of either Interferon-alpha 2a or 2b. The protective activity was observed in the majority of the patients tested (6 out of 8) independent of the amount of apoptosis observed. Furthermore, in contrast to IL-4, IFN-alpha did not up-regulate the expression of Bcl-2. This suggests that B-CLL cells can be prevented from undergoing apoptosis in vitro by at least two different mechanisms: one, triggered for instance by IL-4, is associated with Bcl-2 production and the second triggered by Interferon-alpha is Bcl-2 independent. To elucidate the pathways mobilized by Interferon-alpha we also studied the regulation of c-myc expression in our experimental system. We found that (i) induction of in vitro B-CLL apoptosis was not associated with up-regulation of c-myc, (ii) c-myc expression as assessed by mRNA and protein determinations was increased after in vitro or in vivo Interferon-alpha stimulation. Additional experiments using c-myc specific oligonucleotides demonstrated that when Interferon-alpha-mediated c-myc expression was decreased by 60%, the in vitro protective effect of Interferon-alpha was not modified. Thus our data show that in contrast to the situation in vivo, Interferon-alpha prevents spontaneous in vitro B-CLL cells apoptosis through a Bcl-2-independent pathway which is probably not related to c-myc up-regulation.

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.

Thrombocytopenia in pregnant women infected with human immunodeficiency virus: maternal and neonatal outcome

OBJECTIVES

Our purpose was to evaluate the prevalence of thrombocytopenia related to human immunodeficiency virus among seropositive pregnant women and its impact on maternal and neonatal outcome.

STUDY DESIGN

A retrospective survey of all deliveries of women infected with human immunodeficiency virus in 14 maternity units in France over a 6-year period collected data on mothers who had thrombocytopenia < 100.10(9)/ and their infants.

RESULTS

Among 890 women, 29 were thrombocytopenic (3.2%, 95% confidence interval 2.1% to 4.3%). Thrombocytopenia appeared directly related to human immunodeficiency virus infection in 25 of these women. During pregnancy 16 patients were treated for thrombocytopenia with zidovudine, corticosteroids, or high-dose intravenous gamma globulin. Zidovudine was effective in five of seven cases, and intravenous gamma globulin was effective in five of 11 cases. Cesarean sections were performed in 13 of 29 women. Abnormal intrapartum or postpartum bleeding was recorded in five cases. Among 28 infants for whom neonatal platelet counts were available, only one had thrombocytopenia < 100.10(9)/L at birth; he went on to have early-onset acquired immunodeficiency syndrome.

CONCLUSIONS

The incidence of fetal or neonatal thrombocytopenia appears low and may not justify invasive sampling or routine cesarean delivery. Therapy with zidovudine or intravenous gamma globulin should be considered for women with severe thrombocytopenia, because of the risk of maternal hemorrhage.

Effect of age and exposure group on the onset of AIDS in heterosexual and homosexual HIV-infected patients. SEROCO Study Group

OBJECTIVE

To analyse the influence of age at seroconversion and sexual exposure group on the progression of HIV disease.

DESIGN

This multicentre prospective cohort study involved 443 subjects whose date of HIV infection was known to within +/- 1 year. Individuals whose sexual behaviour was exclusively heterosexual after HIV infection constituted the heterosexual group (n = 131). AIDS-free survival was compared with that of men (n = 312) infected through homosexual sex and who continued homosexual activity after HIV infection. They constituted the homosexual group.

METHODS

The end-point was the onset of an AIDS-defining illness listed in the 1987 revised Centers for Disease Control and Prevention (CDC) criteria. Using the Kaplan-Meier method, AIDS-free survival curves were plotted for three age categories (< 20, 20-39, > or = 40 years). A Cox model was used to quantify the effect of age and to assess the influence of exposure group on AIDS onset after adjustment for age. Because of the high incidence of Kaposi's sarcoma (KS) among homosexual men, a disease that can be an early AIDS-defining illness, multivariate analysis was performed with and without consideration of the occurrence of KS.

RESULTS

Patients aged > or = 40 years at seroconversion progressed more rapidly to AIDS than younger patients (P < 0.006). When age was fitted as a continuous variable and adjusted for exposure group, the relative risk of developing AIDS by any time after seroconversion was 1.34 for a 10-year increase difference [P = 0.03; 95% confidence interval (CI), 1.03-1.77]. After adjustment for age, the relative risk of developing AIDS (CDC criteria) was 2.42 (P = 0.008; 95% CI, 1.18-4.97) among the homosexual men (AIDS cases, n = 56). All cases of KS (n = 19) involved the homosexual group. Excluding KS as a first manifestation of AIDS, homosexual or bisexual subjects had a risk of AIDS of 1.92 (P = 0.07; 95% CI, 0.92-4.03) compared with heterosexual subjects.

CONCLUSIONS

The risk of AIDS increases with age at seroconversion. The more rapid progression towards AIDS in the homosexual group than in the heterosexual group persisted after adjustment for age. Further studies are required to determine the possible role of repeated exposure to HIV or other pathogens acquired sexually.

[Anonymous and free-of-charge centers for screening for HIV infection. Results of 30 months of activity in Public Assistance in Paris hospitals]

The results of 30 months of activity of anonymous and free-of-charge HIV detection centres in Paris hospitals are presented. During this period (April 1988 to December 1990), 15805 subjects were seen. This population accounts for about 11 percent of all French anonymous and free detection centres in 1990, and for 26 percent of the number of subjects consulting in detection centres of the same type. Risk factors could be listed in 8132 consulting subjects: 73 percent were heterosexuals and not drug-addicts; 19.5 percent were homo- or bisexuals; 6 percent were drug-addicts; 0.6 percent were both homosexuals and drug-addicts; 29 percent of the 7806 persons questioned about their use of condoms stated that they used them often or always. A total of 15271 blood samples were taken. The percentage of seropositivity was 4.73 percent with a significant fall from 5.87 percent in 1988 to 4.38 percent in 1990; 23.4 percent of homosexual drug-addicts, 17.6 percent of heterosexual drug-addicts, 9.3 percent of homo- or bisexuals and 1.3 percent of heterosexuals were seropositive. In the seropositive population, 46.4 percent were homo- or bisexuals, 29.8 percent were drug-addicts, 19.7 percent were heterosexuals and 3.7 percent were homosexual drug-addicts. Three subjects had been contaminated by blood transfusion. The percentage of seropositive subjects in our study was superior to the mean found in other anonymous and free detection centres (4.73 percent versus 3 percent in 1990), this probably reflecting the high prevalence of the infection in the Paris region. The seropositive subjects usually belonged to the categories primarily affected by the HIV. The percentage of seropositivity in our drug-addicts (17.6 percent) was much lower than that usually reported in French drug-addicts (30 to 40 percent).

Splenectomy is safe and effective in human immunodeficiency virus-related immune thrombocytopenia

Sixty-eight patients, followed in a prospective cohort study of 185 human immunodeficiency virus (HIV)-infected patients with severe immune thrombocytopenia (platelets < 50 x 10(9)/L), underwent splenectomy, 2 to 41 months (median: 10 months) after immune thrombocytopenic purpura (ITP) was diagnosed. The mean platelet count increased from 18 x 10(9)/L to 223 x 10(9)/L with a persistent increase in 56 (82%). It also led to a significant increase of the mean CD4 cell count from 475 x 10(6)/L to 725 x 10(6)/L within a mean delay of 10 months. In the whole cohort, with a mean follow-up of 63 months (range, 6 to 126), the 5-year estimated rate for progression to acquired immunodeficiency syndrome (AIDS) was 23% (95% confidence interval [CI], 15% to 31%) and the AIDS-free survival was 69% (95% CI, 61% to 77%). To investigate the potential impact of splenectomy, a Cox's multiple regression model was used; as splenectomy was not randomly assigned, it was incorporated as a time-dependent covariate. After adjustment on the CD4 cell count, no statistically significant differences were observed between the splenectomized and the nonsplenectomized patients: AIDS progression rate (P = 0.23), survival (P = 0.64) and AIDS-free survival (P = 0.72) were not influenced by splenectomy. Splenectomy is both effective and safe in the treatment of severe, refractory ITP associated with HIV infection.