Augmented type 1 cytokines and human endogenous retroviruses specific immune responses in patients with acute multiple sclerosis

In vitro antigen- and mitogen-stimulated cytokine production were analysed in multiple sclerosis (MS) patients with either acute (AMS) or stable (SMS) disease and in healthy controls (HC). We also investigated whether immune responses to human endogenous retroviruses (HERV) could be detected in MS and whether these immune responses would be correlated with disease status by analysing cytokine production after stimulation of PBMC with HERV peptides. Results showed that mitogen-stimulated IL-2 and IFN-gamma was augmented and IL-10 was decreased in AMS compared to both SMS and healthy controls. Whereas the production of the metabolically active IL-12 (p70 heterodimer), was comparable in SMS, AMS and HC, production of the total IL-12 (p70 heterodimer and the p40 chain) were augmented in SMS compared to both AMS and HC. HERV-peptides IL-2 and IFN-gamma production was more frequent and more potent in AMS compared to both SMS patients and HC. HERV-specific type 2 cytokine production was more frequent and potent in SMS compared to AMS and HC. Thus a prevalent type 1 cytokine profile was seen in AMS patients, while IL-10 production predominated in SMS individuals.

CCR5-reactive antibodies in seronegative partners of HIV-seropositive individuals down-modulate surface CCR5 in vivo and neutralize the infectivity of R5 strains of HIV-1 In vitro

Exposure to HIV does not necessarily result in infection. Because primary HIV infection is associated with CCR5-tropic HIV variants (R5), CCR5-specific Abs in the sera of HIV-seronegative, HIV-exposed individuals (ESN) might be associated with protection against infection. We analyzed sera from ESN, their HIV-infected sexual partners (HIV+), and healthy controls (USN) searching for CCR5-specific Abs, studying whether incubation of PBMC with sera could prevent macrophage inflammatory protein 1 beta (Mip1 beta) (natural ligand of CCR5) binding to CCR5. Results showed that Mip1 beta binding to CCR5 was not modified by sera of either 40 HIV+ or 45 USN but was greatly reduced by sera of 6/48 ESN. Binding inhibition was due to Abs reactive with CCR5. The CCR5-specific Abs neutralized the infectivity of primary HIV isolates obtained from the corresponding HIV+ partners and of R5-primary HIV strains, but not that of CXCR4-tropic or amphitropic HIV strains. Immunoadsorption on CCR5-transfected, but not on CXCR4-transfected, cells removed CCR5-specific and virus-neutralizing Abs. Epitope mapping on purified CCR5-specific Abs showed that these Abs recognize a conformational epitope in the first cysteine loop of CCR5 (aa 89-102). Affinity-purified anti-CCR5-peptide neutralized the infectivity of R5 strains of HIV-1. Anti-CCR5 Abs inhibited Mip1beta-induced chemotaxis of PBMC from healthy donors. PBMC from two ESN (with anti-CCR5 Abs) were CCR5-negative and could not be stimulated by Mip1beta in chemotaxis assays. These results contribute to clarifying the phenomenon of immunologic resistance to HIV and may have implications for the development of a protective vaccine.

Post-kala-azar dermal leishmaniasis during highly active antiretroviral therapy in an AIDS patient infected with Leishmania infantum

We report a case of post-kala-azar dermal leishmaniasis (PKDL) in a woman with AIDS which occurred 13 months after a diagnosis of visceral leishmaniasis concomitantly with immunological recovery induced by highly active retroviral therapy. Cytokine pattern at the time of visceral leishmaniasis and PKDL diagnosis was studied and pathogenic implications were discussed.

Early immune reconstitution after potent antiretroviral therapy in HIV-infected children correlates with the increase in thymus volume

DESIGN

Despite significant rises in total CD4 T cells, the process of immune reconstitution in adults with HIV infection treated with potent antiretroviral treatment results in a rather slow increase in phenotypically naive lymphocytes. In children more than in adults, thymic function may be at least partly restored when disease-induced immunosuppression is attenuated by pharmacological means.

METHODS

Twenty-five vertically infected and antiretroviral-experienced [zidovudine (ZDV)/ZDV plus didanosine (ddl)] children were prospectively followed during 12 months of treatment with lamivudine (3TC), stavudine (d4T) and indinavir (IDV). The plasma HIV viral load and phenotypic and functional cellular immunity-defining parameters were examined. The relationship between the degree of immune reconstitution and thymus volume assessed by nuclear magnetic resonance was also examined.

RESULTS

An early and steep increase in CD45RA+62L+ T cells was observed in parallel with a sustained decrease in plasma HIV RNA levels and a significant rise in total CD4 T cells. This increase was significantly greater than that observed in CD4+CD45RO+ T cells. Analysis of the CD4 T cell receptor (TCR) beta repertoire and T helper function showed the ability to reconstitute families almost completely absent at baseline, and a substantial improvement of antigen-specific responses by peripheral blood lymphocytes. The rise in CD4 cells and in CD4+CD45RA+62L+ T cells was statistically associated with changes in thymus size observed over time.

CONCLUSION

These data suggest a relevant contribution of the thymus to reconstitution of the peripheral pool of T cells in vertically HIV-infected children treated with potent antiretroviral regimens.

Study of immunological and virological parameters during thalidomide treatment of SIV-infected cynomolgus monkeys

The potential therapeutic utility of thalidomide (Thd), an effective inhibitor of tumor necrosis factor (TNF)-alpha in vitro, was investigated in cynomolgus monkeys (Macaca fascicularis) at 10 months after infection with simian immunodeficiency virus (SIV). Thd-treated macaques (n = 8) received an oral dose (10 mg) daily for 7 days, followed by a wash-out period of 5 weeks. A 2nd cycle of treatment was performed on the same animals at higher doses (20 mg Thd/day) for 14 days. The control monkeys (n = 7) received a placebo for the same period of time. In the present study, we show that Thd, in addition to inhibiting TNF-alpha production after in vitro mitogen stimulation of peripheral blood mononuclear cells (PBMCs), was able to restore the proliferative responses to SIV peptides in monkeys that were infected with SIV. Interestingly, we found that such effects are associated with an increased expression of CD28 cell surface receptors on CD4+ T-cells paralleled by a decrease on CD8+ T-cells. At the same time, significant reduction in either cell-associated viral load or plasma viral RNA was not observed among the SIV-infected monkeys during the two treatment cycles, when compared with the placebo group.

Different immunologic profiles characterize HIV infection in highly active antiretroviral therapy-treated and antiretroviral-naïve patients with undetectable viraemia. The Master Group

BACKGROUND

Suppression of human immunodeficiency virus (HIV) replication can be obtained in chronically infected individuals by highly active antiretroviral therapy (HAART) and can also be observed in antiretroviral-naïve patients. The immunological correlates of these two situations were examined.

DESIGN AND METHODS

Cross-sectional study involving 32 HIV-infected patients with undetectable HIV plasma viraemia (< 500 copies/ml) and either antiretroviral-naive (n = 14) or undergoing HAART therapy with two nucleoside reverse transcriptase inhibitors (NRTI) plus one (n = 13) or two (n = 5) protease inhibitors (PI). CD4 counts, disease duration, and CDC clinical stage were comparable between the two groups of individuals. Immune parameters (antigen- and mitogen-stimulated proliferation and cytokine production; cytokine mRNA; beta chemokine production; HIV coreceptors mRNA) were analysed in all patients.

RESULTS

Results showed immune profiles to be profoundly different in antiretroviral-naive in comparison with HAART-treated patients. Thus: (1) T-cell proliferation to HIV-specific and HIV-unrelated antigens is potent in antiretroviral-naive but suppressed in HAART-treated individuals; (2) interleukin-(IL)2, IL-12 and interferon gamma (IFNgamma) production is robust in naive patients; and (3) a high CCR5/low CXCR4 pattern of HIV coreceptors-specific mRNA is observed in naive but not in HAART-treated patients. In contrast with these observations, no clear differences were detected when beta chemokine production by either peripheral blood mononuclear cells or purified CD8+ T-cells was analysed. Results from HAART-treated patients undergoing therapy with one PI and two NRTI or two PI and two NRTI were in very close agreement.

CONCLUSIONS

These data suggest that control over HIV replication can be independently achieved by pharmacological or immunologic means. HAART is associated with weaker HIV-specific and -non-specific immune responses.

HIV neutralizing IgA in exposed seronegative subjects recognise an epitope within the gp41 coiled-coil pocket

Human immunodeficiency virus (HIV)-specific IgA can be detected in cervical secretions, saliva, and sera of HIV-infected and HIV-uninfected individuals with a known exposure to the virus. IgA from HIV-uninfected exposed seronegative individuals (ESN) neutralize in vitro primary strains of HIV-1. We analyzed the epitopes of HIV recognized by serum HIV-specific IgA of ESN individuals to identify the antigenic correlates of HIV neutralization in exposed-uninfected subjects, and to verify whether different epitopes would be recognized by HIV-specific IgA of ESN and of HIV-infected patients. Results confirmed that HIV-neutralizing IgA are detected in sera of ESN and showed that neutralization of primary HIV strains is mediated by the recognition of different epitopes in HIV-infected patients and ESN. Thus, whereas IgA of HIV+ individuals recognize epitopes expressed both within gp120 and gp41, IgA of ESN exclusively bind to gp41-expressed epitopes. Epitope mapping revealed that the epitope recognized by serum IgA of ESN on gp41 is restricted to aa 581-584 (LQAR) and corresponds to coiled coil pocket in the alpha helic region. In contrast, the epitope seen by IgA of HIV-infected patients on gp41 is identified by two regions; the first is contained within the cystein loop (aa 589-618), the second correspond to C terminal region in the extra membrane region of gp 41 (aa 642-673). Thus, we have identified and characterized the epitopes that mediate neutralization of HIV in individuals in whom infection does not occur despite multiple exposures to the virus. These results have important implications for the development of a new therapy against HIV infection.

Ex-vivo purging of circulating monocytes results in immunovirologic improvement in partially HAART responder HIV-infected patients

AIDS pathogenesis results from a complex array of immune alterations which include, among others, changes in the pattern of cytokine production. Some monocyte-derived cytokines, like TNFalpha play a major role in HIV pathogenesis. TNFalpha transactivates HIV NF-kB thereby inducing viral replication, potentiates HIV replication in lymphomonocytes TNFalpha is one of the main factors of HIV-induced cachexia and might be involved in HAART-associated lipodystrophy. In addition, monocytes are infectable by HIV in vitro and infected monocytes can be recovered from the blood of HIV infected patients. For these reasons, we tested whether renewal of the pool of circulating monocytes by selective monocyte apheresis may improve the immune reconstitution which follows treatment with highly active anti-retrovirals (HAART). HIV-infected HAART receiving (> 1 year) patients who were either virologically non-responders (HIV-1 RNA >50,000 copies/ml) or immunologically non-responders (CD4 counts < 200) were treated with a novel monocyte apheresis device (G-1 Adacolumn). Plasma HIV viral load, proviral DNA and phenotypic and functional immunological analyses were performed. G-1 apheresis was well tolerated, not accompanied by adverse responses, and followed by clinical improvement. TNFalpha production was suppressed and CD4 T cell counts increased. In one G-1 patient with elevated HIV-1 proviral DNA a significant reduction (from 1,500 to 40 copies/10(5) cells) was observed. Neither immunologic nor virologic parameters were modified in the control patients who received HAART alone. Thus, purging of circulating monocytes by G-1 apheresis has a dramatic suppressive effect on TNFalpha production and is followed by both clinical and immunovirological improvement. G-1 apheresis should be considered in patients in whom HAART is only partially effective.

Clinical and immuno-virologic characterization of the efficacy of stavudine, lamivudine, and indinavir in human immunodeficiency virus infection

Clinical, virologic, and immunologic outcomes were analyzed in children with vertically transmitted human immunodeficiency virus (HIV) infection (n = 25) and clinical symptoms and evidence of immunosuppression to establish the efficacy of 18 months' treatment with stavudine, lamivudine, and indinavir. Children were naive for treatment with protease inhibitors and lamivudine and had minimal exposure to stavudine. At 1, 6, 12, and 18 months, the proportions of patients with HIV-RNA <400 copies/mL were 79%, 100%, 94%, 87% in Centers for Disease Control and Prevention (CDC) immunologic class 2 and 50%, 67%, 67%, 72% in CDC immunologic class 3. At 12 months, the median CD4(+) count and percent increased significantly in both CDC immunologic class groups, but to a greater extent in the class 3 group. In the 12- to 18-month period, there were no significant changes within the groups. In both groups there was a steady increase in the proportion and number of children with positive skin test responses. Children in class 2 were more likely to have a positive delayed-type hypersensitivity response and a greater number of positive responses. Lymphocyte proliferative response to recall antigens improved significantly in all patients. The rate of increase in positive test results was faster in children in class 2 than in those in class 3. Only minor clinical events occurred during 18 months of therapy. Potent antiretroviral therapy achieves a sustained benefit in HIV-infected children, but immune reconstitution is more likely achieved in children with less advanced disease.

Immune responses to antigens of human endogenous retroviruses in patients with acute or stable multiple sclerosis

A possible role for human endogenous retroviruses (HERV) in the pathogenesis of MS was investigated by analyzing HERV peptides-stimulated proliferation and cytokine production in MS patients with acute (AMS) or stable (SMS) disease. HERV peptides specific-proliferation and type 1 cytokine production by peripheral blood mononuclear cells was observed in AMS but not in SMS individuals, in whom a type 2 cytokine profile dominates. HERV peptides-stimulated immune responses were modified by changes in disease expression; mediated by CD4+ T lymphocytes; and not related to HLA class II molecules. These data suggest the possibility of a pathogenic role for HERV and HERV-specific immune responses in MS.

Apoptotic cell death and cytokine dysregulation in human immunodeficiency virus infection: pivotal factors in disease progression

The progressive loss of CD4 T lymphocyte is patognomonic of Human Immunodeficiency Virus (HIV) infection and results in immunodeficiency and the appearance of acquired immunodeficiency syndrome (AIDS)-defining pathologies. Although a percentage of CD4 T lymphocytes is destroyed directly by HIV infection, a much higher proportion of lymphocytes remains uninfected and therefore must be destroyed by mechanisms not directly involving viral infection. One such mechanism is apoptotic T cell death (ATCD). ATCD in HIV infection has been shown to be: 1) secondary to cross-linking of CD4 by viral proteins; 2) mediated by both APO-1/Fas and lymphotoxin (LT); and 3) differentially modulated by type 1 and type 2 cytokines. We will briefly analyze the experimental evidences suggesting that ATCD contributes significantly to the immunopathogenesis of HIV/AIDS via depletion of CD4+ T cells.

Human immunodeficiency virus (HIV)-specific IgA and HIV neutralizing activity in the serum of exposed seronegative partners of HIV-seropositive persons

The presence and activity of human immunodeficiency virus (HIV)-specific antibodies were analyzed in the sera of 15 sexually exposed seronegative persons who had systemic HIV-specific cell-mediated immunity and IgA-mediated mucosal immunity and in their HIV-infected partners. The HIV-positive subjects had HIV-specific serum IgG and IgA; the seronegative persons had HIV-specific serum IgA in the absence of IgG. Testing of the seronegative persons 1 year after the interruption of at-risk sex showed that no IgG seroconversion had occurred and that HIV-specific IgA serum concentrations had declined. Serum from the HIV-exposed seronegative persons was analyzed for the ability to neutralize primary HIV-1 isolates. Neutralizing activity was detected in 5 of 15 sera and in 2 cases was retained by serum-purified IgA. Thus, the immunologic picture for resistance to HIV infection should include HIV-specific cell-mediated immunity as well as HIV-specific IgA-mediated mucosal and systemic immunity.

Altered signaling lymphocytic activation molecule (SLAM) expression in HIV infection and redirection of HIV-specific responses via SLAM triggering

Signaling lymphocytic activation molecule (SLAM) is a transmembrane lymphocytic receptor which gets rapidly upregulated following cell activation. SLAM engagement augments T cell expansion and interferon-gamma (IFN-gamma) production independently of CD28. SLAM signaling is regulated by the SLAM-associated protein. We evaluated the expression and function of SLAM on CD4(+) and CD8(+) lymphocytes in HIV-infected individuals with either recently acquired infection (Group A) or asymptomatic HIV infection (Group B) and in healthy controls (HC). Soluble antigen (HIV env peptides and tetanus toxoid)- and mitogen-stimulated proliferation and IFN-gamma and IL-10 production upon SLAM costimulation were also measured. Results showed that: (1) SLAM-expressing CD4(+) and CD8(+) lymphocytes diminish in group A patients compared to both group B patients and HC; (2) SLAM expression on CD4(+) lymphocytes is preferentially associated with the lack of CD7 on cell surface (CD4(+)CD7(-) produce IL-10 but not IFN-gamma); (3) SLAM engagement increases HIV env peptide-stimulated, but neither tetanus toxoid- nor PHA-stimulated proliferation of peripheral blood mononuclear cells (PBMC) in patients but not in HC; and (4) SLAM engagement augments IFN-gamma and reduces IL-10 production by env peptide-stimulated PBMC of HIV-infected individuals. These results demonstrate that early HIV infection results in an altered SLAM expression which correlates with a time-limited impairment of cell-mediated immunity. Furthermore, they show that triggering via SLAM potentiates HIV-specific proliferative responses with simultaneous downregulation of IL-10 and redirection of the response to TH0/TH1.

Aminooxypentane-RANTES, an inhibitor of R5 human immunodeficiency virus type 1, increases the interferon gamma to interleukin 10 ratio without impairing cellular proliferation

Studies have demonstrated that the beta-chemokines RANTES, MIP-1alpha, and MIP-1beta suppress human immunodeficiency type 1 (HIV-1) replication in vitro. Infection with HIV-1 requires expression of CD4 antigen and the chemokine receptor CXCR4 (X4) or CCR5 (R5) on the surface of target cells. The engagement of these receptors with the viral surface proteins is essential for the membrane fusion process. This study investigated the anti-HIV-1 activity of a derivative of RANTES, the CCR5 antagonist aminooxypentane (AOP)-RANTES, on R5 HIV-1 isolates in peripheral blood mononuclear cells. In drug exposure experiments, AOP-RANTES efficiently inhibited viral replication of HIV-1 R5 strains, with a viral breakthrough observed after the withdrawal of the compound. The HIV-1-specific proliferative capacity was maintained under all conditions when compared with controls. An increase in IFN-gamma production accompanied by a parallel decrease in the generation of IL-10 was observed following the in vitro exposure of cells to AOP-RANTES in the presence of three of four HIV-1 R5 isolates. These experiments confirmed that the chemokine receptor antagonist AOP-RANTES was effective as an inhibitor of HIV-1 R5 strain infectivity in peripheral blood mononuclear cells. The capacity of this compound to maintain HIV-1-specific proliferative activity with a shift toward a type 1 cytokine profile makes this compound a unique molecule, one adopting an immunological pathway to limit HIV-1 infection.

Effect of zidovudine postexposure prophylaxis on the development of HIV-specific cytotoxic T-lymphocyte responses in HIV-exposed healthcare workers

We evaluated the effects of zidovudine postexposure prophylaxis (PEP) on the development of human immunodeficiency virus (HIV) envelope-specific cytotoxic T-lymphocyte responses in 20 healthcare workers with occupational exposures to HIV. Seven healthcare workers were treated with zidovudine PEP. Only 1 of 7 treated, versus 6 of 13 not treated, developed an HIV envelope-specific cytotoxic T-lymphocyte response. These data suggest that zidovudine abrogated HIV-specific cytotoxic T-lymphocyte responses. HIV-specific cytotoxic T-lymphocyte responses may be useful as a surrogate marker of HIV replication in the evaluation of new regimens for PEP of occupational HIV exposures.

Immune restoration by combination of a cytostatic drug (hydroxyurea) and anti-HIV drugs (didanosine and indinavir)

Cell activation is essential for HIV infection. CD4+ T lymphocyte activation allows virus replication and CD8+ T lymphocyte activation may contribute to pathogenesis. We combined hydroxyurea, a cytostatic drug that inhibits cell activation and proliferation, with two drugs that inhibit HIV (didanosine and indinavir), to block the "cell activation-virus production-pathogenesis" cycle. HIV was strongly suppressed in treated patients, and the average CD4 count increased to 224/mm3. Compared with a matched group of patients who had declined antiretroviral treatment, treated patients had a significantly lower proportion of activated CD8+ T lymphocytes and a significantly higher number of naive CD8+ and CD4+ T lymphocytes. The proliferative responses to allogeneic and influenza virus antigens were increased in treated patients, and a defect in CD3-zeta expression, the signaling chain of the T cell receptor complex, was reversed. The use of a cytostatic drug was not detrimental to the immune system; on the contrary, the combination of antiviral and cytostatic treatment improved all of the immune parameters tested.

Thymus volume correlates with the progression of vertical HIV infection

BACKGROUND

The thymus is the organ responsible for the maturation and selection of T lymphocytes and is thus pivotal in allowing the development of a functional immune system. Because in HIV infection cell-mediated immune responses are severely impaired, we studied the role of thymus in the control of the progression of HIV infection to AIDS.

METHODS

Thymic volume was analysed by magnetic resonance imaging in 31 vertically HIV-infected children. Plasma HIV viral load and phenotypic and functional cellular immunity-defining parameters were examined in the same patients.

RESULTS

Thymic volume was not correlated with age or nutritional status; thymic volume was nevertheless correlated with CD4 T-lymphocyte counts and with the percentage and absolute number of CD45RA+CD62L+ (naive) T lymphocytes. In addition, the ability of peripheral blood mononuclear cells to proliferate upon tetanus stimulation was directly proportional to thymic volume. Finally, a negative correlation was detected between thymic volume and HIV viral load.

CONCLUSION

Because low HIV plasma viraemia and preserved immune function are favourable prognostic indices in HIV disease, these data indicate that an immunological, thymic-dependent control of the progression of HIV infection might be possible, at least in vertically transmitted HIV infection.

Redistribution of body fat in HIV-infected women undergoing combined antiretroviral therapy

OBJECTIVES

To investigate the prevalence, metabolic features and risk factors of a particular pattern of fat redistribution (FR), characterized by a progressive enlargement of breast and abdominal girth associated with a wasting of the lower limbs, observed in HIV-infected women treated with combined antiretroviral (ARV) therapy.

DESIGN

Cross-sectional study.

SETTING

Outpatients attending the Institute of Infectious Diseases, University of Milan, Milan, Italy.

PATIENTS AND METHODS

HIV-infected women treated with two or more ARV drugs, observed between December 1997 and February 1998. FR was confirmed by means of a physical examination and dual-energy X-ray absorptiometry (DEXA). The metabolic and endocrinological measurements in patients with FR were compared with those in FR-free women.

RESULTS

FR was observed in 32 out of 306 women (10.5%). DEXA revealed more trunk fat (P < 0.01) and less leg fat (P < 0.001) in the patients with FR than in the matched controls. There were no significant differences in laboratory test results between the two groups. All of the FR patients were taking lamivudine-containing regimens; 20 of them were also taking a protease inhibitor (PI). The association of FR with lamivudine-including regimens was statistically significant (P = 0.017). Among the patients taking lamivudine, the risk associated with treatments including PI was 1.8 (95% CI 0.8-3.8, P = 0.12). A total duration of ARV therapy of more than 1000 days was associated with a greater risk of developing FR (OR 10.8; 95% CI 1.4-80.5; P = 0.0207). Stepwise logistic regression analyses indicated that prolonged ARV therapy and a viral load of more than 10000 copies per ml at the beginning of the last ARV regimen were the only variables that significantly and independently correlated with the risk of FR.

CONCLUSIONS

The observed body modifications are caused by a redistribution of body fat without fat loss that is apparently not associated with hyperlipidemia, altered glucose metabolism or other endocrinological disorders. The development of FR in patients receiving only reverse transcriptase (RT) inhibitors suggests the presence of a PI-independent mechanism that deserves further investigation.

A role for mucosal immunity in resistance to HIV infection

In a recent, thought-provoking novel by Elizabeth McCracken (The Giant's House. Avon Books, New York, 1997), two characters discuss love and its impossibilities. One brashly claims to be "immune to love", explaining the concept to his perplexed interlocutor, "...people become immune to love like they become immune to any disease. Either they had it bad early in life, like chicken pox and that's that; or they keep getting exposed to it in little doses and build up an immunity; or somehow they just don't catch it, something in'em is born resistant. I'm the last type. I'm immune to love and poison ivy". (p. 275) (E. McCracken, The Giant's House. Avon Books, New York, 1997). Substitute the words 'HIV infection' for 'love' and this intriguing metaphor summarizes the state of the art working hypotheses for the phenomenon of resistance to HIV infection in HIV-exposed individuals who, against all odds, do not seroconvert. These hypotheses will be discussed hereafter and particular emphasis will be placed upon a possible role for mucosal immunity in this phenomenon.

The effects of CD40 ligation on peripheral blood mononuclear cell interleukin-12 and interleukin-15 production and on monocyte CD14 surface antigen expression in human immunodeficiency virus-positive patients

Human immunodeficiency virus (HIV) infection causes dysregulation of surface phenotype, of accessory function and of cytokine production from peripheral blood mononuclear cells (PBMCs). As CD40 ligation induces several functional activities in these cells, this stimulation may partially mimic the situation occurring in vivo during an antigen-driven immune response. The aim of this study was to measure cytokine production and immunophenotypic changes induced by CD40 stimulation of PBMCs from HIV-positive patients. Under these experimental conditions, total and heterodimeric interleukin (IL)-12 production from PBMCs was similar, while IL-10 production was increased in HIV-positive patients compared with controls. On the contrary, CD40 ligation did not induce IL-15 production by PBMCs. Surface CD14 was down-modulated, as a consequence of CD40 stimulation, on monocytes from healthy controls but not on monocytes from HIV-positive patients. These data demonstrate that some of the CD40-mediated signals are disturbed in HIV-positive patients. These disturbances may contribute to the immune dysfunction seen in HIV infection.

Intractable pruritus in HIV infection: immunologic characterization

BACKGROUND

Severe, intractable pruritus, often associated with erythematopapular skin lesions and hypereosinophilia, is a condition observed in some nonatopic, HIV-infected patients. We performed immunovirologic analyses of this condition.

METHODS

Immunologic (mitogen-stimulated production of cytokines, tumor necrosis factor-alpha [TNF-alpha], and soluble CD23; serum levels of soluble CD23, ICAM-1, TNF-alpha, IgG, IgE, and IgA) and virologic (HIV viral load) parameters were analyzed in six patients with therapy-resistant pruritus. Hypereosinophilia was present in all these patients. Results were compared to those of seven HIV-seropositive individuals similar to the first one in terms of CD4 counts and clinical staging, but without pruritus.

RESULTS

Hypereosinophilia; hyper-IgE and hyper-IgA; augmented interleukin (IL)-4, IL-5, and sCD23; and reduced interferon-gamma production by mitogen-stimulated peripheral blood mononuclear cells (PBMC) were detected when patients with pruritus were compared to HIV controls. HIV viral load was also augmented in patients in whom pruritus was present.

CONCLUSIONS

The results suggest that therapy-resistant, intractable pruritus accompanied by hypereosinophilia may be used to define a subset of HIV-seropositive individuals showing prototypic hyperactivation of humoral immunity, and in whom augmented HIV viral load is present.