HIV-specific mucosal and cellular immunity in HIV-seronegative partners of HIV-seropositive individuals.

HIV-specific mucosal and cellular immunity was analyzed in heterosexual couples discordant for HIV status in serum and in HIV-unexposed controls. HIV-specific IgA but not IgG was present in urine and vaginal wash samples from HIV-exposed seronegative individuals (ESN), whereas both IgA and IgG were observed in their HIV-seropositive partners; antibodies were not detected in low-risk controls. Envelope protein (Env) peptide-stimulated interleukin-2 (IL-2) production by peripheral blood mononuclear cells (PBMCs) was detected in 9 out of 16 ESNs, 5 out of 16 HIV-infected patients and 1 out of 50 controls. Env peptide-stimulated PBMCs of ESNs produced more IL-2 and less IL-10 compared with those of HIV-infected individuals; no differences were observed in chemokine production or in CCR5 expression. These data demonstrate that a compartmentalized immune response to pathogens is possible in humans and raise the possibility of protective roles for cell-mediated immunity and mucosal IgA in HIV-seronegative individuals exposed to HIV.

Immunological activation markers in the serum of African and European HIV-seropositive and seronegative individuals.

OBJECTIVE: The concentration of type 1 and type 2 cytokines and fibroblast-associated apoptosis-1 soluble receptor (sAPO-1/Fas) was analysed in the sera of Ugandan and Italian HIV-1-seropositive and seronegative individuals. The data were compared to determine whether the immunological status of these groups was different. METHODS: Sixty-seven Ugandan and 30 Italian HIV-positive patients were analysed and stratified according to CD4 counts (group 1, > 500 x 10(6)/l; group 2, 200-500 x 10(6)/l; group 3, < 200 x 10(6)/l). Sera from 15 Ugandan and 11 Italian HIV-negative blood donors were also analysed. Serum concentration of type 1 cytokines [interleukin (IL)-2, IL-12, and interferon (IFN)-gamma] and type 2 cytokines (IL-4 and IL-10), and sAPO-1/Fas were measured by enzyme-linked immunosorbent assay. RESULTS: Serum levels of IL-2, IFN-gamma and IL-10 but not of IL-4 and IL-12, were elevated in HIV-positive group 1 and 2 Africans compared with HIV-positive Italian individuals. IL-4 was mildly augmented in HIV-positive group 3 African patients. Serum concentration of sAPO-1/Fas was reduced in HIV-positive Africans compared with HIV-positive Italian individuals. Finally, serum levels of IL-2 and IL-10 were increased and sAPO-1/Fas reduced when sera of HIV-negative African healthy controls were compared with their Italian counterparts. The ratio of type 1/type 2 cytokines was roughly 1.0 in HIV-negative African controls, and much greater than 1.0 in HIV-negative Italian controls. CONCLUSIONS: These preliminary findings indicate that immune activation is present in African HIV infection. Furthermore, these data raise the possibility that abnormal immune activation and increased susceptibility to antigen-induced cell death is present even in HIV-negative African controls.

Single-cell analysis of cytokine production shows different immune profiles in multiple sclerosis patients with active or quiescent disease.

Peripheral blood mononuclear cells of multiple sclerosis (MS) patients were stimulated with myelin basic protein (MBP) together with anti-CD28 monoclonal antibody and staphylococcal enterotoxin B to optimize cytokine production by antigen-specific cells. Type 1 (IL-2, IL-12, IFNgamma) and pro-inflammatory (TNFalpha, IL-1beta, IL-6) cytokines were augmented in CD4+, CD8+, and CD14+ cells of acute MS patients and of patients undergoing disease reactivation. These cytokines were reduced in IFNbeta-treated and in stable MS patients; type 2 cytokines (IL-4, IL-10) were increased in these patients. Similar immune profiles are seen in MS patients in whom remission is naturally or pharmacologically (IFNbeta) achieved. Cytokine alterations are particularly evident in CD14+ cells, underlying their critical role in the modulation of the immune response.

Immunization with both T cell-dependent and T cell-independent vaccines augments HIV viral load secondarily to stimulation of tumor necrosis factor alpha.

Vaccination of HIV-infected individuals increases HIV viral load, reduces CD4 cell counts, and might influence disease progression. Because these deleterious effects are postulated to be secondary to a direct activation of T lymphocytes induced by the immunogen, we compared immunologic and virologic effects of a T cell-dependent and a T cell-independent vaccine. Seventeen HIV-infected children were immunized with influenza (FLU) (T cell-dependent) or pneumococcal (PNEUMO) (T cell-independent) vaccines. HIV viral load and type 1 (IL-2 and IFN-gamma) and type 2 (IL-4 and IL-10) cytokine production were evaluated before and 7, 14, and 28 days after vaccination. Slopes of CD4 cell counts analyzed 6 months before and 6 months after vaccination were not significantly different. HIV viral load increased in both groups of children despite the fact that type 1 cytokine production and the type 1-to-type 2 ratio increased in FLU-vaccinated but not in PNEUMO-vaccinated patients. Thus, an increase in HIV viral load in the absence of T cell activation (as measured by cytokine production) was observed in PNEUMO-vaccinated children. Because polysaccharides of the bacterial cell wall stimulate TNF-alpha production by monocyte-macrophages and TNF-alpha was shown to stimulate HIV replication directly on activation of NF-kappa b after binding the long terminal repeat (LTR) sequences of HIV, we measured TNF-alpha production and observed a significant increase in both groups of vaccines. These data suggest that an increase in HIV viral load can be observed in vaccinated HIV-infected children even independent of direct antigen-induced activation of T lymphocytes, and that augmented production of TNF-alpha might play a role in this phenomenon.

A possible role for the cortisol/anticortisols imbalance in the progression of human immunodeficiency virus.

The progression of HIV infection is accompanied by complex alterations in the production of adrenal steroids. Cortisol levels are increased in HIV infection whereas those of dehydroepiandrosterone (DHEA), a physiologic antagonist of the immunoregulatory activities of cortisol, decrease. The progression of HIV infection to AIDS is also characterised by a shift from a type 1 to type 2 cytokine production. Thus, defective production of interferon gamma (IFN gamma), interleukin (IL)-2, and IL-12 as well as increased production of IL-4, IL-5, IL-6, and IL-10 are observed in HIV-seropositive individuals and are proposed to be in vitro immunologic marker of progression. Cortisol and pharmacological doses of glucocorticoids (GC) suppress IL-2 and IFN gamma production and favour the production of IL-4. Furthermore, GC and IL-4 stimulate the differentiation of B lymphocytes into IgE producing plasma cells, the concentration of which augments in HIV infection. Finally, GC induce programmed cell death (PCD) in a variety of different cells, including mature T lymphocytes, and type 2 cytokines were recently proposed to augment the susceptibility of T lymphocytes to PCD. It was suggested that the progressive shift from type 1 to type 2 cytokine production characteristic of HIV infection could be at least partially provoked by the increase in the production of cortisol and the reduction of DHEA. This hypothesis is discussed within the scenario of an endrocrinologic imbalance being responsible for HIV progression at least partially via increased susceptibility of HIV + CD4 lymphocyte to PCD.

Type 1 and type 2 cytokines in HIV infection -- a possible role in apoptosis and disease progression.

The progression of HIV-infected subjects to AIDS was recently postulated to be controlled by the balance between type 1 cytokines (mainly enhancing cell-mediated immunity) and type 2 cytokines (mainly augmenting antibody production). Thus, progression of HIV infection was suggested to be accompanied by a decline of in vitro production of interleukin-2 (IL-2), IL-12 and interferon gamma (IFN-gamma) (type 1 cytokines) and an increase in the production of IL-4, IL-5, IL-6 and IL-10 (type 2 cytokines) by peripheral blood mononuclear cells of HIV-seropositive patients. According to this hypothesis, clinical markers of progression would be considered the loss of the ability to elicit a delayed-type hypersensitivity reaction to ubiquitous antigens (secondary to defective IL-2 production), hyper-IgE (secondary to increased IL-4 production) and hypereosynophilia (secondary to increased IL-5 production). The type 1 to type 2 shift was suggested to be predictive for the following events: (i) reduction in CD4 counts; (ii) time to AIDS diagnosis; (iii) time to death. Support for this hypothesis stems from the recent observation that a strong type 1/weak type 2 cytokine production profile was observed in HIV-seropositive patients with delayed or absent disease progression, whereas progression of HIV infection was characterized by a weak type 1/strong type 2 cytokine production profile. PBMC of HIV-seropositive individuals are susceptible to antigen-induced cell death (AICD) after antigen recognition via T-cell receptor (TcR). While TcR-induced AICD is seen in CD4+ and CD8+ cells programmed cell death induced by recall antigens is preferentially observed in CD4+ cells, a situation more closely resembling the CD4 depletion of HIV infection. Because type 1 cytokines reduce, whereas type 2 cytokines augment T-lymphocyte AICD, an increase in the concentration of type 2 cytokines could result in the decline in CD4+ cells seen in HIV infection.

Serum auto antibodies presence in multiple sclerosis patients treated with beta-interferon 1a and 1b.

To verify the possible effect of IFN-beta treatment on auto antibodies development in multiple sclerosis (MS) we studied 69 MS patients before and during the treatment with IFN-beta 1b (n=35) and IFN-beta 1a (n=20) for 27 and 12 months respectively, and, as controls, 14 untreated MS patients. The serum, collected every 3 months from all the patients, was investigated for the presence of antinuclear (ANA), anti-smooth muscle (ASMA), anti-mitochondrial (AMA), anti-native DNA (nDNA) anti-cardiolipin (aCL), anti-parietal cells (APCA), anti-microsomal (AMC) and anti-tireoglobulin (ATG) antibodies. Among the IFN-beta 1b-treated MS patients an increase of the frequency and of the level of ANA, AMC and ATG was observed. ASMA and ANA antibodies were already present in about 45% of the MS patients before the treatment and fluctuated over the time. In one patient the treatment was interrupted after 6 months because of the occurrence of high ASMA level and of an autoimmune hepatitis. The data obtained in the smaller number of MS patients treated with IFN-beta 1a were very similar. No increase in aCL level was observed during both the IFN treatments. Our results indicate that the treatment with IFN-beta induces an increase of AMC and ATG antibodies in MS patients and confirm that, although rare, autoimmune diseases could be observed. The possible effect of these auto antibodies on the treatment efficacy and on MS clinical course need to be further investigated.

Endothelin and nitric oxide levels in cerebrospinal fluid of patients with multiple sclerosis.

In order to investigate the potential role of endothelins (ETs) and nitric oxide (NO) in the pathogenesis of multiple sclerosis (MS) we evaluated the levels of these vasoactive mediators in cerebrospinal fluid (CSF) of relapsing remitting MS patients and in a group of subjects with other neurological diseases (OND) and in a control group of subjects without neurological disease. Eighty patients affected from clinically diagnosed MS were selected, 44 of them were studied during an acute clinical attack and 36 in a stable phase. The OND group included 21 subjects affected by degenerative non inflammatory (n=9) and inflammatory (n=12) neurological disease while the control group included 22 subjects with cancer of the prostate (n=11) and with bladder disease (n=11). ET levels were significantly increased in CSF of relapsing remitting MS patients with an acute clinical attack in comparison with those in a stable phase, the OND group and the control group. Moreover significant differences were observed among the four groups with regard to the NO levels: MS patients in a stable and acute phase like OND group have high levels of NO compared to the control group. Since the blood-brain barrier index values did not differ significantly between the three groups, the data of this study suggest an important role for NO and ET in cerebral microcirculation in MS patients.

Pentoxifylline improves cell-mediated immunity and reduces human immunodeficiency virus (HIV) plasma viremia in asymptomatic HIV-seropositive persons.

The effects of pentoxifylline on immunologic and virologic parameters were evaluated in 10 human immunodeficiency virus-infected patients not receiving antiretroviral treatment. Patients were asymptomatic, had 300-500 CD4 cells/microL, and received pentoxifylline (1200 mg/day orally) for 4 months. Peripheral blood mononuclear cells were tested before and at five time points during therapy. A transient increase in CD4 cells was observed in 8 of 9 patients, and CD8 cells increased in 7 of 9 patients. These increases were negatively correlated with susceptibility to in vitro mitogen-stimulated apoptotic cell death. Pentoxifylline had a temporary effect on mitogen-stimulated cytokine production; thus, interferon-gamma, interleukin (IL)-2, tumor necrosis factor-alpha, and lymphotoxin increased more than IL-10. Pentoxifylline also potentiated antigen-stimulated IL-2 production and proliferation in 8 of 9 patients and induced significant but transient decreases in plasma viremia in 7 of 9 patients. These preliminary findings suggest that pentoxifylline in vivo has an interesting but temporary influence on both immunologic and virologic parameters.

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.

Long-term resistance to HIV infection in vertical HIV infection: cytokine production, HIV isolation, and HIV phenotype define long-term resistant hosts.

We analyzed immunologic (CD4 and CD8 slopes; interferon-gamma, interleukin-2, interleukin-10, and chemokines production; concentration of IgE; beta 2-microglobulin) and virologic (p24; HIV isolability and phenotype; plasma viremia) parameters in HIV vertically infected children > or = 8 years of age without disease progression or mild symptoms and an absolute CD4+ count > or = 500/microliter with CD4+ percentage > or = 25%. The results were compared to those of two control groups: (1) slow progressors, children > or = 8 years of age with moderate symptomatology and/or moderate CD4 depletion, and (2) progressors, children > or = 8 years of age with severe clinical disease and/or severe CD4 depletion. Pediatric long-term resistant hosts were characterized by higher production of interleukin-2 and interferon-gamma and lower production of interleukin-10, normal concentration of IgE, HIV isolates with a non-syncytium-inducing phenotype, and lower plasma viremia. This condition was not associated with the concentration of beta 2-microglobulin, p24, and chemokines, or with HIV isolability. The IL-10/IL-2 ratio best correlated with both CD4 counts and disease progression. Thus, vertically infected children showing resistance to disease progression are immunologically and virologically distinct from those in whom progressive HIV infection is observed.