Maurizio Setti

Impairment of CD8+ T Suppressor Cell Function in Patients with Active Systemic Lupus Erythematosus

Alteration of T cell suppression function has been recognized in patients with systemic lupus erythematosus (SLE). Recently, CD8+ T suppressor lymphocytes (CD8+ Ts) have been generated in vitro by incubating purified CD8+ T cells with IL-2 and GM-CSF. Using this method, we generated CD8+ Ts from patients affected by SLE. No major differences were found in the CD8+ Ts phenotype between SLE patients and healthy subjects. CD8+ Ts from SLE patients with active disease did not inhibit the anti-CD3 mAb-induced proliferation of autologous PBMC, whereas CD8+ Ts from SLE patients in remission exerted an inhibitory activity comparable to normal subjects. The inhibitory effect of CD8+ Ts cells was neither mediated by cytotoxic activity nor by apoptosis induction. Two cytokines, IFN-γ and IL-6, were found to be responsible for the function of CD8+ Ts. In fact, counteraction of CD8+ Ts suppression activity was obtained by blocking IFN-γ with a specific Ab or by inhibiting CD8+ Ts-mediated IL-6 secretion by an antisense oligonucleotide. Interestingly, CD8+ Ts from SLE patients showed a peculiar cytokine pattern characterized by an impaired secretion of IL-6 and an increased secretion of IL-12. Thus, it appears that an altered balance between inhibitory (IL-6) and stimulatory (IL-12) cytokines might be responsible for the functional impairment of CD8+ Ts in SLE patients.

CD8+CD28− T Regulatory Lymphocytes Inhibiting T Cell Proliferative and Cytotoxic Functions Infiltrate Human Cancers

Tumor growth is allowed by its ability to escape immune system surveillance. An important role in determining tumor evasion from immune control might be played by tumor-infiltrating regulatory lymphocytes. This study was aimed at characterizing phenotype and function of CD8+CD28− T regulatory cells infiltrating human cancer. Lymphocytes infiltrating primitive tumor lesion and/or satellite lymph node from a series of 42 human cancers were phenotypically studied and functionally analyzed by suppressor assays. The unprecedented observation was made that CD8+CD28− T regulatory lymphocytes are almost constantly present and functional in human tumors, being able to inhibit both T cell proliferation and cytotoxicity. CD4+CD25+ T regulatory lymphocytes associate with CD8+CD28− T regulatory cells so that the immunosuppressive activity of tumor-infiltrating regulatory T cell subsets, altogether considered, may become predominant. The infiltration of regulatory T cells seems tumor related, being present in metastatic but not in metastasis-free satellite lymph nodes; it likely depends on both in situ generation (via cytokine production) and recruitment from the periphery (via chemokine secretion). Collectively, these results have pathogenic relevance and implication for immunotherapy of cancer.

Vδ1 T lymphocytes producing IFN-γ and IL-17 are expanded in HIV-1–infected patients and respond to Candida albicans

In early HIV-1 infection, Vdelta1 T lymphocytes are increased in peripheral blood and this is related to chemokine receptor expression, chemokine response, and recirculation. Herein we show that, at variance with healthy donors, in HIV-1-infected patients ex vivo-isolated Vdelta1 T cells display cytoplasmic interferon-gamma (IFN-gamma). Interestingly, these cells coexpress cytoplasmic interleukin-17 (IL-17), and bear the CD27 surface marker of the memory T-cell subset. Vdelta1 T cells, isolated from either patients or healthy donors, can proliferate and produce IFN-gamma and IL-17 in response to Candida albicans in vitro, whereas Vdelta2 T cells respond with proliferation and IFN-gamma/IL-17 production to mycobacterial or phosphate antigens. These IFN-gamma/IL-17 double-producer gammadelta T cells express the Th17 RORC and the Th1 TXB21 transcription factors and bear the CCR7 homing receptor and the CD161 molecule that are involved in gammadelta T-cell transendothelial migration. Moreover, Vdelta1 T cells responding to C albicans express the chemokine receptors CCR4 and CCR6. This specifically equipped circulating memory gammadelta T-cell population might play an important role in the control of HIV-1 spreading and in the defense against opportunistic infections, possibly contributing to compensate for the impairment of CD4(+) T cells.

Significant NK cell activation associated with decreased cytolytic function in peripheral blood of HIV-1-infected patients

One of the hallmarks of HIV‐1 infection is represented by the finding of massive T cell activation in peripheral blood lymphocytes of infected patients. An impairment of NK cell function during HIV‐1 infection is also detected, and is associated with decreased expression of natural cytotoxicity receptors (NCR). In this study we tried to determine whether also NK cells are affected by relevant activation and whether this could be associated with decreased NK cell function. In 18 viremic HIV‐1‐infected patients, freshly drawn purified peripheral NK cells displayed significant levels of activation with an incomplete pattern (HLA‐DR+CD69+CD25–NKp44–). Activated (HLA‐DR+CD69+) peripheral NK cells expressed an NCRdull phenotype as determined by cytofluorometric analysis in all the patients, and did not derive from a homogeneous/oligoclonal expansion in vivo as analyzed by expression of HLA‐specific inhibitory NK cell receptors. As determined by cytotoxicity assays, activated NK cells showed a decreased cytolytic function in HIV‐1‐infected patients. Thus, the decrease in NK cell function observed during HIV‐1 infection is associated not only with decreased NCR expression, but also with significant and incomplete NK cell activation in vivo. These results suggest a consistent continuous involvement of the innate immune response in the failure to control viral replication.

Small intestinal bacterial overgrowth in patients suffering from scleroderma: clinical effectiveness of its eradication.

OBJECTIVES:After the skin, the gastrointestinal tract is the second most common target of systemic sclerosis (SSc).AIM:Our aims were to investigate orocecal transit time (OCTT) and the presence of small intestinal bacterial overgrowth (SIBO) in SSc as a cause of intestinal symptoms.METHODS:Fifty-five SSc patients and 60 healthy controls, sex and age matched, entered the study. Enrolled subjects completed a questionnaire for intestinal symptoms and a global symptomatic score (GSS) was calculated. OCTT and the presence of SIBO were assessed by a lactulose breath test (LBT). Patients with SIBO were treated with rifaximin 1,200 mg/day for 10 days. Finally, a second questionnaire and LBT were performed 1 month after the end of therapy.RESULTS:The prevalence of SIBO was higher in SSc patients compared with controls (30/54 vs 4/60, respectively, P < 0.001). OCTT was significantly slower in SSc patients compared with controls (150 min, 25–75th percentile 142.5–165 vs 105 min, 25–75th percentile 90–135, respectively, P < 0.001). In patients with SIBO, the median GSS score was 8 (25–75th percentile 3.25–10.75). Eradication of SIBO was achieved in 73.3% of patients, with a significant reduction of symptoms in 72.7% of them (GSS score 2, 25–75th percentile 1–3, P < 0.05).CONCLUSIONS: These data suggest that SIBO occurs more frequently in SSc patients than in controls. Intestinal symptoms in these patients may be related to this syndrome and its eradication seems useful to improve clinical features. OCTT is significantly delayed in SSc patients, suggesting an impairment of intestinal motility, a further risk factor for the development of SIBO.

In vitro immunosuppressive activity of soluble HLA class I and Fas ligand molecules:do they play a role in autologous blood transfusion?

BACKGROUND: The immunomodulatory effects of allogeneic blood transfusion may contribute to a poor prognosis in patients with cancer who are undergoing surgery, and clinical trials have been carried out to investigate whether these patients would benefit from autologous blood donation. As the immunomodulatory effects of allogeneic blood transfusion have been related to soluble molecules released from residual WBCs during storage, the in vitro immunomodulatory activity of soluble molecules detected in supernatants from stored autologous blood was evaluated.

Natural killer cells in HIV controller patients express an activated effector phenotype and do not up-regulate NKp44 on IL-2 stimulation

Control of HIV replication in elite controller (EC) and long-term nonprogressor (LTNP) patients has been associated with efficient CD8+cytotoxic T-lymphocyte function. However, innate immunity may play a role in HIV control. We studied the expression of natural cytotoxicity receptors (NKp46, NKp30, and NKp44) and their induction over a short time frame (2–4 d) on activation of natural killer (NK) cells in 31 HIV controller patients (15 ECs, 16 LTNPs). In EC/LTNP, induction of NKp46 expression was normal but short (2 d), and NKp30 was induced to lower levels vs. healthy donors. Notably, in antiretroviral-treated aviremic progressor patients (TAPPs), no induction of NKp46 or NKp30 expression occurred. More importantly, EC/LTNP failed to induce expression of NKp44, a receptor efficiently induced in activated NK cells in TAPPs. The specific lack of NKp44 expression resulted in sharply decreased capability of killing target cells by NKp44, whereas TAPPs had conserved NKp44-mediated lysis. Importantly, conserved NK cell responses, accompanied by a selective defect in the NKp44-activating pathway, may result in lack of killing of uninfected CD4+NKp44Ligand+ cells when induced by HIVgp41 peptide-S3, representing a relevant mechanism of CD4+ depletion. In addition, peripheral NK cells from EC/LTNP had increased NKG2D expression, significant HLA-DR up-regulation, and a mature (NKG2A−CD57+killer cell Ig-like receptor+CD85j+) phenotype, with cytolytic function also against immature dendritic cells. Thus, NK cells in EC/LTNP can maintain substantially unchanged functional capabilities, whereas the lack of NKp44 induction may be related to CD4 maintenance, representing a hallmark of these patients.

Prevalence of transmitted HIV-1 drug resistance in HIV-1 infected patients in Italy: evolution over 12 years and predictors

OBJECTIVES Transmitted HIV-1 drug resistance (TDR) can reduce the efficacy of first-line antiretroviral therapy. PATIENTS AND METHODS A retrospective analysis was performed to assess the prevalence and correlates of TDR in Italy over time. TDR was defined as the presence of at least one of the mutations present in the surveillance drug resistance mutation (SDRM) list. RESULTS Among 1690 antiretroviral therapy-naive patients, the most frequent HIV subtypes were B (78.8%), CRF02_AG (5.6%) and C (3.6%). Overall, TDR was 15%. TDR was 17.3% in subtype B and 7.0% in non-B carriers (P < 0.001). TDR showed a slight, although not significant, decline (from 16.3% in 1996-2001 to 13.4% in 2006-07, P = 0.15); TDR declined for nucleoside reverse transcriptase inhibitors (from 13.1% to 8.2%, P = 0.003) but remained stable for protease inhibitors (from 3.7% to 2.5%, P = 0.12) and non-nucleoside reverse transcriptase inhibitors (from 3.7% to 5.8%). TDR to any drug was stable in B subtype and showed a decline trend in non-B. In multivariable analysis, F1 subtype or any non-B subtype, compared with B subtype, and higher HIV RNA were independent predictors of reduced odds of TDR. CONCLUSIONS Prevalence of TDR to nucleoside reverse transcriptase inhibitors seems to have declined in Italy over time. Increased prevalence of non-B subtypes partially justifies this phenomenon.

Non‐Antigen‐Specific CD8+ T Suppressor Lymphocytes in Diseases Characterized by Chronic Immune Responses and Inflammation

Abstract: Recent studies on regulatory lymphocytes demonstrate that CD8+ T suppressor (Ts) cells may have great relevance in controlling immune system homeostasis and avoiding development of chronic inflammatory diseases. Among the three subpopulations of CD8+ Ts cells so far recognized in humans, the type 2 (non‐antigen‐specific) cell is characterized by the capacity to inhibit both T cell proliferation and cytotoxic T lymphocyte activity through secretion of soluble factors. Previous work has shown the impairment of in vitro generation of type 2 CD8+ Ts cells from the peripheral blood of relapsed patients with multiple sclerosis, systemic lupus erythematosus, or systemic sclerosis. Here, similar findings are demonstrated for patients with human immunodeficiency virus or chronic hepatitis C virus infection. Furthermore, the presence of type 2 CD8+ Ts cells infiltrating diseased tissues in patients with autoimmune thyroiditis or cancer is shown. Collectively, these findings suggest that type 2 CD8+ Ts cells may be involved in the control of pathologic chronic immune responses, contributing in some cases to the pathogenesis of the disease.

Flu vaccination with a virosomal vaccine does not affect clinical course and immunological parameters in scleroderma patients.

Safety and efficacy of adjuvanted vaccines in autoimmune individuals raises growing clinical and scientific interest. Protection from influenza would bring particular benefits in these patients with common cardiac and respiratory impairment. This study evaluates efficacy, clinical safety and immune effects of the administration of a single dose of a virosomal flu vaccine in 46 scleroderma patients. The following parameters were evaluated before and after administration of Inflexal: clinical conditions, inflammation and autoimmunity parameters, humoral response, lymphocyte proliferation and cytokine production upon flu antigen stimulation by specific and non-specific cells. Inflexal was found effective in scleroderma patients. In no subject was worsening of clinical conditions, inflammation and immunological parameters observed.