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Background: Interferon-beta is used to reduce disease activity in multiple sclerosis, but its action is incompletely understood, individual treatment response varies among patients, and biological markers predicting clinical benefits have yet to be identified. Since it is known that multiple sclerosis patients have a deficit of the regulatory T-cell subsets, we investigated whether interferon-beta therapy induced modifications of the two main categories of regulatory T cells (Tregs), natural and IL-10-secreting inducible Tr1 subset, in patients who are biologically responsive to the therapy.Methods: T-cell phenotype was determined by flow cytometry, while real-time PCR was used to evaluate interferon-beta bioactivity through MxA determination, and to measure the RNA for IL-10 and CD46 molecule in peripheral blood mononuclear cells stimulated with anti-CD46 and anti-CD3 monoclonal antibodies, which are known to expand a Tr1-like population.Results: Interferon-beta induced a redistribution of natural Treg subsets with a shift of naive Tregs towards the ‘central memory-like’ Treg population that expresses the CCR7 molecule required for the in vivo suppressive activity. Furthermore, in a subgroup of treated patients, the CD46/CD3 co-stimulation, probably through the Tr1-like subset modulation, increased the production of RNA for IL-10 and CD46. The same group showed a lower median EDSS score after two years of therapy.Conclusions: The selective increase of ‘central memory-like’ subset and the involvement of the Tr1-like population may be two of the mechanisms by which interferon-beta achieves its beneficial effects. The quantification of RNA for IL-10 and CD46 could be used to identify patients with a different response to interferon-beta therapy. [ABSTRACT FROM AUTHOR]

Purpose of the study Although HIV infection impacts the proportion and phenotype of regulatory T-cells (Tregs), discrepant results have been reported depending on the surface markers employed to characterize them and on the patient populations. In addition, the effects of a long-term combined antiretroviral therapy (cART) on Treg cells have not been thoroughly documented. Our study investigated the frequency and number of Tregs and their phenotype in two different groups of HIV-infected patients: one aviremic undergoing long-term cART and one viremic naïve to cART showing a similar CD4+ cell count. Methods Thirty-six HIV+ patients with sustained suppression of plasma viremia (<37 copies/mL) on effective cART for more than 6 years and 22 HIV+patients naïve to cART and without clinical signs of opportunistic infections or tumors at the time of study (untreated group) were included in the study. Healthy donors (HD) were used as control. Flow cytometry on fresh whole blood was used to quantify total Tregs (defined as CD25+CD127low/-CD4+ cells) and the following Treg subsets: naïve (CD45RA+CCR7+) Tregs, central-memory like Tregs (CD45RA-CCR7+, TregCM), effector-memory like Tregs (CD45RA-CCR7−, TregEM) Statistical comparisons of the percentages and number of Tregs and Treg subpopulations were performed by ANOVA or Kruskal-Wallis test. Analysis of covariance was employed in order to adjust for the effect of the age. The Spearman's test was used to assess correlations. Summary of results In viremic untreated and aviremic long-term cART-treated patients the percentage and number of the total Treg cells were not different from those of HD. However, the analysis of Treg phenotype showed a marked redistribution of the Treg subpopulations: in the untreated viremic patients, both the percentage and number of the TregCM subset decreased compared to HD and cART-treated patients, whereas only the percentage of naïve Tregs increased. In particular, the percentage of TregCM was inversely correlated with the viral load (r=−0.51; p=0.016). Conclusions In our aviremic long-term cART-treated and viremic untreated patients, the total Treg cell population seems to be unaffected by HIV infection. However, our results showed that the analysis of the naïve and memory-like Treg subsets may provide a better understanding of the real contribution of Tregs in HIV disease and therapy. [ABSTRACT FROM AUTHOR]

Background: Assessment of T-cell diversity, besides giving insights about the molecular basis of tumor antigen recognition, has clinical implications since it provides criteria for evaluating antigen-specific T cells clinically relevant for spontaneous and vaccine-induced anti-tumor activity. Melan-A is one of the melanoma antigens most frequently recognized by peripheral and tumor-infiltrating lymphocytes in HLA-A2+ melanoma patients. Many clinical trials involving anti-tumor vaccination have been conducted using modified versions of this peptide.Methods: We conducted an in-depth characterization of 210 T-cell receptor beta chain (TRB) clonotypes derived from T cells of HLA-A2+ melanoma patients displaying cytotoxic activity against natural and A27L-modified Melan-A peptides. One hundred and thirteen Melan-A-specific clonotypes from melanoma-free subjects, 199 clonotypes from T-cell clones from melanoma patients specific for melanoma antigens other than Melan-A, and 305 clonotypes derived from T cells of HLA-A2+ individuals showing unrelated specificities, were used as control. After sequence analysis, performed according to the IMGT definitions, TRBV and TRBJ usage, CDR3 length and amino acid composition were compared in the four groups of clonotypes.Results: TRB sequences of Melan-A-specific clonotypes obtained from melanoma patients were highly heterogeneous, but displayed a preferential usage of few TRBV and TRBJ segments. Furthermore, they included a recurrent "public" amino acid motif (Glycine-Leucine-Glycine at positions 110-112-113 of the CDR3) rearranged with dominant TRBV and TRBJ segments and, in one case, associated with a full conservation of the entire TRB sequence.Conclusion: Contrary to what observed for public anti-Melan-A T-cell receptor alpha motifs, which had been identified in several clonotypes of both melanoma patients and healthy controls, the unexpectedly high contribution of a public TRB motif in the recognition of a dominant melanoma epitope in melanoma patients may provide important information about the biology of anti-tumor T-cell responses and improve monitoring strategies of anti-tumor vaccines. [ABSTRACT FROM AUTHOR]

Abstract: Background: Polymorphic light eruption (PLE) is the most common autoimmune photodermatosis. Plasmacytoid dendritic cells (PDCs) are important mediators of innate antimicrobial immunity involved in the pathogenesis of many inflammatory skin diseases. In addition to PDCs, regulatory T cells (Tregs) are involved in controlling inflammation and adaptive immunity in skin by their immunosuppressive capacity. Objective: The aim of this study was to investigate the presence of PDCs and Tregs in photoexposed skin from PLE compared to healthy skin. Methods: Patients with PLE diagnosis and healthy controls were recruited and underwent a photoprovocative test. A 4‐mm punch biopsy was taken from the site of positive photoprovocation test reaction, and immunohistochemistry for BDCA2 as marker for PDCs, CD4 and FOXP3 as markers for Tregs was performed. Double immunostain for FOXP3 and CD4 was performed as well. Absolute counts for CD4, BDCA2 and FOXP3 were performed in at least 5 High Power Fields (HPF). Percentage of CD4‐, BDCA2‐ and CD4FOXP3‐positive cells over the total inflammatory infiltrate was assessed for each case. Results: We enrolled 23 patients and controls. BDCA2+ cells were present in 91.3% of PLE skin samples and 100% of healthy volunteer. Both in PLE patients and healthy controls, PDCs distribution was mainly dermic (P < 0.05). Compared to healthy controls, both epidermic and dermic BDCA2+ cells count were significantly higher in PLE patients (P < 0.05). Both in PLE patients and healthy controls, Tregs distribution was mainly dermic (P < 0.05). The presence of both CD4+ cells and FOXP3+ cells was significantly higher in the dermis of PLE patients compared to controls (P < 0.05). Relative percentages of cellular infiltrations confirmed these results. Conclusions: D‐PDCS and Tregs may play a significant role in the development of PLE, and dermal distribution of PDCs in PLE skin biopsies seems to confirm a possible overlap with cutaneous lupus erythematosus (CLE). [ABSTRACT FROM AUTHOR]

The article presents a study which examines the reduction of newly produced T and B lymphocytes and T-cell receptor repertoire (TCR) diversity in the peripheral blood of multiple sclerosis (MS) patients treated with fingolimod. The study is investigated by real-time polymerase chain reaction (PCR), immune phenotyping, and spectratyping. Results show that newly produced T and B lymphocytes were reduced while T-cell repertoire increased after 12 months of treatment.

The immunomodulating activity of glatiramer acetate on T-cells of multiple sclerosis patients has only been partially clarified. The objective of this work was to investigate whether glatiramer acetate modifies thymic release of newly produced T-cells and the peripheral composition of the T-cell repertoire. T-cell receptor excision circles, thymicnaive (CD4+CD45RA+CCR7+CD31+) T helper cells, and central (CD4+CD45RA-CCR7+) and effector (CD4+CD45RA-CCR7-) memory T-cells were evaluated in 89 untreated patients, 84 patients treated for at least 1 year, and 31 patients beginning treatment at the time of inclusion in the study and then followed-up for 12 months; controls were 81 healthy donors. The T-cell repertoire was analysed in selected samples. The percentage of thymicnaive T helper cells was diminished in untreated patients, but rose to control values in treated subjects; a decrease in central memory T-cells was also observed in treated patients. Follow-up patients could be divided into two subgroups, one showing unmodified thymicnaive T helper cells and T-cell diversity, the other in which the increased release of new T-cells was accompanied by modifications of the T-cell repertoire. Glatiramer acetate modifies the peripheral T-cell pool by activating a thymopoietic pathway of T-cell release that leads to a different setting of T-cell diversity and, likely, to a dilution of autoreactive T-cells. [ABSTRACT FROM AUTHOR]

Background: To determine the role of interferon-alpha in controlling HIV infection we phenotypically and functionally analyzed circulating plasmacytoid dendritic cells (pDC), which are known to be the highest interferon-alpha producing cells, in 33 perinatally infected HIV+ patients undergoing standard antiretroviral therapy.Methods: Circulating pDC were identified by flow cytometry using anti-BDCA-2 monoclonal antibody and by measuring BDCA-2 mRNA by real-time PCR, while tissue-resident pDC were identified by immunohistochemistry. mRNA for interferon-alpha and MxA, a gene that is specifically induced by interferon-alpha, was quantified in peripheral blood cells by real-time PCR, while serum interferon-alpha protein was measured by ELISA.Results: While median values of pDC, both in terms of percentage and absolute number, were not statistically different from age-matched controls, interferon-alpha mRNA was increased in HIV-infected patients. However, in a group of patients with long disease duration, having a low number of both pDC and CD4+ lymphocytes and a significant increase of serum interferon-alpha, MxA mRNA was produced at high level and its expression directly correlated with HIV RNA copy numbers. Furthermore in patients displaying a low CD4+ blood cell count, a severe depletion of pDC in the tonsils could be documented.Conclusion: HIV replication unresponsive to antiretroviral treatment in perinatal-infected patients with advanced disease and pDC depletion may lead to interferon-alpha expression and subsequent induction of MxA mRNA. Thus, the latter measurement may represent a valuable marker to monitor the clinical response to therapy in HIV patients. [ABSTRACT FROM AUTHOR]