A phenotypical analysis carried out by indirect immunofluorescence and two-color cytofluorometry showed that the number of lymphocytes bearing the gamma delta T cell receptor (TcR) heterodimer was dramatically increased in the blood of six children with Brucella melitensis infection. Most in vivo expanded gamma delta T cells reacted with a monoclonal antibody which identifies V delta 2 gene products and a significant proportion expressed CD25 and HLA-DR activation antigens. In addition, whereas only a few gamma delta T lymphocytes were CD8+, nearly all were CD4-. Highly enriched populations of both alpha beta and gamma delta T cells were obtained by negative immunoselection from three subjects with brucellosis sampled during convalescence. Despite the different form of their TcR, the proliferation of these two major T cell subsets in response to a mitogenic anti-CD3 monoclonal reagent (OKT3) was optimal. In contrast, alpha beta, but not gamma delta, T lymphocytes proliferated vigorously in response to the antigenic stimulus elicited by heat-killed Brucella. Further studies are, therefore, needed to determine whether the selective expansion of the gamma delta T cell subpopulation observed during the clinical course of the infection is driven by antigenic determinant(s) borne by the pathogen in vivo or is due to host-derived stimuli, such as autologous heat-shock proteins expressed on the surface of the infected cells.
The aim of this study was to investigate the possible relationship between the degree of inflammatory infiltration of salivary glands in Sjögren's syndrome (SS) and the different demographic, clinical and serological features of the disease. A quantitative assessment of the extension of the infiltrates was performed on histology samples from the labial salivary glands (LSG) of 82 patients with primary SS, by calculating the ratio of the infiltrated area to the total area of glandular tissue in the samples. The correlations between the amount of inflammatory infiltrate and the main features of the disorder were then analysed. A significant negative correlation between the degree of LSG infiltration and the patient's age at disease onset was observed (P < 0.05). In contrast, the percentage of infiltrate did not correlate with the disease duration. A significant correlation was found between the degree of infiltration of the salivary tissue and (i) the total number of extraglandular features (P < 0.01) and (ii) the presence of specific extraglandular features such as Raynaud's phenomenon (P < 0.05), vasculitis (P < 0.0001), lymph node or spleen enlargement (P < 0.05) and leucopenia (P < 0.02). Finally, patients with antinuclear antibodies, anti-SSA/Ro antibodies, or anti-SSA/Ro plus anti-SSB/La antibodies showed a more widespread inflammatory infiltration in the LSG tissue than patients without these autoantibodies (P < 0.01). The degree of infiltration in the salivary tissue was significantly greater in those patients with anti-SSA/Ro plus anti-SSB/La antibodies in their sera than in patients with anti-SSA/Ro antibodies alone (P < 0.05). In conclusion, patients with SS and active inflammatory infiltration of the salivary glands usually experience an earlier disease onset and a larger number of systemic extraglandular manifestations. In addition, the antibodies directed against certain nuclear/cytoplasmic specificities, and particularly those which react with the SSB/La antigen, seem to play a key role in enhancing the autoimmune process in the salivary glands.
SUMMARY
The expression and the functional role of the CD26 (1F7) T cell surface molecule, an ectoenzyme which seems to represent a functional collagen receptor of T lymphocytes and to have a role in T cell activation, were analysed in both peripheral blood (PB) and synovial fluid (SF) T cell samples from patients with active and inactive rheumatoid arthritis (RA). Although patients with active disease displayed higher percentages of PB CD26+ CD4+ T cells than inactive RA and control subjects, CD26 antigen expression on RA SF T lymphocytes was low. The anti‐1F7 binding to the T cell surface, that led to CD26 antigen modulation and enhancement of both IL‐2 synthesis by, and 3H‐TdR incorporation of, anti‐CD3‐ or anti‐CD2‐triggered PB T cells in RA and control subjects, was unable to affect significantly both expression and functional activity of RA SF T lymphocytes. Since the 1F7 antigen spontaneously reappeared on the surface of unstimulated SFT cells after 2‐5 days of culturing, the low IF7 antigen expression of anti‐lF7 in the SF T cell compartment may be the result of in vivo molecule modulation exerted by the natural ligand in the joint, with important implications for T cell activation and lymphokine synthesis.
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