Reduced circulating natural killer T cells and gamma/delta T cells in patients with systemic sclerosis.

Objective: To evaluate peripheral blood mononuclear cells (PBMC) expressing natural killer (NK) cell surface markers (CD16 and CD56, in both CD3- and CD3+ cells) and g/d T cell receptors (TCR) involved in non-MHC-restricted cytotoxicity, assessing their possible relationship with clinical and laboratory variables in patients with systemic sclerosis (SSc).

Methods: We submitted 50 patients with SSc to detailed clinical and laboratory assessment, and also performed PBMC subset analyses by direct dual immunofluorescence and flow cytometry.

Results: No statistically significant differences were found in the percentages or the absolute numbers of total lymphocytes, of B cells, and of CD4+ T cells.

Human CD26 expression in transgenic mice affects murine T-cell populations and modifies their subset distribution.

CD26 is a type II transmembrane glycoprotein with dipeptidyl peptidase (DPPIV) activity, constitutively expressed in different cell types and contributing to T-cell activation by acting as costimulatory molecule. Although data suggest an important role for CD26 within the immune system, the physiologic function of this molecule is still unknown. To investigate the role of CD26 in vivo we have produced transgenic mice expressing the human molecule in T cells.