IN-VIVO ACTIVATED T-LYMPHOCYTES FROM INSULIN-DEPENDENT DIABETES-MELLITUS (IDDM) PATIENTS DISPLAY HETEROGENEOUS EXPRESSION OF T-CELL RECEPTOR V-BETA AND CYTOKINE GENES

Peripheral blood T lymphocytes from 33 patients with insulin dependent diabetes mellitus (IDDM) were tested for the expression of four activ ation markers (CD69, CD25, HLA-DR and VLA-1) that differ for their kin etics of appearance on the cell surface. T cells that expressed CD25 o r HLA-DR (intermediate appearance activation markers) were significant ly increased in 6 patients who suffered predominantly from long-standi ng IDDM. CD69 (early activation marker) was found hyperexpressed in 2 patients with recent onset IDDM. Overexpression of VLA-1 (late activat ion marker) was observed only in 1 patient with long lasting IDDM. In vivo activated T cells from five patients were separated according to the expression of HLA-DR or CD25 and their T cell receptor (TcR) varia ble region beta (V beta) repertoire was investigated by reverse transc riptase-polymerase chain reaction and by staining with a panel of TcR V beta specific monoclonal antibodies. These experiments showed that V beta gene expression was heterogeneous in all of the cases tested. Fi nally, the expression of the genes encoding for interleukin 2 (IL2), i nterferon gamma (IFN gamma), interleukin 4 (IL4) and interleukin 5 (IL 5) by in vivo activated T cells was investigated in five patients usin g RT-PCR. These genes were found to be expressed in different combinat ions, without any evidence for an in vivo expansion of T helper 1 (TH1 )- or T helper 2 (TH2)-like cells.