γδ Receptor Bearing T Cells in Scleroderma: Enhanced Interaction with Vascular Endothelial Cellsin Vitro

In view of the documented perivascular mononuclear cell infiltration in the involved organs in scleroderma (SSc) and the reported accumulation of γδ-T cells in SSc skin and lung, we evaluated γδ-T cell interaction with endothelial cells (EC)in vitro.γδ- and αβ-T cells were isolated from BPMN of SSc patients with early diffuse disease and of matched control subjects by an immunomagnetic method after stimulation with mycobacterium lysate and interleukin-2 for 2 weeks. Lymphocyte adhesion, proliferation, and cytotoxicity to EC were investigated. SSc γδ-T cells adhered to cultured EC and proliferated at higher rates than control cells. Furthermore, significant EC cytotoxicity by SSc γδ was seen. The cytotoxicity was blocked by addition of anti-γδ-TCR antibody and by anti-granzyme A antibody but not by anti-MHC class I and II antibodies. Expression of granzyme A mRNA was seen in five/five SSc γδ-T cells and in one/five control cells. αβ-T cells from both SSc and control subjects were significantly less interactive with EC than γδ-T cells. The data demonstrate EC recognition by SSc γδ-T cells and propose γδ-T cells as a possible effector cell type in the immune pathogenesis of SSc.