SURFACE EXPRESSION AND RELEASE OF SOLUBLE FORMS OF CD8 AND CD23 IN CD40-ACTIVATED AND IL-4-ACTIVATED MONONUCLEAR-CELLS FROM PATIENTS WITH GRAVES-DISEASE (GD)

We investigated the effect of T cell-dependent B cell activation on th e surface expression and release of the soluble forms of CD8 and CD23 by peripheral blood mononuclear cells (PBMC) obtained from patients wi th GD, versus patients with Hashimoto's thyroiditis, and normal contro ls. Incubating the PBMC with anti-CD40 MoAbs and IL-4 increased the so luble CD23 levels in cells from all three groups. An increase in the n umber of CD23(+) cells was observed in the PBMC from the patients with GD, but not in PBMC from Hashimoto's thyroiditis or controls. Less so luble CD8 was released from anti-CD40 antibody and IL-4-stimulated PBM C obtained from patients with GD relative to those from the controls. In addition, the number of CD8(+) cells was significantly reduced in s timulated PBMC from the GD patients relative to those from controls. I ncubation of PBMC with anti-CD40 antibody plus IL-4 did not affect the proportions of CD4(+), CD20(+), Fas(+)CD4(+), and Fas(+)CD8(+) cells. The addition of T-3 to cultured PBMC from controls did not reproduce the changes in CD23(+) and CD8(+) cells noted in the samples from GD p atients. Thus, T cell-dependent B cell activation, mediated by a CD40 pathway, may reduce the number of CD8(+) cells, causing exacerbation o f GD.