[Interleukin-2 production by peripheral blood mononuclear cell from patients with myasthenia gravis--correlation with...

Interleukin-2 (IL-2) production by peripheral blood mononuclear cell (PBM) and the frequency of surface IgG+ B cells (%) were studied in 17 patients with myasthenia gravis (MG) and 12 controls. Culture supernatants from phytohemagglutinin (PHA)-stimulated peripheral blood mononuclear cell from patients with MG and controls were added to IL-2 dependent proliferative cultures (CTLL-2). Following 24 hr of culture, 3H-Tdr was added and cultured for an additional 6 hr. Cultures were harvested and 3H-Tdr incorporation was determined. In comparison with controls we found significantly increased synthesis of IL-2 in patients with MG (p < 0.05). Highest synthesis was found in severe cases and there were highly significant correlation between IL-2 synthesis and clinical severity score (R = 0.85, p < 0.05). These findings suggest that the ability of IL-2 synthesis by PBM may reflect severity of patients with MG. B cells expressing surface IgG, considered to be differentiated B cells, were less frequent in severe cases (R = -0.67, p < 0.05). It may be that the B cells with further differentiation are transformed into plasma cells expressing other markers such as PCA-1 in severe patients with MG.