Inhibition of lymphocyte DNA synthesis by plasma from patients with Kawasaki disease.

Plasma obtained from patients with Kawasaki disease during the acute phase markedly inhibited DNA synthesis in autologous peripheral blood lymphocytes (PBLs) stimulated by phytohaemagglutinin-P (PHA-P) or concanavalin A (Con A). The inhibition became less marked with the progression of the disease and there was no effect on DNA synthesis in PBLs stimulated by pokeweed mitogen (PWM). The plasma also inhibited DNA synthesis in PBLs obtained from healthy adults. The postulated suppressors markedly inhibited DNA synthesis in PBLs from healthy adults stimulated by PHA-P, Con A, purified protein derivative (PPD) or mixed lymphocyte culture reaction (MLR) but they had little effect on the DNA synthesis stimulated by PWM or protein A. With respect to the mechanism, the suppression was found to be potentiated by an increase in the concentration of the patients' plasma, and not to be associated with cytotoxicity nor with a deficiency of factor(s) indispensable for PBL proliferation. It was also evident that the suppression was not related to the concentration of the stimulant, to the lengths of the culturing period nor to the presence of prostaglandins.