Serum inhibitor of phytohemagglutinin-induced lymphocyte proliferation in Bartter syndrome.

Serum from four patients with Bartter syndrome inhibited the response to phytohemagglutinin of autologous and homologous (healthy donor) lymphocytes. The abnormal response was normalized in three patients by the administration of indomethacin (2 mg/kg/day), a known inhibitor of prostaglandin synthesis. The serum prostaglandin E2 concentration of these patients before indomethacin therapy was significantly increased (P less than 0.02), as compared with that in controls. The serum PGE2 concentration measured in two of three patients undergoing indomethacin therapy was normal. Because PGE2 is known to inhibit the response of lymphocytes to phytohemagglutinin, we postulate that PGE2 may mediate the reduced blastogenic response observed in patients with Bartter syndrome.