[Effect of histamine-blocking substances on mitogen-induced lympho proliferation in rheumatic diseases]

Peripheral blood lymphocytes of patients with rheumatoid arthritis, psoriatic arthritis and healthy controls, isolated by a ficoll density gradient, were incubated with different concentrations of histamine, cimetidine and diphenhydramine (DPH) and simultaneously stimulated with phytohemagglutinine (PHA). In comparison to healthy control persons the lymphoproliferation rate in arthritic patients could be increased about 20% by addition of the histamine-blocking agents cimetidine and DPH. This suggests the existence of in vivo histamine-induced suppressor cells in arthritic patients, which can be inhibited by receptor blocking agents.