Seasonal variation in fibrinolysis in patients with rheumatoid arthritis

Abstract

Venous blood samples were taken from 15 patients aged between 28 and 68 years (mean age 49.5) at eight week intervals and at a standard time of day. t-PA and PA1 were measured by chromogenic substrate assays (Kabi). Mean levels of t-PA were found to be high in June, July and August compared to the winter months (P<0.001) and PAI levels were found to be lower in the same three months (P<0.05). These results show that fibrinolytic capacity is reduced in the winter months compared to the summer months of june, July and August in patients with rheumatoid arthritis. Further study is required in normal individuals and in other groups of patients since this could be a contributory factor towards the higher incidence of vasculitis in rheumatoid arthritis and other vascular incidents in the winter months.