Increased serum leukotriene B4 level in the active stage of rheumatoid arthritis in children.

The possible association of leukotriene B4 (LTB4)-like activity with the development of active rheumatoid arthritis was studied in 25 children with the disease and in 15 normal subjects. Serum LTB4-like activity was found to be significantly higher in the active stage of the disease when compared with the values obtained from patients during the inactive stage and from healthy children. No correlation was found between LTB4-activity and other laboratory parameters, e.g. haemoglobin level, white cell count and erythrocyte sedimentation rate.