Platelet count and disease activity in juvenile rheumatoid arthritis.

Blood samples from 41 children with juvenile rheumatoid arthritis (JRA) were studied. The platelet count was tested for possible relationship and correlation with a number of clinical and laboratory parameters. High platelet count was associated with active disease, presence of secondary amyloidosis, and poor functional capacity. The platelet count was positively correlated with the erythrocyte sedimentation rate, anemia, and granulocytosis. The platelet count thus seems to provide an additional parameter of disease activity in patients with JRA.