Parameters of improvement in patients with rheumatoid arthritis treated with cyclophosphamide

Abstract Nine patients with rheumatoid arthritis were treated with cyclophosphamide. A significant decrease in joint score was seen in 8 patients after 2 months of treatment. At this time there were significant decreases in the monocyte and small lymphocyte counts. Leukopenia was not observed nor were significant changes in other common laboratory parameters observed at this time. Significant decreases in immunoglobulin levels occurred only after 10 months of treatment. Total depletion of small lymphocytes occurred in 7 of 9 patients at 33 weeks. These findings suggest that improvement on cyclophosphamide may be related to decreases in circulating small lymphocytes and monocytes and that levels of these cells in blood rather than the development of leukopenia be used as a guide to dosage.