Contrasting effect of oral and intravenous cyclophosphamide treatment on phenotypes of human peripheral blood lymphocytes.

Twenty three rheumatoid arthritis (RA) patients treated with cyclophosphamide (CTX) were observed for 6 months. Eight patients received CTX in a single intravenous dose (group I) and 15 orally in a single daily dose (group II). The surface antigens of lymphocytes, isolated from peripheral blood, were determined using immunofluorescence method. The clinical improvement was observed both in group I and in group II of patients. However, in patients receiving CTX intravenously amelioration of the disease appeared quicker. The percentage of CD3+ and CD8+ T cells remained unchanged. In group I we observed decrease in the number of CD4+ T cells (60.1 +/- 11.5% and 43.8 +/- 12.5%, before and after treatment respectively, p < 0.01), in group II this level remained unchanged. In both groups the percentage of CD19+ B cells decreased (14.7 +/- 9.2% and 8.0 +/- 6.1%, before and after treatment respectively in group I, p < 0.01; 17.4 +/- 12.3% and 11.0 +/- 7.1%, before and after treatment respectively in group II, p < 0.01). Moreover, the percentage of activated T cells (CD25+ cells and HLA-DR+ cells) was reduced in both groups.