Increased peripheral blood B-cells expressing the CD5 molecules in association to autoantibodies in patients with lupus erythematosus and evidence to selectively down-modulate them

The present investigation has been undertaken to analyze absolute and relative CD5+ B-cell numbers in patients with lupus erythematosus (LE), and concomitant B-CLL, and to monitor them under therapy. Peripheral blood lymphocytes of LE-patients, and healthy controls were analyzed by flow cytometry and direct immunofluorescence technique. Patients were treated with low-dose methotrexate (MTX). Before and during MTX treatment laboratory monitoring has been done. LE-patients had increased percentages of CD5+CD19+ as compared to controls (p < 0.0002), the absolute number of CD5+ B-cells was equal in controls and patients. Autoantibodies were positively correlated to the number of CD5+ B-cells in LE-patients. In a total of 140 LE-patients one male patient suffered from both LE and B-CLL (0.7%). He had increased absolute and relative CD5+ B-cells. MTX induced significant decrease of both total B-cell numbers, and CD5+ B-cells. The decrease of CD5+CD19+ cells was more pronounced than the decrease of total B-cells. Apoptosis rate increased in parallel to the drop-down of elevated CD5+CD19+ cells. Peripheral T-cell subsets remained stable under low-dose MTX. Both absolute and relative numbers of CD5+CD19+ cells should be taken into account in patients with LE. MTX seems to decrease B-cells, and preferentially to down-regulate B-cells expressing the CD5 molecule, which opens new therapeutic options and cell biological activities. The mechanism is unclear but apoptosis induction seems to be likely. (C) 2004 Elsevier SAS. All rights reserved.