Treatment with rituximab affects both the cellular and the humoral arm of the immune system in patients with SLE

Herein we investigated how rituximab-induced B cell depletion affected leukocyte subpopulations and antibody titers in SLE patients. We focused our analysis on time points related to absence and return of B cells after depletion. A correlation was found between the baseline frequency and time to repoputation; the fewer B cells initially, the longer to their return. White the few B cells remaining after treatment were of memory, double-negative (IgD-CD27-), and CD5+ phenotype, the returning B cells were mainly naive, indicating de novo production of B cells. Serum levels of IgG and antibodies against Ro52, Ro60, La44, measles and tetanus remained unchanged, while decreases in IgM, IgE, anti-dsDNA and anti-Clq antibodies were observed. Additionally, a significant increase in activated CD4+ and CD8+ Tcells, as well as CD25(bright)FOXP3(+) regulatory Tcells was observed. In conclusion, both the humoral and the cellular immune systems were affected by treatment with rituximab. (c) 2006 Elsevier Inc. All rights reserved.