Normalization of serum-free light chains in patients with systemic lupus erythematosus upon rituximab treatment and correlation with biological disease activity

• Published in: Clinical rheumatology 2011-05, Vol.30 (5), p.685-689
• Main Authors: Chiche, L., Cournac, J.M., Mancini, J., Bardin, N., Thomas, G., Jean, R., Schleinitz, N., Kaplanski, G., Durand, J.M., Boucraut, J., Harlé, J.R.
• Format: Article
• Language: English
• Subjects: Adult; Antibodies, Monoclonal, Murine-Derived - therapeutic use; Autoimmunity; Complement C3 - biosynthesis; Female; Humans; Immunoglobulin A - blood; Immunoglobulin G - blood; Immunoglobulin Light Chains - blood; Immunoglobulin M - blood; Immunologic Factors - therapeutic use; Lupus Erythematosus, Systemic - drug therapy; Male; Medicine; Medicine & Public Health; Middle Aged; Original Paper; Retrospective Studies; Rheumatology; Rituximab; Treatment Outcome
• ISSN: 0770-3198; 1434-9949
• DOI: 10.1007/s10067-010-1674-1

Increased free light chain (FLC) levels have been reported as useful in various autoimmune conditions. We investigated how FLC concentrations change upon B cell targeted therapy in systemic lupus erythematosus (SLE) patients and if they correlate with disease activity. We retrospectively studied 11 SLE patients without renal failure, whom were treated with rituximab. Quantitative determination of IgG, IgA, IgM, and serum FLC was performed before and after rituximab. At baseline, 70% had abnormal serum FLC levels, including increased kappa and lambda levels, while the kappa/lambda ratio was normal for all. A strong correlation was observed between complement C3 fraction and kappa levels ( r  = −0.929, P