The effect of anti-CD40 ligand antibody on B cells in human systemic lupus erythematosus.
OBJECTIVE
To determine the immunologic effects of anti-CD40 ligand (anti-CD40L) therapy in 5 patients with systemic lupus erythematosus nephritis who participated in an open-label study of a humanized anti-CD40L monoclonal antibody.


METHODS
Serum and peripheral blood mononuclear cells were obtained before, during, and after treatment, and the frequency of Ig and anti-DNA antibody-secreting B cells was analyzed by enzyme-linked immunospot assay and by analysis of Epstein-Barr virus (EBV)-transformed B cell lines. To determine the effect of treatment on somatic mutation of Ig genes, reverse transcriptase-polymerase chain reaction was performed on messenger RNA from 4 patients, using primers specific for the DP-47 heavy chain gene and for IgG. Finally, B cell phenotype was investigated using flow cytometry.


RESULTS
Even a brief period of treatment with anti-CD40L markedly reduced the frequency of IgG and IgG anti-DNA antibody-producing B cells, and these changes persisted for several months after cessation of treatment. To confirm these findings, EBV-transformed B cell lines were screened from each of 3 patients, and a 10-fold decrease in anti-DNA antibody-secreting cell lines was found after treatment in all 3 patients. Few differences in mutation patterns were observed before and after treatment; however, the frequency of germline-encoded DP-47 sequences was significantly increased before treatment and normalized following treatment. Flow cytometric analysis of B cells revealed expansion of a CD27-/IgD- B cell subset in some of the patients, which did not change with treatment.


CONCLUSIONS
These are the first mechanistic studies of the effect of anti-CD40L therapy in human autoimmune disease. The results suggest that further studies of CD40L blockade are warranted.
Huang
Weiqing
W
Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA.
Sinha
Jayashree
J
Newman
Jeffrey
J
Reddy
Bhoompally
B
Budhai
Lalbachan
L
Furie
Richard
R
Vaishnaw
Akshay
A
Davidson
Anne
A
D000328:Adult; D000974:Antibodies, Antinuclear / Q000235:genetics / Q000276:immunology; D000911:Antibodies, Monoclonal / Q000494:pharmacology*; D001402:B-Lymphocytes / Q000276:immunology*; D015415:Biomarkers; D023201:CD40 Ligand / Q000276:immunology*; D002461:Cell Line, Transformed; D005260:Female; D005434:Flow Cytometry; D004854:Herpesvirus 4, Human / Q000235:genetics; D006801:Humans; D007124:Immunoenzyme Techniques; D007074:Immunoglobulin G / Q000235:genetics / Q000276:immunology; D066298:In Vitro Techniques; D008181:Lupus Nephritis / Q000276:immunology* / Q000628:therapy*; D008297:Male; D009154:Mutation / Q000276:immunology; D012333:RNA, Messenger / Q000032:analysis
D000974:Antibodies, Antinuclear; D000911:Antibodies, Monoclonal; D015415:Biomarkers; D007074:Immunoglobulin G; D012333:RNA, Messenger; D023201:CD40 Ligand