Semaphorin 3A is a marker for disease activity and a potential immunoregulator in systemic lupus erythematosus.
BACKGROUND
Semaphorin 3A (sema3A) and neuropilin-1 (NP-1) play a regulatory role in immune responses and have a demonstrated effect on the course of collagen induced arthritis. This study was undertaken to evaluate the role of sema3A and NP-1 in the pathogenesis of systemic lupus erythematosus (SLE) and the specific effect of sema3A on the auto-reactive properties of B cells in SLE patients.


METHODS
Thirty two SLE and 24 rheumatoid arthritis (RA) patients were assessed and compared with 40 normal individuals. Sema3A serum levels were measured and correlated with SLE disease activity. The in vitro effect of sema3A in reducing Toll-like receptor 9 (TLR-9) expression in B cells of SLE patients was evaluated.


RESULTS
Sema3A serum levels in SLE patients were found to be significantly lower than in RA patients (55.04 ± 16.30 ng/ml versus 65.54 ± 14.82 ng/ml, P = 0.018) and lower yet than in normal individuals (55.04 ± 16.30 ng/ml versus 74.41 ± 17.60 ng/ml, P < 0.0001). Altered serum sema3A levels were found to be in inverse correlation with SLE disease activity, mainly with renal damage. The expression of both sema3A and NP-1 on B cells from SLE patients was significantly different in comparison with normal healthy individuals. Finally, when sema3A was co-cultured with cytosine-phosphodiester-guanine oligodeoxynucleotides (CpG-ODN)-stimulated B cells of SLE patients, their TLR-9 expression was significantly reduced, by almost 50% (P = 0.001).


CONCLUSIONS
This is the first study in which a reduced serum level of sema3A was found in association with SLE disease activity. It also raises the possibility that sema3A may have a regulatory function in SLE.
Division of Allergy and Clinical Immunology, Bnai-Zion Medical Center, Rappaport Faculty of Medicine, Technion, Haifa-31048, Israel.
Zahava
Z
Vadasz
Tharwat
T
Haj
Katalin
K
Halasz
Itzhak
I
Rosner
Gleb
G
Slobodin
Dina
D
Attias
Aharon
A
Kessel
Ofra
O
Kessler
Gera
G
Neufeld
Elias
E
Toubi
D001402:B-Lymphocytes / Q000276:immunology / Q000378:metabolism; D015415:Biomarkers / Q000097:blood*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D008180:Lupus Erythematosus, Systemic / Q000097:blood* / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D040121:Semaphorin-3A / Q000097:blood*
D015415:Biomarkers; D040121:Semaphorin-3A