Premium
Secreted Semaphorin 5A Activates Immune Effector Cells and Is a Biomarker for Rheumatoid Arthritis
Author(s) -
Gras Christiane,
EizVesper Britta,
Jaimes Yarua,
Immenschuh Stephan,
Jacobs Roland,
Witte Torsten,
Blasczyk Rainer,
Figueiredo Constança
Publication year - 2014
Publication title -
arthritis and rheumatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.106
H-Index - 314
eISSN - 2326-5205
pISSN - 2326-5191
DOI - 10.1002/art.38425
Subject(s) - immunology , immune system , medicine , cytokine , rheumatoid arthritis , proinflammatory cytokine , inflammation
Objective To investigate the role of the multifunctional protein semaphorin 5A (Sema5A) in modulating cellular immune responses and as a biomarker in rheumatoid arthritis (RA). Methods A soluble form of recombinant Sema5A was used to assess its effect on the functions of primary T cells and natural killer (NK) cells isolated from the peripheral blood of healthy donors. Cell proliferation and expression of transcription factors were determined by flow cytometry. Cytokine secretion was analyzed using Luminex technology. Serum samples obtained from 145 patients with RA and control serum samples obtained from healthy individuals or patients with non‐RA rheumatic diseases were analyzed for the presence of secreted Sema5A, using enzyme‐linked immunosorbent assays and immunoblotting. Results Soluble Sema5A strongly increased T cell and NK cell proliferation and induced the secretion of proinflammatory Th1/Th17 cytokines. Accordingly, Sema5A stimulation caused significant up‐regulation of T‐bet and retinoic acid receptor–related orphan nuclear receptor γt levels in T cells. In addition, significantly elevated levels of secreted Sema5A were detected in the serum of patients with RA compared with control serum. Sema5A levels were highest in patients with RA who were positive for the RA biomarker anti‐cyclic citrullinated peptide ( P < 0.001 versus patients with systemic lupus erythematosus and patients with Sjögren's syndrome) and correlated with the levels of rheumatoid factor. Conclusion Soluble Sema5A is a potent activator of T cells and NK cells in vitro, and high serum levels of Sema5A are associated with RA. Taken together, the results indicate that Sema5A contributes to the pathogenesis of RA through antigen‐independent T cell and NK cell activation. Hence, Sema5A is a promising complementary biomarker for the diagnosis of RA.