Role of Surface APRIL (A Proliferation Inducing Ligand, CD256) Expression in Patients with Rheumatoid Arthritis

Background: A Proliferation Inducing Ligand (APRIL) is a member of the tumour necrosis factor (TNF) superfamily and is released by activated T and B cells, monocytes, dendritic cells, macrophages, neutrophils, myelocytes, astrocytes, and adipocytes. The aim of the study was to evaluate the APRIL; CD256 surface expression on circulating monocytes in rheumatoid arthritis (RA) patients and disease activity.

Methods: This case control study was conducted on 60 subjects They were classified into two groups: group 1: 20 apparently healthy subjects as a reference group., group 2: 40 patients with RA according to DAS28, they were subdivided into two equal subgroups: active rheumatoid arthritis. and inactive rheumatoid arthritis

Results: There was a statistical increase in surface APRIL expression in active group and inactive group when compared to normal controls and there was also statistical increase in surface APRIL expression level in active group when compared to inactive group. There was no significant correlation between surface APRIL expression with RF (p=0.745) Anti CCP (p=0.375), Hb (p= 0.056), PLT (p= 0.980), WBCs (p= 0.252), AMC (p= 0.890).

Conclusions: Surface APRIL expression is increased on circulating monocyte subsets in RA patients where it is highly correlated with the activity of the disease. Monocytes in patients with RA is shifted toward intermediate and non-classical monocytes, populations of monocytes known to produce the inflammatory cytokines TNF-α important in the pathogenesis of RA.