B cell population:
B lymphocytes play several critical roles in the pathogenesis of rheumatoid arthritis. They are the source of the rheumatoid factors (RF) and anti-cyclic-citrullinated peptide (anti-CCP), which contribute to immune complex formation and complement activation in the joints (2).
There is different B cell subpopulation according to the stage of maturation and activity. Distinction of this subpopulation can be done by detection of different CD molecules expressed on cell surface (3). From all sub-population this research will focus on these immunophenotypes; immature, mature, memory and B-reg cells by using CD 19, CD24, CD38 \& CD27 respectively.
Joa˜ o E. Fonseca and his team found the reduction in B cell subpopulation especially (Pre- switched memory B cells) both in RA and Arthritis in the early stage. This observation not related to using methotrexate or corticosteroid in the treatment. They used the classification of B cells with CD 19 mainly and then IgD and CD27 to identify B cells (4).
Gabriella Sármay team found that the number of B-reg CD19+ CD27+ IL-10+ cells in peripheral blood is fewer in RA patients compared with healthy controls (5).
Interleukin 10:
Interleukin (IL)-10 functions as an anti-inflammatory cytokine in rheumatoid arthritis. IL-10 mRNA levels were significantly elevated in synovial fluid mononuclear cells (SFMCs) from patients with RA compared with PBMCs peripheral blood mononuclear cells (PBMCs) from RA patients or healthy volunteers according to Isomäki P (6).
IL 10 is primarily produced by monocytes mainly and, then by lymphocytes; type 2 T helper cells (TH2), mast cells, CD4+CD25+Foxp3+ regulatory T cells, and in a certain subset of activated T cells and B cells (7).
