Rheumatoid arthritis (RA) is a chronic autoimmune inflammatory disease affecting 
the joints and surrounding tissue. Identification of novel proteins associated 
with the progression of a disease is a prerequisite for understanding the 
pathogenesis of RA. The present study was undertaken to identify the potential 
biomarkers from a less explored biological sample such as synovial fluid (SF) 
cells which is specific for RA and to analyze their functional aspects using 
proteomic approach. Two-dimensional gel electrophoresis (2-DE) was performed 
using synovial fluid cells of RA and osteoarthritis (OA) patients, and 7 
differentially expressed proteins were identified using matrix-assisted laser 
desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS/MS). 
Αlpha-Taxilin (α-Taxilin) has been found as one of the novel, significantly up 
regulated protein in RA. It has been validated in the synovium, synovial fluid 
(SF), SF cells, and plasma samples by Western blot, enzyme-linked immunosorbent 
assay (ELISA), fluorescence-activated cell sorting (FACS), immunohistochemistry 
(IHC), and real-time PCR. The identification of autoantibody against α-Taxilin 
and in silico studies has further helped us to understand its involvement in 
disease mechanism. The present study will therefore provide knowledge towards 
the etiology of RA that pave the way for suitable prognostic marker 
identification along with other clinical parameters.