HP and rheumatoid arthritis: Out of 23 differential protein spots, 9 protein spots were successfully identified by MALDI-TOF MS/MS [Table 2].The identified proteins included haptoglobin (β-chain), haptoglobin alpha 2 chain, alpha 1 microglobulin, serum amyloid, albumin and apolipoprotein which were upregulated in the sera of RA patients as compared to healthy control.