RHEUMATOID-FACTOR AND SERUM IGG, IGM AND IGA LEVELS IN RHEUMATOID-ARTHRITIS WITH VASCULITIS

  • 1 January 1976
    • journal article
    • research article
    • Vol. 5  (1) , 1-6
Abstract
A significant increase in the rheumatoid factor [RF] titer in rheumatoid arthritis [RA] patients with vasculitis is reported. A significant rise in IgG [immunoglobulin G] and IgA levels was found in uncomplicated RA, when compared with a normal population. The IgM levels were not elevated in this group of RA patients. In the RA patients with vasculitis, the 3 Ig classes are increased when compared with the normal population, and the IgM level is increased when compared with the uncomplicated RA group. Significant relation was found between log IgM and log RF titer in the RA group with vasculitis. The mild reduction of serum (by dithiothreitol 0.004 M) causes a complete negativity of RF in all cases. Hemagglutination and latex precipitation in vitro are induced by IgM-RF and not by IgG and IgA-RF molecules. Only free sites of IgM-RF play a functional role in the determination of the RF-titer. Increase in IgM in RA patients with vasculitis is partially due to the presence of free IgM-RF molecules in serum. Hidden IgM-RF molecules in patients with lower RF titer are not quantified by immunodiffusion methods.