IGA AND IGM RHEUMATOID FACTORS IN SERUM, SALIVA AND OTHER SECRETIONS - RELATIONSHIP TO IMMUNOGLOBULIN RATIOS IN SYSTEMIC SICCA SYNDROME AND RHEUMATOID-ARTHRITIS

  • 1 January 1983
    • journal article
    • research article
    • Vol. 52  (1) , 75-84
Abstract
Paired serum and saliva samples from 7 patients with systemic sicca syndrome (SSS), 15 patients with rheumatoid arthritis and a positive Schirmer''s test (RA+), 15 patients with rheumatoid arthritis and negative Schirmer''s test (RA-) and 14 normal individuals were analyzed for albumin and Ig concentration and IgA and IgM rheumatoid factor (RF) activity. Protein levels in saliva were higher in SSS and RA+, but when corrected for serum concentration and salivary flow rate only the IgG ratio remained significantly elevated in SSS (P < 0.01) and RA- (P < 0.05) and the IgM ratio was reduced in RA- (P < 0.05) compared to controls. Although IgM RF activity in serum and saliva was strongly correlated (P < 0.001) in all 3 patient groups, the activity in saliva was considerably lower than serum activity. In the 2 (RA) patients tested, IgM RF in saliva contained secretory component. Mean salivary IgA RF activity varied between 34% (RA-) and 84% (SSS) of serum activity and correlated with serum activity in SSS (P < 0.001) and RA- (P < 0.01). IgA RF in saliva, but not in serum, contained secretory component. Additional demonstration of IgA RF activity in nasal and duodenal secretions in SSS may be related to involvement of the common mucosal immune system.