Most labs measure titers of IgM RF in rheumatoid arthritis patients. Interestingly, IgE RF was detected in a low percentage of RA patients (9%) [1]. IgE RF correlated better with extra articular manifestations than IgM RF in at least one study [2]. Have other laboratories investigated the potential association between IgE RF and extra articular manifestations? If so, what are your findings? Is there any association between IgE RF and allergies or sensitivities in RA patients?
1 Banchuin N, Janyapoon K, Sarntivijai S, Parivisutt L. Re-evaluation of ELISA and latex agglutination test for rheumatoid factor detection in the diagnosis of rheumatoid arthritis. Asian Pacific journal of allergy and immunology 1992;10(1):47-54.
2 Herrmann D, Jager L, Hein G, Henzgen M, Schlenvoigt G. IgE rheumatoid factor. Occurrence and diagnostic importance in comparison with IgM rheumatoid factor and circulating immune complexes. J. Investig. Allergol. Clin. Immunol. 1991;1(5):302-307.
Potentially interesting findings. We have no data in this area. Technically difficult to measure. Were IgA and/or IgG RFs measured in these cohorts?
Good to hear that!
In our RA cohort from Sudan, we investigated the three RF isotopes (Ig A, IgG and IgM) and may be valuable to test for IgE RF and their association to extra-articular manifestation.
Thanks Kathy
Interesting topic indeed! Considering prevalence of IgE subtype in the whole RF autoantibodies I do not anticípate a significant predictability of IgE in extra-articular manifestations (EAM) of RA. Moreover EAM are more relevant and prevalent in Spondyloarthritis which is seronegative in nature. I would kindly suggest to look for correlation between baseline RF and burden of disease in RA and long term response to biologics (robust data for Rituximab but never properly explored for anti TNF drugs)
Thank you all for responding with your invaluable insights and perspectives! In regards to the testing of all the isotypes of RF, the Banchuin et al article investigated the epidemiology of IgM RF, IgA RF, IgG RF, IgD RF and IgE RF. The Hermann et al article only reported on IgM and the IgE RF factor titers. Thank you very much, Maria for your potential explanations / mechanisms for an association between IgE and extraarticular manifestations. Some RA patients self-report sensitivity to various compounds that affect their joint flexibility, tenderness, and inflammation. I wonder if IgE RF could potentially contribute to the phenomena.
Thanks for your insights! Kathy
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