High IgE in rheumatoid arthritis (RA) patients is complexed with anti-IgE autoantibodies

Abstract

This study presents data on more than 300 RA and allergic patients analysed for their serum levels of anti-immunoglobulin isotype autoantibodies and IgE. We observed high levels of IgE in sera of RA and allergic patients. Interestingly, we measured significantly higher specific IgE levels against Alternaria but not against nine other allergens in the RA compared with the allergic group. As expected, anti-IgG autoantibodies (rheumatoid factors (RF)) of different isotypes were detected in sera from RA patients only. However, we found increased titres of complexed anti-IgE autoantibodies in all RF+ groups and in the allergic group. These findings may explain why despite elevated IgE levels a decreased prevalence of allergic diseases in RA patients has been observed.

Fig. 1

Determination of free and complexed anti-IgE. (a) Free anti-IgE measured by two different preparations of IgE: SUS11 (□) and JW8 (▪). (b) Complexed anti-IgE measured by BSW17 (□) and Le27 (▪). Values displayed represent mean ± s.d.

Fig. 2

Quantification of total and allergen-specific IgE. (a) Total serum IgE (kU). (b) Alternaria-specific IgE (rel. optical density (OD)). (c) IgE specific for nine allergens measured by immunodot assay (rel. OD). Results are expressed as a mean value of all nine allergens and for each patient group.