biostudies-literatureUnknown62(1)Derksen VFAMFOREUMDutch Arthritis Foundation<h4>Objective</h4>Mucosal initiated immune responses may be involved in the pathophysiology of RA. The most abundant immunoglobulin at mucosal surfaces is IgA, of which two subclasses exist: IgA1 and IgA2. IgA2 is mainly present at mucosal sites and has been ascribed pro-inflammatory properties. As IgA subclasses might provide insights into mucosal involvement and pro-inflammatory mechanisms, we investigated IgA responses in sera of RA patients.<h4>Methods</h4>In two cohorts of RA patients, the EAC and IMPROVED, total IgA1 and IgA2 were measured by ELISA. Furthermore, IgA subclass levels of RF and anti-citrullinated protein antibodies (anti-CCP2) were determined. The association of these IgA subclass levels with CRP and smoking was investigated.<h4>Results</h4>Total IgA1 and IgA2 were incrRheumatology (Oxford, England)407-416https://www.ebi.ac.uk/biostudies/studies/S-EPMC9788813biostudies-literatureIn rheumatoid arthritis patients, total IgA1 and IgA2 levels are elevated: implications for the mucosal origin hypothesis.PMC9788813Allaart CFvan der Woude DToes REMVan der Helm-Van Mil AHMDerksen VFAMHuizinga TWJfalseIn rheumatoid arthritis patients, total IgA1 and IgA2 levels are elevated: implications for the mucosal origin hypothesis.<h4>Objective</h4>Mucosal initiated immune responses may be involved in the pathophysiology of RA. The most abundant immunoglobulin at mucosal surfaces is IgA, of which two subclasses exist: IgA1 and IgA2. IgA2 is mainly present at mucosal sites and has been ascribed pro-inflammatory properties. As IgA subclasses might provide insights into mucosal involvement and pro-inflammatory mechanisms, we investigated IgA responses in sera of RA patients.<h4>Methods</h4>In two cohorts of RA patients, the EAC and IMPROVED, total IgA1 and IgA2 were measured by ELISA. Furthermore, IgA subclass levels of RF and anti-citrullinated protein antibodies (anti-CCP2) were determined. The association of these IgA subclass levels with CRP and smoking was investigated.<h4>Results</h4>Total IgA1 and IgA2 were incr2022-01-01T00:00:00Z2022 Dec2025-04-19T18:09:38.292Z2025-04-19T18:09:38.292ZS-EPMC97888133541696310.1093/rheumatology/keac237