Fig. 4.

Correlation between IgA subclasses and CRP in seropositive RA patients

Correlation between IgA subclass levels and CRP levels in (A) IMPROVED seropositive RA patients and in (B) EAC seropositive patients, calculated using Spearman’s rank correlation coefficient (r_s). In RF IgA subclass analyses, only patients positive for both RF IgA1 and RF IgA2 are included. For anti-CCP2 IgA1 analysis, only anti-CCP2 IgA1 positive patients are included. Of note, RF and anti-CCP2 IgA subclass levels were not titrated.