CD19 and rheumatoid arthritis: However, RA subjects exhibited substantially increased phosphoprotein responses to BCR stimulation in the CD19+CD27−IgD+IgMllow/− B cell subset, as compared to normal controls (total pTyr mean±SE % increase of 121.4±30.6 vs. 22.5±31.0 in RA and control groups, respectively (p = 0.05)), suggesting that the breach of PIT in RA patients occurs regardless of the age (data previously reported [2]).