Decreased CD4 T Cells with Rituximab Infusions Save

Rituximab (RTX) is a monoclonal antibody directed against the CD20 antigen on B cells and when administered causes a marked depletion of CD20+ B cells.  Yet the exact mechanism by which B cell directed therapy results in long lasting clinical improvement in rheumatoid arthritis is unknown.

French researchers have noted that RTX therapy also results in a timely decrease in CD4+ T-cells.  Moreover, those patients who do not exhibit a CD4+ T-cell decrease are more likely to be RTX non-responders.

Between July 2007 and July 2013 they studied RA patients treated with RTX and followed lymphocyte subsets by phenotyping, along with routine clinical assessments before and after each cycle. 

Patients received up to seven cycles of RTX and it was noted that CD4+ T cells decreased concurrently with disease activity score. Patients who were non-responders to this first RTX cycle tended to experience a milder depletion of CD4+ T cells than did the responders.  As expected depletion of B cells was similar in both responders and nonresponders.

It appears that CD4+ T-cell counts may be a biomarker of RTX response to rituximab in RA patients and may add to our understanding the mechanisms by which B cell depletion may down-regulate chronic synovitis in RA.