How do we dose maintenance rituximab in AAV to optimise B cell depletion but minimise hypogammaglob? Drug levels may be the answer. In this cohort (n=61) trough >550ng/mL: all B cell depleted >1000ng/mL: all got hypogammaglob very interesting concept! #ACR20 ABST1438 @RheumNow https://t.co/0pcl0BW2Tv