Assessment of serum FcμR by EC-specific HM6 vs solFcμR-specific HMD22 mAbs. In our previous studies, CLL B cells expressed much higher levels of FcμR on their cell surface than B cells from healthy controls, and this enhancement was more evident in better outcome IGHV-mutated, CD38-, or early Rai-stage CLL patients than in IGHV-unmutated, CD38+ or advanced Rai-stage patients (10). The gene discussed is CD38; the disease is B-cell chronic lymphocytic leukemia.