In all four patients with B cell lymphoma studied (three with mantle cell lymphoma and one with small B cell lymphoma), we observed that a 30-min incubation of lymphoma cells with 10 mg/ml MβCD significantly decreased binding of anti-CD20 (B9E9) mAb, while binding of anti-CD19 mAb was affected to a lesser extent (Figure 8). The gene discussed is CD19; the disease is lymphoma.