Influenza = specific IgM B cells were prevalent in the pre-RTX group (median sfc/106 lymphocytes, 55[0 to 1704] and controls (sfc/106 lymphocytes 30[0 to 3,500]) as compared with the post-RTX group (sfc/106 lymphocytes, 3[0 to 277]). The gene discussed is CD40LG; the disease is influenza.