Radioimmunotherapy with iodine-131 tositumomab in patients with low-grade non-Hodgkin's B-cell lymphoma does not induce loss of acquired humoral immunity against common antigens

Thirty-one previously untreated patients with follicular low-grade B-cell n on-Hodgkin's lymphoma expressing the CD20 antigen were treated with iodine- 131 tositumomab therapy between 1996 and 1998. The therapy led to a tempora ry depletion of peripheral blood B-lymphocytes. Recovery of B-cells occurre d in most cases by 3 to 6 months and in all patients by 12 months postthera py. A temporary decline in T-cell subpopulations, but no reduction in serum immunoglobulin levels, could be observed. ELISA techniques were used to de tect specific antibodies against rubella, mumps, varicella tester, measles, and tetanus. Almost all patients remained seropositive against the differe nt antigens during the 1- to a-year follow-up. No significant reduction in antibody concentrations to tetanus or measles could be detected. The data s how that acquired humoral immunity against common antigens appears to be pr eserved despite a temporary loss of B-lymphocytes. (C) 2001 Academic Press.