CYTOMEGALOVIRUS ANTIBODY AVIDITY IN ALLOGENEIC BONE-MARROW RECIPIENTS- EVIDENCE FOR PRIMARY OR SECONDARY HUMORAL RESPONSES DEPENDING ON DONOR IMMUNE STATUS

The reconstitution of the human cytomegalovirus (CMV) antibody respons e in CMV seropositive bone marrow transplant patients was investigated by comparing 11 patients whose donors were CMV seropositive with 8 wh ose donors were CMV seronegative. Evidence for primary or secondary re sponses to CMV was sought by determining IgG antibody avidity using an avidity index method, and antibody titre over a period of up to 3 yea rs after transplant. For the patients whose donors were CMV seropositi ve, the results showed the characteristics of a secondary response, i. e., rising antibody titres of high avidity immediately after transplan t. In contrast, the patients with CMV seronegative donors showed evide nce of a primary antibody response usually occurring at about 250 days after transplant, i.e., rising antibody levels initially of low avidi ty maturing to high avidity over the following 100 to 200 days. It is concluded that a secondary response and hence transfer of humoral immu nity had occurred in those patients whose donor was CMV seropositive, whereas a delayed primary response occurred in those patients whose do nor was CMV seronegative. (C) 1996 Wiley-Liss, Inc.