DECLINING LYMPHOCYTE COUNTS FOLLOWING CYTOMEGALOVIRUS (CMV) INFECTIONARE ASSOCIATED WITH FATAL CMV DISEASE IN BONE-MARROW TRANSPLANT PATIENTS

A previous pilot study conducted on 12 bone marrow transplant recipien ts suggested that detection of cytomegalovirus (CMV) in lymphocytes wa s associated with a drop in lymphocyte counts and death due to CMV dis ease. To test the association between decreasing lymphocytes and CMV-r elated death, we undertook a retrospective study of 332 CMV-infected p atients transplanted between 1987 and 1990. The patients were divided into three groups: I = 170 patients who survived their infection and w ere alive at the time of the study; II = 103 patients who died of caus es other than CMV infection; and III = 59 patients who died of CMV dis ease. Lymphocyte counts were analyzed during a 24-day period, starting 10 days before the day of first positive CMV culture (day 0). Lymphoc yte counts were significantly lower in Group III from day 0 through da y +14 (p<.001 vs. group I; and p=.002 vs. group II). Multivariate stat istical analysis was used to adjust for other differences between the groups that might influence lymphocyte numbers. Average lymphocyte cou nts in patients who died of CMV disease decreased by an average of 35% after day 0. The differences in lymphocyte counts remained independen t of the effects of acute graft-vs.-host disease (GVHD), time since tr ansplant, transplant type, and high-dose steroid treatment. In summary , these data suggest that in some patients a drop in lymphocyte counts is a consequence of CMV infection associated with fatal CMV disease. Whether this can be attributed to direct infection of lymphocytes, a d efective immune response, or some other mechanism remains to be determ ined.