Congenital cytomegalovirus: immunological alterations.

Immunological studies on 29 children with congenital cytomegalovirus (CMV) infection were performed. Two groups of patients were considered according to the presence or absence of clinical symptoms. Asymptomatic patients had increased numbers of natural killer (NK) cells (CD 16+), activated NK cells (CD16+/HLA-DR+), and activated suppressor/cytotoxic cells (CD8+/HLA-DR+/TAC+). In addition, cells from this group of patients showed increased NK activity against fibroblasts infected with CMV and a significant proliferative response to CMV antigens. In contrast, cells from symptomatic patients had reduced NK activity against fibroblasts infected with CMV and a defective proliferative response to CMV antigens. In both groups, the number of total T, T-helper, and T-suppressor/cytotoxic cells was normal, as was the ratio of helper/suppressor. The reported differences in the immunological parameters between the asymptomatic and symptomatic patients suggest that cell-mediated immunity may play an important role in determining the outcome of the infection.