Cytomegalovirus encephalitis in a child with adenosine deaminase-deficient severe combined immune deficiency: a neuropathologic study.

Cytomegalovirus (CMV) encephalitis is exceptional in patients with genetically determined immune deficiency syndromes. Neuropathologic findings of CMV encephalitis were present at postmortem examination in a child we treated for severe combined immune deficiency. Cultured skin fibroblasts of this male infant revealed a deficiency of adenosine deaminase (ADA). Lacking a suitable bone marrow donor, we used transfusions of red blood cells as a source of ADA. However, the child developed encephalopathy and died at 16 months. The main neuropathologic findings were numerous, widely distributed inclusion-bearing and CMV antigen-positive cells; a complete lack of inflammatory reaction; and cell-to-cell fusion of infected cells reflecting the child's severely impaired immune response.