Cytomegalovirus infection in leucocytes after bone marrow transplantation demonstrated by mRNA in situ hybridization.

Cytomegalovirus (CMV) infection in leucocytes after bone marrow transplantation (BMT) was identified using a 35S-labelled antisense RNA probe specific for CMV immediate early (IE) gene mRNA. 54 patients were examined regularly up to 14 weeks after BMT. 36 after allogeneic BMT and 18 after autologous BMT. Only mononuclear cells with monocyte morphology were CMV IE mRNA positive. The number of CMV positive leucocytes was higher after allogeneic BMT than after autologous BMT (P = 0.006), and in patients with acute graft-versus-host disease (GvHD) II-IV than with GvHD O-I (P = 0.06). In patients who later developed chronic GvHD, the mean value of CMV infected leucocytes during the first week after BMT was higher than in patients without chronic GvHD (P = 0.034). Patients with symptomatic CMV infection had greater numbers of CMV infected leucocytes during the fourth and fifth week after BMT than patients without CMV disease, but the difference did not reach statistical significance. CMV infection of monocytes may be an important factor in the early onset of CMV infection and of GvHD.