Cytomegalovirus pneumonitis after kidney transplantation is not caused by plugging of cytomegalic endothelial cells only

In addition to life-threatening pneumonia, cytomegalovirus (CMV) may also c ause subclinical pulmonary dysfunction after kidney transplantation. To inv estigate the role of plugging of cytomegalic endothelial cells in the pulmo nary capillary bed, we prospectively determined specific carbon monoxide di ffusion capacity (KCOc) and its components: the pulmonary diffusing membran e factor (Dm) and pulmonary capillary blood volume (Vcap) before and during CMV infection in 13 kidney transplant recipients and 13 controls. During C MV infection, mean KCOc decreased significantly by 28 % of the initial valu e (mean KCOc 79 vs 109; P < 0.005) due to a decrease in both Vcap and Dm. T he KCOc in controls showed a significantly smaller decrease due to a slight ly lower Vcap. We conclude that kidney transplant recipients with CMV infec tion have significant pulmonary diffusion disturbances due to a combination of lower Vcap and lower Dm. The most likely explanation for this phenomeno n is a local inflammatory process due to CMV and not plugging of cytomegali c endothelial cells only.