Alteration of bronchoalveolar cells during murine cytomegalovirus interstitial pneumonitis.

In BALB/c mice, murine cytomegalovirus (MCMV) in conjunction with a single dose of cyclophosphamide (CP) induces a diffuse interstitial pneumonitis not seen with either virus or CP alone. To gain insight into the host immune mechanisms operating in the lung during interstitial pneumonitis, we examined the cells recovered in bronchoalveolar lavage (BAL) fluids of mice with MCMV with and without CP. During MCMV interstitial pneumonitis, there was a significant increase in the total BAL cells recovered, primarily because of an influx of lymphocytes bearing the Thy 1.2 marker. Although the number of cells with Lyt 1 and Lyt 2 markers increased, the most significant increase was in the proportion of lymphocytes with surface asialo-GM1. Delineating the roles of these various cell populations may provide insight into the pathogenetic mechanisms leading to CMV interstitial pneumonitis.