Pulmonary inflammation in autoimmune MRL/Mp-lpr/lpr mice. Histopathology and bronchoalveolar lavage evaluation.

Early detection of lupus pneumonitis is difficult because it requires lung biopsy. The authors describe here in detail the age-related histologic changes in pulmonary inflammation, the age-related changes in bronchoalveolar lavage (BAL), and the effect of cyclophosphamide (8 mg/kg) on pulmonary inflammation and bronchoalveolar lavage in MRL/Mp-lpr/lpr mouse, an animal model of systemic lupus erythematosus. To assess the evolution of pulmonary inflammation and response to cyclophosphamide therapy, they compared the age-related progression of pulmonary inflammation with sequential changes in BAL cell populations in this autoimmune mouse model. A striking similarity was noted between age-related changes in pulmonary inflammation and lymphocyte counts in BAL. A trend to reduction in histologic evidence of inflammation was reflected by lymphocytes in BAL in cyclophosphamide-treated (8 mg/kg/day) males but not in females. There was a striking sex-related difference in that the histologic evidence of pulmonary inflammation and bronchoalveolar lavage lymphocyte count in cyclophosphamide-treated males was significantly lower than cyclophosphamide-treated females of the same age.