Immunologic studies in cow's milk-induced pulmonary hemosiderosis.

Antibodies to cow's milk proteins (CMP) were studied by radioallergosorbent tests to determine the quantity and immunoglobulin class of these antibodies in nine patients with precipitins to cow's milk. Three of these patients had pulmonary hemosiderosis (PH); in one other patient pulmonary hemosiderosis was suspected, but not proven. Three patients had nonhemosiderosis chronic lung disease and two had other diseases. Age-matched control subjects were also studied. The quantity and immunoglobulin class distribution of antibodies to CMP were similar in all patients; the quantity of anti-CMP antibody was significantly greater in patients than in control subjects (P less than 0.001). In addition, complement-fixing antibody to CMP was not detected in either patients' or controls' sera. Lymphocyte responses to CMP were studied in three patients with PH, three individuals with other manifestations of milk hypersensitivity (positive controls), and nine negative control subjects. Patients and positive control subjects responded to CMP with greater tritiated thymidine incorporation than the negative control subjects (P less than 0.05). However, no significant difference in response to CMP was observed between the PH patients and the positive control subjects. Antibodies to human lung tissue were studied in the sera of all patients with PH and two negative control subjects. Antibodies to human lung and rat lung were detected in one patient with PH.