Autoimmune cytotoxic granulocyte antibodies in normal persons and various diseases

Of 400 female and 58 normal nonommunized male sera approximately 10% were cytotoxic for a panel of allogeneic granulocytes. Sera with strong alloreactivity were also autoreactive, which emphasized the large autoimmune component of most alloantisera against granulocytes. The cytotoxic granulocyte autoantibodies were complement dependent, of the IgM class, and exhibited optimum cytotoxic activity in vitro at 5 degrees C precomplement incubation temperatures with papain-treated cells. The sera were unreactive with autologous or allogeneic B and T lymphocytes, monocytes, and red blood cells but were cytotoxic for adult and cord granulocytes, eosinophils, and chronic myeloid leukemia cells. Granulocyte autoantibodies were present in 53% of sera from 57 patients with systemic lupus erythematosus (p less than 0.00002) but were not found in increased frequency in the sera of patients with 28 other diseases. We conclude that a single tissue-specific antigenic determinant(s) called “G” may be present on granulocytes and is the target of naturally occurring autoantibodies.