High incidence of horse serum protein allergy in various autoimmune disorders

In 186 persons (68 patients suffering from different so-called autoimmune diseases, 30 kidney recipients, 38 control patients from a surgical ward, and 50 healthy volunteers) the immune response to horse IgG was examined. The lowest rate of sensitization was found in kidney transplant recipients (3%) and the highest in autoimmune patients (33%). After excluding 39 patient who had received horse serum treatment prior to the examination, it was found that without previous injection of horse serum, 27% of the patients with autoimmune disease were sensitized to horse IgG. Compared to the other groups (kidney transplant recipients, 4%: surgical controls, 0%; healthy volunteers, 3%), this difference was statistically significant (p is less than 0.01).