Serum sickness and plasmacytosis: A clinical, immunologic and hematologic analysis

Abstract

A mild case of serum sickness following an injection of equine tetanus antitoxin is reported. During the illness there was a plasmacytosis amounting to 30 per cent of the white cells in the peripheral blood. Three months after the illness, a skin test with equine serum produced an intense local reaction and the reappearance of plasmacytosis. Precipitating antibody was demonstrated against three types of equine globulins, two of which are known to carry antibodies. The patient's precipitins were γ 2-globulins, while her hemagglutinins were both γ 2- and γ 1-globulins. Skin sensitizing antibody was also found and it sedimented with the 7S globulins. In four cases of serum sickness with 1 to 3 per cent plasmacytosis and in four cases without plasmacytosis, antibodies were found to have developed to the same horse serum antigens, and no distinction could be made between the two groups in respect to the classes of antibodies developed. All patients had 7S antibody, whereas 19S antibody was found only in two. No single immunologic factor could be correlated closely with plasmacytosis.