Serologic Findings in Patients with Primary Atypical Pneumonia

Abstract

In a study of 89 patients with primary atypical pneumonia a large majority was found to develop cold hemagglutinins and streptococcus MG agglutinins. Four individuals developed antibodies for a virus of the psittacosis group indicating an infection with one of these agents. No instance of Q fever was found in the 25 patients whose serums were tested for antibodies against this agent. In 5 additional patients who had atypical pneumonia associated with erythema multiforme exudativum, cold hemagglutinins were present, and two of these patients showed a rise in titer in complement-fixation tests for psittacosis. A history of exposure to sick pigeons was a significant observation with respect to the development of psittacosis antibodies.