Value of Lymph-Node Biopsy in the Diagnosis of Acute Acquired Toxoplasmosis

Abstract

The histologic findings supporting a diagnosis of toxoplasmic lymphadenitis, in lymph-node biopsies from 31 patients, were correlated with serologic studies. The Sabin-Feldman dye test was positive in all cases, with titers ranging from 1024 to 32,768; 81 per cent were 4096 or greater. The IgM immunofluorescent-antibody test was positive in 97 per cent of these cases. In contrast only 24 per cent of 114 patients with malignant lymphoma showed a positive dye test, with titers ranging from 4 to 1024, and only two exceeding 256, and only one patient was positive in the IgM immunofluorescent-antibody test. Of 87 surgical patients, the dye test was positive in 36 per cent, the range of titers varying from 16 to 2048, only five exceeding 256 and only one patient showing a positive IgM immunofluorescent-antibody test. These results provide further evidence of the distinctive nature of the histologic changes in toxoplasmic lymphadenitis, which should enable the pathologist to make a confident diagnosis of acute acquired toxoplasmosis. This study also emphasizes the need for clinicians to consider toxoplasmosis in the differential diagnosis of lymphadenopathy. (N Engl J Med 289:878–881, 1973)