VALUE OF LYMPH-NODE BIOPSY IN THE DIAGNOSIS OF ACQUIRED TOXOPLASMOSIS

Toxoplasmic lymphadenitis generally involves a solitary lymph node in the head and neck regions, without systemic symptoms. In order to dete rmine the frequency of toxoplasmic lymphadenitis, we reviewed the hist ological sections of 731 consecutive patients with reactive lymph node hyperplasia. Amongst 731 patients, 112 had histological features supp orting a diagnosis of toxoplasmic lymphadenitis (15.3 per cent). In 80 of these patients (71 per cent), either Indirect Haemaglutination tes t (IHA), in 37 cases, or the Enzyme-Linked Immunosorbent Assay (ELISA) for detecting toxoplasmic IgG or IgM antibodies, in 43 cases, were pe rformed. In 76 out of 80 patients (95 per cent), histological features correlated well with serological studies. The IHA test was positive i n 30 patients with a titre of 1/64 or higher. The IgG-ELISA test was p ositive in 11 whereas the IgM-ELISA test was positive in 28 patients. These results provide further evidence of the distinctive nature of th e histological changes in toxoplasmic lymphadenitis, which should enab le the clinician to make a confident diagnosis of acute acquired toxop lasmosis.