Utility of antibodies against a 22 kD molecule of Dirofilaria immitis in the diagnosis of human pulmonary dirofilariasis.

To assess the characteristics of an ELISA test for the diagnosis of human pulmonary dirofilariasis, we studied the sera of 24 subjects with other helmintoses and of 37 patients suffering from non-parasitic focal lung diseases, comparing them with negative and positive sera. ELISA and Western blot with complete somatic antigen and ELISA with protein Di22 (specifically recognized in cases of lung dirofilariasis) were performed. With ELISA SA the false positive rate was 25% in cases with other parasitoses and 30% in cases with focal lung diseases. ELISA Di22 decreases this positivity levels. Only 2 cases with visceral larva migrans (8.3%) and a case with lung nodules metastatic from renal adenocarcinoma (2.7%) were positive. ELISA Di22 therefore greatly decreases the false positive rate of ELISA SA.