BACKGROUND: Dirofilaria immitis is a nematode parasite of canids that, in endemic areas, can infect humans. The use of adult somatic antigens for the diagnosis of human dirofilariasis has the disadvantage of a low sensibility because of cross-reactivity with other helminths, specially with IgM antibodies. We describe in this work proteins of the adult somatic antigenic complex that are specifically recognized by human IgM. METHODS: Human sera with different characteristics were analyzed by an enzyme-linked immunosorbent assay (ELISA) for the detection of anti-D. immitis IgM seropositive individuals. Moreover, an enzyme-linked immuno-electro-transfer blot (EITB) was performed for the detection of polypeptides that specifically react with IgM anti-D. immitis. RESULTS: EITB analysis shows that 2 proteins of 44 and 18 kD are recognized by IgM in human sera from an endemic area with a high antibody titer against D. immitis measured by ELISA. Sera from a non-endemic area and from patients suffering from other parasitic and non-parasitic diseases did not recognize these antigens. CONCLUSIONS: We believe that the 44 kD protein could be a good marker of recent D. immitis infection.
BACKGROUND:Dirofilaria immitis is a nematode parasite of canids that, in endemic areas, can infect humans. The use of adult somatic antigens for the diagnosis of human dirofilariasis has the disadvantage of a low sensibility because of cross-reactivity with other helminths, specially with IgM antibodies. We describe in this work proteins of the adult somatic antigenic complex that are specifically recognized by human IgM. METHODS:Human sera with different characteristics were analyzed by an enzyme-linked immunosorbent assay (ELISA) for the detection of anti-D. immitis IgM seropositive individuals. Moreover, an enzyme-linked immuno-electro-transfer blot (EITB) was performed for the detection of polypeptides that specifically react with IgM anti-D. immitis. RESULTS: EITB analysis shows that 2 proteins of 44 and 18 kD are recognized by IgM in human sera from an endemic area with a high antibody titer against D. immitis measured by ELISA. Sera from a non-endemic area and from patients suffering from other parasitic and non-parasitic diseases did not recognize these antigens. CONCLUSIONS: We believe that the 44 kD protein could be a good marker of recent D. immitis infection.