Leishmania-specific immunoglobulin subclass response was evaluated in 133 patients infected with Leishmania braziliensis. The indirect immunofluorescent antibody test (IFAT) was employed with amastigotes of L. mexicana amazonensis as antigen. Among the 133 sera obtained at consultation fo rdiagnosis of active lesions, IgM was detected in 54 following absorption with Staphylococcus aureus Cowan strain I, and in 5 sera prior to absorption. IgM reactive with Leishmania antigen was only found in sera from patients whose lesions had envolved over past two months or less. Leishmania-specific IgG was detected in all sera prior to absorption. Sera obtained at the time of recurrence of after complete healing of lesions presented only specific IgC. The combined use of the Montenegro skin test and specific IgM increased the sensitivity of immunodiagnostic methods in patients with lesions of less than 2 months duration. Normal control volunteers were negative for specific IgM and unreactive to Montenegro skin testin. Among 16 patients with non-leishmanial lesion, 3 with sporotrichosis showed IgG reactive with Leishmania; none, including 4 with lesions of less than two months duration, showed specific IgM. We conclude that in patients infected with L. brasiliensis the presence of specific IgG and IgM is associated with the time of lesion evolution and the primary or recurrent nature of the lesions. In addition, the combined use of IgM titer and Montenegro reactivity is of potential utility in the diagnosis of early lesions.
indirect immunofluorescence; Leishmania braziliensis; amastigotes; tegumentary leishmaniasis; isorypes; early diagnosis