Leishmaniasis in Brazil: X. some observations on intradermal reactions to different trypanosomatid antigens of patients suffering from cutaneous and mucocutaneous leishmaniasis

Abstract

In spite of the difficulty of antigen standardization, paired intradermal skin tests demonstrated qualitative differences between leishmanin and in vitro exo-antigen. Some of these differences may be due to the destruction of certain antigens by phenol, while others seem to reflect basic antigenic differences. Leishmania mexicana amazonensis in vitro exo-antigen produced immediate anaphylactic responses in 74 · 4% of the patients with parasitologically proven cutaneous leishmaniasis. Although more individuals responded to leishmanin, 82 · 4% as compared to 73 · 9%, the leishmanial in vitro exo-antigen gave significantly larger delayed responses. Trypanosoma cruzi trypamosomin elicited delayed reactions, while trypanosomal in vitro exo-antigen only produced immediate anaphylactic reactions in persons with active cutaneous leishmaniasis. Significantly more immediate anaphylactic responses were seen in L. brasiliensis guyanensis infections, and more marked responses occurred in infections of 6 months or less duration. Patients with mucocutaneous leishmaniasis had larger delayed responses than individuals with cutaneous infections due to L. b. braziliensis. Individuals with diffuse anergid cutaneous leishmaniasis had negative delayed reactions to all antigens, but two had weak anaphylactic reactions. Arthus-type responses were uncommon; they occurred in 4 people with mucocutaneous leishmaniasis, and in 3 with cutaneous leishmaniasis caused by L. b. guyanensis. No hypersensitivity reactions were seen in patients with Chagas' disease.