Diffuse cutaneous leishmaniasis: A disease due to an immunological defect of the host

Abstract

Diffuse cutaneous leishmaniasis, with its characteristic diffusion of lesions, great abundance of parasites, anergy to skin tests with the specific antigen and resistance to treatment, has been described as a disease produced by a special strain of Leishmania, L. pifanoi . Our concept is that this form of leishmaniasis is due, not to a different type of parasite, but to an immunological defect of the human host, which makes him respond with these special clinical and parasitological manifestations. The basis for our belief is: (1) epidemiologically, the disease appears as isolated cases in endemic areas; (2) accidental inoculation of a laboratory technician with a strain taken from an animal with diffuse cutaneous leishmaniasis lesions produced a nodule with the clinical, pathological and parasitological characteristics of an American cutaneous lesion, with a strongly positive leishmanin reaction; (3) the coexistence, in a leishmaniasis focus, of two patients living in the same house, one of whom had diffuse cutaneous leishmaniasis and the other American cutaneous leishmaniasis; (4) clinical and pathological characteristics of an experimental inoculation in human volunteers with material obtained from diffuse cutaneous leishmaniasis lesions. This produced, in all the hosts, a typical American cutaneous leishmaniasis type of response.