Intralesional isotype profiles in human localized cutaneous leishmaniasis lesions

Abstract

This immunocytochemical study evaluates the presence of IgG1-4, IgA and IgE immunoglobulins in active lesions of 25 localized cutaneous leishmaniasis patients from three bioclimatic areas (Awa, Afa and Bsha) in Mérida State, Venezuela. All immunoglobulin isotypes except IgE were detected, with variable intensity, in one or more of the epidermal or dermal components of skin lesions. IgG1 and IgG2 were detected significantly more frequently than IgG3, IgG4 and IgA. The ranking of the isotypes according to frequency of detection was the same in all areas: IgG1 = IgG2 > IgG3 = IgG4 = IgA, but considered as whole, all isotypes were detected significantly more frequently in patients from the Awa area than in those from the Bsha area. The predominant expression of isotypes IgG1 and IgG2 suggests a preferential Th1 like immune response. Anti-Leishmania immunoserum stained only parasites and their debris, suggesting that most of the immunostaining was nonspecific.

Figure 1

Immunocytochemical staining of skin sections from human localized cutaneous leishmaniasis. a) Immunoglobulin G3 deposits in plasma cells. X800. b) Immunoglobulin A deposits in dermis: intercellular matrix (IM); blood vessel (V) and dermis-epidermis junction (J). X 312.5. c) Immunoglobulin G1 deposits in granuloma. X 800. d) Immunoglobulin G2 deposits in keratinocytes of the upper layer of epidermis. X 500.

Figure 2

Immunoglobulin isotypes detected in lesions of human localized cutaneous leishmaniasis from three areas of Mérida State, Venezuela. Columns and bars represent the mean of Immunoglobulin isotypes and standard errors for Awa (open columns), Afa (dark shaded columns) and Bsha (light shaded columns) areas respectively.