Evaluation of the Cutaneous Immunological Milieu Before and After Treatment With Meglumine Antimoniate in Dogs Naturally Affected by Leishmaniosis due to Leishmania infantum.

backgroundCanine leishmaniosis (CanL) is a zoonotic disease of variable severity. The typical immune response is driven by an exaggerated humoral immune response. Protective immunity is mediated by pro-inflammatory cytokines that enhance macrophage leishmanicidal activity.

objectiveTo evaluate the cutaneous and the systemic immune responses as well as the cutaneous parasitic load in affected dogs before and after 28 days of treatment with meglumine antimoniate. ANIMALS: Twelve dogs with CanL and skin lesions, treated with meglumine antimoniate at a target dose of 100 mg/kg subcutaneously every 24 h, were prospectively enrolled. METHODS AND MATERIALS: Before and after 28 days of treatments, blood samples and skin biopsies were collected. Circulating levels of host defence peptides, leptin and cytokines were determined via enzyme-linked immunosorbent assay (ELISA). Paraffin-embedded skin biopsies were processed for routine immunofluorescence and positive cells were identified using commercially available anti-canine antibodies. Parasitic load also was determined via molecular methods. All variables were statistically analysed with the significance level set at 0.05.

resultsAmong the cutaneous cell types investigated, there was a decrease in the number of T-box transcription factor TBX21 (Tbet CONCLUSIONS AND CLINICAL RELEVANCE: The results of this study show that the reduction of cutaneous parasitic load after meglumine antimoniate treatment results in downregulation of innate and adaptive cutaneous inflammatory responses.