The −2518 bp promoter polymorphism at CCL2/MCP1 influences susceptibility to mucosal but not localized cutaneous leishmaniasis in Brazil

Abstract

Mucosal leishmaniasis (ML) follows localized cutaneous leishmaniasis (CL) caused by Leishmania braziliensis. Proinflammatory responses mediate CL self-healing but are exaggerated in ML. Proinflammatory monocyte chemoattractant protein 1 (MCP-1; encoded by CCL2) is associated with CL. We explore its role in CL/ML through analysis of the regulatory CCL2 −2518 bp promoter polymorphism in CL/ML population samples and families from Brazil. Genotype frequencies were compared among ML/CL cases and control groups using logistic regression and the family-based association test (FBAT). MCP-1 was measured in plasma and macrophages. The GG recessive genotype at CCL2 −2518 bp was more common in patients with ML (N = 67) than in neighborhood control (NC; N = 60) subjects (OR 1.78; 95% CI 1.01–3.14; P = 0.045), than in NC combined with leishmanin skin-test positive (N = 60) controls (OR 4.40; 95% CI 1.42–13.65; P = 0.010), and than in controls combined with CL (N = 60) patients (OR 2.78; 95% CI 1.13–6.85; P = 0.045). No associations were observed for CL compared to any groups. FBAT (91 ML and 223 CL cases in families) confirmed recessive association of ML with allele G (Z = 2.679; P = 0.007). Higher levels of MCP-1 occurred in plasma (P = 0.03) and macrophages (P < 0.0001) from GG compared to AA individuals. These results suggest that high MCP-1 increases risk of ML.