Notably, patients with American cutaneous leishmaniasis (ACL—20.17 ± 1.63 pg/mL), patients with type 2 diabetes mellitus (T2DM—23.60 ± 7.29 pg/mL), and patients with both diseases (23.53 ± 3.22 pg/mL) exhibited higher TNF-α levels compared to the control group (10.20 ± 2.67 pg/mL). This evidence concerns the gene TNF and type 2 diabetes mellitus.