Considering the interaction between IL-18, IL-12, and IFN-γ and the genetic aspects possibly involved in susceptibility to PCM and the lack of studies on this disease, the present study aimed to analyze the IL18-607 C/A (rs1946518), IL12A-504 G/T (rs2243115), and IFNGR1-611 A/G (rs1327474) SNPs, for the first time to our knowledge, in a cohort of Brazilian patients with PCM, also presenting a brief review of studies on these SNPs in infectious diseases. The gene discussed is IL12A; the disease is infectious disease.