Association of ICAM-1 (K469E) and MCP-1-2518 A > G polymorphism with risk of Japanese encephalitis in North Indian population

Abstract Background Japanese encephalitis virus (JEV) is most important cause of viral encephalitis worldwide. The pathogenesis of this is probably attributed to the host genetic makeup. Intercellular adhesion molecule-1 (ICAM-1) and monocytes chemoattractant protein-1 (MCP-1) play a vital role in host defense mechanism against flavivirus causing encephalitis. We assessed the possible genetic association between ICAM-1 (K469E) and MCP-1-2518 A > G polymorphisms and Japanese Encephalitis in North Indian population. Methods We studied ICAM-1(K469E) and MCP-1-2518 A > G polymorphisms with the help of polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis. Expression of ICAM-1 and MCP-1 were determined at mRNA and protein levels in JE patients and healthy controls by real-time polymerase chain reaction and enzyme-linked immunosorbent assay (ELISA). Results Homozygous (E/E) genotype of ICAM-1 was associated with clinical severity (p = 0.015) and outcome (p = 0.04) of JE, whereas, heterozygous (A/G) genotype of MCP-1-2518 A > G was associated with outcome in JE patients (p = 0.01). Among severe cases of JE, a higher level of ICAM-1 was observed in patients with E allele (E/K + E/E) of ICAM-1 (K469E) than non-E allele (K/K). The level of MCP-1 was found significantly increased in JE patients with homozygous (G/G) genotype when compared to wild (A/A) genotype of MCP-1-2518 A > G (p = 0.03). Conclusion ICAM-1 (K469E) and MCP-1-2518 A > G polymorphisms lead to increased level of ICAM-1 and MCP-1 in Japanese Encephalitis which may be associated with severity as well as an adverse outcome of the disease. ICAM-1 (K469E) polymorphism may affect host susceptibility to Japanese encephalitis in North Indian population.