Objective: The aims of this study were to evaluate whether the presence of -2518A/G polymorphism in the distal regulatory region of the monocyte chemotactic protein-1 (MCP-1) was associated with tuberculosis (TB) in Chongqing Han population and to find whether it has a significant impact on the pediatric patient.
Method: One hundred children [ < or = 15 years old, mean age (7.3+/-4.6) years, 53 male, 47 female] and one hundred adults [51 male, 49 female, age (44.6+/-13.5) years with TB] and 200 healthy controls of comparable age were screened for genotype by PCR-sequence-specific primer (SSP) method. MCP-1 levels in the sera were detected by ELISA.
Result: (1) TB patients and controls showed different single nucleotide polymorphism (SNP) distribution patterns (58%, 36%). MCP-1 alleles -2518G was associated with increased TB susceptibility (P<0.01). (2) The -2518 GG genotypes was associated with increased TB susceptibility (32% in TB patients and 13% in non-TB controls respectively, P<0.01). (3) The odds of developing TB in genotypes GG were higher than those in homozygous AA, and the risk was higher in children than in adult (7.0-fold in children and 5.1-fold in adults, respectively). (4) Cases of homozygous GG had the highest plasma levels of MCP-1, which increased the likelihood of developing TB. Furthermore, higher levels were observed in children than in adults.
Conclusion: These findings suggest that persons bearing the MCP-1 genotype GG produce high concentrations of MCP-1, which increases the risk of active TB infection in Chongqing Han people. These findings are more significant in child patients than in adult patients with TB.