Sequence variations in the MBL gene and their relationship to pulmonary tuberculosis in the Chinese Han population

The mannan binding lectin (MBL) gene is thought to play a role in human innate immune response to tuberculosis (TB) infection.

To investigate the possible association between MBL sequence variants and TB infection in the Chinese Han population.

A total of 152 male pulmonary tuberculosis (PTB) patients and 293 healthy male subjects were recruited. Six MBL single nucleotide polymorphisms (SNPs) (A/B, A/C, A/D, H/L, Y/X and P/Q) were genotyped and haplotyped using the combined analysis of polymerase chain reaction using sequence-specific primers (PCR-SSP) and the PCR-sequence specific oligonucleotide probe (PCR-SSOP) assay. The genotype and haplotype frequencies were compared between TB cases and controls using an unconditional logistic regression model.

Neither the genotypes nor the haplotypes of the five loci were significantly associated with the disease when considered individually. After the haplotypes were regrouped, however, the XB haplotype group coding for diminished MBL levels was present at a significantly higher frequency in the patients compared with the YA group (OR 1.57, 95% CI 1.02-2.41, P < 0.05).

No convincing evidence of association between MBL sequence variants and PTB was observed individually, although the low-producing XB haplotype group may serve as a minor risk factor for PTB infection in the male Chinese Han population.