HLA class II alleles and salivary numbers of mutans streptococci and lactobacilli among young adults in Japan

To investigate the genetic predisposition toward the accumulation of oral microorganisms, the association between the alleles of HLA-DQA1, -DQB1 and -DRB1 and the salivary numbers of mutans streptococci and lactobacilli were examined in 102 young adults in Japan. HLA-DQA1*0102, DQB1*0604, DRB1*0802, and DRB1*1302 were weakly associated with the numbers of lactobacilli in saliva samples (P<0.05). HLA-DQB1*0601 was associated with the salivary numbers of mutans streptococci (P<0.01). Two HLA class II haplotypes, HLA-[DRB1*0802-DQA1*0301-DQB1*0302] and HLA-[DRB1*1302-DQA1*0102-DQB1*0604], were also weakly associated with the salivary numbers of lactobacilli (P<0.05). These observations suggest that HLA class II alleles may be related to the salivary populations of oral microorganisms, such as mutans streptococci and lactobacilli.