Objective: To study whether there is a relationship between HLA-B alleles and low natural killer(NK) cell activity in Chinese.
Methods: The subjects were 34 unrelated healthy individuals (10 males and 24 females), aged 25-60 years, and 31 individuals (17 males and 14 females) from 11 families, aged 22-70 years, previously genotyped for HLA class I, II, complotypes and haplotypes that were assigned based on family studies. The unrelated individuals were typed for HLA-A, -B antigen by a microcytotoxicity assay and all the subjects were tested for NK cell activity by lactate dehydrogenase (LDH) enzyme-release assay.
Results: Statistical analysis showed that 30 lysis unit(LU) was the cutoff value of low and high NK reactors. The frequency of low reactor individuals homozygous for HLA-B was significantly higher than that for those for HLA-DR(P< 0. 05). The associated genes included HLA-B13, B40, B46, B7, B57, defined as NKB1 genes, and HLA-B44 as NKB2 gene. Family studies provide further evidence that the genes controlling low NK cell activity were located in the MHC region and it was a recessive trait.
Conclusion: There were recessive genes associated with HLA-B controlling low NK cell activity in Chinese. The NKB alleles were partly different from those found in Caucasian.