Influence of HLA-DR2 on perforin-positive cells in pulmonary tuberculosis

Abstract

Perforin is one of the key effector molecules of cytotoxic T cells and natural killer cells. The influence of HLA-DRB1 alleles on peripheral blood perforin-positive CD4, CD8, CD16 and CD56 cells was studied by flow cytometry. HLA-DRB1 typing was done in normal healthy subjects (NHS: n = 156) and patients with pulmonary tuberculosis (PTB: n = 102) by polymerase chain reaction-based sequence-specific oligonucleotide hybridization method. We observed a significantly decreased percentage of total perforin-positive cells (per +) (P = 0.0004); CD8+/Per+ (P = 0.0005); CD16+/Per+ (P = 0.05) and CD56+/Per+ cells (P = 0.001) in HLA-DR2-positive PTB patients compared to non-DR2 patients. Subtyping of HLA-DR2-positive subjects at the allelic level revealed that the percentage of CD8+/Per+ cells did not differ among DRB1*1501 and DRB1*1502 patients while a trend towards a decreased percentage of CD16+/Per+ and CD56 +/Per+ cells was noticed in DRB1*1501 patients compared to DRB1*1502 patients. The present study suggests that HLA-DR2 may be associated with down-regulation of perforin-positive cytotoxic lymphocytes and natural killer cells in pulmonary tuberculosis. © 2007 The Authors.