Immunologic significance of HLA class I genes in measles virus-specific IFN-gamma and IL-4 cytokine immune responses.

The variability of immune responses modulated by human leukocyte antigen (HLA) genes and secreted cytokines is a significant factor in the development of a protective effect of measles vaccine. We studied the association between type 1 helper T cells (Th1)- and Th2-like cytokine immune responses and HLA class I alleles among 339 schoolchildren who previously received two doses of the measles vaccine. Median values for measles-specific interferon gamma (IFN-gamma) and interleukin-4 (IL-4) cytokines were 40.7 pg/ml [interquartile range (IQR) 8.1-176.7] and 9.7 pg/ml (IQR 2.8-24.3), respectively. Class I HLA-A (0101 and 3101) and HLA-Cw (0303 and 0501) alleles were significantly associated with measles-virus-induced IFN-gamma secretion. HLA-A3101 and Cw0303 were associated with a higher median IFN-gamma response, while A0101 and Cw0501 were associated with lower measles-specific IFN-gamma response. We found limited associations between HLA class I gene polymorphisms and Th2-like (IL-4) immune responses after measles vaccination, indicating that HLA class I molecules may have a limited effect on measles-vaccine-induced IL-4 secretion. Understanding the genetic factors that influence variations in cytokine secretion following measles vaccination will provide insight into the factors that influence both cell-mediated and humoral immunity to measles.