CD4 and stomach disorder: Chen et al. demonstrated that HpaA88–100-specific CD4+ T cell response was immunodominant in subjects expressing HLA-DRB1*1501 and HLA-DRB1*1501-restricted immunodominant CD4+ T-cell response to HpaA88–100 was related with reduced risk of severe H. pylori-associated gastric diseases (Chen et al., 2013).