Association between Cryptosporidium infection and human leukocyte antigen class I and class II alleles

Background. Cryptosporidium species are a common cause of diarrhea, which can be severe and protracted in young children and immunocompromised individuals. Methods. A cohort of 226 Bangladeshi children aged 2-5 years was prospectively followed for >3 years to study the role of host genetics in susceptibility to infection, as well as the community impact of cryptosporidiosis on this population. Results. Ninety-six children (42.5%) received a diagnosis of Cryptosporidium infection. A total of 51 (22.6%) had asymptomatic infection. Fifty-eight (25.7%) had cryptosporidiosis, of whom 17 (29.3%) had recurrent disease. Children with cryptosporidiosis presented early, and most had abdominal pain and a short course of diarrhea. Infected children were more likely to carry the human leukocyte antigen (HLA) class II DQB1*0301 allele, particularly those with asymptomatic and symptomatic infection (P = .009); a strong association was found between carriage of the DQB1*0301/DRB1*1101 haplotype and development of both asymptomatic and symptomatic infection (P = .008). Infected children were also more likely to carry the B*15 HLA class I allele. Conclusions. This is the first study to describe a possible genetic component of the immune response to Cryptosporidium infection, which includes HLA class I and II alleles. Cryptosporidiosis in Bangladeshi children aged 2-5 years is common and often recurrent, but the duration is shorter and the abdominal pain greater than that described in children aged <2 years.