Evidence for HLA class II susceptible and protective haplotypes for osteomyelitis in pediatric patients with sickle cell anemia

We investigated the association of human leukocyte antigen (HLA) class II alleles and haplotypes with the pathogenesis of sickle cell anemia (SCA) osteomyelitis. SCA patients comprised 42 patients with osteomyelitis and 150 patients without osteomyelitis; HLA-DRB1* and HLA-DQB1* genotyping was performed by polymerase chain reaction-sequence-specific priming (SSP). DRB1*100101 (P value corrected for the number of different alleles tested, Pc=0.003) was positively associated with osteomyelitis. At the haplotype level, DRB1*100101-DQB1*050101 (Pc=0.001) was more prevalent among patients, while DRB1*030101-DQB1*0201 (Pc=0.020) and DRB1*040101-DQB1*0302 (Pc=0.039) were more prevalent among SCA controls, thereby conferring disease susceptibility or protection to these haplotypes, respectively. These results show that specific HLA haplotypes influence SCA osteomyelitis risk and that specific HLA types may serve as markers for identifying SCA patients at high risk for osteomyelitis.