Genetic polymorphism of the mannose-binding protein gene in children with sickle cell disease: identification of three new variant alleles and relationship to infections

Mannose-binding protein (MBP) is a serum lectin that participates in the in nate immune response. MBP deficiency may constitute a risk factor in the de velopment of infections. Three MBP structural variants have been identified with a dominant effect on MBP serum concentration, Similarly, polymorphism s in the promoter of the corresponding gene (HSMBP1B) have been related to variations of MBP concentration in serum. Children with sickle cell disease (SCD) have an increased susceptibility to infections with encapsulated org anisms resulting in meningitis, septicaemia, and osteomyelitis, We have inv estigated the HSMBP1B genotype in 242 children with SCD living in Paris, Ap art from the known variant alleles, we identified three novel ones and repo rt their distribution in our sample population. In addition, we found rathe r unexpectedly an increased frequency of the variant alleles in patients wh o had not suffered severe infections.