Serotype-specific pneumococcal disease may be influenced by mannose-binding lectin deficiency.

Previous studies of the association between the mannose-binding lectin pathway deficiencies and invasive pneumococcal disease are inconclusive. Invasiveness of Streptococcus pneumoniae is dependent on serotype. We aimed to determine the association between invasive pneumococcal disease and MBL2 and MASP2 genetic variants, regarding serotype distribution. A hospital-based case-control study was conducted in children admitted to hospital in rural Mozambique in June 2002-November 2003. The study included children admitted to hospital with invasive pneumococcal disease, in whom S. pneumoniae was isolated from blood and subsequently serotyped. Sequence-based typing analysis of amplicons covering the polymorphic regions of MASP2 (exon 3) and MBL2 (promoter and exon 1) was performed. An overall high frequency of MBL2 genotypes associated with low serum levels of MBL (43%) was found. Carriers of MBL-deficient genotypes were associated with invasive pneumococcal disease produced by low-invasive serotypes (OR 5.55, 95% CI 1.4-21.9; p = 0.01). Our data suggest that susceptibility to pneumococcal disease among MBL-deficient patients may be influenced by serotype invasiveness. Type-specific capsular serotype of S. pneumoniae would need to be taken into account in further genetic association studies of invasive pneumococcal disease.