Deficiency of mannose-binding lectin and burden of infection in children with malignancy: a prospective study

Background Infection is a major cause of morbidity and mortality in children with malignancy. Individuals with serum deficient in mannose-binding lectin (MBL)-an important component of the innate immune system-are more susceptible to infection than those with adequate concentrations. In this study, we investigated the capacity of this protein to influence infectious complications in children undergoing treatment for malignancy. Methods We enrolled 100 children receiving chemotherapy for malignancy at a children's hospital in London, UK. The frequency, duration, and causes of febrile neutropenic episodes were recorded, and MBL genotype and phenotype were determined by heteroduplex analysis and ELISAs, respectively. Serial MBL concentrations were also measured in patients during febrile episodes, and the results correlated with the MBL genotype (A/A indicating wild type, O/O indicating homozygous for MBL structural-gene mutations, and A/O indicating heterozygous for such mutations). Findings In the A/A patients, MBL concentrations almost doubled by day 7 of the febrile neutropenic episode before declining by day 14 (p=0.004). By contrast, fn patients with MBL mutations, concentrations did not alter significantly during the neutropenic episode. In the 6 months after initial diagnosis, most patients had at least one febrile neutropenic episode, but the median duration in patients with MBL mutations was twice as long as that in children with the wildtype genotype (20.5 days vs 10.0 days; p=0.014). Individuals with the lowest serum MBL concentrations at the time of diagnosis (<1000 g/L) had a higher median number of days of febrile neutropenia than did individuals with higher concentrations of MBL (p=0.012). Interpretation MBL deficiency seems to have an important influence on the duration of febrile neutropenic episodes in children with malignancy. This finding suggests that MBL infusions could represent a new therapeutic approach which would aid the management of chemotherapy-induced complications in this population of children.