MANNOSE-BINDING LECTIN AND SUSCEPTIBILITY TO INFECTIONS

Key words: Mannose-binding lectin, Complement, Cystic fibrosis, Innate immunity, Opsonisation, Meningococcal disease

Mannose-binding lectin (MBL) is an acute phase protein, belonging to the collectins family, involved in host innate immunity. It binds to surface mannose-rich glycoproteins of several microorganisms, inducing phagocytosis by opsonic and complement activating properties. Both heterozygous and homozygous carriers of MBL-gene variant alleles seem more susceptible to some infections. However, low serum MBL levels are not likely the only cause of clinical illness. More probably an overt clinical pathology occurrs when an MBL-deficient status associates with some other immune defect or disease. Recent studies have shown an association between MBL-gene variant alleles and meningococcal-disease susceptibility. In addition, a low-producing MBL gene phenotype seems to be associated with a poor prognosis in cystic fibrosis. Some evidence also exists about a role of MBL in some autoimmune diseases.