The pharmacokinetics, and clinical and biological effects of MBL replacement therapy in MBL-deficient children during chemotherapy-induced neutropenia were studied.

Mannan Binding Lectin (MBL) is a member of the lectin pathway of the complement system and plays an important role in the innate immune system. MBL replacement in MBL-deficient children with chemotherapy-induced neutropenia represents a new approach to lower the risk of febrile episodes, of hospital admission, of prolonged use of intravenous antibiotics and of severe infections.

The aim of the Phase II study is to find evidence for the correct prediction of plasma levels of MBL necessary for clinical effects and biological efficacy, to confirm the dosage regimen needed to reach the required MBL plasma levels, and reconfirm the safety and lack of side-effects.

Inclusion Criteria:

• Children ages 0 - 12 years, during chemotherapy, and expected to become neutropenic
• MBL deficiency by genotype or phenotype (< 100 ng/ml)
• Informed consent and assent of patient and/or legal representative

Exclusion Criteria:

• Inability or unwillingness to comply with the protocol or likely inability to complete the study period
• Known allergic reactions to MBL and other human plasma products
• Participation in other investigational drug studies within the last month
• Clinically relevant abnormalities in: serum immunoglobulins IgG, IgA, IgM; blood counts; complement factors measured by AP50, CH50; urine protein and cell counts; serum creatinine and liver enzymes, as routinely determined for regular patient care.