ARDS as presenting symptom in an infant with CD40L deficiency (Hyper-IgM syndrome Type 1).

We report on a 4 month old male infant with respiratory syncytial virus (RSV) infection leading to acute respiratory distress syndrome (ARDS). A diagnostic algorithm including extended infectiological and immunological work-up revealed absence of CD40-ligand. ARDS was treated successfully with a complex respiratory therapy plus intravenous immunoglobulin substitution. Molecular analysis detected mutations in the CD40L gene (Hyper-IgM syndrome Type 1). The case underlines the importance of an extended diagnostic work-up in an uncommonly severe course of respiratory infection in early infancy.