Chronic Granulomatous Disease

Abstract

Chronic granulomatous disease (CGD) is the most common symptomatic phagocytic defect. It is caused by mutations in genes encoding protein subunits of the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase complex. CGD is characterized by a defective intracellular killing of phagocytosed organisms due to a defective oxidative burst in the neutrophils and macrophages. It is inherited in either X-linked recessive or autosomal recessive pattern. Staphylococcus aureus and Aspergillus species are the most common organisms reported. Infections with Burkholderia, Serratia, and Nocardia warrant a screen for CGD. Suppurative lymphadenitis, cutaneous abscesses, pneumonia and diarrhea constitute the most common problems in children with CGD. A small percentage of children develop autoimmune manifestations (e.g., rheumatoid arthritis, systemic lupus erythematosus, colitis, autoimmune hepatitis) and warrant immunosuppression. X-linked carriers of CGD are at an increased risk of developing autoimmune diseases. Nitroblue-tetrazolium dye reduction test and dihydro-rhodamine assay by flow cytometry are the screening tests for this disorder. While most children do well on long term antibiotic and antifungal prophylaxis, those with severe forms warrant hematopoietic stem cell transplant. The role of regular interferon-γ injections is debatable. Evidence for white cell transfusions is sparse, and gene therapy is under trial.This current review highlights various aspects and studies in CGD. X-linked form of CGD has been noted to carry a poorer prognosis compared to autosomal recessive variants. However, recent evidence suggests that outcome in CGD is determined by the amount of residual NADPH oxidase activity irrespective of mode of inheritance.

Keywords: CYBB gene; Chronic granulomatous disease; Dihydrorhodamine assay; NADPH oxidase complex; NCF1 gene; NCF2 gene.