Neutrophil-specific granule deficiency
Neutrophil-specific granule deficiency (SGD), also called lactoferrin deficiency, is a rare inherited immune disorder. In SGD, neutrophils (a type of white blood cell) lack two kinds of granules they normally use to fight germs: specific granules and gelatinase granules.
Most SGD cases come from mutations in the CEBPE gene, which controls the development of certain blood cells. It is usually inherited in an autosomal recessive way (both copies of the gene are mutated). In one reported case, a defect in a related gene, GFI1, was involved.
Because the CEBPE mutation disrupts neutrophil maturation, cells can’t progress past the promyelocyte stage in the bone marrow. As a result, they don’t form secondary (specific) and tertiary (gelatinase) granules. Lactoferrin—the major enzyme in specific granules—and defensins are largely absent from these neutrophils, while other granule components like lysozyme, cathepsin, and elastase are mostly normal. The lack of these granule proteins weakens the body’s ability to fight infection. Neutrophils may also show impaired chemotaxis (reduced movement toward infection signals) due to missing granule-related receptors. A characteristic finding is a pseudo-Pelger-Huet anomaly, with hyposegmented nuclei in neutrophils and eosinophils.
Clinical features usually appear in early life and include repeated, unusual bacterial and fungal infections (for example Staphylococcus aureus, Pseudomonas aeruginosa, other Enterobacteriaceae, and Candida). Infections can cause skin ulcers or abscesses, pneumonia, and chronic lung disease. Infants may have vomiting, diarrhea, and poor growth. Infections can lead to sepsis, ear and mastoid infections, and swollen lymph nodes.
Diagnosis can be made by looking at a blood smear: Wright-stained neutrophils lack secondary granules. Genetic testing can identify a CEBPE mutation.
Treatment focuses on controlling infections: high-dose antibiotics for active infections and prophylactic antibiotics to prevent future ones. In severe cases, treatments such as GM-CSF therapy or a bone marrow transplant may be considered.
Prognosis varies and is hard to predict, but with proper treatment many patients live into adulthood. SGD is extremely rare; it was first described in 1980, and only a few cases have been reported since.
This page was last edited on 2 February 2026, at 07:29 (CET).