Neutrophil-specific granule deficiency ( previously known as lactoferrin deficiency) is a rare congenital immunodeficiency characterized  by an increased risk for pyogenic infections due to defective production of specific granules and gelatinase granules in patient neutrophils. Symptoms and signs
Atypical infections are the key clinical manifestation of SGD. Within the first few years of life, patients will experience repeated pyogenic infections by species such as Staphylococcus aureus, Pseudomonas aeruginosa or other Enterobacteriaceae, and Candida albicans. Cutaneous ulcers or abscesses and pneumonia and chronic lung disease are common. Patients may also develop sepsis, mastoiditis, otitis media, and lymphadenopathy. Infants may present with vomiting, diarrhea, and failure to thrive.Diagnosis can be made based upon CEBPE gene mutation or a pathognomonic finding of a blood smear showing lack of specific granules. Neutrophils and eosinophils will contain hyposegmented nuclei (a pseudo-Pelger–Huet anomaly). Genetics
A majority of patients with SGD have been found to have mutations in the CEBPE (CCAAT/enhancer-binding protein epsilon) gene, a transcription factor primarily active in myeloid cells. Almost all patients have been found to be homozygous for the mutation, suggesting the disease is autosomal recessive. One patient, heterozygous for the mutation, was found to be deficient in GFI1, a related gene. Pathophysiology
The defect in CEBPE appears to block the ability of neutrophils to mature past the promyelocyte stage in bone marrow. Since specific (secondary) and gelatinase (tertiary) granules are only produced past the promyelocyte stage of development, these are deficient in SGD.
Medical use
In the United States, lanadelumab is indicated for patients 12 years and older for the prophylaxis of hereditary angioedema (HAE) attacks. There is no data on the efficacy or safety of lanadelumab in patients under the age of 12 years old. Lanadelumab was not studied in pregnant or breastfeeding women. Adverse events
In a phase 3 randomized controlled trial, which examined the efficacy and safety of lanadelumab in preventing hereditary angioedema attacks, the most common adverse events noted in patients being treated were:
Injection site pain in 42.9% of patients
Viral upper respiratory tract infection in 23.8% of patients
Headache in 20.2% of patients
Injection site erythema in 95% of patients
Injection site bruising in 7.1% of patients
Dizziness in 6.0% of patients

Mechanism of action
Lanadelumab works by binding to an enzyme within the plasma, kallikrein, to inhibit its activity. Kallikrein is a protease that functions to cleave kininogen, subsequently creating kininogen and bradykinin, a potent vasodilator.Patients have hereditary angioedema (HAE) because of a deficiency or dysfunctional C1 inhibitor, which is an enzyme that regulates the activity of the kallikrein-kinin cascade. Poor regulation of the C1 inhibitor results in increased levels of kallikrein and subsequent proteolysis of kininogen. The proteolysis of the kininogen forces an upscaled production of bradykinin and kininogen within the patient. Increased bradykinin levels cause vasodilation, increased vascular permeability, and the succeeding angioedema and pain associated with hereditary angioedema attacks.