STAT3 Hyper IgE Syndrome

Clinical characteristics: STAT3 hyper IgE syndrome (STAT3-HIES) is a primary immune deficiency syndrome characterized by elevated serum IgE, eczema, and recurrent skin and respiratory tract infections, together with several nonimmune features. This disorder typically manifests in the newborn period with a rash (often diagnosed as eosinophilic pustulosis) that subsequently evolves into an eczematoid dermatitis. Recurrent staphylococcal skin boils and bacterial pneumonias usually manifest in the first years of life. Pneumatoceles and bronchiectasis often result from aberrant healing of pneumonias. Mucocutaneous candidiasis is common. Nonimmune features may include retained primary teeth, scoliosis, bone fractures following minimal trauma, joint hyperextensibility, and characteristic facial appearance, which typically emerges in adolescence. Vascular abnormalities have been described and include middle-sized artery tortuosity and aneurysms, with infrequent clinical sequelae of myocardial infarction and subarachnoid hemorrhage. Gastrointestinal (GI) manifestations include gastroesophageal reflux disease, esophageal dysmotility, and spontaneous intestinal perforations (some of which are associated with diverticuli). Fungal infections of the GI tract (typically histoplasmosis, Cryptococcus, and Coccidioides) also occur infrequently. Survival is typically into adulthood, with most individuals now living into or past the sixth decade. Most deaths are associated with gram-negative (Pseudomonas) or filamentous fungal pneumonias resulting in hemoptysis. Lymphomas occur at an increased frequency.

Diagnosis/testing: The diagnosis of STAT3-HIES is established in a proband with typical clinical findings and a heterozygous dominant-negative pathogenic variant in STAT3 identified by molecular genetic testing.

Management: Treatment of manifestations: The mainstay of treatment is prevention of staphylococcal abscesses and pneumonias with anti-staphylococcal prophylactic antibiotics as well as early aggressive treatment of infections. Use of antibiotics and antifungal agents depends on the nature of the infection and the extent of involvement. Antiseptic therapies for the skin such as dilute bleach baths and chlorhexidine are beneficial. Medications such as histamine-1 antagonists to control pruritus are helpful for more significant eczema. There is no known treatment or prevention for the nonimmunologic characteristics, although optimization of calcium and vitamin D intake may be considered to improve bone health. The role of hematopoietic cell transplantation (HSCT) in STAT3-HIES is emerging; while successful transplant recipients have improved infection phenotype, the effect of HSCT on the nonimmunologic aspects of the disease remains unclear.

Surveillance: Periodic chest imaging and high clinical suspicion assist in early detection of lung infections. Culture of skin lesions and sputum samples helps direct therapy. Routine screening of adolescents for early signs of scoliosis is recommended. Dental monitoring is necessary to ensure timely removal of primary teeth to allow eruption of secondary teeth. Evaluation for coronary artery and cerebral aneurysms every three years in adulthood is recommended as well as monitoring for lymphadenopathy in case of increased incidence of lymphoma.

Genetic counseling: STAT3-HIES is inherited in an autosomal dominant manner. The majority of affected individuals have the disorder as the result of a de novo pathogenic variant. Each child of an individual with STAT3-HIES has a 50% chance of inheriting the pathogenic variant. Prenatal testing for a pregnancy at increased risk and preimplantation genetic testing are possible once the STAT3 pathogenic variant in the family has been identified.