Congenital neutropenia: From lab bench to clinic bedside and back

Neutropenia is a hematological condition characterized by a decrease in absolute neutrophil count (ANC) in peripheral blood, typically classified in adults as mild (1-1.5 × 109/L), moderate (0.5-1 × 109/L), or severe (< 0.5 × 109/L). It can be categorized into two types: congenital and acquired. Congenital severe chronic neutropenia (SCN) arises from mutations in various genes, with different inheritance patterns, including autosomal recessive, autosomal dominant, and X-linked forms, often linked to mitochondrial diseases. The most common genetic cause is alterations in the ELANE gene. Some cases exist as non-syndromic neutropenia within the SCN spectrum, where genetic origins remain unidentified. The clinical consequences of congenital neutropenia depend on granulocyte levels and dysfunction. Infants with this condition often experience recurrent bacterial infections, with approximately half facing severe infections within their first six months of life. These infections commonly affect the respiratory system, digestive tract, and skin, resulting in symptoms like fever, abscesses, and even sepsis. The severity of these symptoms varies, and the specific organs and systems affected depend on the genetic defect. Congenital neutropenia elevates the risk of developing acute myeloid leukemia (AML) or myelodysplastic syndromes (MDS), particularly with certain genetic variants. SCN patients may acquire CSF3R and RUNX1 mutations, which can predict the development of leukemia. It is important to note that high-dose granulocyte colony-stimulating factor (G-CSF) treatment may have the potential to promote leukemogenesis. Treatment for neutropenia involves antibiotics, drugs that boost neutrophil production, or bone marrow transplants. Immediate treatment is essential due to the heightened risk of severe infections. In severe congenital or cyclic neutropenia (CyN), the primary therapy is G-CSF, often combined with antibiotics. The G-CSF dosage is gradually increased to normalize neutrophil counts. Hematopoietic stem cell transplants are considered for non-responders or those at risk of AML/MDS. In cases of WHIM syndrome, CXCR4 inhibitors can be effective. Future treatments may involve gene editing and the use of the diabetes drug empagliflozin to alleviate neutropenia symptoms.

Screening for ELANE, HAX1 and GFI1 gene mutations in children with neutropenia and clinical characterization of two novel mutations in ELANE gene

BACKGROUND

Congenital neutropenia is a rare disease. Recurrent infections since young age are the presentation. The most common mutation causing severe congenital neutropenia (SCN) and cyclic neutropenia (CyN) is the ELANE gene. The objectives of this study were to screen the three common genetic mutations of ELANE, HAX1 and GFI1 in children with chronic neutropenia and to describe the clinical characteristics of children who had the mutations.

METHODS

Infants having ANC < 1,000/cu mm or children aged > 1 year having ANC < 1,500/cu mm at least 3 times in 3 months were enrolled in the study. Patients who had acquired neutropenia due to infection, immune deficiency, or drugs were excluded. The ELANE gene was first studied; and if mutations were not identified, the HAX1 and GFI1 genes were further examined.

RESULTS

A total of 60 patients were enrolled in the study. The median (range) age, ratio of female to male, ANC, and last follow-up age were 9.2 (0.5-45.2) months, 1:1.2, 248 (0-1,101) /cu mm, and 19.9 (3.5-202.3) months, respectively. Infections were noted in 67.3% of all patients. ELANE gene mutation was found in only four patients (6.7%), and the rest (56 patients) showed no mutations in the HAX1 and GFI1 genes. In patients without mutations, 66.0% had normal ANC during the follow-up, with a median (range) age for normal ANC of 19.8 (4.0-60.0) months. Two novel mutations p. Ala79del (c.234_236del) and p. Val197GlufsTer18 (c.589_590insAGGCCGGC) were identified, and they respectively cause SCN and CyN. Patients with the two novel mutations presented with several episodes of infection, including pneumonia, sepsis, abscess, otitis media, and gum infection.

CONCLUSION

The genetic screening for ELANE, HAX1, and GFI1 gene mutations in 60 patients with chronic neutropenia could identify four patients (6.7%) with ELANE gene mutation and two novel mutations, p. Ala79del in exon 3 and p. Val197GlufsTer18 in exon 4 causing SCN; and CyN, respectively.

Cyclic neutropenia and concomitant IgA nephropathy: a case report

BACKGROUND

IgA nephropathy (IgAN) is universally recognized as one of the most common primary glomerular diseases in all ages. Cyclic neutropenia (CN) is a rare haematologic disorder that is associated with mutations of the ELANE gene. The co-occurrence of IgAN and CN is extremely rare. This is the first case report of a patient with IgAN and genetically confirmed CN.

CASE PRESENTATION

We report a case of a 10-year-old boy who presented with recurrent viral upper respiratory tract infections accompanied by several episodes of febrile neutropenia, haematuria, proteinuria and acute kidney injury. Upon first admission, his physical examination was unremarkable. His kidney function was impaired, whereas his urine microscopy showed evidence of macroscopic haematuria and proteinuria. Further workup showed elevated IgA. The renal histology was consistent with mesangial and endocapillary hypercellularity with mild crescentic lesions, while immunofluorescence microscopy showed IgA-positive staining, which was characteristic of IgAN. Moreover, genetic testing confirmed the clinical diagnosis of CN, therefore Granulocyte colony-stimulating factor (G-CSF) was initiated to stabilize the neutrophil count. Regarding proteinuria control, the patient was initially treated with an Angiotensin-converting-enzyme inhibitor for approximately 28 months. However, due to progressive proteinuria (> 1 g/24 h), Corticosteroids (CS) were added for a period of 6 months according to the revised 2021 KDIGO guidelines with favorable outcome.

CONCLUSIONS

Patients with CN are more susceptible to recurrent viral infections, which can trigger IgAN attacks. In our case CS induced remarkable proteinuria remission. The use of G-CSF contributed to the resolution of severe neutropenic episodes, viral infections and concomitant AKI episodes, contributing to better prognosis of IgAN. Further studies are mandatory to determine whether there is a genetical predisposition for IgAN in children with CN.

Management of acute cholecystitis in patient with cyclic neutropenia: a case report

BACKGROUND

Cyclic neutropenia is a disease that causes a neutropenic decrease in peripheral blood in a cycle of about 21 days. It is a rare hereditary disorder with an estimated incidence of 0.5-1 cases per million population. The absolute neutrophil count can drop to zero, and neutropenic nadir may last for 3-5 days. This is a rare disease, and there are few reports of abdominal surgery in cyclic neutropenia patients; thus, we report this case of neutrophil count fluctuation and perioperative management.

CASE PRESENTATION

A 31-year-old man with cyclic neutropenia was transferred to our hospital complaining of right season rib pain, but no rebound tenderness. His C-reactive protein was elevated (4.37 mg/L) and computed tomography revealed a large number of small stones in the gallbladder body and an incarceration in the gallbladder neck. He was diagnosed with acute cholecystitis. Ideally, surgical intervention should have been performed immediately, but because his neutrophil count was 300/μL, endoscopic naso-gallbladder drainage was performed and he was provided antibiotics until his neutrophil count increased to acceptable levels. Three days after admission, his neutrophil count had increased and laparoscopic cholecystectomy was performed. For one week after the operation, antibiotics were administered; he had an uneventful postoperative recovery. He was discharged on the seventh postoperative day and provided an oral antibiotic.

CONCLUSIONS

Infection can be serious in patients with cyclic neutropenia, and it is therefore, important to determine the timing of surgery and to apply appropriate perioperative management with drainage and antibiotic administration.

Recurrent Periorbital Cellulitis Secondary to Cyclic Neutropenia

Purpose:

To present a 1-year-old boy with cyclic neutropenia who presented with multiple episodes of periorbital cellulitis (POC).

Methods:

The child presented with three episodes of POC. In the second episode, the cellulitis was associated with nasolacrimal duct obstruction, and in the third episode, a pansinusitis was noted. He underwent a thorough systemic evaluation.

Results:

Patient's evaluation revealed the diagnosis of cyclic neutropenia.

Conclusion:

This report emphasizes the possibility of an underlying immunodeficiency with recurrent POC, even in an apparently healthy child.

Chronic refractory uveitis in a patient with childhood-onset cyclic neutropenia

We report a rare case of chronic refractory uveitis in a patient with childhood-onset cyclic neutropenia (CN). A 19-year-old woman, who had a history of CN beginning at age 2, presented with bilateral chronic nongranulomatous uveitis, complicated cataract, retinal vasculitis, cystoids macular edema, and vitreous hemorrhage. She had recurrent episodes of oral ulcers, tonsillitis, genital ulcers, and folliculitis during neutropenic nadir. After the resumption of granulocyte colony-stimulating factor therapy for her CN, vitreous hemorrhage in both eyes followed. Her eyes were treated with topical corticosteroids, retinal photocoagulation, and cataract surgery. Blood and bone marrow test results confirmed the diagnosis of CN. She also fulfilled the diagnostic criteria of Behçet's disease, though clinical features of her uveitis were dissimilar to those found in that disease.