Diagnostic value of cell bound and circulating neutrophil antibody detection in pediatric neutropenia

Immune-mediated cytopenias (IMCs) after HSCT for pediatric non-malignant disorders: epidemiology, risk factors, pathogenesis, and treatment

Hematopoietic stem cell transplantation (HSCT) represents a curative option for pediatric patients affected by malignant and non-malignant disorders. Several complications may arise during the post-transplantation period, including immune-mediated disorders. Immune-mediated cytopenias (IMCs) account for up to 22% of pediatric HSCT complications, representing an important cause of morbidity and mortality post-HSCT. So far, their pathogenesis is not well-understood, and their management may be very challenging. Further, most patients are refractory to first-line treatment which is based on high-dose intravenous steroids, immunoglobulin, and the monoclonal anti-CD20 antibody - rituximab. No clear consensus has been reached for second- and third-line therapeutic options.

CONCLUSION

We reviewed the epidemiology, risk factors, pathogenesis, and treatment of IMCs, aiming to offer a deeper understanding of these complications as a guide to improving the management of these fragile patients and a cue for the design of tailored clinical trials.

WHAT IS KNOWN

• IMCs arising in the post-HSCT setting represent a rare but potentially life-threatening complication. Younger patients affected by non-malignant disorders are at the greatest risk of IMCs arising after HSCT. Corticosteroids, intravenous immunoglobulin, and rituximab represent the undiscussed first-line therapeutic approach.

WHAT IS NEW

• This review highlitghts how children present unique risk factors for post HSCT IMCs, which are the result of the complex relationship between the immaturity of their infantile immune system and all the perturbing agents and factors which characterize the post-HSCT setting. Future efforts are warranted to establish the best option for refractory patients, for whom a standard and validated approach is not currently available. Among new agents, ibrutinib or bortezomib and fostamatinib or low-dose IL-2 could represent a good therapeutic option for patients with graft-versus-host disease and hemolytic anemia or graft-versus-host disease and thrombocytopenia, respectively.

The European Guidelines on Diagnosis and Management of Neutropenia in Adults and Children: A Consensus Between the European Hematology Association and the EuNet-INNOCHRON COST Action

Neutropenia, as an isolated blood cell deficiency, is a feature of a wide spectrum of acquired or congenital, benign or premalignant disorders with a predisposition to develop myelodysplastic neoplasms/acute myeloid leukemia that may arise at any age. In recent years, advances in diagnostic methodologies, particularly in the field of genomics, have revealed novel genes and mechanisms responsible for etiology and disease evolution and opened new perspectives for tailored treatment. Despite the research and diagnostic advances in the field, real world evidence, arising from international neutropenia patient registries and scientific networks, has shown that the diagnosis and management of neutropenic patients is mostly based on the physicians' experience and local practices. Therefore, experts participating in the European Network for the Innovative Diagnosis and Treatment of Chronic Neutropenias have collaborated under the auspices of the European Hematology Association to produce recommendations for the diagnosis and management of patients across the whole spectrum of chronic neutropenias. In the present article, we describe evidence- and consensus-based guidelines for the definition and classification, diagnosis, and follow-up of patients with chronic neutropenias including special entities such as pregnancy and the neonatal period. We particularly emphasize the importance of combining the clinical findings with classical and novel laboratory testing, and advanced germline and/or somatic mutational analyses, for the characterization, risk stratification, and monitoring of the entire spectrum of neutropenia patients. We believe that the wide clinical use of these practical recommendations will be particularly beneficial for patients, families, and treating physicians.

Pediatric Benign Neutropenia: Assessing Practice Preferences in Canada

Pediatric benign neutropenia is a self-limited condition with a benign clinical course. An approach to this condition is not well-defined in the literature. Our objective was to use a case-based survey to elucidate trends in the diagnosis and management of benign neutropenia among pediatric hematology/oncology practitioners in Canada. We received 46 completed surveys (response rate 66%). At initial presentation with fever and neutropenia, 67% of respondents recommended partial septic workup but 11% recommended no investigations. Nearly 70% recommended admission for empiric intravenous antibiotics, while 24% would discharge home without antibiotics. In a patient with fever and known neutropenia, respondents were more likely to pursue outpatient antibiotic therapy. For investigation of chronic neutropenia, most respondents (60%) do not use antineutrophil antibody testing. Common indications for bone marrow biopsy were severe infection, prolonged neutropenia, or before initiating granulocyte colony stimulating factor. Indications for granulocyte colony stimulating factor were based on severity and frequency of infection. Most respondents (84%) would not recommend antibiotic prophylaxis. Results demonstrate the considerable variability in management of benign neutropenia among pediatric hematology/oncology practitioners in Canada and highlight the need for prospective studies to establish diagnostic criteria for benign neutropenia and evaluate management of fever in this population.

Diagnosis and management of neutropenia in children: The approach of the Study Group on Neutropenia and Marrow Failure Syndromes of the Pediatric Italian Hemato-Oncology Association (Associazione Italiana Emato-Oncologia Pediatrica - AIEOP)

Neutropenia refers to a group of diseases characterized by a reduction in neutrophil levels below the recommended age threshold. The present study aimed to review the diagnosis and management of neutropenia, including a diagnostic toolkit and candidate underlying genes. This study also aimed to review the progress toward the definition of autoimmune and idiopathic neutropenia rising in infancy or in late childhood but without remission, and provide suggestions for efficient diagnostics, including indications for the bone marrow and genetic testing. The management and treatment protocols for common and unique presentations are also reviewed, providing evidence tailored to a single patient.

Consensus opinion on immune-mediated cytopenias after hematopoietic cell transplant for inherited metabolic disorders

Hematopoietic stem cell transplantation (HCT) has been increasingly used for patients with inherited metabolic disorders (IMD). Immune mediated cytopenias (IMCs) after HCT, manifesting as hemolytic anemia, thrombocytopenia, and/or neutropenia, are recognized as a significant complication in this patient population, yet our understanding of the incidence, risk factors, and pathophysiology is currently limited. Review of the published literature demonstrates a higher incidence in younger patients who undergo HCT for a nonmalignant disease indication. However, a few reports suggest that the incidence is even higher among those with IMD (incidence ranging from 10 to 56%). This review summarizes the literature, provides an approach to better understanding of the possible etiology of IMCs, and proposes a diagnostic and management plan for patients with IMD who develop single or multi-lineage cytopenias after HCT.

Idiopathic neutropenia of infancy: Data from the Italian Neutropenia Registry

Autoimmune neutropenia of infancy (AIN) is characterized by low risk of severe infection, tendency to spontaneously resolve and typically onset at ≤4-5 years of age; it is due to auto-antibodies whose detection is often difficult. In case of negativity of 4 antineutrophils autoantibody tests, after having excluded ethnic, postinfection, drug induced, or congenital neutropenia, according to the Italian guidelines the patients will be defined as affected by "idiopathic neutropenia" (IN). We describe the characteristics of 85 IN patients enrolled in the Italian neutropenia registry: they were compared with 336 children affected by AIN. The 2 groups were clinically very similar and the main differences were detection age (later in IN), length of disease (longer in IN) and, among recovered patients, age of spontaneous recovery: the median age at resolution was 2.13 years in AINs and 3.03 years in INs (P = .00002). At bivariate analysis among AIN patients earlier detection age (P = .00013), male sex (P = .000748), absence of leucopenia (P = .0045), and absence of monocytosis (P = .0419) were significantly associated with earlier recovery; in the IN group only detection age (P = .013) and absence of monocytosis (P = .0333) were significant. At multivariate analysis detection age and absence of monocytosis were independently significant (P = 6.7e-05 and 4.4e-03, respectively) in the AIN group, whereas in the IN group only detection age stayed significant (P = .013).