Understanding neutropenia secondary to intrinsic or iatrogenic immune dysregulation

Chronic neutropenia in childhood: experience of a tertiary center

OBJECTIVE

To assess the prevalence of chronic neutropenia (CN) and the clinical profile of patients with CN aged up to 18 years, followed in the pediatric hematology, rheumatology, or immunology outpatient clinic of a tertiary medical center from May 1, 2018, to 30 April 2019.

METHODS

Retrospective observational study carried out by collecting data from the patient's medical charts. CN was defined as absolute neutrophil count (ANC) below 1.5 × 109/L lasting over three months. Autoimmune neutropenia (AIN) was defined by clinical criteria and an over twofold increase in ANC after glucocorticoid stimulation. AIN was considered secondary when associated with autoimmune or immunoregulatory disorders. Wilcoxon and Fisher's exact tests were used to compare variables; the significance level was 5 %.

RESULTS

A total of 1,039 patients were evaluated; 217 (20 %) presented CN. Twenty-one (2 %) had AIN, classified as primary in 57 % of the cases. The average age at the onset of symptoms was 38.6 months. During follow-up, patients had 4.2 infections on average; frequency was higher among patients with secondary AIN (p = 003). Isolated neutropenia occurred in 43 % of the patients with AIN. Neutropenia resolved in eight (38 %) of the 21 patients with AIN within 19.6 months on average. Eight patients with secondary AIN met the criteria for Inborn Errors of Immunity.

CONCLUSION

AIN prevalence was 2 %. Most cases were first evaluated by a pediatric immunologist or rheumatologist rather than a pediatric hematologist. This study highlights the need for a multidisciplinary approach involving a pediatric immunologist, rheumatologist, and hematologist.

Organ-based clues for diagnosis of inborn errors of immunity: A practical guide for clinicians

Inborn errors of immunity (IEI) comprise a group of about 490 genetic disorders that lead to aberrant functioning or the development of distinct immune system components. So far, a broad spectrum of IEI-related manifestations has been noted in the literature. Due to overlapping signs and symptoms of IEI, physicians face challenges in appropriately diagnosing and managing affected individuals. The last decade has witnesses improving in the molecular diagnosis of IEI patients. As a result, it can be the mainstay of diagnostic algorithms, prognosis, and possibly therapeutic interventions in patients with IEI. Furthermore, reviewing IEI clinical complications demonstrates that the manifestations and severity of the symptoms depend on the involved gene that causes the disease and its penetrance. Although several diagnostic criteria have been used for IEI, not every patient can be explored in the same way. As a result of the failure to consider IEI diagnosis and the variety of diagnostic capabilities and laboratory facilities in different regions, undiagnosed patients are increasing. On the other hand, early diagnosis is an almost essential element in improving the quality of life in IEI patients. Since there is no appropriate guideline for IEI diagnosis in different organs, focusing on the clues in the patient's chief complaint and physical exams can help physicians narrow their differential diagnosis. This article aims to provide a practical guide for IEI diagnosis based on the involved organ. We hope to assist clinicians in keeping IEI diagnosis in mind and minimizing possible related complications due to delayed diagnosis.

Peripheral‐blood cytopenia, an early indicator of inborn errors of immunity

Inborn errors of immunity (IEI) are inherited monogenic disorders resulting in defective immune response. Non‐infectious presentations are increasingly more apparent. Widely available, cost‐effective early indicators are needed. Peripheral‐blood cytopenia may be a presenting laboratory feature or an observed secondary phenomenon. This retrospective review of the South African Primary Immunodeficiency Registry (SAPIDR) aimed to assess the haematological indices at presentation and their association with the International Union of Immunological Societies (IUIS) 2019 IEI classification and mortality. Of 396 patients on the SAPIDR, 66% (n = 257) had available haematological results. Sixty percent were males and 85% under 18 years. A majority (53%) had predominantly antibody deficiency. At presentation, infection was prominent (86%) followed by cytopenia (62%). Neutropenia was associated with IUIS III [odds ratio (OR) 3.65, confidence interval (CI) 1.44–9.25], thrombocytopenia with IUIS II (OR 14.39, CI 2.89–71.57), lymphopenia with IUIS I (OR 12.16, CI 2.75–53.73) and pancytopenia with IUSI I (OR 12.24, CI 3.82–39.05) and IUIS II (OR 5.99, CI 2.80–12.76). Cytopenia showed shorter overall survival (OR 2.81, CI 1.288–4.16). Cytopenias that are severe, persistent, unusual and/or recurrent should prompt further investigation for IEI. The full blood count and leucocyte differential may facilitate earlier identification and serve as an adjunct to definitive molecular classification.