How we evaluate and treat neutropenia in adults

Incidental neutropenia: An emergency medicine focused approach

INTRODUCTION

Neutropenia is defined as an absolute neutrophil count (ANC) < 1500 cells/microL and may be discovered incidentally in an asymptomatic, afebrile patient.

OBJECTIVE

This narrative review provides an approach to the afebrile emergency department patient with incidental neutropenia.

DISCUSSION

Neutropenia is an ANC < 1500 cells/microL, with mild neutropenia defined as an ANC ≥ 1000 to <1500 cells/microL, moderate ≥500 to <1000 cells/microL, severe <500 cells/microL, and agranulocytosis <200 cells/microL. Incidental or isolated neutropenia is an ANC < 1500 cells/microL discovered on laboratory testing unrelated to the patient's chief complaint (e.g., chest pain, abdominal pain, shortness of breath, etc.) and not associated with fever or infectious signs and symptoms. There are a variety of etiologies, with inherited forms, dose-dependent drug-induced neutropenia, and infections the most common causes. Testing includes complete blood count with differential and peripheral smear. Management is based on the patient's hemodynamic status, presence of fever, severity of neutropenia, and the peripheral smear. Patients who are critically ill, febrile, have severe neutropenia, or have a concerning peripheral smear (schistocytes, atypical lymphocytes) should undergo hematology consultation. Those with critical illness or fever with neutropenia should receive broad-spectrum antibiotics. Patients who are afebrile, hemodynamically stable, and non-toxic appearing with mild or moderate neutropenia can likely be discharged for repeat testing in one to two weeks.

CONCLUSION

Understanding the approach to incidental neutropenia can improve patient care. Critically ill or febrile patients should be admitted, but select patients may be discharged.

Contextualizing Race and Ethnicity in the Practice of Laboratory Medicine

Race and ethnicity are population descriptors that clinicians and researchers often use to classify humans. The utility of these groupings in research and clinical contexts warrants scrutiny, since these groupings fail to adequately capture genetic diversity and instead, are proxies for the complex interplay of genetic, social, and structural determinants of health. Here, the authors review the concepts of race, ethnicity, and genetics. They also describe laboratory medicine examples where race and ethnicity are used that warrant scrutiny and revision, and areas where greater emphasis on including racialized minorities is necessary to improve health disparities.

Isolated Severe Neutropenia in Adults, Evaluation of Underlying Causes and Outcomes, Real-World Data Collected over a 5-Year Period in a Tertiary Referral Hospital

Background and Objectives: In clinical practice, neutropenia is frequently accompanied by other cytopenia; isolated non-chemotherapy-induced severe neutropenia is less frequent and its differential diagnosis can be challenging. In this real-world study with data collected over a 5-year period in a tertiary referral hospital, we primarily sought to identify underlying causes of isolated severe neutropenia (<0.5 × 109/L). Secondly, we aimed to analyze its management and outcomes. Materials and Methods: From 444,926 screened patients, after exclusion of patients with chemotherapy, radiotherapy, hematological neoplasms, additional cytopenia, and benign ethnic neutropenia, we identified and analyzed data from 70 patients (0.015%) with isolated severe neutropenia. We thus confirmed that the occurrence of isolated severe neutropenia is a rare event, even in a tertiary hospital. Results: The median age at diagnosis was 34 years (range 1-81) and 65% were female. Acute neutropenia was more frequently observed (n = 46/70, 65.7%); the main underlying causes in this group were drugs (n = 36/46, 78%) followed by infections (n = 10/46, 21.7%). We identified 24 (34.3%) patients with chronic neutropenia. The majority of them (n = 12/24, 50%) had an idiopathic form (CIN), 8/24 (33%) were autoimmune (AIN), and 4/24 (17%) were congenital. Conclusions: This study demonstrates the rarity and heterogeneity of isolated severe neutropenia and the steps to consider in its diagnostic work-up and management. Epidemiological characteristics, diagnostic work-up, and management including hospitalizations are described. Due to the high frequency of metamizole-induced neutropenia observed in this study, we want to raise awareness about its use, since this complication generates frequent hospitalizations even in young, otherwise healthy patients. Furthermore, recurrent infections in chronic forms of idiopathic neutropenia were quite common, suggesting a difference in phenotypes and need for therapy consideration depending on the clinical course.

Discerning clinicopathological features of congenital neutropenia syndromes: an approach to diagnostically challenging differential diagnoses

The congenital neutropenia syndromes are rare haematological conditions defined by impaired myeloid precursor differentiation or function. Patients are prone to severe infections with high mortality rates in early life. While some patients benefit from granulocyte colony-stimulating factor treatment, they may still face an increased risk of bone marrow failure, myelodysplastic syndrome and acute leukaemia. Accurate diagnosis is crucial for improved outcomes; however, diagnosis depends on familiarity with a heterogeneous group of rare disorders that remain incompletely characterised. The clinical and pathological overlap between reactive conditions, primary and congenital neutropenias, bone marrow failure, and myelodysplastic syndromes further clouds diagnostic clarity.We review the diagnostically useful clinicopathological and morphological features of reactive causes of neutropenia and the most common primary neutropenia disorders: constitutional/benign ethnic neutropenia, chronic idiopathic neutropenia, cyclic neutropenia, severe congenital neutropenia (due to mutations in ELANE, GFI1, HAX1, G6PC3, VPS45, JAGN1, CSF3R, SRP54, CLPB and WAS), GATA2 deficiency, Warts, hypogammaglobulinaemia, infections and myelokathexis syndrome, Shwachman-Diamond Syndrome, the lysosomal storage disorders with neutropenia: Chediak-Higashi, Hermansky-Pudlak, and Griscelli syndromes, Cohen, and Barth syndromes. We also detail characteristic cytogenetic and molecular factors at diagnosis and in progression to myelodysplastic syndrome/leukaemia.

Rare but There: Ceftriaxone-Induced Neutropenia in a Patient With a Brain Abscess

This case report details the case of a 70-year-old man with Marfan syndrome and hypertension who developed neutropenia after an eight-week course of ceftriaxone, used to treat a brain abscess. Initially presenting with tonic-clonic seizures and headaches, his condition was managed with ceftriaxone and metronidazole. The subsequent drop in neutrophil counts from 7.54 × 10^9/L to 0.87 × 10^9/L leads to the discontinuation of ceftriaxone and the administration of granulocyte-colony stimulating factor (G-CSF), which effectively restored the neutrophil levels. This case highlights that clinicians should be aware of ceftriaxone-induced neutropenia as a potential complication, especially in patients undergoing prolonged therapy. Regular monitoring and timely management are essential for patient safety and favorable outcomes.

Causes and outcomes of non-chemotherapy induced neutropenic fever in hospitalized adults: An observational study

Neutropenic fever in adults undergoing chemotherapy for cancer treatment is a medical emergency and has been the focus of numerous studies. However, there is a paucity of data about non-chemotherapy induced neutropenic fever (non-CINF). We retrospectively reviewed 383 adults with neutropenic fever hospitalized at one academic medical center between October 2015 and September 2020 to characterize the frequency, causes, and outcomes of non-CINF. Twenty-six percent of cases of neutropenic fever were non-chemotherapy induced. Among these, the major causes of neutropenia were hematologic malignancy, infection, and rheumatologic disease, and the major causes of fever were infections. Patients with non-CINF had a higher 30-day mortality than those with chemotherapy induced neutropenic fever (25% vs 13%, P = .01). Non-CINF constituted > 25% of neutropenic fever events in hospitalized adults and was associated with a high mortality rate.

Association of neutrophil defects with oral ulcers but undetermined role of neutrophils in recurrent aphthous stomatitis

Objective

Recurrent oral ulcers and severe periodontal diseases in patients with quantitative or qualitative neutrophil defects highlight the important role of neutrophils in maintaining oral mucosal barrier homeostasis. Recurrent aphthous stomatitis (RAS) is a common oral mucosal disease affecting up to 25% of the population, yet its etiopathogenesis remains unclear, and management is unsatisfactory. This review aims to gain insight into the pathogenesis of RAS.

Design

This narrative review examines the characteristics of oral and blood neutrophils, the associations between neutrophil defects and the occurrence of oral ulcers, and the evidence for the involvement of neutrophils in RAS. To conduct the review, relevant literature was searched in PubMed and Google Scholar, which was then thoroughly reviewed and critically appraised.

Results

Neutropenia, specifically a decrease in the number of oral neutrophils, impaired extravasation, and defective ROS production appear to be associated with oral ulcers, while defects in granule enzymes or NETosis are unlikely to have a link to oral ulcers. The review of the histopathology of RAS shows that neutrophils are concentrated in the denuded area but are latecomers to the scene and early leavers. However, the evidence for the involvement of neutrophils in the pathogenesis of RAS is inconsistent, leading to the proposal of two different scenarios involving either impaired or hyperactive neutrophils in the pathogenesis of RAS.

Successful Management of Neutropenic Sepsis Is Key to Better Survival of Patients With Blood Cancer in Sri Lanka: Real-World Data From the Resource-Limited Setting

PURPOSE

Sepsis is the main cause of nonrelapse mortality, and there are no published data on applicability of supportive care protocols from high-income countries such as Sri Lanka. The aim of the study was to investigate management and mortality of neutropenic episodes among Hemato-Oncology patients.

MATERIALS AND METHODS

Retrospective analysis of clinical characteristics, management, morbidity, and mortality of neutropenic Hemato-Oncology patients presented to the Lanka Hospital Blood Cancer Centre from January 1, 2019 to December 31, 2019 was performed.

RESULTS

A total of 169 neutropenic episodes were identified; 115 (68%) of such episodes were related to chemotherapy. Acute leukemia, lymphoproliferative disorders, and plasma cell disorders accounted for 23%, 69%, and 8% of patients, respectively. The median age of patients who had sepsis was 56 years, whereas that of those who had no sepsis was 53 years (P = .49). The median time to neutropenia was 9 days for those in the sepsis group compared with 8 days in the group that had no sepsis (0.64). The median neutrophil count in the group that had sepsis was 0.06, whereas it was 0.69 in the group that had no sepsis (P ≤ .05). The median time to commencement of antibiotics was 20 minutes.

CONCLUSION

To our knowledge, this is the only documented study related to outcome and successful applicability of western supportive care protocols to Sri Lankan patients with neutropenia. In this study, we have shown that neutropenic sepsis can be successfully managed in the setting of limited resources with service development, following guidelines and staff training.

Small-molecule CBP/p300 histone acetyltransferase inhibition mobilizes leukocytes from the bone marrow via the endocrine stress response

Mutations of the CBP/p300 histone acetyltransferase (HAT) domain can be linked to leukemic transformation in humans, suggestive of a checkpoint of leukocyte compartment sizes. Here, we examined the impact of reversible inhibition of this domain by the small-molecule A485. We found that A485 triggered acute and transient mobilization of leukocytes from the bone marrow into the blood. Leukocyte mobilization by A485 was equally potent as, but mechanistically distinct from, granulocyte colony-stimulating factor (G-CSF), which allowed for additive neutrophil mobilization when both compounds were combined. These effects were maintained in models of leukopenia and conferred augmented host defenses. Mechanistically, activation of the hypothalamus-pituitary-adrenal gland (HPA) axis by A485 relayed shifts in leukocyte distribution through corticotropin-releasing hormone receptor 1 (CRHR1) and adrenocorticotropic hormone (ACTH), but independently of glucocorticoids. Our findings identify a strategy for rapid expansion of the blood leukocyte compartment via a neuroendocrine loop, with implications for the treatment of human pathologies.

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.

Clinical characteristics of neutropenic patients under antithyroid drug: Twelve-year experience in a medical center

BACKGROUND

Thionamide-induced agranulocytosis (TiA) is a rare adverse event with a reported incidence of approximately 0.1% to 1.75%. Prompt recognition of TiA is critical to reduce the mortality rate. However, the differential diagnosis between cases of TiA and non-TiA neutropenia can be challenging due to the potential simultaneous involvement of other causes of neutropenia, such as concomitant chemotherapy, liver dysfunction, or infection. The aim of the present study was to investigate the possible factors associated with the development of TiA.

METHODS

This was a retrospective cohort study of patients treated with antithyroid drugs (ATDs) in Taipei Veterans General Hospital, Taipei, Taiwan, from 2006 to 2018. Patients who developed a neutropenic event during treatment with ATDs were identified from their medical records. The diagnosis of TiA was based on the following: (1) development of neutropenia during treatment or within 7 days after previous exposure to the same ATDs; (2) complete resolution of neutropenia within 1 month after discontinuation of the culprit drug with an absolute neutrophil count (ANC) >1500/μL; and (3) exclusion of other causes of neutropenia. The incidence and risk factors of TiA were analyzed and compared with those of non-TiA neutropenia.

RESULTS

Among 6644 patients treated with ATDs, 66 (mean age: 53 ± 15 years; 16.2% men) developed a neutropenic event and 20 were diagnosed with TiA (incidence: 0.3%). In the univariate analysis, compared with non-TiA neutropenia, TiA was associated with a lower Charlson Comorbidity Index, shorter treatment duration, lower cumulative ATD dosage, higher ATD dosage, higher ANC, and higher levels of free T4 at the time of the neutropenic event. In the multivariate logistic regression analysis, after adjusting for age, gender and the time to neutropenia, the cumulative ATD dose to neutropenia and ATD dosage at the time of the neutropenic event, Charlson Comorbidity Index, free T4 levels (odds ratio [OR], 4.44; 95% CI, 1.48-13.25), and ANC (OR, 1.00; 95% CI, 1.00-1.01) remained independently associated with TiA.

CONCLUSION

Patients with TiA were more likely to have higher levels of free T4 and ANC at the time of the neutropenic event vs those with non-TiA neutropenia.

How I manage inpatient consultations for quantitative neutrophil abnormalities in adults

Neutrophilia and neutropenia commonly lead to inpatient hematology consultation. Quantitative neutrophil abnormalities have a broad differential and include diagnoses that are important to recognize because they may be associated with increased mortality. Neutrophilia can reflect etiologies such as infection, medications, inflammation, splenectomy, and congenital disorders. Neutropenia can arise from infection, medications, autoimmune destruction, sequestration, nutritional deficiency, malignancy, and congenital neutropenia syndromes. In the evaluation of all abnormalities of neutrophil number, the timing of the change, and the patient's historical neutrophil count are crucial.

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.

Neutropenia in pediatric solid organ transplant

Neutropenia is generally defined as an absolute neutrophil count in the circulation of less than 1500/mm³ and occurs in up to 25%-30% of pediatric solid organ transplant recipients (SOT) within the first year after transplantation. In the SOT population, neutropenia is most often a result of drug-induced bone marrow suppression but can also be secondary to viral infection, nutritional deficiencies, lymphoproliferative infiltrate, and inherited causes. Outcomes for patients with neutropenia vary by degree of neutropenia and type of solid organ transplant. Management of neutropenia should begin by addressing the underlying cause, including reducing or removing medications when appropriate, treating infections, and addressing nutrient deficiencies; however, consultation with an experienced pediatric hematologist and use of granulocyte colony-stimulating factor (G-CSF) may be helpful in some cases. Overall, data on clinical outcomes for G-CSF use remain limited, but observational studies may support its use in patients with infections or severe neutropenia.

Morbidity and Mortality of Neutropenic Patients in Visceral Surgery: A Narrative Review

Leukocytes are essential for the function of the immune system and cell–cell interaction in the human body, but hematological diseases as well as chemotherapeutic treatments due to cancer lead to occasionally or even permanent leukocyte deficiency. Normally, more than 50% of leukocytes are neutrophilic granulocytes, and leukopenia is, therefore, mostly characterized by a decrease in neutrophilic granulocytes. The consequence of neutropenia is increased susceptibility to infection, but also healing disorders are suggestable due to the disturbed cell–cell interaction. While there is no surgical treatment for leucocyte disorders, patients suffering from neutropenia are sometimes in need of surgery for other reasons. Less is known about the morbidity and mortality of this patients, which is why this narrative review critically summarizes the results of recent research in this particular field. The results of this review suggest that neutropenic patients in need of emergency surgery have a higher mortality risk compared to non-neutropenic patients. In contrast, in elective surgery, there was not a clear tendency for a higher mortality risk of neutropenic patients. The role of neutrophilic granulocytes in inflammation and immunity in surgical patients is emphasized by the results, but most of the evaluated studies showed methodological flaws due to small sample sizes or risk of bias. Further research has to evaluate the risk for postoperative complications, particularly of infectious complications such as surgical site infections, in neutropenic patients undergoing elective surgery, and should address the role of neutrophilic function in postoperative morbidity and mortality.

Use of Diagnosis Codes to Find Blood Transfusion Adverse Events in Electronic Health Records

OBJECTIVE

Electronic health records (EHRs) and big data tools offer the opportunity for surveillance of adverse events (patient harm associated with medical care). We used International Classification of Diseases, Ninth Revision, codes in electronic records to identify known, and potentially novel, adverse reactions to blood transfusion.

METHODS

We used 49,331 adult admissions involving critical care at a major teaching hospital, 2001-2012, in the Medical Information Mart for Intensive Care III EHRs database. We formed a T (defined as packed red blood cells, platelets, or plasma) group of 21,443 admissions versus 25,468 comparison (C) admissions. The International Classification of Diseases, Ninth Revision, Clinical Modification , diagnosis codes were compared for T versus C, described, and tested with statistical tools.

RESULTS

Transfusion adverse events (TAEs) such as transfusion-associated circulatory overload (TACO; 12 T cases; rate ratio [RR], 15.61; 95% confidence interval [CI], 2.49-98) were found. There were also potential TAEs similar to TAEs, such as fluid overload disorder (361 T admissions; RR, 2.24; 95% CI, 1.88-2.65), similar to TACO. Some diagnoses could have been sequelae of TAEs, including nontraumatic compartment syndrome of abdomen (52 T cases; RR, 6.76; 95% CI, 3.40-14.9) possibly being a consequence of TACO.

CONCLUSIONS

Surveillance for diagnosis codes that could be TAE sequelae or unrecognized TAE might be useful supplements to existing medical product adverse event programs.

How I manage autoimmune cytopenias in patients with lymphoid cancer

Autoimmune conditions can occur in a temporary relationship with any malignant lymphoma. In many instances, treatment at diagnosis is not required, but symptomatic autoimmune conditions represent an indication for treatment, particularly in chronic lymphoproliferative diseases. Treatment is selected depending on the predominant condition: autoimmune disease (immunosuppression) or lymphoma (antilymphoma therapy). Steroids and anti-CD20 antibodies are effective against both conditions and may suppress the autoimmune complication for a prolonged period. The efficacy of B-cell receptor inhibitors has provided us with novel insights into the pathophysiology of antibody-producing B cells. Screening for underlying autoimmune conditions is part of the lymphoma workup, because other drugs, such as immunomodulators and checkpoint inhibitors, should be avoided or used with caution. In this article, we discuss diagnostic challenges and treatment approaches for different situations involving lymphomas and autoimmune cytopenias.

Case Report: High Doses of Intravenous Immunoglobulins as a Successful Treatment for Late Onset Immune Agranulocytosis After Rituximab Plus Bendamustine

Late onset neutropenia (LON) related to rituximab or rituximab plus chemotherapy is defined as an unexplained absolute neutrophil count of ≤1.5 × 10⁹/L starting at least four weeks after the last rituximab administration. LON is infrequent and its pathophysiology remains unknown. There are no guidelines or consensus strategies for the optimal management of patients developing LON. The majority of the patients recover promptly with no specific treatment and only some cases need to be managed with granulocytic colony stimulating factor (G-CSF), usually with a rapid response. Here, we describe a 69-year-old patient with Waldenström's macroglobulinemia who presented a septic event in the context of severe LON after rituximab plus bendamustine. The diagnosed of agranulocytosis was established by bone marrow examination. Interestingly, anti-neutrophil antibodies bound to the patient's granulocytes were found suggesting an autoimmune mechanism. The patient did not respond to G-CSF but achieved a rapid response after high doses of intravenous immunoglobulins with full white blood cell recovery.

Recurrent severe neutropenia following doxycycline use in a young healthy woman

A 29-year-old woman was hospitalized for fever, pharyngitis, and severe neutropenia after recent use of doxycycline and other antimicrobials. Three years later, she again presented with severe neutropenia after recent doxycycline use. Diagnostic workups were unyielding. This is only the second published case of severe neutropenia associated with doxycycline use.

Diagnosis and therapeutic decision-making for the neutropenic patient

Determining the cause of a low neutrophil count in a pediatric or adult patient is essential for the hematologist's clinical decision-making. Fundamental to this diagnostic process is establishing the presence or lack of a mature neutrophil storage pool, as absence places the patient at higher risk for infection and the need for supportive care measures. Many diagnostic tests, eg, a peripheral blood smear and bone marrow biopsy, remain important tools, but greater understanding of the diversity of neutropenic disorders has added new emphasis on evaluating for immune disorders and genetic testing. In this article, a structure is provided to assess patients based on the mechanism of neutropenia and to prioritize testing based on patient age and hypothesized pathophysiology. Common medical quandaries including fever management, need for growth factor support, risk of malignant transformation, and curative options in congenital neutropenia are reviewed to guide medical decision-making in neutropenic patients.

How to Make the Right Diagnosis in Neutropenia

Isolated neutropenia without anemia or thrombocytopenia is a common clinical problem. The etiology of neutropenia may vary from transient bone marrow suppression, caused by self-limited viral illnesses, to previously undiagnosed congenital syndromes or serious systemic diseases. Consequently, determining the underlying cause of neutropenia and what treatment is required can be challenging. Acquired neutropenia is common and most of the times an etiologic factor can be found. Congenital neutropenia (CN) is rare, and we still have a lot to learn from mutational analysis as to the exact role of gene abnormalities in the pathogenesis of these complex diseases. This mini-review discusses a proposed approach to neutropenia in the adult patient.

Infection risks in multiple myeloma: a systematic review and meta-analysis of randomized trials from 2015 to 2019

BACKGROUND

Patients with multiple myeloma (MM) remain at an increased risk of infection due to the disease process, as well as the ensuing treatments.

METHODS

We performed a systematic review to evaluate the monthly risk of grade III/IV infection, pneumonia, and neutropenia in patients with myeloma enrolled in randomized clinical trials (RCTs).

RESULTS

The risk of grade III or higher infection, pneumonia, and neutropenia persists among all phases of treatment. There was no statistical difference in grade III or higher infection, pneumonia, and neutropenia between frontline and relapsed/refractory setting. In the maintenance setting, the complications of infection, pneumonia, and neutropenia were low, but not negligible. Three-drug regimens were no more likely than two-drug regimens to have an increased risk of Grade III or higher infection.

CONCLUSIONS

This is the first study to quantify the monthly risk of grade III or higher infection, pneumonia, and neutropenia across different treatment regimens in the frontline, maintenance, and relapsed/refractory settings. The results of our systematic review demonstrate a significant risk for severe infection, pneumonia, and neutropenia in patients with MM. Further studies are needed to determine the value of antibiotic prophylaxis in a broader myeloma patient population, as well as other approaches that will further mitigate the morbidity and mortality related to infection in this vulnerable patient population.

Continuation of Treatment With Clozapine After an Episode of Neutropenia

BACKGROUND

Clozapine is the most effective in treatment-resistant schizophrenia. Neutropenia is an adverse effect of the drug requiring treatment discontinuation. This study related treatment continuation with little or no interruption after a neutropenia episode. The study contrasted from rechallenge studies after an extended treatment interruption.

METHODS

This retrospective chart audit examined 37 patients with an episode of neutropenia. It described characteristics of patients continuing treatment with minimal interruption.

FINDINGS

Thirty-one patients continued treatment after an initial treatment interruption for less than 3 days. A probable cause for neutropenia other than clozapine was identified in 14 patients. Twelve patients continued treatment with a change in the absolute neutrophil counts threshold to 1000/μL to determine treatment cessation. Most patients recovered from the index episode of neutropenia within 2 days. They also frequently presented with recurring benign episodes of low neutrophil cell counts during treatment than a comparative group.

IMPLICATIONS

The study recommends modifying clozapine treatment protocol absolute neutrophil count thresholds to less than 1000/μL to determine treatment cessation. Consideration of other probable causes for neutropenia, diurnal variations in cell counts, and laboratory errors reduced preemptive discontinuation of treatment. A risk-benefit approach supports continuing clozapine treatment after an episode of neutropenia.

Neutropenia in patients with hyperthyroidism: Systematic review and meta-analysis

BACKGROUND AND OBJECTIVE

Neutropenia, a low absolute neutrophil count (ANC), may be a sign of new-onset hyperthyroidism. The aim of this systematic review and meta-analysis was to provide the most reliable estimates of prevalence, degree and response to treatments of neutropenia in the pure hyperthyroidism setting.

METHODS

A comprehensive literature search was performed in PubMed and Scopus databases for retrieving articles in English and non-English languages reporting ANC values/neutropenic cases at presentation and after therapy in patients with hyperthyroidism. A proportion meta-analysis was performed with DerSimonian and Laird method (random-effects model). Pooled data were presented with 95% confidence intervals (95% CI) and displayed in a forest plot. I² statistic index was used to quantify the heterogeneity among the studies. Sensitivity analyses for the prevalence of neutropenia and the mean of ANC in hyperthyroid patients were performed by excluding the studies without full details. Trim and fill analysis and Egger's linear regression test were carried out to evaluate the publication bias. A two-sided P-value of <.05 was regarded as significant for all analyses. The National Heart, Lung and Blood Institute Quality Assessment Tool was used to evaluate the quality of studies included.

RESULTS

The literature search yielded 1880 studies of which 13 studies were included for systematic review and meta-analysis. Results of the meta-analysis demonstrated that the prevalence of neutropenia in newly diagnosed and untreated patients with Graves' hyperthyroidism was 10% (CI 5%-19%, I² 88.6%) and summary mean ANC value in neutropenic was 1.4 ± 0.3 × 10⁹ /L. In all neutropenic patients under ATD therapy neutropenia resolved, thus without the worsening of the baseline ANC values or the development of agranulocytosis. The sensitivity analyses showed similar results as those of the main analyses. For all outcomes, the publication bias was not statistically significant or not calculable.

CONCLUSIONS

Graves' disease per se is associated with neutropenia in about 10% of cases. Neutropenia usually appears as a mild to moderate laboratory abnormality with no detectable consequences. Subnormal/mild neutropenia should not be regarded as a contraindication to use ATDs, and clinicians should know that treating hyperthyroidism they have a significant chance to normalize ANC too.

Awan Z, Abouzaid AA, Elbahaie HM, Al Amoudi SM, Andarawi M, F Shehata S. The Prevalence of Isolated Neutropenia at High Altitude in Southern Saudi Arabia: Does Altitude Affect Leucocyte Count?

INTRODUCTION

Isolated neutropenia is a common problem in hematology practice. Benign ethnic neutropenia (BEN) is the common form of neutropenia worldwide and it affects mainly African and Middle Eastern ethnicities. Most cases of isolated mild and moderate neutropenia are benign and associated with no clinical significance. The aim of this study was to estimate the prevalence of isolated neutropenia at high-altitude southern Saudi Arabia.

METHODS

A large dataset of complete blood counts (CBCs) was analyzed for walk-in patients of both genders, of age ranges from 12 to 60 years doing blood tests at a commercial lab for high altitude - 2,270 meters above sea level - (HA) group, and from sea level SL group. Abnormal biochemical or CBC results were excluded before analysis.

RESULTS

For HA group, 3123 CBCs were analyzed and for SL group 18,427 CBCs were analyzed. The prevalence of mild neutropenia, defined as absolute neutrophil count (ANC) in the range of 1.0-.5× 109/L, was 12.4% (n=399) versus 5.6% (n=1025), while moderate neutropenia, defined as ANC of 0.5-1 × 109/L, was present 6% (n=191) versus 1.45% (n=269) in the high altitude and sea level groups, respectively. Severe neutropenia, defined as neutrophil count less than 0.5-1 × 109/L, was rare in both groups.

CONCLUSION

Isolated neutropenia is common in Saudis living at high altitude. While benign ethnic neutropenia (BEN) is thought to be the major contributing factor to this high prevalence, other factors including environmental factors and altitude are possible contributing factors along with underlying ethnic neutropenia.

A Next-Generation Sequencing Test for Severe Congenital Neutropenia: Utility in a Broader Clinicopathologic Spectrum of Disease

Severe congenital neutropenia (SCN) is a collection of diverse disorders characterized by chronically low absolute neutrophil count in the peripheral blood, increased susceptibility to infection, and a significant predisposition to the development of myeloid malignancies. SCN can be acquired or inherited. Inherited forms have been linked to variants in a group of diverse genes involved in the neutrophil-differentiation process. Variants that promote resistance to treatment have also been identified. Thus, genetic testing is important for the diagnosis, prognosis, and management of SCN. Herein we describe clinically validated assay developed for assessing patients with suspected SCN. The assay is performed from a whole-exome backbone. Variants are called across all coding exons, and results are filtered to focus on 48 genes that are clinically relevant to SCN. Validation results indicated 100% analytical sensitivity and specificity for the detection of constitutional variants among the 48 reportable genes. To date, 34 individuals have been referred for testing (age range: birth to 67 years). Several pathogenic and likely pathogenic variants have been identified, including one in a patient with late-onset disease. The pattern of cases referred for testing suggests that this assay has clinical utility in a broader spectrum of patients beyond those in the pediatric population who have classic early-onset symptoms characteristic of SCN.

The Role of Bone Marrow Evaluation in Clinical Allergy and Immunology Practice: When and Why

Allergists and immunologists rely on other specialists for higher risk procedures such as biopsies of the lung or gastrointestinal tract. However, we perform and interpret a handful of procedures ourselves. Training programs have historically required competency for prescribing immunoglobulin infusions, patch testing, rhino laryngoscopy, lung function testing, and provocation testing for airway hyperreactivity even though other specialists often perform them. Bone marrow aspirations and biopsies are not included in fellowship training assessments despite a significant number of marrow evaluations being requested by allergists and immunologists. For example, nearly 1 marrow assessment per month has been requested over 2 years for patients in the Allergy Immunology Clinic at Walter Reed National Military Medical Center. Marrow assessments are often required for diagnosis, monitoring, and treatment-related toxicities. Interpretive and procedural competency would benefit the field given the range of diseases in clinical immunology practice that require marrow assessment. We have generated a comprehensive list of the major conditions that might require bone marrow assessments in any Allergy and Immunology practice. We then summarize the specific tests that must be ordered and show how to determine sample quality. Finally, some providers may desire procedural competency and for those individuals we discuss tips for the procedure.

Outcomes of Isolated Neutropenia Referred to Pediatric Hematology-Oncology Clinic

BACKGROUND

Children with isolated neutropenia (absolute neutrophil count [ANC] <1500/μL) are frequently referred to pediatric hematology and oncology clinics for further diagnostic evaluation. Scant literature exists on interventions and outcomes for isolated neutropenia. We hypothesized that children will have resolution of their neutropenia without the need for intervention(s) by a pediatric hematologist and oncologist.

METHODS

We performed a 5.5-year institutional review board-approved retrospective chart review of children referred to our pediatric hematology and oncology clinics for isolated neutropenia. Neutropenia was categorized as mild (ANC of 1001-1500/μL), moderate (ANC of 500-1000 μL), severe (ANC of 201-500/μL), or very severe (ANC of ≤200/μL).

RESULTS

Among 155 children referred with isolated neutropenia, 45 (29%) had mild neutropenia, 65 (42%) had moderate neutropenia, 30 (19%) had severe neutropenia, and 15 (10%) had very severe neutropenia. Only 29 (19%) children changed to an ANC category lower than their initial referral category. At a median follow-up of 12 months, 101 children had resolution of neutropenia, 40 children had mild neutropenia, 10 children had moderate neutropenia, 3 children had severe neutropenia, and 1 patient had very severe neutropenia. A specific diagnosis was not identified in most (54%) children. The most common etiologies were viral suppression (16%), autoimmune neutropenia (14%), and drug-induced neutropenia (8%). Black children had a 3.5 higher odds of having persistent mild neutropenia. Six (4%) children received granulocyte colony-stimulating factor therapy.

CONCLUSIONS

Most children referred for isolated neutropenia do not progress in severity and do not require subspecialty interventions or hospitalizations.

Reporting Sysmex XN Absolute Neutrophil Count in Samples with Leukocyte Analyzer Flagging

OBJECTIVE

To provide faster laboratory data reporting, we evaluated the accuracy of Sysmex XN (Sysmex Inc, Kobe, Japan) absolute neutrophil count (ANC) in the presence of analyzer flagging.

METHODS

Sysmex XN and manual microscopy ANC were compared with 80 autovalidated control specimens and with 280 study specimens with analyzer flagging regarding immature granulocytes (IG) >3% or other leukocyte abnormalities. Specimens with ambiguous neutrophil clusters were excluded.

RESULTS

A slight positive overall method bias was seen for Sysmex XN compared to manual microscopy (n = 280), 0.025 (95% confidence interval [CI], -0.023 to 0.069) × 109/L. With IG > 10% (n = 123) the bias was larger, but not clinically significant, 0.17 (95% CI, 0.060-0.25) × 109/L. No clinically significant difference was seen in neutropenic (ANC < 1.5 × 109/L) specimens (n = 91), 0.070 (95% CI, -0.013 to 0.14) × 109/L.

CONCLUSION

These data indicate that Sysmex XN ANC can be reported in the presence of certain analyzer flagging to improve patient care.

Idiosyncratic Drug-Induced Neutropenia and Agranulocytosis in Elderly Patients

Agranulocytosis is a rare, but serious and life-threatening hematologic disorder in elderly patients. Idiosyncratic drug-induced agranulocytosis (IDIA) has been classically defined by a neutrophil count below 0.5 × 10⁹/L. The annual incidence of IDIA in Europe is about 1.6–9.2 cases per million inhabitants. Increasing age and female sex have been considered as risk factors for the development of this condition. Besides, it is well known that older people take on average more drugs than younger people. This condition is most often associated with the intake of antibacterial agents, antiplatelets, antithyroids, antipsychotics, antiepileptics and nonsteroidal anti-inflammatory drugs (NSAIDs). Initially, agranulocytosis may present without symptoms, but may quickly progress to a severe infection and sepsis. The causative drug should be immediately stopped. In febrile patients, blood cultures and where indicated, site-specific cultures should be obtained and early treatment with empirical broad-spectrum antibiotics started. Even with adequate treatment, the mortality rate is higher in elderly patients reaching up to 20%. Hematopoietic growth factors have proven to be useful as they shorten the duration of neutropenia. However, data on neutropenia and agranulocytosis in the elderly meeting the criteria of evidence-based medicine are still poor in the literature. This review analyzes the results of our experience as well as other published studies of the universal literature.

Clozapine rechallenge and initiation despite neutropenia- a practical, step-by-step guide

Clozapine remains the only drug treatment likely to benefit patients with treatment resistant schizophrenia. Its use is complicated by an increased risk of neutropenia and so there are stringent monitoring requirements and restrictions in those with previous neutropenia from any cause or from clozapine in particular. Despite these difficulties clozapine may yet be used following neutropenia, albeit with caution. Having had involvement with 14 cases of clozapine use in these circumstances we set out our approach to the assessment of risks and benefits, risk mitigation and monitoring with a practical guide.

Incidence of Severe Chronic Neutropenia in South Korea and Related Clinical Manifestations: A National Health Insurance Database Study

Background and objectives: Severe chronic neutropenia (SCN) is a condition in which absolute neutrophil counts remain at a low level (under 500/µL) over months or years. Because of the rare onset of SCN, its epidemiology, prognosis, and clinical manifestations have not yet been fully understood. In particular, large-cohort studies in Asian countries are still insufficient. Therefore, in this study, national health insurance data was used to investigate the epidemiologic features and prognosis of SCN in South Korea. Materials and Methods: The data from the Health Insurance Review and Assessment database recorded between 1 January 2011 and 31 December 2015 were explored. SCN was defined based on the ICD-10 code, registry of benefit extension policy, and inclusion criteria of the study. After identifying patients with SCN, annual incidence and their co-morbidities were analyzed. Results: Among the initially identified patients with severe neutropenia (N = 2145), a total of 367 patients had SCN and were enrolled. The annual incidence rate of SCN ranged from 0.12 to 0.17 per 100,000 person-year (PY) during the study period. The highest incidence was observed in pediatric patients aged between 0 to 9 years (N = 156), followed by women in their fifties (N = 43). The total incidence rate was 0.17 in females and 0.12 in males (Relative risk (RR): 1.43, 95%, CI: 1.16–1.76). The most common accompanying condition was mild respiratory infection, but about 3.2% of patients progressed to hematologic malignancy after an average of 2.4 years. Conclusions: This nationwide population-based epidemiological study showed that incidence of SCN is higher in pediatrics and middle-aged women. As progression to hematologic malignancy was significantly higher in the age of in 45–49 years old, careful follow-up is necessary in this group. However, since this study lacks the molecular information, these finding need to be interpreted with great caution.

Age-related prevalence and clinical significance of neutropenia - isolated or combined with other cytopenias: Real world data from 373 820 primary care individuals

Neutropenia (NP), that is, an absolute blood neutrophil count (ANC) <1.5 g/L, accompanies various diseases. However, the clinical significance of NP, detected in routine complete blood cell counts (CBC) in primary care, is poorly characterized. Here, from a primary care resource with ANCs from >370 000 individuals, we identified and followed neutropenic subjects for the next 4 years for novel ICD-10 based diagnoses of viral infections and hematological malignancies (ie, previously identified major outcomes in NP individuals) in Danish nationwide health registers. Risk estimates were assessed for children/adolescents (1-18 years) and adults (19-90 years) in relation to NP severity, and for isolated NP, bi- or pancytopenias. We found that NP was observed in 4.9% of children and in 1.9% of adults. The lower the ANC, the likelier was a diagnosis of viral infections or hematological malignancies established during the ensuing 4 years. Among neutropenic children, unspecified viral infections predominated, followed by mononucleosis (with other cytopenias in only 7% and 25% of the cases, respectively). All NP children with acute leukemia presented with bi- or pancytopenia from start of follow-up. In NP adults, hepatitis, followed by HIV, were the most common infections, and acute myelogenous leukemia (AML) and myelodysplastic syndromes (MDSs) the predominating hematological malignancies. Adult NP patients, subsequently diagnosed with hepatitis, HIV or AML, MDS, were bi- or pancytopenic in 42%, 47%, 90% and 91% of cases, respectively. Thus, presence of NP in even one CBC may be the first sign of a latent viral or hematological disorder requiring careful follow-up.

Autoimmune cytopenias (AIC) following allogeneic haematopoietic stem cell transplant for acquired aplastic anaemia: a joint study of the Autoimmune Diseases and Severe Aplastic Anaemia Working Parties (ADWP/SAAWP) of the European Society for Blood and Marrow Transplantation (EBMT)

This retrospective study explored the incidence of autoimmune cytopenia (AIC) in 530 paediatric and adult patients with acquired aplastic anaemia (aAA) who underwent first allogeneic HSCT between 2002 and 2012. AIC was a rare complication with a cumulative incidence of AIC at 1, 3, 5 and 10 years post HSCT of 2.5% (1.2-3.9 95% CI), 4.4% (2.6-6.2 95% CI), 4.6% (2.8-6.5 95% CI) and 5.1% (3.1-7.2 95% CI). Overall survival at 5 years after diagnosis of AIC was 85.9% (71-100 95% CI). Twenty-five patients were diagnosed with AIC at a median of 10.6 (2.6-91.5) months post HSCT. Eight (32%) patients were diagnosed with immune thrombocytopenia (ITP), seven (28%) with autoimmune haemolytic anaemia (AIHA), seven (24%) with Evans syndrome and four (16%) with autoimmune neutropenia (AIN). Treatment strategies were heterogeneous. Complete responses were seen in 12 of 25 patients, with death in three patients. In multivariable Cox analysis of a subgroup of 475 patients, peripheral blood stem cell (PBSC) transplant was associated with higher risk of AIC compared with bone marrow (BM) when conditioning regimens contained fludarabine and/or alemtuzumab (2.81 [1.06-7.49 95% CI]; p = 0.038), or anti-thymocyte globulin (ATG) (2.86 [1.11-7.37 95% CI]; p = 0.029). Myeloablative conditioning was associated with a lower risk of AIC compared with reduced intensity conditioning (RIC) in fludarabine and/or alemtuzumab (0.34 [0.12-0.98 95% CI]; p = 0.046) and ATG containing regimens (0.34 [0.12-0.95 95% CI]; p = 0.04). These findings provide clinically useful information regarding the incidence of a rare and potentially life-threatening complication of allogeneic HSCT for aAA, and further support for BM as the preferred stem cell source for transplant of patients with aAA.

Clozapine-associated neutropenia in Latin America: incidence report of 5380 Chilean users

Systematic information about Latino clozapine users is still scarce. Our aim was to evaluate the risk of clozapine-associated neutropenia in a Chilean cohort using the last Food and Drug Administration's recommendations for clozapine monitoring. Findings should improve clinical practice and promote changes in clozapine guidelines in Latin America. We conducted a retrospective observational study of 5380 Chilean clozapine users that started clozapine treatment between 2003 and 2015. The absolute risk of severe neutropenia was 0.61% (33/5380) with an incidence of 0.086 cases per 100 person-years of follow-up. 87.9% of cases with severe neutropenia appeared during first 18 weeks. Cases of mild neutropenia were 3.9% of total sample and occurred almost constantly without a specific risk time. 77.5% of cases of moderate or severe neutropenia didn't present an event of mild neutropenia before. 22.8% of clozapine users (1227/5380) discontinued treatment for any cause and 4.2% (225/5380) due to neutropenia in any severity level. Clozapine-associated neutropenia risk in Latino users is similar than in the rest of the world. The evidence of a very low risk for severe neutropenia and the behaviour of mild neutropenia cases confirm the feasibility of changes in Latin American clozapine guidelines using current Food and Drug Administration's recommendations as a model.

Benign ethnic neutropenia

Benign ethnic neutropenia (BEN) is one of the most common causes of chronic neutropenia seen in individuals of African, Middle Eastern and West Indian descent, affecting many individuals worldwide. Despite its prevalence, many physicians are not familiar with this benign condition, resulting in unnecessary evaluation and testing for neutropenia in otherwise healthy individuals. Clinically, patients with BEN are at no increased risk of infection despite their neutropenia. Implications of this condition are highlighted in those patients receiving therapies that have a known side effect of neutropenia, most commonly chemotherapy agents. Studies have suggested that disparities in survival among those patients receiving chemotherapy between patients of European decent and African decent may be attributed to measured neutropenia in these populations, questioning whether BEN could be an influential factor. This review encompasses all aspects of benign ethnic neutropenia, providing information about this condition and helping to guide clinical decision-making as to when an aggressive work up and referral are indicated and when it is appropriate to monitor. Additionally, we review the role of genetic studies in identifying the genes related to BEN, summarize the theories that offer the most accepted mechanisms behind the condition, and address the importance of pursuing larger studies to assess the implication of BEN in oncology patients as well as patients taking neutropenia-causing medications.

Treatment effectiveness of levamisole plus prednisolone on oral lichen planus patients with emphasis on levamisole-induced agranulocytosis or pancytopenia

BACKGROUND/PURPOSE

Physicians' and dentists' knowledge of levamisole-induced agranulocytosis or pancytopenia remains incomplete. This study aimed to evaluate the treatment effectiveness of levamisole plus prednisolone on oral lichen planus (OLP) patients with emphasis on levamisole-induced hematological changes.

METHODS

Ninety patients with erosive OLP were given 120 mg/day new levamisole (Levazol) and 15 mg/day prednisolone for three consecutive days each week. Three cases with levamisole-induced blood-cytopenias were assessed and treated within one year.

RESULTS

Most patients reported significant pain relief and showed no evidence of erosive OLP after 4-8 weeks of treatment with few side effects; nevertheless, three female patients developed agranulocytosis or granulocytopenia with concomitant thrombocytopenia or pancytopenia within 2-6 weeks after levamisole (Levazol) treatment. One case with previously unknown double episodes of agranulocytosis revealed her first episode following interruption of levamisole (Decaris) treatment for 4 months. High fever and sore throat were the most common symptoms, but two agranulocytosis cases remained asymptomatic one week before diagnosis, and were treated with levamisole withdrawal and empiric antimicrobial initiation as well as utilization of granulocyte colony-stimulating factors. Neutrophil recovery took about 1 week, but over 4 weeks in one of the cases (an elderly patient) with septic shock.

CONCLUSION

Agranulocytosis or pancytopenia usually developed within 2 months after levamisole treatment, but it might be delayed. Agranulocytosis was more likely to occur in females and onset was acute. Levamisole is an effective immunomodulator for OLP patients; however, it should be used with caution and administered with regular blood monitoring.

A genome-wide association study in individuals of African ancestry reveals the importance of the Duffy-null genotype in the assessment of clozapine-related neutropenia

Individuals of African ancestry in the United States and Europe are at increased risk of developing schizophrenia and have poorer clinical outcomes. The antipsychotic clozapine, the only licensed medication for treatment-resistant schizophrenia, is under-prescribed and has high rates of discontinuation in individuals of African ancestry, due in part to increased rates of neutropenia. The genetic basis of lower neutrophil levels in those of African ancestry has not previously been investigated in the context of clozapine treatment. We sought to identify risk alleles in the first genome-wide association study of neutrophil levels during clozapine treatment, in 552 individuals with treatment-resistant schizophrenia and robustly inferred African genetic ancestry. Two genome-wide significant loci were associated with low neutrophil counts during clozapine treatment. The most significantly associated locus was driven by rs2814778 (β = -0.9, P = 4.21 × 10^-21), a known regulatory variant in the atypical chemokine receptor 1 (ACKR1) gene. Individuals homozygous for the C allele at rs2814778 were significantly more likely to develop neutropenia and have to stop clozapine treatment (OR = 20.4, P = 3.44 × 10^-7). This genotype, also termed "Duffy-null", has previously been shown to be associated with lower neutrophil levels in those of African ancestry. Our results indicate the relevance of the rs2814778 genotype for those taking clozapine and its potential as a pharmacogenetic test, dependent on the outcome of additional safety studies, to assist decision making in the initiation and on-going management of clozapine treatment.

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).

Lymphopenia and risk of infection and infection-related death in 98,344 individuals from a prospective Danish population-based study

BACKGROUND

Neutropenia increases the risk of infection, but it is unknown if this also applies to lymphopenia. We therefore tested the hypotheses that lymphopenia is associated with increased risk of infection and infection-related death in the general population.

METHODS AND FINDINGS

Of the invited 220,424 individuals, 99,191 attended examination. We analyzed 98,344 individuals from the Copenhagen General Population Study (Denmark), examined from November 25, 2003, to July 9, 2013, and with available blood lymphocyte count at date of examination. During a median of 6 years of follow-up, they developed 8,401 infections and experienced 1,045 infection-related deaths. Due to the completeness of the Danish civil and health registries, none of the 98,344 individuals were lost to follow-up, and those emigrating (n = 385) or dying (n = 5,636) had their follow-up truncated at the day of emigration or death. At date of examination, mean age was 58 years, and 44,181 (44.9%) were men. Individuals with lymphopenia (lymphocyte count < 1.1 × 109/l, n = 2,352) compared to those with lymphocytes in the reference range (1.1-3.7 × 109/l, n = 93,538) had multivariable-adjusted hazard ratios of 1.41 (95% CI 1.28-1.56) for any infection, 1.31 (1.14-1.52) for pneumonia, 1.44 (1.15-1.79) for skin infection, 1.26 (1.02-1.56) for urinary tract infection, 1.51 (1.21-1.89) for sepsis, 1.38 (1.01-1.88) for diarrheal disease, 2.15 (1.16-3.98) for endocarditis, and 2.26 (1.21-4.24) for other infections. The corresponding hazard ratio for infection-related death was 1.70 (95% CI 1.37-2.10). Analyses were adjusted for age, sex, smoking status, cumulative smoking, alcohol intake, body mass index, plasma C-reactive protein, blood neutrophil count, recent infection, Charlson comorbidity index, autoimmune diseases, medication use, and immunodeficiency/hematologic disease. The findings were robust in all stratified analyses and also when including only events later than 2 years after first examination. However, due to the observational design, the study cannot address questions of causality, and our analyses might theoretically have been affected by residual confounding and reverse causation. In principle, fluctuating lymphocyte counts over time might also have influenced analyses, but lymphocyte counts in 5,181 individuals measured 10 years after first examination showed a regression dilution ratio of 0.68.

CONCLUSIONS

Lymphopenia was associated with increased risk of hospitalization with infection and increased risk of infection-related death in the general population. Notably, causality cannot be deduced from our data.

Effect of circadian variation on neutrophil mobilization to the peripheral blood in benign constitutional neutropenia

Benign constitutional neutropenia (BCN) is an asymptomatic condition characterized by mild chronic neutropenia in patients with no history of recurrent infections. Most patients are referred for further testing, increasing health care costs. We present an alternative form of assessment of individuals with BCN based on neutrophil circadian variation. The objective of this study was to evaluate whether circadian variations of neutrophil counts would result in neutrophil values higher than neutropenia threshold in individuals with BCN. Absolute neutrophil counts (ANCs) were evaluated in 102 patients with BCN (<1500 cells/μL) and 60 age- and sex-matched controls. Paired blood counts were performed in the early morning and in the early afternoon. We observed a significant difference between morning and afternoon ANC in BCN patients (879 cells/μL, 95% CI 745-1028, p < 0.001), as well as in the controls (619 cells/μL, 95% CI 443-796, p < 0.001). The ANC increase between the two evaluations was significantly greater in BCN patients compared with controls: 83% and 27%, respectively (p < 0.001). The ANC increment was higher in the groups with a lower morning ANC: 105%, 63%, and 27% in the <1000, 1000-1500, and >1500 cells/μL groups, respectively (p < 0.001). Of all BCN patients, 73% presented with >1500 cells/μL in the afternoon and 16% improved from the <1000 cells/μL to the 1000-1500 cells/μL category. In conclusion, neutrophil circadian variation measurement allows many BCN patients to be excluded from the neutropenia threshold. We identified a simple, easy, and feasible way to assess neutrophil reserve in patients with BCN with a potential reduction in costs of the assessment.

Utilization of G-CSF and GM-CSF as an alternative to discontinuation in clozapine-induced neutropenia or leukopenia: A case report and discussion

Clozapine remains the definitive gold standard for treatment-resistant schizophrenia despite limitations in use because of hematological abnormalities. Neutropenia or leukopenia are often treated with interruption of clozapine treatment, frequently resulting in clinical decompensation, hospitalization, increased burden to patient care, and increased risk of suicide. Colony-stimulating factors, including granulocyte colony-stimulating factors and granulocyte-macrophage colony-stimulating factors, are cytokines that stimulate proliferation and differentiation of myeloid precursor cells. Their use in the prevention and treatment of clozapine-associated neutropenia presents an alternative to clozapine discontinuation in certain cases. We present a case report of successful periodic granulocyte-macrophage colony-stimulating factor use with clozapine in a patient with treatment-resistant schizophrenia, as well as discussion of a practical approach to patients with possible clozapine-induced neutropenia or leukopenia.

Non-linear association between long-term outcome and preoperative neutrophil-to-lymphocyte ratio in patients undergoing curative resection for gastric cancer: a retrospective analysis of 1335 cases in a tetrachotomous manner

Objective

Although the prognostic utility of the pretreatment neutrophil-to-lymphocyte ratio (NLR) has been widely reported for gastric cancer and several other malignancies, the optimal patient stratification methodologies for such analyses have yet to be established. We aimed to examine the predictive value of preoperative NLR in patients with operable gastric cancer, and to elucidate whether or not the relationship between long-term outcome and pretreatment NLR is monotonically linear.

Methods

Preoperative data from 1335 patients who underwent curative surgery for gastric cancer were retrospectively evaluated. Patients were divided into four groups (Q1-Q4) according to preoperative NLR (1.59, 2.11 and 2.96). Survival time was calculated applying the Cox proportional hazard model to both univariate and multivariate estimates.

Results

On univariate Cox regression analysis, preoperative NLR was significantly associated with overall survival (OS) and relapse-free survival (RFS). On subsequent multivariate analysis, preoperative NLR, as a tetrachotomous variable, was independently associated with OS and RFS (P = 0.028, 0.023, respectively). When comparing Q1 with Q3 or Q4 in multivariate analysis, there were no significant prognostic differences in OS (P = 0.23, 0.37, respectively) and RFS (P = 0.26, 0.46, respectively). The Q2 group showed significantly longer RFS than the Q1 group (hazard ratio 0.69, 95% confidence interval 0.48-0.99, P = 0.048).

Conclusions

Although preoperative NLR was significantly associated with long-term outcome in gastric cancer patients, the association was not linear.

Synthesis and Biological Evaluation of 1,3,8-Triazaspiro[4.5]decane-2,4-dione Derivatives as Myelostimulators

Spiroconnected N-alkoxyalkylpiperidine hydantoins were obtained via the Strecker reaction of cyanohydrin with ammonium carbonate. 1,3,8-Triazaspiro[4.5]decane-2,4-diones have shown the myelostimulating activity in the artificially induced (with cyclophosphamide) myelodepressive syndrome. The compounds significantly accelerated the regeneration of lymphocyte and granulocyte cell pool of bone marrow hematopoiesis.

New monogenic disorders identify more pathways to neutropenia: from the clinic to next-generation sequencing

Neutrophils are the most common type of leukocyte in human circulating blood and constitute one of the chief mediators for innate immunity. Defined as a reduction from a normal distribution of values, neutropenia results from a number of congenital and acquired conditions. Neutropenia may be insignificant, temporary, or associated with a chronic condition with or without a vulnerability to life-threatening infections. As an inherited bone marrow failure syndrome, neutropenia may be associated with transformation to myeloid malignancy. Recognition of an inherited bone marrow failure syndrome may be delayed into adulthood. The list of monogenic neutropenia disorders is growing, heterogeneous, and bewildering. Furthermore, greater knowledge of immune-mediated and drug-related causes makes the diagnosis and management of neutropenia challenging. Recognition of syndromic presentations and especially the introduction of next-generation sequencing are improving the accuracy and expediency of diagnosis as well as their clinical management. Furthermore, identification of monogenic neutropenia disorders is shedding light on the molecular mechanisms of granulopoiesis and myeloid malignancies.

Evaluating the Effect of the Changes in FDA Guidelines for Clozapine Monitoring

BACKGROUND

Concerns exist that clozapine is underutilized in the management of treatment-resistant schizophrenia. Although a 2015 change in the US Food and Drug Administration (FDA) monitoring recommendations lowered the threshold of the absolute neutrophil count for treatment interruption from 1,500/μL to 1,000/μL and removed white blood cell count thresholds from the monitoring algorithm, the implications of this policy change on clozapine interruptions remain unknown.

METHODS

We analyzed outpatient prescribing records for antipsychotic medications in the Veterans Integrated Service Network 7 (VISN 7) database between 1999 and 2012 to assess the potential impact of the recent changes in FDA neutropenia monitoring recommendations on clozapine treatment discontinuation. We evaluated results of complete blood count monitoring to compare percentages of patients who developed or would have developed ≥ 1 hematologic event under the previous and current FDA guidelines in the first year following initiation of clozapine.

RESULTS

From a cohort of 14,620 patients with schizophrenia (ICD-9-295.x), 246 patients received clozapine treatment (1.7%). No agranulocytosis was observed during the study period. Under the former recommendations, 5 patients in the clozapine initiation cohort (n = 160, 3.1%; 95% CI, 0.43-5.83) qualified for treatment interruption during the first year of clozapine treatment, while only 1 patient (0.6%) qualified under the current recommendations. Under the former recommendations, hematologic events occurred at a similar rate for individuals taking and not taking clozapine.

CONCLUSIONS

While clozapine remains an underused medication, the new FDA monitoring guidelines are likely to substantially reduce the percentage of patients who meet criteria for clozapine-associated hematologic events requiring treatment interruption. This decrease may reduce the clinical burden of managing patients on clozapine and therefore increase the number of individuals treated with this uniquely effective medication. However, prospective studies of individuals treated under the new guidelines are needed to fully assess safety of the FDA's change.