Clinical outcomes of patients referred for asymptomatic neutropenia: A focus on racial disparities in hematology

Clinical parameters of patients with Duffy null phenotype: a single centre, retrospective review

We characterise the clinical parameters of patients referred for isolated neutropenia who were found to express the Duffy null phenotype and subsequent diagnosis of Duffy null associated neutrophil count (DANC). This is a single-centre, retrospective review of adult patients (18 years and over) who were referred to a tertiary hospital for further investigation of isolated neutropenia between June 2023 and February 2024. Patient demographics, co-morbidities, ethnicity, medications, laboratory results and final diagnosis were obtained from electronic database and chart reviews. Data were collated and analysed using descriptive statistics. A total of 34 patients (35.3% male) were identified, with a median age of 43 years (IQR 31, 61). The median absolute neutrophil count was 1.42×109/L (IQR 0.74, 1.80). Ten patients (29.4%) referred for isolated neutropenia were subsequently found to have another cytopenia. Ten patients (29.4%) had confirmed Duffy null status, with all 10 patients reporting African heritage. Of those with confirmed Duffy null status, there was no history of recurrent infections, constitutional symptoms or other causes of isolated neutropenia. Of those who expressed Duffy positive phenotype (n=24), three patients (12.5%) were found to have a causative haematological disorder. Other causes of neutropenia in the cohort included autoimmune (20.6%), cyclical (5.9%) and drug-related (5.9%). Ten patients (29.4%) had no cause identified or had spontaneous resolution of their neutropenia. DANC was the most common cause of referred isolated neutropenia. Initial investigations could be limited to assessing Duffy null status in asymptomatic patients from African heritage.

Secondary Neutropenias

Neutrophils are a critical component of immunity, particularly against bacteria and other pathogens, but also in inflammation and tissue repair. As a consequence, individuals with neutropenia, defined by a reduction in absolute neutrophil counts, exhibit a strong propensity to severe infections that typically present with muted symptoms. Neutropenias encompass a heterogeneous set of disorders, comprising primary neutropenias, in which specific genes are mutated, and the more common secondary neutropenias, which have diverse non-genetic causes. These include hematological and other cancers, involving both direct effects of the cancer itself and indirect impacts via the chemotherapeutic, biological agents and cell-based approaches used for treatment. Other significant causes of secondary neutropenias are non-chemotherapeutic drugs, autoimmune and other immune diseases, infections and nutrient deficiencies. These collectively act by impacting neutrophil production in the bone marrow and/or destruction throughout the body. This review describes the biological and clinical manifestations of secondary neutropenias, detailing their underlying causes and management, with a discussion of alternative and emerging therapeutic approaches.

Psychological toxicity in classical hematology

Although considered "benign," mild blood count abnormalities, genetic factors imparting inconsequential thrombotic risk, and low-risk premalignant blood disorders can have significant psychological and financial impact on our patients. Several studies have demonstrated that patients with noncancerous conditions have increased levels of anxiety with distress similar to those with malignancy. Additionally, referral to a classical hematologist can be a daunting process for many patients due to uncertainties surrounding the reason for referral or misconstrued beliefs in a cancer diagnosis ascribed to the pairing of oncology and hematology in medical practice. If not properly triaged, incidental laboratory abnormalities can trigger extensive and costly evaluation. These challenges are compounded by a lack of consensus guidance and generalizability of modern reference ranges that do not adequately account for common influencing factors. Although often benign, incidental hematologic findings can lead to emotional suffering and careful consideration of the potential psychological and financial duress imparted to an individual must be considered. In this article, we will review the current literature describing the psychological effect of some commonly known hematologic conditions, identify benign causes for variations in hematologic laboratory values, and provide recommendations to reduce psychological toxicity as it pertains to hematologic testing.

Development of Duffy Null-Specific Absolute Neutrophil Count Reference Ranges

This study establishes a Duffy null phenotype–specific absolute neutrophil count reference range to optimize care and improve health equity.