Diagnosis and management of isolated neutropenia: A survey of pediatric hematologist oncologists

BACKGROUND

Isolated neutropenia is a common referral to pediatric hematology oncology (PHO) physicians. There are no established consensus guidelines in the diagnosis and management of patients with isolated, asymptomatic, and incidentally discovered neutropenia.

METHODS

A survey was distributed to PHO physicians on the American Society of Pediatric Hematology Oncology member discussion page to determine the common diagnostic and management decisions regarding patients with isolated neutropenia and to explore beliefs regarding the term "benign ethnic neutropenia."

RESULTS

One hundred twenty-six PHO attending physicians completed the survey. The most common tests reportedly ordered for this patient population included complete blood cell count (CBC) (98%), peripheral smear (75%), antineutrophil antibody testing (29%), and immunoglobulins (24%). Providers were more likely to order an antineutrophil antibody in toddlers (p = .0085), and antinuclear antibody (ANA) panels in adolescents (p < .001). Half of providers do not request additional CBCs prior to their initial consultation, and most suggest referring patients with mild neutropenia after confirming a declining absolute neutrophil count (ANC) (51%). The three most important factors influencing ongoing follow-up included: history of recurrent/severe infections (98%), family history of blood disorders (98%), and more severe/progressively worsening neutropenia (97%). Seventy percent of respondents have diagnosed patients with "benign ethnic neutropenia," and 75% support replacement of the term to "typical neutrophil count with Fy(a-/b-) status," if confirmed with red cell phenotyping.

CONCLUSION

We identified practice patterns of PHO physicians for the diagnosis and management of patients referred for asymptomatic and isolated neutropenia. These data provide the framework to conduct cost-effectiveness studies.

Immunodeficiency and bone marrow failure with mosaic and germline TLR8 gain of function

Inborn errors of immunity (IEI) are a genetically heterogeneous group of disorders with a broad clinical spectrum. Identification of molecular and functional bases of these disorders is important for diagnosis, treatment, and an understanding of the human immune response. We identified 6 unrelated males with neutropenia, infections, lymphoproliferation, humoral immune defects, and in some cases bone marrow failure associated with 3 different variants in the X-linked gene TLR8, encoding the endosomal Toll-like receptor 8 (TLR8). Interestingly, 5 patients had somatic variants in TLR8 with <30% mosaicism, suggesting a dominant mechanism responsible for the clinical phenotype. Mosaicism was also detected in skin-derived fibroblasts in 3 patients, demonstrating that mutations were not limited to the hematopoietic compartment. All patients had refractory chronic neutropenia, and 3 patients underwent allogeneic hematopoietic cell transplantation. All variants conferred gain of function to TLR8 protein, and immune phenotyping demonstrated a proinflammatory phenotype with activated T cells and elevated serum cytokines associated with impaired B-cell maturation. Differentiation of myeloid cells from patient-derived induced pluripotent stem cells demonstrated increased responsiveness to TLR8. Together, these findings demonstrate that gain-of-function variants in TLR8 lead to a novel childhood-onset IEI with lymphoproliferation, neutropenia, infectious susceptibility, B- and T-cell defects, and in some cases, bone marrow failure. Somatic mosaicism is a prominent molecular mechanism of this new disease.

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.

Red blood cell transfusion therapy for sickle cell patients with frequent painful events

BACKGROUND

Recurrent pain events or chronic pain are among the most common complications of sickle cell disease. Despite attempts to maximize adherence to and dosing of hydroxyurea, some patients continue to suffer from pain. Our institution developed a program to initiate chronic red blood cell transfusions for one year in patients clinically deemed to have high healthcare utilization from sickle cell pain, despite being prescribed hydroxyurea.

PROCEDURE

An institutional review board approved retrospective study to evaluate the health outcomes associated with a one-year red blood cell transfusion protocol in sickle cell patients experiencing recurrent pain events as compared with the health outcomes for these patients in the one year prior to receiving transfusion therapy. We performed a matched-pair analysis using a Wilcoxon signed rank to determine the impact of transfusion therapy on clinic visits, emergency department visits, hospital admissions, hospitalization days, and opioid prescriptions filled.

RESULTS

One year of transfusion therapy significantly reduced the number of total emergency department visits for pain (6 vs 2.5 pain visits/year, P = 0.005), mean hospitalizations for pain (3.4 vs 0.9 pain admissions/year), and mean hospital days per year for pain crisis (23.5 vs 4.5, P = 0.0001), as compared with the one year prior to transfusion therapy. We identified no significant difference in opioid prescriptions filled during the year of transfusion therapy.

CONCLUSION

Patients with frequent pain episodes may benefit from one year of transfusion therapy.

Impact of early analgesia on hospitalization outcomes for sickle cell pain crisis

BACKGROUND

Painful events are the leading cause of hospitalizations for patients with sickle cell disease. Individualized pain plans targeting patient-specific maximum opioid dosing may shorten hospitalization length and are recommended by national guidelines. Prior to implementing individualized sickle cell pain plans, we tested the hypothesis that a shorter time to achieve a maximum opioid dose would improve hospitalization outcomes.

PROCEDURE

Two-year IRB-approved, retrospective study of pediatric patients admitted for vaso-occlusive crisis (VOC). We recorded the emergency department admission time, order entry time for the maximum opioid dose during the hospitalization, and time of discharge orders.  We categorized patients as infrequent if they required <3 admissions for VOC over two years and patients as frequent if they required ≥3 admissions for VOC over two years. To account for multiple admissions, generalized linear modeling was performed.

RESULTS

We identified 236 admissions for acute pain observed in 108 patients. Achieving an earlier maximum opioid dose was significantly associated with shorter length of hospitalization for frequent and infrequent pain patients (both P ≤ 0.0001). As total hospitalization length can be impacted by the time a maximum opioid order was placed, we also analyzed hospitalization length after the maximum opioid order was placed. Frequent pain patients who achieved earlier analgesia had a significantly shorter hospitalization from the time the maximum opioid order was placed (P = 0.03) while no association was found for infrequent pain patients (P = 0.84).

CONCLUSIONS

Early achievement of maximum analgesia improved hospitalization outcomes and warrant further investigation in prospective studies of individualized pain plans.

Outcomes in Mild to Moderate Isolated Thrombocytopenia

OBJECTIVES

Incidental isolated mild to moderate thrombocytopenia is a frequent laboratory finding prompting a referral to pediatric hematology-oncology. We tested the hypothesis that patients with isolated asymptomatic mild thrombocytopenia would not progress to require an intervention from a pediatric hematologist-oncologist.

METHODS

This is a 5-year retrospective review of 113 patients referred to pediatric hematology-oncology for isolated thrombocytopenia. Initial, lowest, and current platelet counts along with clinical course and need for interventions were recorded. Thrombocytopenia was categorized as mild (platelet count: 101-140 × 10³/μL), moderate (platelet count: 51-100 × 10³/μL), severe (platelet count: 21-50 × 10³/μL), and very severe (platelet count: ≤20 × 10³/μL).

RESULTS

Eight of 48 patients (17%) referred for initial mild isolated thrombocytopenia progressed to moderate thrombocytopenia at 1 visit. At present, 2 of these patients have moderate thrombocytopenia, 17 remain with mild thrombocytopenia, and 29 patients have resolved thrombocytopenia. Nine of 65 patients (14%) referred for moderate thrombocytopenia progressed to severe or very severe thrombocytopenia on 1 occasion. At present, no patients have severe thrombocytopenia, 18 remain with moderate thrombocytopenia, 14 improved to mild thrombocytopenia, and 33 have resolved thrombocytopenia. Only 3 patients required interventions from a hematologist, whereas 10 patients required therapy from other subspecialties.

CONCLUSIONS

We only identified 3 patients (3%) with mild to moderate thrombocytopenia who required an intervention from a hematologist to improve platelet counts. Patients with isolated mild thrombocytopenia with a normal bleeding history and physical examination findings frequently have normalized their platelet counts within 1 month.