Natural History Study for BEN

Completed

• Conditions: Leukocyte Disorders; Leukopenia; Neutropenia; Agranulocytosis; Hematologic Diseases

• Registration Number: NCT00059423
• Lead Sponsor: National Heart, Lung, and Blood Institute (NHLBI)

Brief Summary

In recent decades, hematologists have noticed that persons of African descent sometimes have lower white blood cell counts of a certain type, called granulocytes. These cells help to fight infections. The lower number of granulocytes in this situation does not appear to lead to more infections, and these individuals do not have any symptoms. This condition is called benign ethnic neutropenia (BEN), and is observed in a small percentage of individuals of African descent. This study will investigate the condition by studying people with and without BEN.

The goals of this study are to:

1. identify individuals of African descent with BEN.

2. determine the effects of two drugs, G-CSF and dexamethasone, on granulocyte production and movement.

3. determine whether there are differences in those with and without BEN in the way genes are stimulated after the administration of G-CSF and dexamethasone.

Study participants will be asked to interview with the research team, undergo physical exams, donate a blood sample, and receive G-CSF by injection, followed by dexamethasone (orally) about three weeks later. They also will be required to undergo apheresis three times, a procedure in which blood is drawn from a donor and separated into its components. Some components are retained for research analyses, such as granulocytes, and small amount of blood; the remainder is returned by transfusion to the donor. This procedure will be required of participants before they receive G-CSF, the day after they receive G-CSF, and the day after they receive dexamethasone. Gene messages (mRNA will be isolated from granulocytes, and analyzed to better understand granulocyte growth and movement.

Detailed Description

Benign ethnic neutropenia (BEN) is defined by peripheral blood absolute neutrophil count less than 1.5 x 10 (9) per liter without an increase in infections. This condition has been described in individuals of African descent. Although these individuals have normal myeloid maturation on bone marrow examinations, they appear to release fewer neutrophils into the circulation when stimulated by hydrocortisone, compared to normal controls. This suggests that there may be differences in the regulation of neutrophil release or trafficking. In the past decade, granulocyte-colony stimulating factor (G-CSF) has been widely used in a variety of clinical settings, from patients with chemotherapy-induced neutropenia to normal volunteers for peripheral blood stem cell collection. G-CSF, however, has not been used in individuals with BEN. Furthermore, gene expression in neutrophil proliferation and trafficking has not been studied in these individuals. The purpose of this study are to (1) identify individuals with BEN; (2) follow the natural history of BEN; (3) determine if there is a familial inheritance pattern; (4) characterize and compare neutrophil response to dexamethasone and G-CSF; (5) compare the pattern of neutrophil gene expression by microarray analyses; and (6) determine if mutations are present at the DNA level to account for gene expression pattern differences in individuals of African descent with and without BEN at baseline, post dexamethasone, and post G-CSF stimulation.

Study Timeline

• Study First Submitted QC: 2003-04-24
• Study First Submitted: 2003-04-25
• Study First Posted: 2003-04-25
• Study Start: 2003-06-03
• Primary Completion: 2019-04-23
• Status Verified: 2020-06
• Study Completion: 2020-06-26
• Last Update Submitted: 2024-03-21
• Last Update Posted: 2024-03-22

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 178

Inclusion Criteria

Not provided

Exclusion Criteria

Not provided

Study & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Primary Outcome Measures

Name	Time	Method
Serial blood counts in BEN	Ongoing	In our study, we hope to further elucidate the etiology of BEN in research subjects by isolating granulocyte mRNA after G-CSF and dexamethasone stimulation, applying microarray analyses to screen for gene expression differences, and confirming expression pattern differences by DNA analyses. We will focus on genes that are important in the proliferation and trafficking of neutrophils,such as PRV-1, elastase, myeloblastin, transcription factor PU.1, CAAT enhancing binding protein-alpha (C /EBP), stromal derived factor-1 (SDF-1), and CXC receptor-4 (CXCR4).

Trial Locations

Locations (1)

National Institutes of Health Clinical Center, 9000 Rockville Pike; 🇺🇸 Bethesda, Maryland, United States