Human cyclic neutropenia transferred by allogeneic bone marrow grafting

Area of Science:

• Hematology
• Immunology
• Genetics

Background:

• Human cyclic neutropenia shares clinical and etiological similarities with cyclic neutropenia observed in grey collie dogs.
• The underlying cause of cyclic neutropenia, specifically whether it originates from a transplantable hematopoietic stem cell defect, remained unconfirmed in humans.
• Understanding the cellular basis of cyclic neutropenia is crucial for developing effective therapeutic strategies.

Observation:

• A patient undergoing bone marrow transplantation for relapsed acute lymphoblastic leukemia received a transplant from a histocompatible sibling donor.
• Following the transplantation, the patient developed cyclic neutropenia, characterized by cyclical reductions in neutrophil counts.
• The donor was identified as the source of the condition, indicating a heritable or stem cell-related etiology.

Findings:

• The successful transfer of cyclic neutropenia from a donor to a recipient via bone marrow transplantation provides direct evidence.
• This finding confirms that cyclic neutropenia in humans, like in the canine model, is indeed caused by a defect in hematopoietic stem cells.
• The transplanted stem cells from the donor engrafted and produced neutrophils exhibiting the characteristic cyclical pattern.

Implications:

• This study validates the hematopoietic stem cell defect hypothesis for human cyclic neutropenia.
• It suggests that genetic factors or stem cell abnormalities are responsible for the disease.
• The findings have significant implications for donor screening, genetic counseling, and potential future gene therapies for cyclic neutropenia.