Hematogones: a multiparameter analysis of bone marrow precursor cells.

Area of Science:

• Pediatric Hematology
• Cell Biology
• Immunology

Background:

• Morphologically distinct lymphoid cells, termed hematogones (HGs), can be abundant in pediatric bone marrow.
• Expanded HGs can be mistaken for acute lymphoblastic leukemia (ALL) or metastatic tumors.
• The clinical significance and biologic features of expanded HGs are not fully understood.

Purpose of the Study:

• To correlate clinical, morphologic, and flow cytometric features of bone marrow samples with substantial HG numbers.
• To investigate the biologic properties of HGs using cytochemical, molecular, and cytogenetic analyses.
• To assess the clinical outcomes of children with expanded HGs.

Main Methods:

• Analysis of bone marrow samples from 12 children with 8-55% HGs.
• Morphologic, cytochemical, flow cytometry, molecular, and cytogenetic evaluations.
• Clinical follow-up for up to 3 years.

Main Results:

• Flow cytometry confirmed HGs represent a spectrum from B-cell precursors to mature B cells.
• DNA content was normal, with no clonal abnormalities identified by cytogenetics or gene rearrangement studies.
• None of the patients developed acute leukemia or bone marrow tumor involvement.

Conclusions:

• Expanded HGs in children do not appear to be a precursor to acute leukemia or solid tumors.
• HGs may play a role in immune recovery and hematopoiesis.
• Further research is needed to fully elucidate the role of HGs.