Functional hyposplenism after hematopoietic stem cell transplantation

Area of Science:

• Hematology
• Immunology
• Transplantation Medicine

Background:

• Functional hyposplenism is a known complication following hematopoietic stem cell transplantation (HSCT).
• Pitted red blood cell counts are used to assess hyposplenism.
• The relationship between hyposplenism and the severity of chronic graft-versus-host disease (cGvHD) requires further investigation.

Purpose of the Study:

• To investigate the transient nature and disease severity correlation of hyposplenism in pediatric HSCT patients with cGvHD.
• To evaluate the prevalence of hyposplenism in adult HSCT patients, including those with cGvHD and overlap syndromes.
• To determine if abnormal pitted red cell counts can guide antibiotic prophylaxis in all HSCT recipients.

Main Methods:

• Retrospective review of 36 pediatric HSCT patients' pitted red cell counts and clinical data (2005-2013).
• Prospective evaluation of a cohort in a multicenter adult HSCT biomarker trial.
• Comparison of pitted red cell counts with clinical outcomes, including acute GvHD (aGvHD) and cGvHD.

Main Results:

• Fourteen of 22 pediatric patients with aGvHD/cGvHD exhibited abnormal pitted red cell counts, often associated with gastrointestinal disease.
• In the adult cohort, abnormal pitted red cell counts were observed in control patients (3/10), classic cGvHD (3/10), and overlap syndrome (5/9).
• Hyposplenism was present in HSCT patients without diagnosed late aGvHD/cGvHD.

Conclusions:

• Hyposplenism, indicated by abnormal pitted red cell counts, is prevalent in HSCT patients, irrespective of GvHD diagnosis.
• Current antibiotic prophylaxis guidelines for encapsulated bacteria after HSCT may need revision.
• Abnormal pitted red cell counts could serve as a valuable biomarker for guiding antibiotic prophylaxis in all HSCT patients.