Increased polyclonal CD5+ B1a lymphocytes in a haploidentical stem cell transplant recipient

Robert A. Hillard, Lazaros J. Lekakis, Joseph F. Pulliam

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


Background: Atypical lymphocyte populations may be seen in the peritransplant setting. In this case report, we describe an unusually high number of CD5+ B-cells (B1a cells) following transplant. Methods: B1a cells identified during routine follow-up by immunophenotypic analysis in a middle-aged man who had a haploidentical stem cell transplant for acute myeloid leukemia were compared with a reference set of post-transplant samples. Results: Increased but polyclonal B1a cells were identified with 100% donor chimerism. Conclusions: Our case demonstrates that a high absolute number of B1a cells may be seen post-transplant and should not be confused with an atypical CD5 + lymphoproliferative disorder. Furthermore, the population of polyclonal CD5+ B lymphocytes from the patient's donor is prominent 7 months post-transplant. This suggests that the maintenance of CD5+ B1 cells prior to conversion to adult-type CD5- B2 cells is not hindered by the recipient adult stromal environment.

Original languageEnglish (US)
Pages (from-to)119-121
Number of pages3
JournalCytometry Part B - Clinical Cytometry
Volume80 B
Issue number2
StatePublished - Mar 1 2011
Externally publishedYes


  • B1a lymphocytes
  • lymphocyte subsets
  • transplant

ASJC Scopus subject areas

  • Cell Biology
  • Histology
  • Pathology and Forensic Medicine


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