Polyclonal CD5+/CD19+ B1a lymphocytes after allogeneic stem cell transplantation: a potential diagnostic pitfall
Autops. Case Rep
; 10(2): e2020147, Apr.-June 2020. graf
Article
em En
| LILACS
| ID: biblio-1131811
Biblioteca responsável:
BR26.7
ABSTRACT
In adults, B-lymphocytes comprise approximately 10% of circulating lymphocytes. The majority of peripheral B cells are B2 cells ("Mature" B-cells), which function as part of the humoral adaptive immune system. B1 cells ("Innate-like" B cells) are another sub-class of B lymphocytes, considered as innate immune cells with a characteristic phenotype (CD20+, CD27+, CD43+, CD70-, CD11b+, sIgM++, sIgD+) which can be divided into two subtypes; B1a (CD5+) spontaneously produce broadly reactive natural IgM, and B1b (CD5-) can generate T-cell independent, long-lasting IgM. There is very limited data available, indicating a correlation between allogeneic bone marrow transplantation and an increase in B1a cells. Here we present a case of a 17-year-old female with homozygous sickle cell disease (HbSS disease) who underwent hematopoietic stem cell transplant (HSCT). Approximately seven months post-transplant, she was found to have 16% immature mononuclear cells on complete blood count (CBC)-differential report. A follow-up peripheral blood flow cytometry showed that these cells were polyclonal CD5+/CD20+ B-cells, and comprised 66% of lymphocytes. Further workup and follow up failed to reveal any lymphoproliferative disorders. It is important not to misdiagnose these cells as an atypical CD5+ lymphoproliferative disorder. The presence of B1a cells has not been widely reported in non-neoplastic post-stem cell transplanted patients. This case also adds to and expands our knowledge regarding the presence of increased circulating B1a cells after stem cell transplant in a patient with no history of hematological malignancy.
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Texto completo:
1
Coleções:
01-internacional
Base de dados:
LILACS
Assunto principal:
Transplante de Células-Tronco
Tipo de estudo:
Diagnostic_studies
Limite:
Adolescent
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Female
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Humans
Idioma:
En
Ano de publicação:
2020
Tipo de documento:
Article