Table of Contents
Definition / general | Pathophysiology | Diagrams / tables | Clinical features | Uses by pathologists | Positive staining - normal | Positive staining - disease | Negative stainingCite this page: Pernick N. CD19. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/cdmarkerscd19.html. Accessed November 27th, 2024.
Definition / general
- Common B cell marker (also CD20, CD79a, PAX5)
- Expressed by B cells and follicular dendritic cells
- Early B lineage-restricted antigen present on most pre-B cells, B-ALL and B-CLL cells (OMIM #107265)
Pathophysiology
- Forms a complex with CD21, CD81 and CD225 in the membrane of mature B cells
- Regulates B cell development, activation and differentiation (J Immunol 2003;171:5921)
- May define intrinsic and antigen receptor-induced signaling thresholds critical for clonal expansion of the B cell pool and humoral immunity (Curr Dir Autoimmun 2005;8:55, Science 1992;256:105, Exp Hematol Oncol 2012;1:36)
Clinical features
- Defects in CD19 cause immunodeficiency common variable type 3 (OMIM #613493), characterized by antibody deficiency, hypogammaglobulinemia, recurrent bacterial infections and an inability to mount an antibody response to antigen
- CD19 count may be useful to screen for B cell lymphoproliferative disorders (Clin Chem Lab Med 2011;49:115)
- Adoptive transfer of anti-CD19-chimeric antigen receptor-expressing T cells may be effective for B cell malignancies (Blood 2010;116:4099, Sci Transl Med 2013;5:177, Blood 2013;122:4129)
Uses by pathologists
- Detection of B cells
- Diagnosis of B disorders
- May be more sensitive than CD20 in detecting B cell acute leukemias (Zhongguo Shi Yan Xue Ye Xue Za Zhi 2005;13:943)
Positive staining - normal
- Pre-B cells, B cells; follicular dendritic cells
- Hematogones in bone marrow by flow cytometry
Positive staining - disease
- B cell lymphomas and leukemias, but often weak / negative in follicular lymphoma or diffuse large B cell lymphoma (Histopathology 2006;48:239, Cytometry B Clin Cytom 2005;63:28)
- Occasionally myeloid leukemias (AML - Am J Clin Pathol 1998;109:211, AML with t(8;21) - Oncogene 2010;29:2927, AML-M0 - Am J Clin Pathol 2001;115:876, CML blast phase - Am J Clin Pathol 2004;121:836)
- Occasionally anaplastic large cell lymphoma by flow cytometry (Am J Clin Pathol 2003;119:205)
- Rarely T cell lymphoma (Cytometry B Clin Cytom 2009;76:142, Case Rep Hematol. 2013;2013:183134)
Negative staining
- Plasma cells, basophils, mast cells
- Myeloma (Am J Clin Pathol 2004;121:482, Am J Clin Pathol 2012;137:377), most T cell lymphomas
- Often L&H cells in lymphocyte predominant Hodgkin lymphoma, often post-transplant B cell lymphoproliferative disorder