# CD19 expression (CD19-positive)

Source: https://onco.cc/biomarkers/cd19-expression/  
OnCo record `cd19-expression` (Biomarker). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

CD19 is the B-cell surface protein that blinatumomab, CAR-T cells and several antibodies aim at. Blinatumomab's label requires CD19-positive leukaemia; the CAR-T labels assume it, and losing CD19 is the commonest way the disease escapes.

## Summary

CD19 is read by flow cytometry on blood or marrow blasts, or by immunohistochemistry on lymphoma tissue. Blinatumomab (Blincyto) is labelled for CD19-positive B-cell precursor ALL (in remission with MRD of 0.1 percent or more, in consolidation, and relapsed or refractory); tisagenlecleucel, axicabtagene ciloleucel, lisocabtagene maraleucel and brexucabtagene autoleucel are CD19-directed CAR-T products whose labels describe the disease by histology rather than by a CD19 threshold; tafasitamab and loncastuximab tesirine are CD19-directed antibodies for DLBCL. Antigen loss or lineage switch after CD19-directed therapy is documented in the labels' clinical sections and is the reason CD22- and CD20-directed options exist.

## Fields

- Kind: Biomarker
- Last checked: 2026-09-23
- Also known as: CD19-positive; CD19+; CD19 expression; CD19 positive B-ALL; CD19 loss; CD19-negative relapse
- Tags: biomarker; surface-antigen

## Sources

- BLINCYTO prescribing information (DailyMed): https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=38b482a8-960b-4591-9857-5031ecb830aa

## Connected records

- biomarkers: [CD20 expression (CD20-positive)](https://onco.cc/biomarkers/cd20-expression/), [CD22 expression (CD22-positive)](https://onco.cc/biomarkers/cd22-expression/), [CD30 expression (CD30-positive)](https://onco.cc/biomarkers/cd30-expression/)
- cancers: [Acute lymphoblastic leukaemia](https://onco.cc/cancers/all-leukemia/), [Diffuse large B-cell lymphoma](https://onco.cc/cancers/dlbcl/), [Follicular lymphoma](https://onco.cc/cancers/follicular-lymphoma/), [Mantle cell lymphoma](https://onco.cc/cancers/mantle-cell-lymphoma/), [Relapsed and refractory acute lymphoblastic leukaemia in children](https://onco.cc/cancers/all-paediatric-relapsed/)
- drugs: [Axicabtagene ciloleucel](https://onco.cc/drugs/axicabtagene-ciloleucel/), [Blinatumomab](https://onco.cc/drugs/blinatumomab/), [Brexucabtagene autoleucel](https://onco.cc/drugs/brexucabtagene-autoleucel/), [Lisocabtagene maraleucel](https://onco.cc/drugs/lisocabtagene-maraleucel/), [Loncastuximab tesirine](https://onco.cc/drugs/zynlonta/), [Tafasitamab](https://onco.cc/drugs/tafasitamab/), [Tisagenlecleucel](https://onco.cc/drugs/tisagenlecleucel/)
- terms: [Antigen escape (antigen loss, lineage switch)](https://onco.cc/terms/antigen-escape/), [Flow cytometry (immunophenotyping)](https://onco.cc/terms/flow-cytometry/), [Minimal / molecular residual disease (MRD)](https://onco.cc/terms/mrd/)
- targets: [CD19](https://onco.cc/targets/cd19/)

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JSON: https://onco.cc/api/v1/entities/cd19-expression.json