# HLA-DR

Source: https://onco.cc/targets/hla-dr/  
OnCo record `hla-dr` (Target). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

HLA-DR is the display case that antigen-presenting cells use to show fragments to helper T cells. When monocytes lose it, the immune system is suppressed, which happens in advanced cancer and severe illness.

## Summary

HLA-DR is an MHC class II molecule, the structure on which antigen-presenting cells display peptide to CD4 helper T cells, and the alpha chain HLA-DRA is the gene given here. Two uses matter in oncology. It is part of how dendritic cells, B cells and monocytes are identified in a panel; and low HLA-DR on monocytes is a recognised sign of immune suppression, used as a marker of the suppressed myeloid state seen in advanced cancer and critical illness. Myeloid-derived suppressor cells are defined partly by that absence.

## Fields

- Kind: Target
- Last checked: 2026-10-16
- Also known as: HLA-DRA; MHC class II DR
- Tags: immune-marker
- Symbol: HLA-DRA
- Class: surface-antigen
- Biology: MHC class II molecule presenting peptide to CD4 T cells; the alpha chain HLA-DRA is given here.
- Where found: Dendritic cells; B cells; Monocytes and macrophages; Activated T cells

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/HLA-DR
- HGNC:4947: https://www.genenames.org/data/gene-symbol-report/#!/hgnc_id/HGNC:4947

## Connected records

- targets: [CD11c](https://onco.cc/targets/cd11c/), [CD4](https://onco.cc/targets/cd4/), [HLA-A](https://onco.cc/targets/hla-a/)
- pathways: [Antigen presentation & immune editing](https://onco.cc/pathways/antigen-presentation-immunoediting/)

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JSON: https://onco.cc/api/v1/entities/hla-dr.json