===== Immune Biomarker =====

An **immune biomarker** is a measurable indicator related to the immune system that reflects immune activation, suppression, or regulation. These biomarkers are used in **diagnosis**, **prognosis**, and **monitoring** of diseases, especially in oncology, immunology, and infectious diseases.

==== Examples ====
  * '''CD4+ T cells''': reflect helper T cell levels (e.g., HIV monitoring)
  * '''CD8+ T cells''': indicate cytotoxic immune activity (e.g., cancer response)
  * '''PD-L1''': predicts response to immune checkpoint inhibitors
  * '''IL-6''': pro-inflammatory cytokine elevated in systemic inflammation
  * '''CRP''': general marker of inflammation

==== Categories ====
  * Cell surface markers (e.g., CD3, CD4, CD8)
  * Soluble proteins (e.g., cytokines, chemokines, antibodies)
  * Gene expression profiles (e.g., IFN-γ response signatures)
  * Functional assays (e.g., lymphocyte activation tests)

==== Relevance ====
Immune biomarkers are essential in:
  * Identifying immune-related diseases
  * Stratifying patients for treatment (e.g., immunotherapy)
  * Monitoring therapeutic response or disease progression

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See also: [[immune_biomarker_distribution]] | [[spatial_distribution]] | [[pd-l1]] | [[cd8]]