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.

• '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

• 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)

Immune biomarkers are essential in:

• Identifying immune-related diseases
• Stratifying patients for treatment (e.g., immunotherapy)
• Monitoring therapeutic response or disease progression

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