The IP-10 test is performed to quantify levels of Interferon gamma-induced protein 10 (IP-10 or CXCL10) in blood or other biological fluids, primarily to assess immune activation associated with infections, autoimmune diseases, and inflammatory disorders. It is widely used in research and clinical contexts, particularly for diagnosing and monitoring tuberculosis (TB) and for evaluating viral infections and immune-mediated pathologies where interferon-gamma (IFN-γ) signaling is implicated. Since IP-10 is induced exclusively by interferons and circulates in the blood at much higher levels than the interferons themselves, this chemokine serves as an excellent marker for assessing the biological activity of IFN-γ and, consequently, T-cell or T-cell-driven immune activation.
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IP-10 is a chemokine secreted by monocytes, endothelial cells, and fibroblasts in response to IFN-γ stimulation. It functions by binding to the CXCR3 receptor on immune cells such as activated T lymphocytes and natural killer (NK) cells, facilitating their chemotactic migration to sites of inflammation. As a downstream marker of IFN-γ activity, IP-10 plays a key role in the amplification of Th1-type immune responses, which are critical in host defense against intracellular pathogens and tumor cells.
In tuberculosis, IP-10 levels are consistently elevated in both active and latent infections, making the test a potential adjunct or alternative to interferon-gamma release assays (IGRAs) (e.g. QuantiFERON), particularly in settings where those assays show reduced sensitivity, such as in children or immunocompromised individuals. Because IP-10 levels often correlate with disease burden and treatment response, serial measurements may help assess the effectiveness of therapy or detect early signs of relapse.
Elevated IP-10 concentrations have also been documented in viral infections such as HIV, hepatitis B and C, and COVID-19, where it serves as an indicator of ongoing immune activation and potential tissue damage. Similarly, autoimmune conditions such as systemic lupus erythematosus, multiple sclerosis, and rheumatoid arthritis show increased IP-10 expression, highlighting its role in chronic inflammatory conditions.
High IP-10 levels typically indicate an active or chronic immune response, and are often associated with worsening inflammation, progressive disease, or non-responsiveness to treatment. Conversely, decreased or normalized IP-10 levels may reflect effective immune regulation, therapeutic success, or resolution of the underlying pathology.
Due to its sensitivity to immune activation, the IP-10 test is increasingly integrated into diagnostic panels, clinical trials, and biomarker discovery programs, offering insight into the dynamics of the host immune system. While not disease-specific, it is a valuable indicator of cell-mediated immune activity and an emerging tool in personalized diagnostics.
