Cluster of differentiation 163 (CD163) is a type I transmembrane scavenger receptor predominantly expressed on monocytes and tissue macrophages. It binds hemoglobin–haptoglobin (Hb–Hp) complexes, mediating their endocytosis and protecting tissues from hemoglobin-induced oxidative damage. CD163 is a member of the scavenger receptor cysteine-rich (SRCR) family, with a molecular weight of ~130 kDa. Its restricted expression to macrophage lineage cells makes it a reliable marker for immunohistochemistry (IHC) in formalin-fixed, paraffin-embedded (FFPE) tissues.
Biological Significance of CD163
- Lineage-specific expression: CD163 is largely restricted to monocytes and macrophages, including tissue-resident macrophages; peripheral blood monocytes express lower levels, upregulated under anti-inflammatory conditions.
- Hemoglobin scavenging and anti-inflammation: CD163 facilitates clearance of Hb–Hp complexes and modulates anti-inflammatory macrophage responses.
- Macrophage maturation and function: Its expression reflects differentiation status and functional specialization of macrophages in tissues.
Diagnostic Utility in Hematopathology
- Macrophage identification in IHC: CD163 reliably highlights macrophages and histiocytes in FFPE tissues, providing higher specificity than CD68 in certain contexts.
- Prognostic relevance: Elevated CD163+ tumor-associated macrophages have been correlated with clinical outcomes in hematologic malignancies such as classical Hodgkin lymphoma, supporting prognostic assessment.
- Lineage determination: CD163 expression aids in distinguishing histiocytic and monocytic neoplasms from other hematopoietic disorders.
Key Features of CE/IVD-Validated Anti-CD163 Antibodies
- High specificity and reproducibility for detecting CD163 on FFPE macrophages and histiocytes.
- Validated performance in both automated and manual IHC workflows, yielding consistent membranous and cytoplasmic staining patterns aligned with macrophage distribution.
- Monoclonal antibody formats with defined host species and clone information to support standardization in diagnostic pathology.
