CCR1 (C-C chemokine receptor type 1, CD191) is a member of the beta chemokine receptor family and is a GPCR (G protein-coupled receptor). Knockout studies in mice show that this gene functions in host protection from inflammatory response and is important for susceptibility to viruses and parasites. It is upregulated in macrophages and microglia during the inflammatory response and during myelination in the spinal cord of mice with autoimmune encephalomyelitis. CCR1 is a useful marker for early Alzheimer’s disease, and positivity is strongly correlated with dementia state and is found in plaque-like structures in the hippocampus and entorhinal cortex. Furthermore, CCR1 is involved in the pathogenesis of multiple myeloma and also renal diseases where it regulates myeloid cell kidney infiltration. In immunohistochemistry, CCR1 has positive membranous staining in dendritic cells, monocytes and macrophages, neutrophils, eosinophils, basophils and lymphocytes. References: Nucleic Acids Res. 2009 Jan; 37(Database issue): D32–D36, PMID: 18927115; J Neuroinflammation. 2007 May 7;4:14, PMID: 17484785; Am J Pathol 2012;180:1040, PMID: 22203055; Future Med Chem 2011;3:1889, PMID:22023033; Ann Neurol. 2003 Nov;54(5):638-46, PMID: 14595653