{"entity":{"id":"cd52","kind":"target","name":"CD52","aka":[],"tldr":"CD52 is a small protein on nearly all lymphocytes and the target of alemtuzumab, a profoundly immunosuppressive antibody once used in CLL and now mostly in transplant conditioning, T-cell leukaemia and multiple sclerosis.","summary":"Alemtuzumab (Campath, 2001 for fludarabine-refractory CLL; 2007 first line, CAM307) depletes B and T cells by CDC/ADCC. Its CLL indication was withdrawn commercially in 2012 when it was repositioned for MS (Lemtrada), but it remains available through a programme and is standard in T-prolymphocytic leukaemia (~90% response), in reduced-intensity and haploidentical transplant conditioning, and for GVHD prevention. CMV reactivation and prolonged lymphopenia limit it.","asOf":"2026-09-08","wikipedia":"https://en.wikipedia.org/wiki/CD52","links":[{"label":"CAM307 (JCO 2007)","url":"https://doi.org/10.1200/JCO.2007.12.9098"},{"label":"Kataoka et al., Nat Genet 2015: integrated molecular analysis of 426 adult T-cell leukaemia/lymphoma cases","url":"https://doi.org/10.1038/ng.3415"}],"tags":["gap-fill"],"related":[],"cancers":["cll","peripheral-t-cell-lymphoma","non-hodgkin-lymphoma"],"sections":[],"technologies":["monoclonal-antibody","allogeneic-hsct"],"targets":[],"drugs":["alemtuzumab","allo-647"],"companies":["sanofi"],"institutions":[],"pathways":[],"terms":["adcc"],"trials":[],"people":[],"bottlenecks":[],"keyPapers":["paper-hillmen-j-clin-oncol"],"journals":[],"dependsOn":[],"notes":["Lymphoma: Chronic lymphocytic leukaemia, T-cell prolymphocytic leukaemia and most peripheral T-cell lymphomas, at near-universal and very high surface density. Also on healthy cells: Normal B and T lymphocytes, monocytes, macrophages, eosinophils and dendritic cells, and the epithelium of the male reproductive tract. What the medicine does: CD52 is a tiny glycopeptide of 12 amino acids anchored to the membrane by a glycosylphosphatidylinositol tail, present at extremely high density, which makes it an efficient complement-fixing target. Alemtuzumab is the antibody; in lymphoma it is reserved for T-cell disease where little else works. How tumours lose it: Loss of the glycosylphosphatidylinositol anchor removes the antigen without touching the gene, and CD52-negative escape has been described after alemtuzumab in T-cell disease. What that costs the patient: The most profound lymphopenia of any antibody used in lymphoma, with CD4 counts that can stay low for a year or more, and with it cytomegalovirus reactivation, Pneumocystis pneumonia and fungal infection. Prophylaxis and viral monitoring are not optional with this drug."],"symbol":"CD52","role":[],"sources":[],"specificity":"tumour-associated","distribution":"few-types","specificityNote":"Tumour-associated overexpression: 1 cell-killing or cell-finding medicine (ALLO-647) aim at the antigen, which HPA finds with no normal tissue stained high; the medicine relies on the tumour carrying more of it than the normal tissue it shares it with. HPA CD52: RNA tissue enriched (epididymis 34,114 nTPM); no normal tissue stained high. Distribution: 2 cancer families in the corpus carry a prevalence row, label threshold or catalogue link for it (Leukaemia, Lymphoma); Open Targets associates it with 1 specific cancer type at or above 0.5 (B-cell chronic lymphocytic leukemia). (Rule 5 of scripts/fetch-target-specificity.ts.)","specificitySources":[{"label":"Human Protein Atlas CD52 tissue","url":"https://www.proteinatlas.org/ENSG00000169442-CD52/tissue","note":"RNA tissue and blood lineage specificity, normal tissue antibody staining (version 25.1, CC BY-SA 3.0)"},{"label":"Human Protein Atlas CD52 pathology","url":"https://www.proteinatlas.org/ENSG00000169442-CD52/pathology","note":"patients per staining level per cancer type (version 25.1, CC BY-SA 3.0)"},{"label":"Open Targets ENSG00000169442 associations","url":"https://platform.opentargets.org/target/ENSG00000169442/associations","note":"cancer associations at or above 0.5 (CC0)"}],"hgnc":"HGNC:1804","ensembl":"ENSG00000169442","uniprot":"P31358","entrez":"1043","firstDescribed":1991,"firstDescribedBasis":"sequence","firstDescribedNote":"Earliest sequence paper UniProt cites for the protein: Xia M.-Q. et al, Eur. J. Immunol, 1991, \"Characterization of the CAMPATH-1 (CDw52) antigen: biochemical analysis and cDNA cloning reveal an unusually small peptide backbone\".","firstDescribedSource":"https://pubmed.ncbi.nlm.nih.gov/1711975/","biology":"GPI-anchored 12-amino-acid glycopeptide of unknown function on lymphocytes, monocytes and the male reproductive tract; extremely high surface density makes it an efficient complement-fixing target.","whereFound":["CLL, T-PLL, PTCL (near-universal)","Normal B and T lymphocytes, monocytes"],"targetClass":"surface-antigen","prevalence":[{"cancerId":"cll","pct":100,"measure":"Surface CD52 on essentially all B and T lymphocytes (Campath label); CLL cells uniformly CD52-positive","source":"https://www.accessdata.fda.gov/drugsatfda_docs/label/2007/103948s5070lbl.pdf","note":"IHC survey of 294 haematologic neoplasms: vast majority of CLL/SLL positive (Rodig 2006, doi:10.1158/1078-0432.CCR-06-1275)"},{"cancerId":"peripheral-t-cell-lymphoma","pct":92.3,"measure":"Flow cytometry, surface CD52 in PTCL-NOS (12 of 13); ATLL 94.1%, CTCL 87.5%, ALCL 50%, NK/T 25%","source":"https://doi.org/10.1111/j.1365-2141.2009.07606.x","note":"Small series; paraffin IHC found most PTCL-NOS negative (Rodig 2006), so test each case before alemtuzumab"}]},"route":"/targets/cd52/","neighbours":{"cancer":[{"id":"cll","kind":"cancer","name":"Chronic lymphocytic leukaemia","route":"/cancers/cll/"},{"id":"cutaneous-t-cell-lymphoma","kind":"cancer","name":"Cutaneous T-cell lymphoma (mycosis fungoides and Sezary syndrome)","route":"/cancers/cutaneous-t-cell-lymphoma/"},{"id":"angioimmunoblastic-t-cell-lymphoma","kind":"cancer","name":"Nodal T-follicular helper cell lymphoma, angioimmunoblastic type (angioimmunoblastic T-cell lymphoma)","route":"/cancers/angioimmunoblastic-t-cell-lymphoma/"},{"id":"non-hodgkin-lymphoma","kind":"cancer","name":"Non-Hodgkin lymphoma (all types)","route":"/cancers/non-hodgkin-lymphoma/"},{"id":"peripheral-t-cell-lymphoma","kind":"cancer","name":"Peripheral T-cell lymphomas (including cutaneous T-cell lymphoma)","route":"/cancers/peripheral-t-cell-lymphoma/"},{"id":"sezary-syndrome","kind":"cancer","name":"Sezary syndrome","route":"/cancers/sezary-syndrome/"}],"technology":[{"id":"allogeneic-hsct","kind":"technology","name":"Allogeneic stem cell transplantation","route":"/technologies/allogeneic-hsct/"},{"id":"monoclonal-antibody","kind":"technology","name":"Monoclonal antibodies","route":"/technologies/monoclonal-antibody/"}],"drug":[{"id":"alemtuzumab","kind":"drug","name":"Alemtuzumab","route":"/drugs/alemtuzumab/"},{"id":"allo-647","kind":"drug","name":"ALLO-647","route":"/drugs/allo-647/"}],"company":[{"id":"sanofi","kind":"company","name":"Sanofi","route":"/companies/sanofi/"}],"term":[{"id":"adcc","kind":"term","name":"ADCC (antibody-dependent cellular cytotoxicity)","route":"/terms/adcc/"},{"id":"lymphoma-bio-htlv1","kind":"term","name":"HTLV-1, Tax and HBZ in adult T-cell leukaemia/lymphoma","route":"/terms/lymphoma-bio-htlv1/"},{"id":"lymphoma-bio-lineage-antigen-cost","kind":"term","name":"What it costs to aim at a lineage antigen","route":"/terms/lymphoma-bio-lineage-antigen-cost/"}],"paper":[{"id":"paper-hillmen-j-clin-oncol","kind":"paper","name":"Alemtuzumab compared with chlorambucil as first-line therapy for chronic lymphocytic leukemia","route":"/key-papers/paper-hillmen-j-clin-oncol/"}]}}