# CD52

Source: https://onco.cc/targets/cd52/  
OnCo record `cd52` (Target). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

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 Its CLL indication was withdrawn commercially in 2012 when it was repositioned for MS (Lemtrada), but it remains available through a programme and is standard in T-prolymphocytic leukaemia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.

## Fields

- Kind: Target
- Last checked: 2026-09-08
- Tags: gap-fill
- Symbol: CD52
- Class: surface-antigen
- 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.
- Where found: CLL, T-PLL, PTCL (near-universal); Normal B and T lymphocytes, monocytes

## 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.

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/CD52
- CAM307 (JCO 2007): https://doi.org/10.1200/JCO.2007.12.9098
- Kataoka et al., Nat Genet 2015: integrated molecular analysis of 426 adult T-cell leukaemia/lymphoma cases: https://doi.org/10.1038/ng.3415

## Connected records

- cancers: [Chronic lymphocytic leukaemia](https://onco.cc/cancers/cll/), [Cutaneous T-cell lymphoma (mycosis fungoides and Sezary syndrome)](https://onco.cc/cancers/cutaneous-t-cell-lymphoma/), [Nodal T-follicular helper cell lymphoma, angioimmunoblastic type (angioimmunoblastic T-cell lymphoma)](https://onco.cc/cancers/angioimmunoblastic-t-cell-lymphoma/), [Non-Hodgkin lymphoma (all types)](https://onco.cc/cancers/non-hodgkin-lymphoma/), [Peripheral T-cell lymphomas (including cutaneous T-cell lymphoma)](https://onco.cc/cancers/peripheral-t-cell-lymphoma/), [Sezary syndrome](https://onco.cc/cancers/sezary-syndrome/)
- technologies: [Allogeneic stem cell transplantation](https://onco.cc/technologies/allogeneic-hsct/), [Monoclonal antibodies](https://onco.cc/technologies/monoclonal-antibody/)
- drugs: [Alemtuzumab](https://onco.cc/drugs/alemtuzumab/), [ALLO-647](https://onco.cc/drugs/allo-647/)
- companies: [Sanofi](https://onco.cc/companies/sanofi/)
- terms: [ADCC (antibody-dependent cellular cytotoxicity)](https://onco.cc/terms/adcc/), [HTLV-1, Tax and HBZ in adult T-cell leukaemia/lymphoma](https://onco.cc/terms/lymphoma-bio-htlv1/), [What it costs to aim at a lineage antigen](https://onco.cc/terms/lymphoma-bio-lineage-antigen-cost/)
- key papers: [Alemtuzumab compared with chlorambucil as first-line therapy for chronic lymphocytic leukemia](https://onco.cc/key-papers/paper-hillmen-j-clin-oncol/)

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