CD52positive

CD52positive refers to cells or tissues that express the CD52 protein on their surface. CD52 is a glycoprotein belonging to the tetraspanin family and is found chiefly on mature lymphocytes, including T cells, B cells, natural killer cells, and some myeloid cells. By contrast, cells such as erythrocytes, platelets, and most non‑hematopoietic cells lack CD52 expression.

The presence of CD52 on lymphocytes makes it an attractive target for therapeutic antibodies, most notably alemtuzumab (Campath‑1H). This monoclonal antibody binds CD52 with high affinity, leading to complement‑mediated lysis or antibody‑dependent cellular cytotoxicity of CD52positive cells. As a result, alemtuzumab is used in conditions such as chronic lymphocytic leukemia, multiple sclerosis, and certain lymphomas where depletion of CD52positive lymphocytes benefits the patient.

Diagnostic use of CD52 is typically conducted via flow cytometry, immunohistochemistry or immunofluorescence. In flow cytometry, a fluorescently labelled antibody against CD52 can identify and quantify CD52positive populations in a mixed cell sample. This method assists in immunophenotyping of lymphoid malignancies and in monitoring residual disease after treatment.

CD52 expression can vary among subsets of the immune system. For example, memory T cells and activated B cells frequently display higher levels of CD52 compared with naïve T cells. This differential expression can inform both research and clinical decision‑making, such as predicting response to ant‑CD52 therapies.

Because CD52 is a broadly expressed surface marker on circulating immune cells, therapies targeting it must consider potential off‑target effects. Long‑term depletion of CD52positive cells can lead to immunosuppression, increased infections, and altered immune repertoire. Consequently, treatment regimens are carefully dosed, monitored, and sometimes combined with prophylactic measures to mitigate adverse outcomes.