CD52 expression in non-mycotic T- and NK/T-cell lymphomas.

CD52 antigen (Campath-1) is expressed in high density by lymphocytes and monocytes. Campath-1H or alemtuzumab, a human anti-CD52, has been shown to be effective in T-cell malignancies; however, there is very limited information on CD52 expression in T-cell lymphoma (TCL). This study retrospectively investigated 97 TCL cases by immunohistochemistry using paraffin sections to elucidate the CD52 expression rates in various TCL sub-types. Fourteen cases of angioimmunoblastic T-cell lymphoma (AITL) were excluded as there were no reliable criteria to differentiate whether the CD52-positive cells were neoplastic T-cells, which are usually small-sized, or the usually abundant, small-to-large residual/reactive B-cells in this lymphoma sub-type. In the remaining 83 tumors, CD52 was expressed in 29 (35%) tumors including 8/17 (47%) NK/T-cell lymphomas, 14/35 (40%) unspecified peripheral TCLs and 4/18 (22%) anaplastic large cell lymphomas. There was no statistical significance in CD52 expression in terms of patient age, gender, nodal vs extra-nodal presentation or tumor sub-types. The authors recommend performing CD52 immunostaining for future clinical trials of alemtuzumab on TCL patients and to correlate the staining results with treatment outcome.