Presence of activated lymphocytes in the peripheral blood of patients withhalo nevi

Background: The involution of the central pigmented lesion in halo nevus (H N) seems to be mediated by an immune response against self antigens express ed by melanocytes. Objective: We assessed the presence of activated lymphocytes in the periphe ral blood lymphocytes from patients with HN. Methods: Peripheral blood was obtained from patients with HN associated wit h benign pigmented lesions (5) or melanoma (2) as well as from patients wit h melanoma without HN (5) and healthy subjects (10). Activated lymphocytes were detected by flow cytometry analysis using monoclonal antibodies (mAb) against CD69, CD71, CD98, HLA-DR, and activated beta(1) integrins (HUTS-21 mAb). Results: The peripheral blood lymphocytes from patients with HN, associated with either benign or malignant lesions, exhibited a significantly higher expression of all activation markers studied compared with patients with me lanoma without HN or compared with healthy subjects. Therefore the peripher al blood of HN patients contained a significant fraction of lymphocytes wit h an activated. (CD69(+), HLA-DR+, CD96(bright)), Cell proliferating (CD71( bright)), and high adhesive (HUTS-21(bright)) phenotype. These activated ce lls disappeared from peripheral blood after the surgical resection of the s kin lesion. Conclusion: Our findings further support the involvement of immune activati on in HN phenomenon.