Immune reactions in benign and malignant melanocytic lesions: lessons for immunotherapy

Abstract

SummarySpontaneous regression of benign and malignant melanocytic lesions can be a visible sign of immunosurveillance. In this review, we discuss different immune reactions against melanocytic lesions: halo nevus, Meyerson's nevus, regression in melanoma and melanoma-associated depigmentation. These entities present with particular clinical aspects, histology and evolution. In all entities, a melanocyte-specific T-cell reaction has been assumed but a different degree of melanocyte destruction is present. A focus on the immune responses in melanocytic lesions reveals several aspects of an adequate skin immunity and may help to identify the key points in the immune destruction of melanocytes. These insights can add to the knowledge of how to optimize immunotherapeutic strategies in melanoma.

Dermoscopy, Reflectance Confocal Microscopy and Immunohistochemical Analysis in Melanocytic Lesions with Meyerson's Phenomenon

“…Meyerson's phenomenon had a predilection for spring and summer months, but we did not find an association with sunburns or UV exposure. Some authors suggest that UV exposure may promote an expression of antigens in the nevus cells, explaining the cellular immune mechanisms against them [3,20]. Rapid and total regression of halo dermatitis after excision of the central lesion was observed in all of our cases, suggesting that the melanocytic lesion is specifically stimulating the inflammatory response.…”

“…Comparison between Sutton's nevi and Meyerson's phenomenon illustrates the plasticity of immune-mediated reactions against melanocyte-specific antigens. They are at opposite poles of the same immunological spectrum, but evolution of halo dermatitis to halo nevus has been reported, as well as coexistence of both phenomena in the same patient [20]. Hence, they should be differentiated.…”

“…These infiltrating T cells have a reduced expression of interleukin-2 receptors in contrast to its marked expression in allergic contact dermatitis. The modest presence of CD8+ cells in Meyerson's phenomenon also differs from the CD8+ immune mechanisms involved in halo nevi, explaining the lack of histological regression of the melanocytic lesion [20]. …”

Clustering of Cutaneous Melanoma in Health Care Workers of a Dermatological Day Hospital Unit

“…The prognostic implications of regression in melanoma are unclear. Various studies have come to different conclusions, and several authors have suggested an adverse effect on prognosis [14]. However, in theory, an immune response eliminating the tumor cells should be expected to have a beneficial influence.…”

Immune cells in the melanoma microenvironment hold information for prediction of the risk of recurrence and response to treatment

“…Melanoma is known as an immunogenic tumor, and signs of immunosurveillance, such as spontaneous regression with the simultaneous onset of vitiligo, have been reported to occasionally occur in this tumor type [1]. The peripheral blood of melanoma patients possesses a relatively large amount of T cells or antibodies that recognize melanoma antigens.…”