Radiation-induced melanoma-associated leucoderma, systemic antimelanoma immunity and disease-free survival in a patient with advanced-stage melanoma: a case report and immunological analysis.

BACKGROUND: Melanoma is an immunogenic tumour. The development of skin depigmentation or melanoma-associated leucoderma (MAL) has been associated with favourable clinical outcome in patients with metastatic melanoma, especially after immunotherapy. Evidence for clinically meaningful enhancement of melanoma-directed autoimmunity, as indicated by MAL, after radiotherapy without immunotherapy has not yet been published. OBJECTIVES: We investigated whether a patient with stage IV melanoma, who developed leucoderma in the irradiated skin areas following radiotherapy and experienced exceptional disease-free survival of 3 years despite brain metastasis, possessed antimelanoma immunity that could be linked to the favourable disease course. METHODS: A detailed immunological analysis was performed consisting of immunohistochemistry of several melanoma tissues, and analyses of T cells isolated from the blood and MAL skin tissue for melanocyte/melanoma specificity and functionality, as well as the presence of a melanoma-specific antibody response. RESULTS: Immunological analyses showed the presence of CD8+ T cells and antibody responses directed against melanocyte differentiation antigens expressed in the primary tumour, lymph node and brain metastasis, indicating adequate tumour recognition by activated T cells. CONCLUSION: The immune responses found in this patient, probably enhanced by radiotherapy, are thought to have contributed to his favourable clinical course. Radiotherapy may act as local immunotherapy in patients with melanoma by destroying melanocytes, leading to the induction, or enhancement, of already existent antimelanoma immunity. As in patients treated with immunotherapy, this may lead to MAL, also at distant sites from the treated area. This patient is a clear example of the positive prognostic value of MAL, which is possibly induced by radiotherapy, for patients with melanoma.

Melanocyte antigen-specific antibodies cannot be used as markers for recent disease activity in patients with vitiligo.

BACKGROUND: Objective parameters to assess disease activity in non-segmental vitiligo are lacking. Melanocyte antigen-specific antibodies are frequently found in the sera of patients with vitiligo and the presence of these antibodies may correlate with disease activity. OBJECTIVE: To investigate the relationship between melanocyte antigen-specific antibodies and recent disease activity in patients with vitiligo and to evaluate the potential usefulness of this objective parameter in daily clinical practice. METHODS: The prevalence of tyrosinase, melanoma antigen recognized by T-cells-1 (MART1), melanin-concentrating hormone receptor-1 (MCHR1), gp100 and tyrosine hydroxylase (TH) antibodies was evaluated in 21 patients with non-segmental vitiligo and in 20 healthy controls. RESULTS: In 21 patients, nine (42.8%) showed antibody responses against tyrosinase, MART1, MCHR1, gp100 or TH. No antibody responses were found in the 20 controls. No correlation was found between the presence of antibodies and recent disease activity or other clinical characteristics such as age, gender, extension and duration of vitiligo. CONCLUSIONS: In this study, 42.8% of the vitiligo patients showed an antibody response to melanocyte antigen-specific antigens. However, the presence of antibodies against melanocytes did not correlate with recent disease activity or other relevant disease parameters, and for the moment screening for these antibodies in individual patients does not appear to be clinically relevant.