Circulating gammadelta T cells in young/adult and old patients with cutaneous primary melanoma

BACKGROUND: In a previous study we demonstrated the existence of numerical and functional alterations of gammadelta T cells in healthy elderly. Recently, we analysed the involvement of gammadelta T lymphocytes in malignant melanoma, describing a lower frequency of circulating gammadelta T cells, an altered pattern of cytokine production, and an impaired in vitro expansion of these cells in primary cutaneous melanoma patients. METHODS: In this study we investigated the existence of numerical and functional alterations of circulating gammadelta T cells in young/adult and old melanoma patients, comparing the data obtained with age-matched healthy subjects. RESULTS: We demonstrated that the number of circulating gammadelta+ T cells was significantly and similarly reduced in young/adult and old melanoma patients and in old healthy subjects in comparison with young healthy donors. The decrease was due to a reduction of Vdelta2 T cells whereas the number of Vdelta1 T cells was not affected. A higher percentage of gammadelta+ T cells producing TNF-alpha was found in old healthy donors, whereas a reduced number of TNF-alpha-producing gammadelta+ T cells was present in melanoma patients independently by age. No significant difference was observed in IFN-gamma production. After a 10-day in vitro culture, both the percentage and the expansion index of gammadelta T cells, and in particular of Vdelta2 subset, were significantly and similarly reduced both in young/adult and old melanoma patients, and in healthy aged people, in comparison with young/adult healthy subjects. CONCLUSIONS: Our study demonstrates that the numerical and functional impairment of gammadelta T cells found in melanoma patients is not correlated with age and that it has characteristics very similar to the alterations of gammadelta T cells found in old healthy subjects. We suggest that a similar impairment of gammadelta T cell population may be related to the increased susceptibility to tumors present in the elderly as well as in the pathogenesis of malignant melanoma.