Alpha/beta- and gamma/delta TCR(+) lymphocyte infiltration in necrotising choroidal melanomas

To detect specific tumour infiltrating T cells (TIL) carrying antigen specific MHC-I restricted receptor genes on necrotising and non-necrotising malignant melanomas and to correlate the findings with clinical data.

alpha/beta- and gamma/delta- TIL were determined by immunohistochemical staining in melanomas of patients with known follow up of more than 10 years. An antigen retrieval method was used to determine variable genes delta1 and gamma1 on TCR(+) cells by an anti-TCR Vdelta1 and anti-CrgammaM1, and of Valpha and Vbeta TCR(+) by an anti-pan-TCR(+) alpha/beta antibody.

Intratumoral TIL were present in 86 of 113 (76.1%) necrotising melanomas (NMM) v 21 of 100 (21%) in non-necrotising melanomas (MM); of these, Valpha/beta- TCR(+) cells were present in 52 of 74 (70.3%) TIL harbouring NMM v four of 21 (19%) MM; Vgamma1 in 29 of 74 (39.2%) NMM v two of 21 (10%) MM; and Vdelta1 in 39 of 74 (52.7%) NMM v three of 21 (14%) MM. Extratumoral lymphocytic infiltration was seen in 86 (76.1%) NMM including Valpha/beta TCR(+) cells in 10 (11.6%) cases, v five (5%) MM cases with no Valpha/beta TCR(+) cells detected. Vgamma1 and Vdelta1 TCR(+) cells were not found in extratumoral infiltrates.

In NMM, the median survival was 69.3 (range 6-237) months, 19 of 74 patients (25.7%) survived 5 years, and mortality was associated with advanced stage (p<0.001), patient age (p<0.023), and extent of necrosis (p<0.048). Survival was increased with evidence of Vgamma1 and Vdelta1 TCR(+) cells (p<0.026).