ANALYSIS OF T-CELL RECEPTOR-ALPHA-BETA VARIABILITY IN LYMPHOCYTES INFILTRATING MELANOMA PRIMARY TUMORS AND METASTATIC LESIONS

The T cell receptor (TCR) alpha beta variable(V) gene family usage of tumour-infiltrating lymphocytes (TIL) in four different primary human malignant melanomas and their corresponding metastatic lesions was cha racterized using a recently developed method based on the reverse-tran scription-coupled polymerase chain reaction (RT-PCR). All patients wer e typed for HLA-A1 and -A2, either serologically or by a newly develop ed RT-PCR method. Two of these patients expressed HLA-A2, one the HLA- A1 haplotype and one further patient was heterozygous HLA-A1/A2. The p rognostic parameters for all four patients indicated that rapid progre ssion of the disease was to be expected. However, only two of the pati ents showed rapid progression, while the remaining two patients are st ill alive after more than 3 years. In TIL in primary melanomas, a poss ible correlation was suggested between HLA-A2 and the preferential usa ge of the TCR V gene families V alpha 4, V alpha 5, V alpha 22 and V b eta 8, whereas the V beta 3 gene family appeared to be expressed toget her with HLA-A1. Other highly expressed V gene families, apparently no t restricted to either HLA-A1 or -A2, were V alpha 1 (expressed in thr ee of four primary tumours) and V alpha 21 (expressed in two of four t umours). We found no evidence suggesting any correlations between the haplotypes HLA-A1 and -A2 and preferential V gene family expression in the metastatic lesions, and the only common feature was V alpha 8, wh ich was found to be highly expressed in two out of three subcutaneous metastases. The V gene families, which were highly expressed in the pr imary tumour were generally not, or only Very weakly, expressed in met astases and vice versa, possibly reflecting a change in the phenotype of the metastatic melanoma target cells. With regards to patient 0368, it was possible to obtain and study material from two subcutaneous me tastases. The first metastasis was excised more than a year after the primary tumour, showing a completely different V region repertoire. Th e second metastasis was excised at surgery 2 years after primary surge ry and likewise showed a dramatic shift in comparison to the first sub cutaneous metastasis. Although the present study only included a small number of patients, it suggests that the estimation of V gene express ion, if applied to a larger amount of patient material, might make it possible to substantiate further the suggested correlations between th e T cell response against the tumour, HLA and antigen expression. Such studies will be of obvious interest in the further analysis of new im munotherapeutic regimens involving the T cell response against tumours .