QUANTIFICATION OF IMMUNOCOMPETENT CELLS IN TESTICULAR GERM-CELL TUMORS

The immunocompetent cells present in the different histological patter ns of 43 testicular germ cell rumours were evaluated. CD3 + and CD45RO + (UCHL1 +) T lymphocytes, CD68 + and MAC 387 + macrophages, CD20 +(L 26 +) B lymphocytes, and kappa and lambda + plasma cells were counted. The number of immunocompetent cells per mm(2) of tumour tissue, exclu ding the necrotic areas, was evaluated. Microscopic fields were random ly selected by two observers. In order to guarantee randomization each surface was divided into parts, numbered through a lattice, and some fields were chosen via a random numbers table. This procedure yielded significantly different counts from those obtained on subjective selec tion. The number of T-lymphocytes and macrophages was higher in semino mas than in the non-seminomatous testicular germ cell tumours (P <0.05 ) Embryonal carcinomas had more T-lymphocytes than immature teratomas. No significant differences were found among testicular germ cell tumo urs with regards to the B-lymphocytes, with the exception of the high number of B-lymphocytes in mature teratomas. Kappa + and lambda + plas ma cells were few in the testicular germ cell rumours. Randomization i n the quantification of immunocompetent cells in testicular germ cell tumours is a good means for evaluation of immune response in all the t umour mass, not only in the areas with the most intense inflammatory c ell infiltrate, and permits comparison of testicular germ cell tumours with other malignant tumours. Study of immunocompetent cells in every histological type of testicular germ cell tumour is useful in compari ng them with other extra-testicular germ cell tumours.