Quantitation of tumour-infiltrating lymphocytes. (A) CD3, (B) CD4, (C) CD8, and (D) CD57-positive TILs observed in KM871-treated patient biopsy samples (P1-P17) and age-matched, sex-matched non-KM871-treated melanoma patients (C1-16). Mean (± SD) cell numbers were calculated from observations of 5-10 high-power field views of each biopsy sample.