CD4 and Hermansky-Pudlak syndrome: In normal-appearing tissue samples, the average number of CD4+ and CD8+ cells per HPF were 1.78 ± 2.7 (median 0.6) and 2.28 ± 2.17 (median 1.47), respectively; whereas, in GBM samples the average number of CD4+ and CD8+ cells per HPS were 6.18 ± 6 (median 3.64) and 6.14 ± 8.91 (median 3.07), respectively.