CD5 and lymphoma: The intensity of MHC class II expression by the lymphoma cells, expressed as the ratio of geometric mean fluorescence intensity of MHC II+:MHC II− cells within the CD5− subset of the ‘All’ gate, was also of prognostic significance (Figure 5D): TTR was longer in those cases with expression ratios less than or equal to the median value (≤4.40, median 22 days, >4.40, median 10 days; p = 0.017).