CTLA4 and infection: We found strong evidence that PD-1+ cells had the highest infection frequency of tat/rev/RRE+ proviruses compared to DN cells, CTLA-4+ cells and DP cells within this data (p<0.00001 for all; Figure 4A), however with strong evidence that these differences did vary across participants for PD-1+ vs DN (participant effect modification p=0.0001) and PD-1+ vs CTLA-4+ (participant effect modification p=0.0005) (Table 1).