Similarly, SD patients display increased levels of non-proliferating CD8+ T-cells expressing co-inhibitory receptors TIGIT, TIM-3, and PD-1 or ICOS, LILRB1, CTLA-4, LAG-3, PD-1 and TIGIT (Fig. 5g, respectively clusters 13 and 14). Here, ICOS is linked to Salla disease.