FAS and chronic graft versus host disease: When comparing the biomarkers’ profile at T2 (20 days after the initial ophthalmological evaluation and 27 days since symptoms’ onset), a group of elevated biomarkers was observed in both cases (Factor D [12], Fas/CD95 [13,14,15], TRAIL-R2/DR5/TNFRSF10B [16,17,18], CXCL5, and IL-6), while another group of biomarkers was specifically heightened in the chronic GVHD case (Figure 5—right side: CCL5, CXCL5, G-CSF, and IL-1β).