CTLA4 and Sepsis: Both B- and CD4+ T-lymphocytes from patients with sepsis seem to overexpress the exhaustion marker programmed death 1 (PD-1) and its ligand PD-L1 [3], and T-lymphocytes also have been shown to overexpress inhibitory markers such as T-cell immunoglobulin and mucin domain-containing protein-1 (TIM-1), lymphocyte activation gene 3 (LAG-3), and cytotoxic T-lymphocyte-associated protein 4 (CTLA4) [29].