SIRPA and acute respiratory distress syndrome: However, in contrast to ARDS BAL, proinflammatory mediator treatment decreased expression of both MerTK (Figure 4B, mean fold change −0.58, p = 0.015) and CD163 (Figure 4C, mean fold change −0.58, mean fold change −0.55, p = 0.005) while increasing expression of SIRPα (Figure 4D, mean fold change 2.48, p = 0.036).