CD86 and acute respiratory distress syndrome: Nevertheless, the expression level of left lung CD86 in the BLM + LHA, BLM + MHA, BLM + HHA, and BLM + MIX HA groups statistically differed from that of the BLM group (Figure 5D), suggesting that administering HA at various molecular weights could reduce the differentiation and transformation of M1 macrophages in the left lung of rats with severe ARDS.