CD44 and infection: High-molecular-weight (HMW)-HA (103–104 kD), which exists as ECM in tissues, is incorporated into cells in a CD44-dependent manner, and then is secreted from them as low-molecular-weight (LMW)-HA (<500 kD) to ultra-LMW (ULMW)-HA (<10 kD) under normal and pathological conditions,12 particularly at the site of infection and inflammation.13, 14