PCSK9 and hepatitis A virus infection: More recently, PCSK9 has been found to be actively involved in host defense in infectious diseases (e.g., sepsis, hepatitis), so there could be possible interactions between PCSK9 and various immunomodulators, including antimicrobial peptide LL-37 [29,30] Future studies are warranted to investigate whether LL-37 could bind with PCSK9 to restore the function of LDLR and its impacts on long-term LDL-C levels, which would provide essential evidence about whether LL-37 could be a potential antagonist for PCSK9.