All C and D recommendations were the highest grade of evidence of these guidelines, which means recommendations are extracted from case series, single case reports, or poor-quality cohort and casecontrol studies for the C recommendations, and expert opinion without explicit critical appraisal or based on physiology or bench research for the D recommendations
CS, cigarette smoke
found that carnitine supplementation modified the production of various cytokines, such as interferon-, tumor necrosis factor-, interleukins-2, 4, 6, vascular endothelial growth factor, granulocyte-macrophage colony stimulating factor, and insulin-like growth factor-1 in serum and peritoneal fluid as tested using the immunofluorescence or ELISA technique [19]
doi: 10.1186/s13075-018-1537-8 145 BoehmeMWGaoIKNordenCLemmelEM
It remains experimental in immune system support