ABSTRACT: Sepsis is one of the leading causes of mortality in non-cardiac intensive care units, and the need for markers of progression and severity are high. Also, treatment of sepsis is highly debated and potential new targets of treatment are of great interest. In the previous issue of Critical Care Kumaraswamy and colleagues have investigated whether plasma apolipoprotein M (apoM) is affected during different grades of sepsis, septic shock and systemic inflammatory response syndrome. Interestingly, plasma apoM was significantly decreased in all groups of patients with a relationship to severity of disease. This identifies apoM as a potential new biomarker in sepsis. It also underscores the possibility that altered high-density lipoprotein in sepsis patients can affect the course of disease. Thus, since apoM is the carrier of Sphingosine-1-P (S1P), a molecule with great influence on vascular barrier function, the study presented raises the interest and relevance for further studies of apoM and S1P in relation to sepsis and inflammation.