Figure 5 -. Relationship between MASPs and COVID-19 comorbidities. Changes in MASPs levels have already been associated with COVID-19 risk factors, such as sex, diabetes, kidney, cardiovascular, cerebrovascular, and chronic obstructive pulmonary disease (COPD). Genetic polymorphisms in the MASP1 and MASP2 genes influence the expression levels of these proteins. COPD: high levels in plasma and increased detection in situ, after MASP-2 was associated with risk (thick pink arrow), MASP-1 has not yet been associated/investigated with COPD, but the evidence leads us to suggest that MASP-1 function is also a risk factor to these patients (green arrow). Arterial Hypertension and Cardiovascular Disease (CVD): high levels of MASP-1 and MASP-2 have been associated with risk. The participation of MASP-1 in the coagulation cascade contributes to the formation of clots, worsening CVD. Chronic kidney disease (CKD): high levels of MASP-2 are associated with ischemia-reperfusion injury (IR), and MASP-1 seems to play crucial roles in chronic kidney disease, as well as its associated symptoms and conditions, such as IR and kidney transplantation. Diabetes (DM): the natural hyperglycemic status, uncontrolled activation of the lectin pathway, with elevated MASPs concentration in DM patients, might partially explain why those individuals belong to the group with higher incidence and severity of COVID-19. Immunodeficiency and Immunosuppression: MASPs levels have been associated with the condition and outcome of HIV and immunosuppressed patients, who also can be considered more vulnerable to COVID-19 infection. Apparently, MASP-1 and MASP-2 levels were not associated with susceptibility to infections in patients with immunosuppression, for this reason, the topic is not represented in this figure. Cerebrovascular diseases: MASP-1 and MASP-2 show increased proteolytic activity in the ischemic stroke, inflammation, and clots formation. Sex: About two-thirds of COVID-19 patients are men, who also have a higher expression of MASP-1 and lower expression of MASP-2. The disseminated intravascular coagulation observed in severe COVID-19 are representations such as the formation of clots in the organs where this activity has already been observed. The thickness of the arrows indicates MASP expressions in each comorbidity. The blue arrows correspond to MASP-1 and the pink arrows to MASP-2. The dashed pink line means a decrease in MASP-2 expression.