Ficolins are a family of pattern recognition molecules containing both a collagen-like domain and a fibrinogen-like domain that are capable of activating the complement system, through association with MASPs, on the surface of microorganisms. In human, three Ficolins are known: Ficolin-1 (M-ficolin), Ficolin-2 (L-ficolin), and Ficolin-3 (H-ficolin). Ficolin-1, is mainly expressed by monocytes, granulocytes and lung cells and is present locally in areas of inflammation. However, it was recently also found in serum suggesting that Ficolin-1 also has a role in systemic immunity like Ficolin-2 and Ficolin-3. Functional analysis of Ficolin-1 has demonstrated that it binds specifically to capsular polysaccharides of some microorganisms. Furthermore, it was shown that Ficolin-1 facilitates the uptake of E. coli by a leukemic monocyte lymphoma cell line, suggesting that it functions as a phagocytic receptor on the surface of circulating monocytes. Low cord blood concentration of Ficolin-1 has been associated with higher necrotizing enterocolitis-associated fatality in premature infants and polymorphisms in the Ficolin-1 gene are associated with the development of rheumatoid arthritis and susceptibility to leprosy.