Generally, a major complication of complement insufficiency is an enhanced susceptibility toward infection. Several studies have shown low MBL serum levels (genetically derived) are correlated with enhanced development of systemic immune response syndrome/sepsis in patients admitted to the intensive care unit (126, 127) . Low MBL serum concentrations were also associated with the development of pneumonia after surgery in colorectal cancer patients (128) . Similarly, MASP-2 deficiency caused increased infection rates with Streptococcus pneumoniae (129) . Furthermore, there is evidence for a higher rate of chorioamnionitis in patients with low MBL levels and preterm birth (130) . Low MBL serum levels appear to be associated with recurrent spontaneous abortion based on in utero infection. This was proposed by Kruse et al. (131) , who demonstrated that patients with MBL levels <100 ng/mL had a higher abortion rate. Some urogenital infections such as vulvovaginitis, herpes simplex virus-2 infection, vulvovaginal candidiasis and vestibulitis appear to be linked to low MBL levels in comparison to healthy controls (132) (133) (134) . Downstream complement deficiencies are typically associated with recurrent invasive infections of Neisseria meningitidis and gonorrhea (135) .