Staphylococcus epidermidis - virulence factors and innate ... - Munin

hemoglobinuria (PNH) and also for treatment of atypical variants of hemolytic uremic syndrome
(HUS) (146-149). During the recent (summer 2011) outbreak of Escherichia coli O104:H4 in
Germany, case-reports indicate a good therapeutic response of eculizumab in severe shiga-toxinassociated
HUS (150).
Specific aspects in neonates
There is no transfer of complement factors across the placenta (151). The fetus begins
synthesizing complement proteins at 6-14 weeks of gestation (152). However, the major
development of the complement system in the fetus occurs late in the pregnancy, and
complement factors does not reach adult levels until after birth (153). McGreal et al. recently
published a paper summarizing the current knowledge on the complement system in term and
preterm born neonates (154).
Compared to adults, the levels of complement factors in the classical pathway vary between ~50-
80% in term infants and ~30-80% in preterm infants (153-157). The levels of some of the factors
in the classical pathway, such as C1q and C4, are clearly correlated to the gestational age (153,
156, 158, 159). Davis et al. followed the classical complement factors during the first months of
life and showed that C1q remained low the first 6 months, while C2 and C4 reached adult levels
during the first months of life (160).
Compared to adults, the levels of complement factors in the alternative pathway vary between
~40-65% in term infants and ~50-60% in preterm infants (153-158, 161, 162). The only
exception is factor D that seems to show higher titers in term infants than in adults (155, 163).
18