The complement system participates in both innate and acquired immune responses.
Deficiencies in any of the protein components of this system are generally uncommon and …

The third complement component (C3) is a multifunctional glycoprotein that interacts with
numerous serum proteins, cell surface receptors, and membrane-associated regulatory …

The complement protein C4, encoded by two genes (C4A and C4B) on chromosome 6p, is
the most polymorphic among the MHC III gene products. We investigated the molecular …

The disease course of a complete C4-deficient patient in the US was followed for 18 years.
The patient experienced multiple episodes of infection, and he was diagnosed with systemic …

Although a heterozygous deficiency of either complement component C4A or C4B is
common, and each has a frequency of∼ 20% in a Caucasian population, complete …

The most common of the complement deficiencies in populations of European origin is a
genetic deficiency of the second component of complement (C2). 1 Rheumatologic …

Complement component C6 is a part of the lytic membrane attack complex formed during
complement activation. Animal modeling to define the role of C5a vs. C5b-9 in human …

C3 is a central protein of the complement system, which is important to immune defense and
provides a link between innate and adaptive immunity. Three pathways of complement …

Inherited deficiency of complement C3 has been described in guinea pigs, dogs and 20
humans. Homozygous deficiency of C3 is associated with recurrent pyogenic infections by …

As a preformed defense system, complement faces a delicate challenge in providing an
immediate, forceful response to pathogens even at first encounter, while sparing host cells in …