Simple Method To Distinguish between Primary and Secondary C3 Deficiencies

ABSTRACT Due to the increasing numbers of reported clinical cases of complement deficiency in medical centers, clinicians are now more aware of the role of the complement system in the protection against infections caused by microorganisms. Therefore, clinical laboratories are now prepared to perform a number of diagnostic tests of the complement system other than the standard 50% hemolytic component assay. Deficiencies of alternative complement pathway proteins are related to severe and recurrent infections; and the application of easy, reliable, and low-cost methods for their detection and distinction are always welcome, notably in developing countries. When activation of the alternative complement pathway is evaluated in hemolytic agarose plates, some but not all human sera cross-react to form a late linear lysis. Since the formation of this linear lysis is dependent on C3 and factor B, it is possible to use late linear lysis to routinely screen for the presence of deficiencies of alternative human complement pathway proteins such as factor B. Furthermore, since linear lysis is observed between normal human serum and primary C3-deficient serum but not between normal human serum and secondary C3-deficient serum caused by the lack of factor H or factor I, this assay may also be used to discriminate between primary and secondary C3 deficiencies.

[1]  R. Thompson,et al.  REACTIVE LYSIS: THE COMPLEMENT-MEDIATED LYSIS OF UNSENSITIZED CELLS , 1970, The Journal of experimental medicine.

[2]  P. Taylor,et al.  The complement system , 1998, Current Biology.

[3]  J. Barbosa,et al.  Complement haemolytic activity (classical and alternative pathways), C3, C4 and factor B titres in healthy children , 1999, Acta paediatrica.

[4]  M. Kirschfink,et al.  Complement factor I deficiency in a family with recurrent infections. , 1997, Immunopharmacology.

[5]  P. Taylor,et al.  Systemic lupus erythematosus, complement deficiency, and apoptosis. , 2000, Advances in immunology.

[6]  R. Thompson,et al.  REACTIVE LYSIS: THE COMPLEMENT-MEDIATED LYSIS OF UNSENSITIZED CELLS , 1970, The Journal of experimental medicine.

[7]  R. Thompson,et al.  Reactive haemolysis--a distinctive form of red cell lysis. , 1968, Immunology.

[8]  L. Isaac,et al.  Inherited Complete Factor I Deficiency Associated with Systemic Lupus Erythematosus, Higher Susceptibility to Infection and Low Levels of Factor H , 2001, Scandinavian journal of immunology.

[9]  F. Rosen,et al.  Deficiency of C3 inactivator in man. , 1971, Journal of immunology.

[10]  L. Isaac,et al.  Deficiency of human complement factor I associated with lowered factor H. , 2000, Clinical immunology.

[11]  M. Pangburn,et al.  Relation of putative thioester bond in C3 to activation of the alternative pathway and the binding of C3b to biological targets of complement , 1980, The Journal of experimental medicine.

[12]  J. Heremans,et al.  Immunochemical quantitation of antigens by single radial immunodiffusion. , 1965, Immunochemistry.

[13]  V. Brade,et al.  Purification and some properties of a heat labile serum factor (UP); identity with glycine-rich beta-glycoprotein and properdin factor B. , 1973, Hoppe-Seyler's Zeitschrift fur physiologische Chemie.

[14]  J. Prahl,et al.  Third component of human complement: purification from plasma and physicochemical characterization. , 1976, Biochemistry.

[15]  M. Walport,et al.  Hereditary complement factor I deficiency. , 1994, QJM : monthly journal of the Association of Physicians.

[16]  E. Reis,et al.  Hereditary Human Complement C3 Deficiency Owing to Reduced Levels of C3 mRNA , 2001, Scandinavian journal of immunology.

[17]  M. Walport,et al.  2 – The Complement System , 2000 .