title: Alternative complement pathway in hypocomplementemic/normal C1s-C1 inhibitor complex patients with SLE.
abstract: To test whether alternative complement pathway activation explains normal C1s-C1 inhibitor complex in hypocomplementemic (low CH50cl) patients with systemic lupus erythematosus, we examined alternative pathway hemolytic complement (CH50alt) factor B, and Ba fragment in hypocomplementemic sera with normal and with elevated C1s-C1 inhibitor complex. Sera with and without high C1s-C1 inhibitor complex were similar in CH50cl, C3, and C4. There was little evidence for important alternative complement pathway activation in either group, but patients with classical pathway activation (elevated C1s-C1 inhibitor complex) had slightly lower CH50alt and slightly higher factor B and Ba compared to patients with normal C1s-C1 inhibitor complex. Pregnant patients did not differ from non-pregnant patients. Alternative complement pathway activation does not account for hypocomplementemia in this group of patients.
authors.affiliation: Hospital for Special Surgery, Cornell University Medical Center, New York, New York.
authors.forename: R A
authors.initials: RA
authors.lastname: Levy
authors.forename: T
authors.initials: T
authors.lastname: Qamar
authors.forename: M D
authors.initials: MD
authors.lastname: Lockshin
mesh_terms: D003167:Complement Activation; D003173:Complement C1s / Q000378:metabolism*; D011415:Complement Factor B / Q000378:metabolism; D015941:Complement Hemolytic Activity Assay; D003170:Complement Pathway, Alternative; D003165:Complement System Proteins / Q000172:deficiency*; D005260:Female; D006801:Humans; D008180:Lupus Erythematosus, Systemic / Q000150:complications / Q000276:immunology*; D011247:Pregnancy; D011248:Pregnancy Complications / Q000276:immunology
chemical_list: D003165:Complement System Proteins; D003173:Complement C1s; D011415:Complement Factor B