C4A deficiency and elevated level of immune complexes: the mechanism behind increased susceptibility to systemic lupus erythematosus.

2.50
Hdl Handle:
http://hdl.handle.net/2336/30453
Title:
C4A deficiency and elevated level of immune complexes: the mechanism behind increased susceptibility to systemic lupus erythematosus.
Authors:
Traustadottir, Kristín H; Sigfusson, Asbjörn; Steinsson, Kristjan; Erlendsson, Kristjan
Citation:
J. Rheumatol. 2002, 29(11):2359-66
Issue Date:
1-Nov-2002
Abstract:
OBJECTIVE: Studies of an Icelandic cohort showed that susceptibility to systemic lupus erythematosus (SLE) in individuals with C4A deficiency was increased only in the presence of increased concentrations of immune complexes. We investigated the interaction of C4A deficiency with elevated concentrations of immune complexes in healthy individuals; i.e., how different levels of C4A affected the activation of C4 and C3 and subsequent binding of increased immune complex load to human red blood cells (RBC). METHODS: Forty-five healthy individuals having different levels of C4A were studied, 8 with homozygous C4AQ0, 12 with heterozygous C4A deficiency, and 25 with normal C4A. For comparison to the complement status present after prolonged disease activity, 5 patients with SLE homozygous for C4AQ0 were also studied. RESULTS: The results showed that intact immune complex-RBC binding is dependent on the levels of immune complex-bound C3 fragments, which correlate to the levels of IC-bound C4Ad (R = 0.677, p = 0.02), but not on levels of IC-bound total C4d (R = 0.451, p = 0.16). Immune complex binding to RBC was also evaluated in increasing immune complex load. C4A deficient sera had less ability to bind the increased immune complex load to RBC than sera with normal C4A. These results are consistent with the presence of increased amounts of poorly opsonized immune complexes in C4A deficiency, leading to increased precipitation in tissues and initiation of a self-perpetuating cycle. CONCLUSION: Susceptibility to SLE is increased in individuals with C4A deficiency as C3 opsonization of immune complexes becomes insufficient at elevated immune complex concentrations.
Description:
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Additional Links:
http://www.jrheum.com/abstracts/abstracts02/2359.html

Full metadata record

DC FieldValue Language
dc.contributor.authorTraustadottir, Kristín H-
dc.contributor.authorSigfusson, Asbjörn-
dc.contributor.authorSteinsson, Kristjan-
dc.contributor.authorErlendsson, Kristjan-
dc.date.accessioned2008-06-25T09:50:37Z-
dc.date.available2008-06-25T09:50:37Z-
dc.date.issued2002-11-01-
dc.date.submitted2008-06-25-
dc.identifier.citationJ. Rheumatol. 2002, 29(11):2359-66en
dc.identifier.issn0315-162X-
dc.identifier.pmid12415592-
dc.identifier.urihttp://hdl.handle.net/2336/30453-
dc.descriptionTo access publisher full text version of this article. Please click on the hyperlink in Additional Links fielden
dc.description.abstractOBJECTIVE: Studies of an Icelandic cohort showed that susceptibility to systemic lupus erythematosus (SLE) in individuals with C4A deficiency was increased only in the presence of increased concentrations of immune complexes. We investigated the interaction of C4A deficiency with elevated concentrations of immune complexes in healthy individuals; i.e., how different levels of C4A affected the activation of C4 and C3 and subsequent binding of increased immune complex load to human red blood cells (RBC). METHODS: Forty-five healthy individuals having different levels of C4A were studied, 8 with homozygous C4AQ0, 12 with heterozygous C4A deficiency, and 25 with normal C4A. For comparison to the complement status present after prolonged disease activity, 5 patients with SLE homozygous for C4AQ0 were also studied. RESULTS: The results showed that intact immune complex-RBC binding is dependent on the levels of immune complex-bound C3 fragments, which correlate to the levels of IC-bound C4Ad (R = 0.677, p = 0.02), but not on levels of IC-bound total C4d (R = 0.451, p = 0.16). Immune complex binding to RBC was also evaluated in increasing immune complex load. C4A deficient sera had less ability to bind the increased immune complex load to RBC than sera with normal C4A. These results are consistent with the presence of increased amounts of poorly opsonized immune complexes in C4A deficiency, leading to increased precipitation in tissues and initiation of a self-perpetuating cycle. CONCLUSION: Susceptibility to SLE is increased in individuals with C4A deficiency as C3 opsonization of immune complexes becomes insufficient at elevated immune complex concentrations.en
dc.language.isoenen
dc.publisherJournal Of Rheumatology Publishing Coen
dc.relation.urlhttp://www.jrheum.com/abstracts/abstracts02/2359.htmlen
dc.subject.meshAntigen-Antibody Complexen
dc.subject.meshComplement C3en
dc.subject.meshComplement C4aen
dc.subject.meshErythrocytesen
dc.subject.meshHeterozygoteen
dc.subject.meshHumansen
dc.subject.meshImmunoglobulin Gen
dc.subject.meshLupus Erythematosus, Systemicen
dc.subject.meshProtein Bindingen
dc.titleC4A deficiency and elevated level of immune complexes: the mechanism behind increased susceptibility to systemic lupus erythematosus.en
dc.typeArticleen
dc.contributor.departmentDepartment of Immunology, Landspitali University Hospital, Reykjavik, Iceland.en
dc.identifier.journalJournal of rheumatologyen

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