Published in:
Open Access
01-12-2015 | Case report
Case report: lupus nephritis with autoantibodies to complement alternative pathway proteins and C3 gene mutation
Authors:
Pilar Nozal, Sofía Garrido, Jorge Martínez-Ara, María Luz Picazo, Laura Yébenes, Rita Álvarez-Doforno, Sheila Pinto, Santiago Rodríguez de Córdoba, Margarita López-Trascasa
Published in:
BMC Nephrology
|
Issue 1/2015
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Abstract
Background
Glomerulonephritis is one of the most severe complications of lupus, a systemic disease with multi-organ involvement, with tissue damage produced mainly by complement activation. As a result of this activation, patients with active lupus present hypocomplementemia during disease flares, but C3 and C4 levels are recovered between episodes.
Case presentation
We present a patient who suffered two lupus nephritis episodes in 5 years, achieving complete remission with treatment after both of them, but with C3 levels persistently below normal range. Genetic study revealed that the patient carried a mutation in heterozygosis in the C3 gene. Serial sera samples were analyzed, and autoantibodies to complement alternative pathway proteins (Factor I, Factor B, C3 and Properdin) were found. Functional assays showed that these autoantibodies cause alternative pathway activation.
Conclusion
This case is the first reported of a heterozygous C3 mutation associated with lupus nephritis and autoantibodies against complement alternative pathway proteins (Factor I, Factor B, C3 and Properdin).These autoantibodies cause activation of this pathway and this fact could explain that the tissue damage is restricted to the kidney.