Autoantigens, sources

Deficiencies of early components of the classical complement pathway (e.g. Clq, Clr/Cls, C2, C3, C4) are associated with the development of systemic lupus erythematosus. The prevalence of systemic lupus erythematosus in homozygous Clq, C4, or C2 deficiency is approximately 90%, 75%, and 10-30%, respectively. The strongest susceptibility genes for the development of systemic lupus erythematosus in humans are null mutants of Clq. Several findings are compatible with the hypothesis that complement deficiency causes systemic lupus erythematosus by the failure to clear immune complexes and apoptotic cells (Botto, 2001). In consequence, uncleared apoptotic bodies may provide the source of the autoantigens that drive the autoimmune response of systemic lupus erythematosus. 

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