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has been cited by the following article:

• TITLE: Low Levels of Complement Factor C4 Not Always Implicate Disease Activity in Systemic Lupus Erythematosus

  AUTHORS: E. J. ter Borg, H. van Velzen-Blad, D. Hamann

  KEYWORDS: Complement; Homozygous C4A Isotype Deficiency; Systemic Lupus Erythematosus

  JOURNAL NAME: International Journal of Clinical Medicine, Vol.4 No.2, February 26, 2013

  ABSTRACT: A lupus patient with a clinically quiescent disease stage will be described who had severely depressed C4 levels while levels of C3 en CH50 were normal. Additional testing revealed a homozygous C4Aisotype deficiency as the cause of the very low C4 levels. It should be emphasized that in SLE, a (very) low C4 level does not always means (subclinical) disease activity.