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

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

Department of Clinical Immunology, St Antonius Hospital Nieuwegein/Utrecht, Nieuwegein, The Netherlands.
Department of Immunopathology and Blood Coagulation, Sanquin Diagnostics, Amsterdam, The Netherlands..
Department of Internal Medicine and Rheumatology, St Antonius Hospital Nieuwegein/Utrecht, Nieuwegein, The Netherlands.

DOI: 10.4236/ijcm.2013.42019                

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.

Keywords

Complement; Homozygous C4A Isotype Deficiency; Systemic Lupus Erythematosus

Conflicts of Interest

The authors declare no conflicts of interest.

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