Hereditary complement deficiency and lupus: report of four Tunisian cases.

The aim of the study was to assess the clinical and immunological profile of lupus erythematosus (LE) patients with inherited complement deficiency (ICD). A laboratory-based study was conducted in which all LE patients with hypocomplementemia were included. ICD was assessed by hemolytic and antigenic assays. Type I C2 deficiency was assessed by polymerase chain reaction (PCR). ICD was diagnosed in four cases. In three systemic LE patients, ICD were: homozygous C2 deficiency in the first case, heterozygous C2 deficiency in the second, and homozygous C1q deficiency in the third case. In a discoid LE patient, a combined homozygous C2 and C6 deficiency was diagnosed. Almost all of our patients presented the classical clinical and immunological features of LE associated with ICD. Severe lupus with renal involvement and recurrent infections was present in half of the patients suggesting that these patients are prone to a serious management.