Selective Complete C1q Deficiency Associated With Systemic Lupus Erythematosus

A 17-year-old girl from Saudi Arabia with systemic lupus erythematosus (SLE) and recurrent infections was found to have a selective complete deficiency of Clq, a component of the complement system. Despite fulfilling the ARA criteria for SLE, she did not have antibodies to DNA or low levels of C3 or C4, but her total serum hemolytic complement activity was absent due to the lack of Clq. The case highlighted the association between isolated Clq deficiency and clinical manifestations of SLE, contributing to the understanding of the disease's immunological aspects.