Selective complete Clq deficiency associated with systemic lupus erythematosus.

We report a case of systemic lupus erythematosus (SLE) and recurrent infections associated with isolated Clq deficiency. A 17-year-old girl from Saudi Arabia was hospitalized with seizures, fever, arthralgia, hair loss, oral ulceration and skin rash. Clinical and laboratory findings fulfilled the ARA preliminary criteria for the classification of SLE. Nonlesional skin contained immunoglobulins and C3 at the dermal-epidermal junction. She did not have antibodies to DNA or low C3 or C4. Total serum hemolytic complement activity was absent due to a total selective absence of Clq. There was no circulating inhibitor of Clq activity. The published experience of isolated selective complete Clq deficiency associated with clinical disease is reviewed.