We describe a patient who developed a systemic lupus erythematosus-like syndrome characterized by bilateral malar erythema, antinuclear antibody, and anti-double-stranded DNA antibody. He was started on hemodialysis (3 timedweek) because of renal failure. He completely lacked total hemolytic complement (CH50) activity, which was subsequently determined to be due to the absence of the first component of complement (Cl). The specificity was further defined, by Ouchterlony analysis using anti-Cls antiserum, and was found to be the C1 subcomponent CIS. There was no absence of Clr. We conclude that this is a case of selective deficiency of Cls.Complement deficiency is a rare condition. To date, several cases of complement component deficiency have been reported (I). Of these individuals, some were deficient in C1 because of an absence of one of the C1 subcomponents Clq, Clr, or C l s (2). Until now, however, no patient has been found to be clearly lacking only Cls, although deficiencies of both C l r and C l s have been described (2). It is known that a defect in one of the early components of complement will often induce a systemic lupus erythematosus (SLEtlike syndrome in which there is bilateral malar erythema, positive antinuclear antibody (ANA), and positive anti-double-stranded DNA (anti-dsDNA) antibody (3). We report here a case of selective CIS deficiency in which the subject exhibited an SLE-like syndrome and renal failure.
CASE REPORTThe patient, a 26-year-old man, was admitted to our hospital on June 18, 1988 because of orthopnea. Pertinent medical history included removal of his left kidney because of hydronephrosis when he was 3 months old. Data concerning the histologic features of the excised kidney were not available. At age 11, he was diagnosed as having chronic nephritis with proteinuria and hematuria. There was nothing notable in his family's medical history.At the time of admission, the patient was somewhat lethargic and orthopneic. His blood pressure was 133/73 mm Hg, and his pulse rate was 72 beatdminute and regular. He had erythema over the malar region bilaterally. The liver, spleen, and kidney were not palpable; no struma could be felt. There was slight pretibial pitting edema. The palpebral conjunctivae were anemic. No abnormality was detected on neurologic examination. A chest radiograph revealed evidence of previous tuberculosis in the right upper lung field, and an enlarged heart (cardiothoracic ratio 58%). Left ventricular ejection at rest was 14%, as determined by a cardiac pool scintigram, and a myocardial scintigram showed decreased uptake in the apex and anterior front.The total serum protein level was 5.8 g d d l , the blood urea nitrogen and serum creatinine levels were elevated (107 mg/dl and 9.4 mg/ml, respectively), and the creatinine clearance rate was decreased (5.9 mlhinute). He had proteinuria (2.5 grdday), and red blood cells were