C4A and infection: Laboratory evaluation showed a significant hypocomplementemia (C3 < 11 mg/dL, C4 < 3 mg/dL, and CH50 < 10 U/mL), high titer antinuclear antibody, anti-dsDNA antibodies, anti-Sjogren's syndrome-related antigen A antibodies, anti-Sjogren's syndrome-related antigen B antibodies, anti-Smith antibodies, anti-ribonucleoprotein antibodies, anti-histone antibodies with a negative malignancy, and infection workup.