C3 and Pancytopenia: The patient was diagnosed with SLE on the basis of fever, hemolytic anemia, pancytopenia, low C3 and C4, proteinuria greater than 0.5 g/day, serous effusion, antinuclear antibody positive, and anti-dsDNA positive, fulfilling the 2019 European League Against Rheumatism/American College of Rheumatology (EULAR/ACR) criteria [5], complicated with lupus nephritis, pancytopenia, hemolytic anemia, serous effusion, lacunar cerebral infarction, and trisomy X syndrome.