Complement assoc. studied by Petri & Durcan in 2399 SLE pts. 55% had low C3 (pesistently low 4%); 47% low C4 (3% persistently low). Low C4 is weak marker clinical & serological Dz. Low C3 linked w/ renal & serological Dz, Low C3/C4 linked to ACL, CVA, DVT https://t.co/KgF7HNEYu8