CFHR1 and systemic lupus erythematosus: However, in contrast to aHUS, where 63% of CFHR3–1 deficient patients are anti-FH positive (33), only 9% of FHR1-deficient SLE patients in our cohort tested positive for anti-FH, indicating a limited pathogenic role of these autoantibodies in FHR1-deficient SLE patients.