Abstract: Objective Anti-H factor antibody-positive hemolytic uremic syndrome(HUS)is a severe subtype of HUS. The clinical characteristics, treatment and outcome of children with such disease were discussed to provide reference for clinical diagnosis and treatment. Methods Clinical data of 7 patients with anti-H factor antibody-positive HUS during May 2011 and Dec. 2017 were retrospectively analyzed, including 5 male and 2 female, aged 5.83 to 13.5(mean 7.93)years. The general condition, pre-infection, clinical characteristics, treatment, outcome and 3-8-year follow-up results were analyzed. Results Pre-infection: upper respiratory tract infection symptoms such as fever and cough were discovered in 57.14%(4/7)patients; digestive system symptoms such as vomiting and abdominal pain manifested in 71.42%(5/7)patients. Clinical features: all children were positive for anti-H factor antibody, ADAMTS13 activity was normal, 2 cases of H factor titer were normal, and the other were decreased; All cases showed moderate to severe anemia, thrombocytopenia, hyperbilirubinemia, massive proteinuria, severe acute kidney damage, and low-complement C3. Renal biopsy was performed in 3 cases and genetic testing in 3 cases. Treatment and outcome: all patients in the acute phase were treated with Gamma globulin, plasma exchange and high-dose methylprednisolone, followed by oral glucocorticoids. The outcome was 1 death and 6 relief, with the mean treatment time of 27.83 days. Five patients were treated with immunosuppressive agents due to persistent abnormalities in urine routine. After 3-8 years of follow-up, 4 patients had complete remission and 2 had partial remission; of the 4 cases who repeated amti H factor antibody examination, 2 were negative and 2 were still positive. Conclusion Children with anti-H factor antibody-positive HUS have severe clinical manifestations. On the basis of symptomatic supportive therapy in the acute phase, early use of plasma exchange, Gamma globulin, combined with high-dose methylprednisol impact therapy, can quickly control the condition. Long-term application of immunosuppressive agents can reduce recurrence and prolong the remission period. H factor antibody and C3 may be used as indicators of prognostic monitoring.

Key words: Hemolytic uremic syndrome, Anti-H factor antibody, Clinical characteristics, Treatment, Follow-up