1- Paediatric Nephrology Unit, Department of Paediatrics, Hospital Dona Estefânia, Centro Hospitalar e Universitário de Lisboa Central, Lisbon, Portugal
- VII Congresso Hispano-Português de Nefrologia Pediátrica e XLVI Congreso Español de Nefrologia Pediátrica. 18 e 19 de Maio de 2023, NOVA Medical School, Lisboa. Poster.
Introduction: Anti-factor H antibodies (aFH) associated aHUS is a unique subgroup of aHUS that is more prevalent in the pediatric population, occurring in about 24% of all children with aHUS. Around 50% of aHUS cases arise from genetic mutations that encode regulatory proteins of the alternate complement pathway. Factor H (FH) is one of these important regulatory proteins. The autoantibodies impair the interaction of FH with C3b causing dysregulation of the alternate pathway of the complement.Eculizumab, an antiC5 antibody that targets terminal complement activation, has transformed outcomes in aHUS. Eculizumab is preferred in patients who possess FH mutations, it further reduces the likelihood of recurrences and seems to be a safe option for the treatment of aFH aHUS in the paediatric population. Several immunosuppressors, like prednisone, cyclophosphamide, azathioprine, mycophenolate mofetil (MMF) and rituximab, have been used as inhibitors of aFH production and as maintenance therapy, reducing relapse risk.
Clinical Case: We present the case of a 6-year-old boy, previously healthy who was diagnosed with aHUS after exclusion of STEC-HUS, thrombotic thrombocytopenic purpura and infectious etiologies. Eculizumab was started about 24h after admission, with excellent clinical and laboratorial response. He was discharged after eight days, maintaining eculizumab treatment fortnightly. Further investigation showed elevated aFH (11100 UA/mL) and a homozygous CFHR3-CFHR1 deletion. Therapy with MMF was started, 1200 mg/m2/day. The titre of aHF have decreased but not normalized. The interval between eculizumab doses was progressively widened up to every 5 weeks. Currently, 15 months after diagnosis, he remains clinically stable with no relapses.
Conclusion: The management of this patient presents a challenge, since there are very few studies regarding the optimal duration of eculizumab, under what circumstances its discontinuation may be safe, and for how long additional immunosuppression should be carried out.
Palavras Chave: aHUS, Anti-factor H Antibodies, eculizumab