Abatacept for treatment-refractory pediatric CTLA4-haploinsufficiency

Clin Immunol. 2021 Aug:229:108779. doi: 10.1016/j.clim.2021.108779. Epub 2021 Jun 8.


CTLA4-haploinsufficiency is a complex disease of immune dysregulation presenting with a broad spectrum of clinical manifestations. CTLA4-Fc fusion proteins such as abatacept have been described to alleviate immune dysregulation in several adult cases of CTLA4-haploinsufficiency. However, until now only few cases of pediatric CTLA4-haploinsufficiency treated with abatacept have been described. Here we present two pediatric cases of severe CTLA4-haploinsufficiency refractory to conventional immunosuppressive therapies that responded rapidly to treatment with abatacept. No side effects were observed during a follow-up period of 7-15 months. While one patient has successfully undergone HSCT the second patient continues to receive abatacept. Our cases demonstrate safe medium-term use of abatacept in the pediatric population.

Keywords: Abatacept; CTLA4-fc fusion protein; CTLA4-haploinsufficiency; Immune dysregulation; Inborn error of immunity.

Publication types

  • Case Reports
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Abatacept / therapeutic use*
  • Adolescent
  • CTLA-4 Antigen / deficiency*
  • CTLA-4 Antigen / genetics
  • CTLA-4 Antigen / immunology
  • Female
  • Haploinsufficiency / genetics
  • Haploinsufficiency / immunology
  • Hematopoietic Stem Cell Transplantation
  • Humans
  • Immune System Diseases / genetics
  • Immune System Diseases / immunology
  • Immune System Diseases / therapy
  • Immunosuppressive Agents / therapeutic use*
  • Male
  • Mutation, Missense
  • T-Lymphocytes, Regulatory / immunology


  • CTLA-4 Antigen
  • CTLA4 protein, human
  • Immunosuppressive Agents
  • Abatacept