Successful Treatment with Sirolimus of a Patient with a Novel CARD11 Germline Mutation in B-Cell Expansion with Nuclear Factor Kappa B and T-Cell Anergy: Case Report and Literature Review.

PURPOSE: B-cell expansion with nuclear factor kappa B and T-cell anergy (BENTA) is an inborn error of immunity characterized by congenital polyclonal B-cell lymphocyte expansion. In this report, we present a case of a girl diagnosed with BENTA carrying a novel CARD11 germline mutation, aiming to clarify the clinical presentation of BENTA by conducting a literature review.

METHODS

Genetic analysis, including whole-exome sequencing, was performed using genomic DNA extracted from the patient's peripheral blood, oral mucosa, and fingernails. Additionally, a comprehensive literature review of cases with BENTA was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

RESULTS

A p.Leu251Pro germline variant in the CARD11 gene was identified in an 18-month-old girl with a genetic diagnosis of BENTA. She required adenoidectomy and tonsillectomy due to airway obstruction causing wheezing. Her symptoms improved with prednisolone and sirolimus. The literature review we conducted identified a total of 34 cases of BENTA. Among these cases, 15 were either asymptomatic or showed improvement without requiring any specific treatment. However, all six reported deaths were diagnosed before the age of 3 years, with two attributed to refractory hemophagocytic syndrome and four caused by opportunistic infections.

CONCLUSION

We present a case of BENTA with life-threatening respiratory symptoms caused by a novel CARD11 germline mutation. The patient showed a positive response to immunosuppressive therapy, including sirolimus. While BENTA is typically regarded as a benign disorder, a literature review revealed that infants with BENTA are at high risk of severe outcomes and require therapeutic intervention.