Successful treatment of BCG-related immune reconstitution inflammatory syndrome following ex vivo T-cell-depleted haploidentical hematopoietic stem cell transplantation: A case report

Case Report: Immune reconstitution inflammatory syndrome after hematopoietic stem cell transplantation for severe combined immunodeficiency

We report a case of immune reconstitution inflammatory syndrome (IRIS) after hematopoietic stem cell transplantation (HSCT). The patient had sever bacillus Calmette–Guerin (BCG) vaccine–caused disseminated infection and had received allogeneic HSCT for X-linked severe combined immunodeficiency disease. After HSCT, complicated by treatment-responding veno-occlusive disease and acute graft-versus-host disease, at the time when immunosuppressants were withdrawn, the patient experienced recurrent fever accompanied by elevated inflammatory indicators. After receiving glucocorticoids and ibuprofen, the patient’s condition improved, and a diagnosis with BCG-related IRIS was made.

Bacillus Calmette-Guerin (BCG) Vaccine-associated Complications in Immunodeficient Patients Following Stem Cell Transplantation

PURPOSE

Bacillus Calmette-Guerin (BCG) is a live attenuated vaccine with the potential of causing severe iatrogenic complications in patients with primary immunodeficiency diseases (PID) before and after hematopoietic stem cell transplantation (HSCT). We aim to investigate risk factors of post-HSCT BCG-related complications in PID patients.

METHODS

A retrospective analysis of pediatric PID patients who had received the BCG vaccine and underwent HSCT at Hadassah-Hebrew University Medical Center, between 2007 and 2019.

RESULTS

We found 15/36 (41.67%) patients who developed post-HSCT BCG-related complications. The most significant risk factor for developing BCG-related complications was T cell deficiency (47.6% of the non-complicated vs 83.3% of the BCGitis and 100% of the BCGosis groups had T cell lymphopenia, p = 0.013). None of the chronic granulomatous patients developed BCG-related manifestation post-transplant. Among T cell-deficient patients, lower NK (127 vs 698 cells/μl, p = 0.04) cell counts and NK-SCID were risk factors for ongoing post-HSCT BCGosis, as was pretransplant disseminated BCGosis (33.3% of patients with BCGosis vs none of the non-BCGosis patients, p = 0.04). Immune reconstitution inflammatory syndrome (IRIS) was observed in 3/5 patients with Omenn syndrome. Prophylactic antimycobacterial treatment was not proven effective.

CONCLUSION

BCG vaccination can cause significant morbidity and mortality in the post-transplant T cell-deficient patient, especially in the presence of pre-transplant disease. Taking a detailed medical history prior to administering, the BCG vaccine is crucial for prevention of this complication.