Late-onset X-linked Chronic Granulomatous Disease in a Female Carrier: Therapeutic Role of Interferon-γ and Hematopoietic Stem Cell Transplantation

X-linked Chronic Granulomatous Disease (CGD) is a rare inherited immunodeficiency characterized by early life-threatening infections from bacteria and fungi in male children. Female carriers of X-linked CGD usually do not develop any manifestations of the disease, yet in rare cases they may present with CGD-related manifestations due to skewed X chromosome inactivation, even in advanced age. Here, we report the case of a 49-year-old woman with no history of previous frequent or severe infections, who presented acutely with life-threatening bilateral pneumonia caused by Nocardia asteroides and was eventually diagnosed with late-onset X-linked CGD due to skewed X chromosome inactivation in white blood cells. Treatment with interferon-γ as a rescue therapy resulted in normalization of the intensity of the oxidative burst in the residual positive cells and resolution of the infection, which was otherwise resistant to conventional treatments. After discharge, however, recurrent severe pulmonary infections despite prophylactic treatments as well as appearance of granulomatous colitis led to considering definitive treatment. Hematopoietic stem cell transplantation from unaffected HLA-identical brother using a non-myeloablative conditioning protocol with intravenous busulfan followed by high-dose peripheral blood stem cell graft and post-transplant cyclophosphamide was successfully performed. After three years of follow-up, white blood cell chimerism remained stable with about 60% donor cells in the myeloid lineage, with no further infections and no recurrence of inflammatory bowel disease.