The Presentation, Diagnosis, and Management of Autosomal Dominant Common Variable Immunodeficiency Type XII with NFKB1 Mutation and Autoimmune Neutropenia Treated with Allogenic Stem Cell Transplantation

<b>Background and Clinical Significance:</b> Common Variable Immunodeficiency (CVID) is a prevalent manifestation of primary immunodeficiency disorder. The current mainstay of treatment is immunoglobulin replacement therapy; however, in patients with severe complications or refractory disease, hematopoietic stem cell transplant (HSCT) is indicated. Despite this, there has been little research regarding HSCT as a treatment for CVID, with few case reports demonstrating clinical benefit. <b>Case presentation:</b> We present a unique case of common variable immunodeficiency Type XII (CVID12) with rare NFKB mutation and its management. A 20-year-old female with autoimmune alopecia, eczema, and a congenital atrophic right kidney presented to the emergency department with a three-month history of intermittent fever, malaise, lymphadenopathy, mouth sores, diarrhea, and odynophagia, accompanied by a 5 lb. unintentional weight loss and night sweats. Previously, she received multiple steroid prescriptions for these symptoms, providing only temporary relief with each course. Lab findings revealed severe neutropenia and imaging demonstrated hepatosplenomegaly and lymphadenopathy. Flow cytometry revealed a slightly atypical CD8-positive T-cell population and bone marrow biopsy revealed variable cellular marrow with trilineage hematopoiesis. Genetic testing confirmed the diagnosis of Autosomal Dominant Common Variable Immunodeficiency Type XII with an NFKB1 mutation. Pre-transplant treatments included monthly IVIG, weekly rituximab, and daily filgrastim, all of which failed to improve her autoimmune neutropenia and hypogammaglobulinemia and failed to reduce her symptomatic burden. Given the patient's young age and refractory autoimmune neutropenia, it was decided to manage them definitively with hematopoietic stem cell transplantation (HSCT). She ultimately underwent allogenic stem cell transplantation (haploidentical, donor was the mother) with 3.96 × 10⁸/kg TNC without immediate post-transplant complications. <b>Conclusions:</b> This article demonstrates a rare case of NFKB1-positive CVID that was successfully treated with HSCT and highlights the importance of considering transplant therapy in younger patients with clinically significant, refractory autoimmune cytopenia.