CD5 B-Cell Predominant Primary Immunodeficiency: Part of the Spectrum of MAGT1 Deficiency.

Background: Selective anti-polysaccharide antibody deficiency (SPAD) with CD5 B-cell predominance and autoimmune phenomena was identified in a male cohort first reported by Antall et al in 1999. The phenotypically likewise and genotypically identical X-linked immunodeficiency with magnesium defect, Epstein-Barr Virus infection, and neoplasia (XMEN) disease was defined as a novel primary immunodeficiency (PID) in 2011. Recent studies of the magnesium transporter 1 (MAGT1) gene mutation reveal glycosylation defects contributing to more phenotypic variance than the "XMEN" title pathologies. The updated title, "X-linked MAGT1 deficiency with increased susceptibility to EBV-infection and N-linked glycosylation defect," was proposed in 2020. Objectives: To reflect the patient population more accurately, a prospective classification update may consider MAGT1 glycobiological errors contributing to phenotypic variance but also pre-genetic testing era reports with CD5 B-cell predominance. Methods: Patient 1 from Antall et al presented at 28 years of age for further immunological evaluation of his CD5/CD19 B-cell predominance diagnosed at 5 years old. Design: Immune re-evaluation done through flow cytometry and next-generation sequencing. Results: Flow cytometry B-cell phenotyping revealed persistent CD5+CD19+ (93%). Flow cytometric histogram quantified reduced activator CD16+CD56+ natural killer and CD8+ T-cell receptor, Group 2, Member D (NKG2D) glycoprotein expression. A c.923-1_934 deletion loss of function mutation was identified in the MAGT1 gene. Conclusion: We suggest the novel PID XMEN, based on its CD5 B-cell predominance, had been discovered and reported over a decade earlier as CD5+ PID based on the MAGT1 mutation found in the same. We encourage consideration of combining these labels and recent findings to offer the most accurate classification of this disease.

Post Autologous Bone Marrow Transplant Associated With a Resultant Mixed Polyclonal/Monoclonal Hyper-IgG3.

There have been few studies illustrating the post immunological phenotype of patients receiving autologous bone marrow transplant (ABMT) for the treatment of diffuse large B-cell lymphoma. High-dose chemotherapy and autologous bone marrow transplantation have been shown to be the only potential curative treatment modalities for B-cell lymphoma. Autologous bone marrow transplantation, although widely utilized in patients with non-Hodgkin lymphoma recurrence, does have an association with immunologic side effects, although serologic changes where rarely reported unless accompanied by recurrent infections. We report the first case of a 62-year-old female patient who experienced recurrent infections, namely, sinusitis and pneumonia, after receiving an ABMT with subsequent hyper-IgG3 phenotype.