Significant differences in B-cell subpopulations characterize patients with chronic graft-versus-host disease–associated dysgammaglobulinemia

Abstract

AbstractManifestations of chronic graft-versus-host disease (cGVHD) can resemble those seen in immunodeficiency states and autoimmune disorders. Reports by us and others suggest an involvement of B cells in the pathogenesis of cGVHD. We investigated B-lymphocyte subpopulations in cGVHD cohorts defined by serum immunoglobulin G (IgG) levels to characterize novel biomarkers for impairment of humoral immunity after allogeneic hematopoietic stem cell transplantation. Seventy-six patients were enrolled a median of 46 months after hematopoietic stem cell transplantation. The hypogammaglobulinemia group had significantly diminished CD19+ B cells (165 vs 454 vs 417 × 106/L) with elevated CD19+CD21low immature (16.5%, 7.7%, and 9.1%) and CD19+CD21int-highCD38highIgMhigh transitional (10.5% vs 4.2% vs 6.3%) B-cell proportions compared with the normogammaglobulinemia and hypergammaglobulinemia groups. CD19+CD10−CD27−CD21high naive B cells were highly elevated in all patients with cGVHD. CD19+CD27+IgD+ non–class-switched (4 vs 12 vs 11 × 106/L) and class-switched (7 vs 35 vs 42 × 106/L) memory B cells were significantly lower in the hypogammaglobulinemia group compared with the others. Besides significantly higher B-cell activation factor/B-cell ratios, significantly more cGVHD patients with hypergammaglobulinemia had autoantibodies compared with the hypogammaglobulinemia subgroup (68% vs 24%, P = .024). In conclusion, B-cell subpopulations can serve as novel cellular biomarkers for immunodeficiency and autoimmunity indicating different pathogenetic mechanisms of cGVHD and encouraging future prospective longitudinal studies.