IgH sequences in common variable immune deficiency reveal altered B cell development and selection

Abstract

Common variable immune deficiency (CVID) is the most common symptomatic primary immune deficiency, affecting ∼1 in 25,000 persons. These patients suffer from impaired antibody responses, autoimmunity, and susceptibility to lymphoid cancers. To explore the cellular basis for these clinical phenotypes, we conducted high-throughput DNA sequencing of immunoglobulin heavy chain gene rearrangements from 93 CVID patients and 105 control subjects and sorted naïve and memory B cells from 13 of the CVID patients and 10 of the control subjects. CVID patients showed abnormal VDJ rearrangement and abnormal formation of complementarity determining region 3 (CDR3). We observed decreased selection against antibodies with long CDR3 regions in memory repertoires and decreased V gene replacement, offering possible mechanisms for increased patient autoreactivity. Our data indicate that patient immunodeficiency might derive both from decreased diversity of the naïve B cell pool and decreased somatic hypermutation in memory repertoires. CVID patients also exhibited abnormal clonal expansion of unmutated B cells relative to controls. Although impaired B cell germinal center activation is commonly viewed as causative in CVID, these data indicate that CVID B cells diverge from controls as early as the pro-B cell stage and suggest possible explanations for the increased incidence of autoimmunity, immunodeficiency, and lymphoma CVID patients.

Deep sequencing and human antibody repertoire analysis

“…Such out-of-frame sequences in healthy subjects usually have longer CDRH3 regions than the productive, but unmutated antibody gene rearrangements seen in naïve B cells in the peripheral blood. This length difference indicates that there is a selection against B cells with long CDR-H3 sequences after precursor B-cell development in the bone marrow, consistent with earlier data from Sanger sequencing analysis of antibody genes in human early precursor B cells, and increased self-reactivity of the antibodies encoded by such B cells [18,19]. A second step of selection against antibodies with long CDR-H3 regions appears to occur during the process of somatic mutation and selection that gives rise to affinity maturation, since the CDR-H3s in mutated antibody genes from memory B cells are even shorter than those found in naïve B cells [19,20].…”

Common variable immune deficiency: Dissection of the variable

“…In addition, decreased diversity of the naive CD27‐B‐cell pool and also decreased somatic hypermutation in CD27 + cells were observed. Since patients also demonstrated clonal expansion of unmutated B cells (preselection), the authors provided new evidence that the B‐cell defects in CVID originated in the pro‐B stage of development in the bone marrow …”

“…Since patients also demonstrated clonal expansion of unmutated B cells (preselection), the authors provided new evidence that the Bcell defects in CVID originated in the pro-B stage of development in the bone marrow. 81…”

B‐cell receptor repertoire sequencing in patients with primary immunodeficiency: a review

“…Based on these observations, the authors concluded that there were no qualitative defects in the naive repertoire of the studied CVID patients. In a recent large study, Roskin et al 34 explored BCR repertoire properties in CVID by conducting high-throughput sequencing of BCR rearrangements in total B-cells and in naive and memory B-cells. Of importance, this study included 93 patients and 105 controls which gave significant power to see differences in repertoire characteristics.…”