Figure 9.

Summary of the four CVIDs groups. The memory B-cell compartment includes GC- and T-independent IgM MBCs, as well as post-GC and T-dependent MBCs of both IgM and switched isotypes. Short-lived plasmablasts (PB) are generated by recent immune responses. Long-lived plasma cells (LLPCs) maintain serum antibody levels in time. Group 1 patients are able to produce all MBCs types. Hypogammaglobulinemia may be explained by the inability to produce LLPCs in this group of CVIDs patients. For patients of groups 2 and 3, the defective CD4+ T-cell function may impair GC development. Patients of group 2 retain the ability to generate T-independent IgM MBCs, whereas all MBCs are missing in group 3. In patients of group 4, the significant reduction of all B-cell populations past the transitional B-cell stage suggests a severe defect in all B-cell functions. The severity of the clinical disease increases in groups 3 and 4.