Common variable deficiency is due to -
Most patients with common variable immunodeficiency have normal or near-normal numbers of B cells in the blood and lymphoid tissues.
These B cells, however, are not able to differentiate into plasma cells.
The clinical manifestations are caused by antibody deficiency.
The feature common to all patients is hypogammaglobulinemia, generally affecting all the antibody classes but sometimes only IgG.
Absent B cells
Reduced number of B cells
Defective B cell differentiation
All of the above