Introduction: Common variable immunodeficiency is a heterogeneous antibody deficiency syndrome with autoimmune and inflammatory complications in a significant proportion of patients. The study was designed to evaluate the role of T regulatory (Treg) cells in common variable immunodeficiency (CVID) patients with autoimmunity.
Methods: The number and frequency of Treg cells (CD4(+), CD25(hi), Foxp3(+)) were evaluated in patients and controls, and Foxp3 expression in different subgroups of CVID patients with common clinical manifestations was compared.
Results: CVID patients had significantly fewer Treg cells than controls, and low frequency of Treg cells was associated with expansion of CD21(lo) B cells in patients. Patients with autoimmunity had significantly reduced frequency but normal numbers of regulatory T cells, whilst patients with splenomegaly had significant reduction in frequency and number of regulatory T cells.
Conclusion: Foxp3 is useful on its own or as an adjunct to classify CVID patients although the possibility of reduction in Treg cells as a secondary phenomenon cannot be excluded.