Failure in antigen responses by T cells from patients with common variable immunodeficiency (CVID)

Area of Science:

• Immunology
• Cellular Biology
• Clinical Medicine

Background:

• Common Variable Immunodeficiency (CVID) is characterized by low immunoglobulin levels and increased susceptibility to infections.
• The precise mechanisms underlying T cell dysfunction in CVID remain incompletely understood.
• Antigen presentation and T cell activation are critical for adaptive immune responses.

Purpose of the Study:

• To investigate antigen-driven T cell responses in patients with CVID.
• To assess T cell proliferation defects in response to recall and neoantigens.
• To explore the potential role of T cell dysfunction in CVID pathogenesis.

Main Methods:

• T cells from CVID patients and healthy controls were cultured using a hanging drop system.
• Cells were stimulated with recall antigens (purified protein derivative, tetanus toxoid) and a neoantigen (HIV env peptide).
• Primary allo-stimulation was used to assess T cell reactivity independently of prior sensitization.

Main Results:

• T cells from all CVID subgroups exhibited markedly reduced responses to purified protein derivative and tetanus toxoid.
• X-linked agammaglobulinaemia T cells showed normal responses, serving as a disease control.
• CVID T cells from two patients failed to respond to a neoantigen, while normal T cells did.

Conclusions:

• A profound defect in antigen-stimulated T cell proliferation exists in CVID patients.
• This defect could stem from either the antigen-presenting cells or the T lymphocytes themselves.
• Impaired T cell function may be the primary cause of reduced B cell rescue and low immunoglobulin production in CVID.