Gamma delta T lymphocytosis associated with common variable immunodeficiency

Area of Science:

• Immunology
• Hematology
• T-cell biology

Background:

• Common variable immunodeficiency (CVID) is a primary immunodeficiency characterized by hypogammaglobulinemia and impaired B-cell differentiation.
• Patients with CVID are prone to recurrent infections, autoimmune phenomena, and an increased risk of malignancy.
• T-cell abnormalities, including lymphopenia and altered T-cell subsets, are increasingly recognized in CVID.

Observation:

• A 28-year-old female with CVID presented with recurrent fevers, pulmonary infiltrates, and unexplained lymphocytosis.
• Flow cytometry revealed an expansion of V-delta 1 gamma delta T lymphocytes, CD4 T lymphocytopenia, and a low CD4/CD8 ratio.
• Functional studies showed impaired T-cell proliferation and cytokine production, with no clear infectious or malignant trigger identified.

Findings:

• The gamma delta T lymphocytosis was persistent and not associated with infection, malignancy, or superantigen stimulation.
• Despite extensive evaluation, the etiology of the expanded gamma delta T cell population in this CVID patient remained undetermined.
• The patient ultimately succumbed to respiratory insufficiency, underscoring the severity of complications in CVID.

Implications:

• This case highlights the complex and often poorly understood T-cell dysregulation occurring in common variable immunodeficiency.
• Further research is needed to elucidate the mechanisms driving gamma delta T lymphocytosis and its clinical significance in immunodeficiency disorders.
• Understanding these T-cell abnormalities may lead to improved diagnostic approaches and therapeutic strategies for CVID patients.