[Cytokines in children with immunodeficiencies]

Area of Science:

• Immunology
• Molecular Biology
• Pediatrics

Background:

• Humoral immunodeficiency, characterized by decreased immunoglobulin production, has an unknown underlying immunological defect.
• Cytokines are known to regulate B cell maturation and differentiation, suggesting their aberrant production may play a role in these diseases.
• Previous research indicates interleukins (IL-1, IL-4, IL-6, IL-10) and interferons (IFNs) influence B cell growth, while the role of tumor necrosis factors (TNF alpha and beta) remains unclear.

Purpose of the Study:

• To investigate the in vitro cytokine production by peripheral blood mononuclear cells (PBMC) in children with various forms of immunodeficiency, specifically IgA deficiency and transient hypogammaglobulinemia of infancy.
• To determine the specific types of TNF (alpha or beta) involved in the observed cytokine dysregulation.
• To assess the production of other key regulatory cytokines (IL-4, IL-10) and identify the cellular sources of cytokine production.

Main Methods:

• Analyzed the release of IL-1, IL-6, IFN, and TNF from PBMCs stimulated with mitogens for 48 hours in patient groups (transient hypogammaglobulinemia, IgA deficiency, Bruton's disease, etc.) and a control group.
• Determined the specific types of TNF (alpha and beta) and other cytokines (IL-4, IL-10) produced.
• Utilized ELISPOT assays and intracellular cytokine staining with fluorochrome-labelled monoclonal antibodies to identify the number and type of cytokine-secreting cells (including CD4+ lymphocytes and CD14+ monocytes).

Main Results:

• Significantly increased secretion of TNF was observed in children with transient hypogammaglobulinemia and IgA deficiency compared to controls.
• Production of TNF alpha, TNF beta, and IL-10 was significantly elevated in transient hypogammaglobulinemia, with increased numbers of TNF alpha-secreting cells.
• In IgA deficiency, TNF alpha release was significantly increased, primarily from CD4+ lymphocytes, suggesting an excessive Th-1 type response contributes to pathology.

Conclusions:

• Elevated TNF alpha production, likely due to enhanced release and increased numbers of secreting cells, is implicated in transient hypogammaglobulinemia and IgA deficiency.
• The findings suggest an excessive Th-1 type immune response may contribute to the pathology of these conditions.
• Increased TNF alpha production, rather than abnormal receptor expression, appears to be the key regulatory factor in these immunodeficiencies.