Diphtheria-tetanus skin testing. Its clinical value for delayed hypersensitivity

Area of Science:

• Immunology
• Dermatology
• Pediatrics

Background:

• Cell-mediated immunity evaluation is crucial in diagnosing immune disorders.
• Skin testing offers an in vivo method for assessing immune function.
• Challenges exist in antigen selection and result interpretation for skin tests.

Purpose of the Study:

• To evaluate the efficacy of diphtheria-tetanus skin testing as a reliable antigen for assessing cell-mediated immunity in pediatric patients.
• To compare skin test results with dermal biopsy findings in both immunodeficient and healthy children.

Main Methods:

• Thirteen pediatric subjects, including seven with immunodeficiencies, underwent skin testing with diphtheria-tetanus antigen.
• Dermal biopsy examinations were performed on all subjects to histologically assess delayed-type hypersensitivity (DTH).
• Skin test reactions were correlated with biopsy results.

Main Results:

• Fifty percent of immunodeficient patients exhibited positive skin test reactions, yet their biopsy results were inconsistent with DTH.
• All healthy control subjects showed histological evidence of DTH, but two presented with negative or equivocal skin reactions.
• Discrepancies between skin test outcomes and biopsy findings were observed in both patient groups.

Conclusions:

• Diphtheria-tetanus skin testing is not a suitable screening tool for immune or inflammatory disorders in children.
• Histological confirmation via skin biopsy is essential for accurate assessment of delayed-type hypersensitivity.
• Current antigen selection and interpretation methods for skin testing require further refinement for pediatric immune evaluations.