Reliability of candida skin test in the evaluation of T-cell function in infancy

Abstract

Background: Both standardized and non-standardized candida skin tests are used in clinical practice for functional in-vivo assessment of cellular immunity with variable results and are considered not reliable under the age of 1 year. We sought to investigate the reliability of using manually prepared candida intradermal test in the evaluation of T cell function in infants during their second year of life. Methods: Twenty-five healthy infants were tested with manually prepared intradermal candida test. Cultured lymphocytes were stimulated with phytohemagglutinin (PHA) and gamma interferon (IFN-γ) levels were measured in the culture supernatant of stimulated and non-stimulated samples using ELISA. Results: The enrolled infants were 14 to 24 months old (mean 19.2 ± 3.13 months). They were 17 boys (68 %) and 8 girls (32 %). Candida skin test was positive in 17 out of the 25 infants (68%). All infants showed increased IFN-γ levels after PHA stimulation (mean ± SD: 0.83±0.29 ng/ml) compared to basal levels (mean ± SD = 0.16 ± 0.16 ng/ml). The increase of IFN γ levels after PHA stimulation ranged from 1.54 to 38 folds. Infants with positive and negative candida tests showed comparable results in terms of clinical and immunological assessment except for weight percentiles for age that were higher among candida positive group. Conclusion: Candida intradermal test is a cost-effective simple test for evaluation of T cell function with 70 % sensitivity in healthy infants above the age of one year. Keywords: Candida, IFN-γ, infants, intradermal, lymphocyte proliferation, PHA stimulation, T cell, Tuberculin