Objective: To examine the purified protein derivative (PPD) response that develops depending upon Th1 immune response in children with juvenile idiopathic arthritis (JIA).
Methods: PPD skin test was performed in 115 children with JIA who were vaccinated with bacillus Calmette-Guerin (BCG), and then they were compared to the PPD response of 45 healthy children of the same age who were vaccinated with BCG. Children with a PPD induration > or = 5 mm were accepted as PPD-positive. PPD induration > or = 10 mm was accepted as a limit for suspecting tuberculosis.
Results: PPD induration size and PPD positivity rates (PPD > or = 5 mm) of children with JIA were significantly lower than those of healthy children. The mean of PPD induration size was significantly lower (p < 0.0001) in patients with either 1 BCG vaccine (3.7 +/- 3.6) or more than 1 BCG vaccine than controls with either 1 BCG vaccine (7.10 +/- 3.2) or more than 1 BCG vaccine (10.05 +/- 4.1). PPD was positive in 35.9% of patients with JIA vaccinated once (n = 32), in 50% of patients with JIA vaccinated more than once (n = 13), in 82.1% of controls vaccinated once (n = 23), and in 88.2% of controls vaccinated more than once. This result was statistically significant (patients, p = 0.03; controls, p = 0.039). It was determined that neither the activity of the disease nor the use of corticosteroid and methotrexate affected the PPD response.
Conclusion: The response to PPD, which is one of the Th1 cell-type responses, was significantly lower in BCG-vaccinated children with JIA compared to healthy children.