Tuberculin anergy in patients with Mycoplasma pneumoniae infection.

Skin testing for delayed hypersensitivity to tuberculin was performed in 36 patients with pneumonia associated with Mycoplasma pneumoniae infection. 22 of these patients had a negative tuberculin reaction when first tested. The tuberculin reaction was negative in 13 out of 16 cases tested during the first 2 weeks after onset of illness, in 6 out of 11 cases tested 15-28 days after onset of illness and in 3 out of 9 cases tested 29-45 days after clinical onset. In 19 patients with a negative tuberculin test in the early phase after onset of illness the test was repeated several weeks or months later. 16 of these cases had a positive tuberculin reaction at the later time period. Two of these cases showed prolonged tuberculin anergy for more than 5 months.