Added value of use of a purified protein derivative-based enzyme-linked immunosorbent spot assay for patients with Mycobacterium bovis BCG infection after intravesical BCG instillations.

In this case series, we describe four cases in which the use of gamma interferon release assays with purified protein derivative (PPD) as a stimulating antigen was able to demonstrate PPD-specific immune activation. This may help to improve the adequate diagnosis of (systemic) Mycobacterium bovis BCG infections after intravesical BCG instillations for bladder carcinoma.