CTLA4 and mesothelioma: In addition, Chiarucci et al., using the same ELISA assay, found a similar increase in sPD-L1 levels (from a median of 70 pg/mL to 1850 pg/mL) in anti-PD-L1 treated mesothelioma patients, while in the anti-CTLA-4 and anti-PD-1 treated patients no such increase could be observed [41].