Fig. 1.

Cytokine production by MAK in vitro when incubated in urine for 2 h at 37°C. Urine samples with MAK were immediately centrifuged, or stored for 2 h at 4°C or 20°C before centrifugation and storage. Results are expressed for each cytokine as mean ± s.d. of the levels observed with the three sampling procedures. No cytokines were detected in the medium containing MAK before instillation, and the urine sample before MAK contained only a low level of IL-18 (>10 pg/ml).