ABSTRACT
BACKGROUND: The pathogenesis of ADPKD is still unknown but the proliferation of cystic epithelia and the fluid secretion to cystic lumen are thought to be important. Cytokines play a pivotal role in growth, differentiation, and apoptosis in general, but there were few reports about the cytokine profile in ADPKD cysts. METHODS: In this study, we measured cytokine content in aerobic culture-negative cystic fluids from 23 patients with symptomatic normal to end-stage (n=3) ADPKD in order to elucidate the possibility that cytokines are related to the development and progression of disease. Enzyme-linked immunosorbent assays (ELISAs) were used to detect IL-1beta, IL-2, IL-4, IL-6, IL-10, and IFN-gamma with commercial kits. RESULTS: Male to female ratio was 6 : 17 and the median age at examination was 52 years (range 36 to 78). IL-1beta was present in 18 of 23[78%] (11 to 173 pg/mL), IL-2 in 18 of 23[78%] (5 to 159 pg/ mL), IL-4 in 9 0f 23[39%] (8 to 156 pg/mL) and IL-6 in 10 of 23[43%] (16 to 1498 pg/mL). IL-10, and IFN-gamma were not detected. IL-1beta concentrations correlated directly with those of IL-2 (r=0.7671). IL- 6 levels in patients with azotemia (n=7) [288.4+/-26.2 (mean+/-S.D.)] were significantly higher than those of normal renal function group (98.3+/-413.9)(p<0.01). Such difference was not found in other cytokines. Cytokine concentrations did not correlate with sodium concentrations, nor with cystic fluid osmolality, indicating that differences in concentrations among fluids could not be explained by differences in water content. And, there was no significant correlation between the intracystic concentrations of these cytokines and the corresponding cyst diameters. CONCLUSION: These data identify proinflammatory cytokines as possible mediators to the morbidity of ADPKD. Especially, IL-6 levels of cystic fluid were elevated in the azotemic ADPKD patients.