Cystatin C as a potential marker for relapse in patients with non-Hodgkin B-cell lymphoma

The concentration of cysteine protease inhibitor cystatin C was determined in sera from 59 patients with non-Hodgkin B-cell lymphoma using ELISA. The sera from 43 age and sex matched healthy blood donors served as controls. Cystatin C was significantly increased in sera of patients without therapy (mean 1136 ± SE 105.7 ng/ml, p = 0.00001) and with therapy (mean 1073 ± 52 ng/ml, p = 0.001) compared to controls (mean 819 ± 28 ng/ml). The highest levels were determined in sera of patients with a relapse (mean 1680 ± 196 ng/ml). By using immunofluorescence staining and confocal microscopy we determined immature dendritic cells as a major population of cystatin C positive cells in affected lymph nodes. Our study reports for the first time that cystatin C is a potential marker for relapse in patients with non-Hodgkin B-cell lymphoma.