Type-I interferon receptor expression: Its circadian rhythm and downregulation after interferon-α administration in peripheral blood cells from renal cancer patients

Objectives: To investigate the regulation of interferon-alpha (IFN-alpha) receptor expression in metastatic renal cell carcinoma (RCC) after IFN-alpha administration. Methods: Blood sampling was carried out in eight patients with metastatic RCC and six healthy volunteers. Flow-cytometric analysis using a monoclonal antibody against the active subunit of the type-I IFN-alpha receptor (IFNAR2) was carried out to examine the circadian rhythm of IFNAR2 expression in peripheral blood mononuclear cells (PBMC) as well as its downregulation after IFN-alpha administration. Results: According to its circadian rhythm IFNAR2 in PBMC had a peak expression at night. Once IFN-alpha is administered, IFNAR2 levels in PBMC showed downregulation within 48 h and recovered within another 48 h. Conclusions: Our findings might support the establishment of an optimal schedule for IFN-alpha administration.