No significant relation of proinflammatory slanDCs with uremic pruritus

The pathogenesis of the pruritus associated with chronic kidney disease-(CKD-aP) is not completely understood. Endocrine, metabolic, neuropathic, and inflammatory disorders were suspected to be the origin of CKD-aP. Based on the hypothesis which suggests that deregulated systemic inflammation may play a crucial role in CKD-a, we investigated the potential relation of an inflammatory monocyte subset (slanDCs) with CKD-aP. Itch questionnaire, visual analogue scale (VAS)-scoring, and Dermatology Life Quality Index (DQLI) were applied for the characterization of itch sensation. VAS-scoring was re-evaluated after 6 months. Monocytes were flow-cytometrically categorized into classical, intermediate, and non-classical subsets. slanDCs are part of the non-classical monocyte subpopulation. Sixty-six hemodialysis patients (CKD5-D) were screened of whom 43 met the study inclusion criteria. In all, 46.5% of patients were scored pruritus-positive (CKD-aP+). CKD-aP severity level of patients was moderate at the start of the study (VAS 5.3 ± 2.5) and remained unchanged after 6 months (VAS: 5.2 ± 1.9, P < 0.757). Thirty percent of patients were affected with mild, 30.0% with moderate, and 35.0% with severe itchiness. In contrast to all other factors tested solely slanDC showed a weak correlation to VAS-score (r = 0.41, P = 0.07). slanDC frequencies between CKD5-D patients with and without itch sensation, however, were not significantly different. Endocrine problems appeared to influence CKD-aP. CKD-aP + patients had significantly higher L-thyroxin supplementation than CKD-aP- (50.0% vs 8.7%, P < 0.005). A binary logistic regression model confirmed the significance of L-thyroxin medication on chronic itch problems of our CKD5-D patients (P < 0.007). There is no clear evidence that slanDCs are related to uremic pruritus. Therefore, other factors underlie the pathophysiology of CKD-aP.