Malassezia yeasts activate the NLRP3 inflammasome in antigen‐presenting cells via Syk‐kinase signalling

Although being a normal part of the skin flora, yeasts of the genus Malassezia are associated with several common dermatologic conditions including pityriasis versicolour, seborrhoeic dermatitis (SD), folliculitis, atopic eczema/dermatitis (AE/AD) and dandruff. While Malassezia spp. are aetiological agents of pityriasis versicolour, a causal role of Malassezia spp. in AE/AD and SD remains to be established. Previous reports have shown that fungi such as Candida albicans and Aspergillus fumigatus are able to efficiently activate the NLRP3 inflammasome leading to robust secretion of the pro‐inflammatory cytokine IL‐1β. To date, innate immune responses to Malassezia spp. are not well characterized. Here, we show that different Malassezia species could induce NLRP3 inflammasome activation and subsequent IL‐1β secretion in human antigen‐presenting cells. In contrast, keratinocytes were not able to secrete IL‐1β when exposed to Malassezia spp. Moreover, we demonstrate that IL‐1β secretion in antigen‐presenting cells was dependent on Syk‐kinase signalling. Our results identify Malassezia spp. as potential strong inducers of pro‐inflammatory responses when taken up by antigen‐presenting cells and identify C‐type lectin receptors and the NLRP3 inflammasome as crucial actors in this process.     

WHO guide on the economic evaluation of influenza vaccination

Influenza is responsible for substantial morbidity and mortality across the globe, with a large share of the total disease burden occurring in low‐ and middle‐income countries (LMICs). There have been relatively few economic evaluations assessing the value of seasonal influenza vaccination in LMICs. The purpose of this guide is to outline the key theoretical concepts and best practice in methodologies and to provide guidance on the economic evaluation of influenza vaccination in LMICs. It outlines many of the influenza vaccine‐specific challenges and should help to provide a framework for future evaluations in the area to build upon.     

The lymphatic system in clinically localized urothelial carcinoma of the bladder: Morphologic characteristics and predictive value

ObjectiveTo assess the lymphatic vessel density (LVD) and lymphangiogenesis in urothelial carcinoma of the bladder (UCB) and to identify predictors of progression in patients treated by transurethral resection (TUR).Materials and methodsOne hundred eleven patients who underwent TUR for UCB were retrospectively included. Lymphatic endothelial cells were stained immunohistochemically [D2-40 (podoplanin) antibody in all samples; Prox-1, LYVE-1, and VEGFR-3 (Flt-4) in subgroups]. LVD was measured in representative intratumoral (ITLVD), peritumoral (PTLVD), and nontumoral (NTLVD) areas using standardized criteria. Double-immunostainings with D2-40/CD-34 were performed to distinguish between blood and lymphatic vessels, and D2-40/Ki-67 stainings were done to detect lymphangiogenesis. Lymph-specific parameters were correlated with pathologic and clinical characteristics. In patients with non-muscle-invasive UCB (n = 76) univariable and multivariable analyses were performed to identify predictors of progression.ResultsThe PTLVD was significantly higher than ITLVD and NTLVD (P < 0.001). Proliferating lymphatic vessels were observed in all specimens assessed with D2-40/Ki-67. Characteristic suburothelial D2-40 positivity was observed in noninvasive pTa tumors. LYVE-1-stainings revealed the existence of tumor-associated macrophages. The presence of intratumoral lymphatic vessels was significantly associated with higher tumor stage, high grade, and sessile growth (all P < 0.001). Muscle-invasive tumors (P = 0.020), higher grade (P = 0.026), the presence of lymphovascular invasion (P < 0.001), and concomitant carcinoma in situ (CIS) (P = 0.020), sessile growth (P = 0.004), and loss of suburothelial D2-40 positivity (P = 0.031) were associated with disease progression in univariable analysis. LVD values in any area were not significantly associated with progression despite detection of proliferating lymphatic vessels. The presence of concomitant CIS was identified as an independent predictor of progression on multivariable analysis (P = 0.041; hazard ratio 4.620).ConclusionsA high peritumoral LVD is present in clinically localized UCB. The presence of intratumoral lymphatic vessels correlates with characteristics of aggressive disease. Lymphangiogenesis occurs; however, the lymph-specific parameters tested in this study cannot be used to predict progression following TUR. The presence of concomitant CIS is an important risk factor for later disease progression in patients with non-muscle-invasive UCB. Our results contribute to the understanding of metastatic tumor spread in UCB.