Induction of human regulatory innate lymphoid cells from group 2 innate lymphoid cells by retinoic acid

BACKGROUND: Group 2 innate lymphoid cells (ILC2s) play critical roles in induction and exacerbation of allergic airway inflammation. Thus, clarification of the mechanisms that underlie the regulation of ILC2 activation has received significant attention. Although ILCs are divided into three major subsets that mirror helper effector T-cell subsets, counterpart subsets of regulatory T (Treg) cells have not been well characterized. OBJECTIVE: We sought to determine the factors that induce regulatory ILCs (ILCregs). METHODS: IL-10+ ILCregs induced from ILC2s by retinoic acid (RA) were analyzed using RNA-sequencing and flow cytometry. ILCregs were evaluated in human nasal tissues from healthy individuals and patients with chronic rhinosinusitis with nasal polyp (CRSwNP), and in lung tissues from house dust mite (HDM)- or saline-treated mice. RESULTS: RA induced IL-10 secretion by human ILC2s, but not type-2 cytokines. IL-10+ ILCregs, converted from ILC2s by RA stimulation, expressed a Treg-like signature with the expression of IL-10, CTLA-4 and CD25, with down regulated effector type 2-related markers such as CRTH-2 and ST2, and suppressed activation of CD4+ T cells and ILC2s. ILCregs were rarely detected in human nasal tissue from healthy individuals or lung tissues from saline-treated mice, but were increased in nasal tissues from patients with CRSwNP and in lung tissues from HDM-treated mice. Enzymes for RA synthesis were up-regulated in airway epithelial cells during type-2 inflammation in vivo and by IL-13 in vitro. CONCLUSION: We have identified a unique immune regulatory and anti-inflammatory pathway by which RA converts ILC2s to ILCregs. Interactions between airway epithelial cells and ILC2s play an important roles in the generation of ILCregs

Interleukins (from IL-1 to IL-38), interferons, transforming growth factor β, and TNF-α: Receptors, functions, and roles in diseases

There have been extensive developments on cellular and molecular mechanisms of immune regulation in allergy, asthma, autoimmune diseases, tumor development, organ transplantation, and chronic infections during the last few years. Better understanding the functions, reciprocal regulation, and counterbalance of subsets of immune and inflammatory cells that interact through interleukins, interferons, TNF-α, and TGF-β offer opportunities for immune interventions and novel treatment modalities in the era of development of biological immune response modifiers particularly targeting these molecules or their receptors. More than 60 cytokines have been designated as interleukins since the initial discoveries of monocyte and lymphocyte interleukins (called IL-1 and IL-2, respectively). Studies of transgenic or gene-deficient mice with altered expression of these cytokines or their receptors and analyses of mutations and polymorphisms in human genes that encode these products have provided essential information about their functions. Here we review recent developments on IL-1 to IL-38, TNF-α, TGF-β, and interferons. We highlight recent advances during the last few years in this area and extensively discuss their cellular sources, targets, receptors, signaling pathways, and roles in immune regulation in patients with allergy and asthma and other inflammatory diseases

Skin barrier damage after exposure to para-phenylenediamine

BACKGROUND: p-Phenylenediamine (PPD) is a strong contact allergen used in hair dye known to cause allergic contact dermatitis (ACD). Both private and occupational exposure to PPD is frequent, but the effect of PPD exposure in non-allergic occupational exposed individuals is unknown. OBJECTIVE: To investigate effects of PPD exposure on the skin of occupationally exposed individuals with and without clinical symptoms. METHODS: Skin biopsies were collected from 4 mild and 5 severe PPD ACD patients and 7 hairdressers without contact dermatitis on day 4 after patch testing with 1% PPD in vaseline. RNA-sequencing and transcriptomics analyses were performed and confirmed by qRT-PCR. Protein expression was analyzed in skin from 4 hairdressers and 1 ACD patient with immunofluorescence staining. Reconstructed human epidermis was used to test the effects of PPD in vitro. RESULTS: RNA-sequencing demonstrated down-regulation of tight junction (TJ) and stratum corneum (SC) proteins in skin of severe ACD patients after PPD exposure. Claudin-1 (CLDN1), claudin-8 (CLDN8), claudin-11 (CLDN11), CLMP, occludin, MAGI1, and MAGI2 expression were downregulated in severe ACD patients. CLDN1 and CLMP expression were downregulated in non-responding hairdressers and mild ACD patients. Filaggrin-1(FLG1), filaggrin-2 (FLG2) and loricrin expression were downregulated in ACD individuals. Confocal microscopy images showed down regulation of claudin-1 and filaggrin 1 and 2. In contrast, 3D skin cultures showed up-regulation of filaggrin-1 in response to PPD but down-regulation of filaggrin-2. CONCLUSION: PPD-exposed skin is associated with extensive transcriptomic changes including down-regulation of TJ and SC proteins even in the absence of clinical symptoms

Single-cell analysis of myeloid cells in HPV+ tonsillar cancer

The incidence of Human Papillomavirus positive (HPV+) tonsillar cancer has been sharply rising during the last two decades. Myeloid cells represent an appropriate therapeutic target due to their ability to orchestrate antigen-specific immunity within the tonsil, the availability of viral antigens, and the proximity of the tumor and the underlying lymphoid tissue. However, the interrelationship of steady-state and inflammatory myeloid cell subsets, and their impact on patient survival remains unexplored. Here, we used single-cell RNA-sequencing to map the myeloid compartment in HPV+ tonsillar cancer. Our analysis unveiled the existence of four dendritic cell lineages, two macrophage polarization processes, and their sequential maturation profiles. We observed an expansion of the myeloid compartment in HPV+ tonsillar cancer, accompanied by interferon-induced cellular responses both in DCs and monocyte-macrophages. Within the DC lineages, we describe a balance shift in the frequency of progenitor and mature cDC favoring the cDC1 lineage in detriment of cDC2s, in HPV+ lesions. Furthermore, we observed that all DC lineages apart from DC5s matured into a common activated DC profile. In turn, the monocyte-macrophage lineage was subjected to early monocyte polarization events, which gave raise to inflammatory-activated, and chemokine-producing macrophages. We validated the existence of most of the single-cell RNA-seq clusters using 26-plex flow cytometry, and described a positive impact of cDC1, activated DCs and macrophages in patient survival using signature scoring. The current study contributes towards the understanding of myeloid ontogeny and dynamics in human papilloma driven tonsillar cancer, and details myeloid biomarkers that can be used to predict therapy effects and assess patient prognosis

Human bocaviruses and paediatric infections

Human bocavirus 1 (HBoV1), belonging to the Parvoviridae family, was discovered in 2005, in nasopharyngeal samples from children with respiratory tract infections. Three additional bocaviruses, HBoV2-4, were discovered in 2009-10. These viruses have mainly been found in faecal samples and their role in human diseases is still uncertain. HBoV1 causes a wide spectrum of respiratory diseases in children, including common cold, acute otitis media, pneumonia, bronchiolitis, and asthma exacerbations. HBoV1 DNA can persist in airway secretions for months after an acute infection. Consequently, acute HBoV1 infection cannot be diagnosed with standard DNA PCR; quantitative PCR and serology are better diagnostic approaches. Because of their high clinical specificity, diagnostic developments such as HBoV1 mRNA and antigen detection have shown promising results. This Review summarises the knowledge on human bocaviruses, with a special focus on HBoV1