New insight into prurigo nodularis: Proadrenomedullin N-terminal 20 peptide mediates mouse mast cell activation via Mrgprb2.

BACKGROUND: Prurigo nodularis (PN) is a chronic inflammatory skin disorder that is characterized by extremely itchy nodules. Proadrenomedullin N-terminal 20 (PAMP) activates mast cell degranulation via Mas-related G protein-coupled receptor X2 (MRGPRX2), which is associated with pruritus in allergic contact dermatitis. However, the mechanisms underlying the action of PAMP and MRGPRX2 in PN remain unclear. OBJECTIVE: To determine the role of PAMP-induced mast cell activation via MRGPRX2 (mouse homologous Mrgprb2) in PN. METHODS: The expression of PAMP and the number of MRGPRX2-expressing mast cells in the skin biopsies of patients with PN, atopic dermatitis (AD), and healthy participants were analyzed using immunohistochemistry and immunofluorescence, respectively. The biphasic response of PAMP9-20 mediated by Mrgprb2 in mouse peritoneal mast cells (PMC) was validated in vitro using qRT-PCR, ELISA, flow cytometry, and siRNA techniques. RESULTS: PAMP expression and the number of MRGPRX2+ mast cells in lesional PN skin, but not in AD, were elevated compared to healthy skin. PAMP9-20 mediates the immediate and delayed phase responses of PMC, such as degranulation, histamine and ß-hexosaminidase release, and secretion of inflammatory factors such as CCL2, TNF-α, and GM-CSF. These effects were inhibited when Mrgprb2 expression was silenced. Silencing Mrgprb2 did not affect the biphasic response of PMC that was induced by IgE-FcεRI activation. CONCLUSIONS: The results show that PAMP mediates mouse mast cell activation via Mrgprb2, which may be involved in the pathogenesis of PN. The PAMP/ Mrgprb2 pathway, independent of classical IgE signaling, could be developed as a candidate drug target for treating PN.

Molecular mechanisms of pruritus in prurigo nodularis.

Pruritus is the most common symptom of dermatological disorders, and prurigo nodularis (PN) is notorious for intractable and severe itching. Conventional treatments often yield disappointing outcomes, significantly affecting patients' quality of life and psychological well-being. The pathogenesis of PN is associated with a self-sustained "itch-scratch" vicious cycle. Recent investigations of PN-related itch have partially revealed the intricate interactions within the cutaneous neuroimmune network; however, the underlying mechanism remains undetermined. Itch mediators play a key role in pruritus amplification in PN and understanding their action mechanism will undoubtedly lead to the development of novel targeted antipruritic agents. In this review, we describe a series of pruritogens and receptors involved in mediating itching in PN, including cytokines, neuropeptides, extracellular matrix proteins, vasculogenic substances, ion channels, and intracellular signaling pathways. Moreover, we provide a prospective outlook on potential therapies based on existing findings.

GWAS of Chronic Spontaneous Urticaria Reveals Genetic Overlap with Autoimmune Diseases, Not Atopic Diseases.

Although chronic spontaneous urticaria (CSU) is a common disease, GWASs of CSU are lacking. We aimed to identify susceptibility SNPs by performing a GWAS in Chinese Han adults with CSU. The discovery cohort included 430 CSU cases and 482 healthy controls. The GWAS findings were validated in 800 CSU cases and 900 healthy controls. Genetic, functional enrichment, and bioinformatic analyses of genome-wide significant SNPs were performed to assess the association between CSU and autoimmunity or atopy. Five genome-wide significant SNPs were identified: rs434124/LILRA3, rs61986182/IGHG1/2, rs73075571/TDGF1, rs9378141/HLA-G, and rs3789612/PTPN22. The first four SNPs were in linkage disequilibrium with autoimmune-related diseases‒associated SNPs and were cis-expression quantitative trait loci in immune cells. The five SNPs-annotated genes were significantly enriched in immune processes. Higher polygenic risk scores and allele frequencies of rs3789612∗T, rs9378141∗C, and rs73075571∗G were significantly associated with autoimmune-related CSU phenotypes, including positive antithyroglobulin IgG, positive anti-FcεRIα IgG, total IgE <40 IU/ml, and positive antithyroid peroxidase IgG but not with atopic or allergic sensitized CSU phenotypes. This GWAS of CSU identifies five risk loci and reveals that CSU shares genetic overlap with autoimmune diseases and that genetic factors predisposing to CSU mainly manifest through associations with autoimmune traits.

RNA sequencing reveals the transcriptome profile of the atopic prurigo nodularis with severe itching.

Prurigo nodularis (PN), characterized by inevitable chronicity and severe pruritus, is most frequently associated with atopy compared with other origins. However, the skin transcriptomic profiling of PN arising from atopic dermatitis (AD), so-called atopic PN (APN), remains unclear. We sought to explore the cutaneous transcriptome of APN with severe pruritus and compare it with classic AD. RNA sequencing was performed on the lesional skin from 13 APN to 11 AD patients with severe pruritus (itch numerical rating scale score ≥ 7) and normal skin from 11 healthy subjects. Quantitative real-time polymerase chain reaction and immunochemistry were used for validation. We detected 1085 and 1984 differentially expressed genes (DEGs) in lesional APN skin and lesional AD skin versus normal skin, respectively. In total, 142 itch/inflammation-related DEGs were identified. Itch/inflammation-related DEGs, such as IL-6, IL-10, IL-13, oncostatin M, and IL-4 receptor, had elevated gene transcript levels in both diseases. The itch/inflammation-related DEGs that increased only in APN were mainly neuroactive molecules, while many inflammatory mediators such as T helper 22-related genes were found to be increased only in AD. Both disorders showed mixed Th1/Th2/Th17 polarisation and impaired skin barrier. In contrast to AD, M1/M2 macrophage activation, tumor necrosis factor production, fibrosis, revascularization and neural dysregulation are unique features of APN. The study findings broaden our understanding of the pathogenesis underlying APN, which provides insights into novel pathogenesis with potential therapeutic implications.

IgE and IgG Anti-Thyroid Autoantibodies in Chinese Patients With Chronic Spontaneous Urticaria and a Literature Review.

Immunoglobulin (Ig) E and IgG anti-thyroid autoantibodies (AAbs) play important roles in the immunopathogenesis of chronic spontaneous urticaria (CSU). To date, association of IgE and IgG AAbs with Chinese CSU patients has not been fully investigated. We aimed to explore prevalence rates of IgE and IgG AAbs in Chinese CSU patients and their association with clinical and laboratory parameters. Serum IgE and IgG AAbs against thyroid peroxidase (TPO) and thyroglobulin (TG), total IgE (tIgE) and specific IgEs were measured using enzyme-linked immunosorbent assay, chemiluminescence microparticle immunoassay and immunoblotting. Meta-analyses and literature review were conducted. The meta-analyses indicated that CSU cases were 4.98, 6.90 and 6.68 times more likely to have positive anti-TPO IgE, anti-TPO IgG and anti-TG IgG (all P < 0.001) compared with controls, respectively, and revealed a positive correlation between the prevalence rates of anti-TPO IgE and anti-TPO IgG (r = 0.53, P = 0.025). A total of 1,100 Chinese Han adult CSU patients and 1,100 ethnicity-, age- and sex-matched healthy controls were recruited from 15 centers. Prevalence rates of anti-TPO IgE, anti-TPO IgG, anti-TG IgE or anti-TG IgG in the patients were all significantly higher than those in the controls. Significant correlations were observed between prevalence rates of anti-TPO IgE and anti-TPO IgG (r = 0.297, P < 0.001) as well as between those of anti-TG IgE and anti-TG IgG in the patients (r = 0.137, P < 0.001). Patients with anti-TPO IgE or anti-TPO IgG had significantly lower tIgE levels (P < 0.001). Positive anti-TPO IgE, positive anti-TPO IgG and tIgE < 40 IU/mL were independent predictors of antihistamine-refractory cases. In conclusion, the prevalence rates of IgE and IgG AAbs in Chinese CSU patients are significantly elevated and reciprocally correlated. This study verifies the results of previous case-control studies of CSU patients from other populations and ethnicities.

Photopatch testing in Chinese patients: A 5-year experience.

BACKGROUND: In 2015, a Chinese expert consensus on photopatch testing (PPT) was established, based on European consensus methodology. OBJECTIVES: To update current information on the prevalence of photoallergic contact dermatitis (PACD) to 20 photoallergens and their clinical relevance in the Chinese context. METHODS: A retrospective analysis of 2372 patients who performed PPT in a tertiary referral center in China between 2015 and 2019 was completed. A total of 1208 PACD reactions were observed in 897 (37.8%) patients, and 413 reactions were of current or past relevance. RESULTS: The proportion of reactions of current or past relevance was 34.2%. The most frequent photoallergens were chlorpromazine, thimerosal, potassium dichromate, and formaldehyde. The ultraviolet absorbers, benzophenone and Para-aminobenzoic acid, showed opposite gender distribution to PACD. Twenty-five patients (1.9%) developed PACD reactions to a newly added photoallergen preparation - fragrance mix I. Patients with chronic actinic dermatitis, widespread exposed-site or generalized dermatitis, and older age were more likely to have PACD. CONCLUSIONS: This study is the first to profile PACD reactions with clinical relevance in China. The prevalence of PACD to culprit photoallergens was affected by regional peculiarities. Attention needs to be paid to the age, body-site distribution, and known diagnoses of patients for the identification of PACD.

Loss of ACSM3 confers worsened prognosis and immune exclusion to cutaneous melanoma.

Aim: Malignant melanoma (MM) is a highly aggressive cutaneous cancer with undetermined underlying genetic disposition. We aim to evaluate prognostic and mechanistic role of ACSM3 in MM. Methods: In silico reproduction of TCGA MM dataset, GEO dataset, GDSC dataset and human protein atlas was performed to establish differential expression of ACSM3. In vitro and in vivo validation using A375 and SKMEL1 MM cells were performed to profile tumorigenic role and functional attribution of the gene. Results: ACSM3 expression was significantly downregulated in MM. Lower expression of ACSM3 conferred worsened prognosis of MM. Lower ACSM3 was observed in Asian ethnicity. Knock-down (KD) and overexpression (OE) of ACSM3 resulted in significant increased and decreased proliferation, invasion and colony formation in MM cells, respectively. Pathway annotation revealed significantly active immune response invoked by ACSM3. Lower ACSM3 expression was associated with decreased CD8+, macrophage and dendritic cell infiltration. Cox regression revealed loss of survival contribution of ACSM3 in the presence of immune infiltrates supporting immune regulatory role of ACSM3. Drug sensitivity analysis revealed BRAF inhibitor PLX-4720 was sensitive in both MM cells. ACSM3 expression showed no correlation with immune checkpoint molecules. Combined ACSM3-OE and PLX-4720 in MM cells showed synergistic inhibition in MM cells and xenograft murine models with no significant toxicity. Conclusion: Loss of ACSM3 was associated with poor prognosis in MM. Overexpression of ACSM3 synergistically inhibited MM with PLX-4720. ACSM3 was potentially associated with immune exclusion in MM. Further validation was warranted in future studies.

Treatment-related adverse events as surrogate to response rate to immune checkpoint blockade.

BACKGROUND: Immune checkpoint blockade (ICB) brings hope to many late-stage cancer patients yet its marker for response remains elusive. METHODS: We developed a hypothesis that treatment-related adverse events (TrAEs) could predict objective response rate (ORR) to ICB. We plotted ORR against corresponding any and grade 3 to 5 (G3-5) TrAEs across a variety of cancer types by performing a meta-analysis using linear regression. RESULTS: We identified 113 eligible studies encompassing 25 types of malignancies that were treated with ICB or ICB-based regimes. A significant linear correlation was observed for any and severe TrAEs, respectively. The correlation coefficient was 0.57 (r = 0.324) for any TrAE and 0.61 (r = 0.37) for G3-5 TrAE. For melanoma, the correlation coefficient was 0.81 (r = 0.57) for any TrAE and 0.65 (r = 0.42) for G3-5 TrAEs. For RCC, the correlation coefficient was 0.86 (r = 0.74) for any TrAE and 0.91 (r = 0.83) for G3-5 TrAE. For NSCLC, the correlation coefficient was 0.55 (r = 0.3) for any TrAE and 0.74 (r = 0.86) for G3-5 TrAE. For UC, the correlation coefficient was 0.47 (r = 0.68) for any TrAE and 0.27 (r = 0.52) for G3-5 TrAE, yet the correlation was insignificant for severe AEs. CONCLUSION: Our findings suggest that over half of ICB responses could be reflected by any adverse events and ∼60% of responses could be reflected by severe AEs. Further validation is needed in individual trials.

Photopatch Testing in Chinese Patients Over 10 Years.

BACKGROUND: Photoallergic contact dermatitis (PACD) is a hypersensitivity reaction that occurs when a previously photosensitized exogenous agent comes into contact with UV radiation. The best method for testing PACD is photopatch testing (PPT). OBJECTIVES: The primary objective of the study was to determine the frequency of PACD to 20 different photoallergens in common usage in China during a 10-year period. METHODS: All patients (n = 6153) who had PPTs done between 2005 and 2014 at the Department of Dermatology of Huashan Hospital, Fudan University, were included. RESULTS: A total of 3767 PACD reactions in 3668 subjects (59.61%) were recorded. Of these allergens, chlorpromazine (CPZ) (51.82%), para-aminobenzoic acid (11.94%), thimerosal (9.81%), potassium dichromate (6.37%), sulfanilamide (5.38%), and formaldehyde (4.7%) were the top 6 allergens that elicited PACD reactions. A comparison of PACD reactions between January 2005 to December 2009 and January 2010 to December 2014 revealed a statistically significant decrease in PACD reaction for chlorpromazine, potassium dichromate, p-aminobenzoic acid, and p-phenylenediamine. Formaldehyde showed a trend toward a statistically significant increase in sensitization over the 10-year period. CONCLUSIONS: In conclusion, positive PACD reactions were most frequent to chlorpromazine in our population. New allergens such as potassium dichromate and formaldehyde should be added to the test series.

Activation of the Blood Coagulation System in Patients with Chronic Spontaneous Urticaria.

BACKGROUND: Ninty-five percent of chronic spontaneous urticaria (CSU) patients presented with signs of thrombin generation, and autologous plasma skin tests score positive. The aim of this study was to assess the initiators of blood coagulation that lead to thrombin generation and fibrinolysis in CSU patients. METHODS: The plasma level of activated factor VII, activator factor XII, fragment F1+2, and D-dimer were measured and analyzed in 103 patients with CSU and 76 control subjects. RESULTS: Mean D-dimer plasma levels were higher in patients than controls (0.41 ± 0.44 µg/mL vs. 0.21 ± 0.26 µg/ mL; p < 0.001). Mean F1+2 plasma levels were higher in patients than controls (11.17 ± 17.65 nM vs. 5.97 ± 9.42 nM; p = 0.048). Mean FVIIa plasma levels were higher in patients than controls (4.09 ± 4.22 ng/mL vs. 2.97 ± 1.59 ng/mL; p = 0.031). However, no significant difference was found on FXIIa plasma levels. On the other hand, all the coagulation factors (D-dimer, FVIIa, and F1+2) were significantly correlated with disease severity. CONCLUSIONS: The extrinsic pathway of the clotting cascade is activated in CSU and is correlated with the disease severity. The involvement of the coagulation pathway in CSU opens new perspectives for a better understanding of the pathogenesis and treatment of the disease.

Comparison between photodynamic therapy with topical application of 5-aminolevulinic acid and CO2 laser therapy in the treatment of cervical condylomata acuminate: a randomized controlled trial.

The present study aimed to evaluate the efficacy of photodynamic therapy with topical applied 5-aminolevulinic acid (ALA-PDT) for the treatment of cervical condylomata accuminate (CA). 161 Patients with cervical CA were randomly divided into ALA-PDT group and CO2 laser (control) group. Patients (n=89) in the ALA-PDT group were treated with topical 5% ALA under occlusive dressing for 3 h followed by irradiation with semiconductor laser at a dose of 1000 J/cm(-2) and a power of 100 mW. Patients were treated 2 weeks later if necessary. Patients (n=72) in the control group were treated with CO2 laser. The treatment was repeated at 1-week interval when necessary. No response rate, complete response rate (CR) and recurrence rate of wart lesions as well as rate of eradication of HPVs were analyzed. The CR rate was 90.2% in the ALA-PDT group and 96.2% in the control group. The eradication rate was 90.2% in the ALA-PDT group and 65.8% in the control group after 3 months of follow-up. Both the eradication rate and recurrence rate in the ALA-PDT group were significantly lower than those in the control group (P<0.001). The adverse event in patients receiving ALA-PDT was mainly mild bleeding. ALA-PDT is a more effective and well-tolerated treatment for cervical CA compared with conventional CO2 laser therapy.

Effective treatment of d-penicillamine induced elastosis perforans serpiginosa with ALA-PDT.

A case of D-penicillamine(DPA) induced elastosis perforans serpiginosa(EPS) in a 32-year-old Chinese man was reported. The presentation lasted two years and was refractory to traditional medical treatment. He was then commenced on 7.6% 5-aminolevulinic acid (ALA) induced photodynamic therapy(PDT) by a LED light of 633 nm at dose levels of 130J/ cm2 for each session with total 3 sessions at one week interval. The patient was tolerated and responded well to this new approach for DPA-induced EPS without any adverse events. The etiology, pathophysiology, natural history, and treatment options for DPA-induced EPS are reviewed, and the authors suggest this method of treatment to be effective and safe for patients of DPA-induced EPS refractory to conventional therapy.

A correlation study on the effects of DNMT1 on methylation levels in CD4(+) T cells of SLE patients.

OBJECTIVE: To study the effect of DNMT1 on CD4(+) T cells in the peripheral blood of systemic lupus erythematosus (SLE) patients. METHODS: To investigate the differential expression of DNMT1 in CD4(+) T cells of SLE patients and healthy individuals, a DNMT1 lentiviral plasmid (pLenti6.3/V5-DNMT1) and a control plasmid (pLenti6.3/V5-GW/LacZ) were constructed and transfected into CD4(+) T cells from the peripheral blood of SLE patients. The transcriptional and translational expression of DNMT1, global genomic DNA methylation, and the production of IgG antibody in the CD4(+) T cells in the peripheral blood of SLE patients were assessed using qPCR analysis, western blotting, flow cytometry, and ELISA, respectively. RESULTS: The expression level of DNMT1 in SLE patients was significantly lower than that in normal humans. The expression of DNMT1 was found to be positively correlated with the methylation level of genomic DNA and negatively correlated with the IgG titration level. DNA sequencing results confirmed that the DNMT1 lentiviral plasmid was successfully constructed. After the CD4(+) T cells from the peripheral blood of SLE patients were transfected with the pLenti6.3/V5-DNMT1 plasmid, the transcription level of the DNMT1 gene was upregulated and abundance of DNMT1 protein significantly increased. Global genomic DNA methylation was enhanced, while the production of IgG antibody was reduced. CONCLUSION: DNMT1 can inhibit the autoimmune response in SLE patients by reversing the abnormally low DNA methylation level in the CD4(+) T cells.