Tissue-resident memory T (TRM) cells are a recently defined subtype of non-recirculating memory T cells with longevity and protective functions in peripheral tissues. As an essential frontline defense against infections, TRM cells have been reported to robustly patrol the tissue microenvironment in malignancies. Accumulating evidence also implicates that TRM cells in the relapse of chronic inflammatory skin diseases such as psoriasis and vitiligo. In light of these developments, this review aims to synthesize these recent findings to enhance our understanding of TRM cell characteristics and actions. Therefore, after providing a brief overview of the general features of the TRM cells, including precursors, homing, retention, and maintenance, we discuss recent insights gained into their heterogeneous functions in skin diseases. Specifically, we explore their involvement in conditions such as psoriasis, vitiligo, fixed drug eruption - dermatological manifestations of drug reactions at the same spot, cutaneous T cell lymphoma, and melanoma. By integrating these diverse perspectives, this review develops a comprehensive model of TRM cell behavior in various skin-related pathologies. In conclusion, our review emphasizes that deciphering the characteristics and mechanisms of TRM cell actions holds potential not only for discovering methods to slow cancer growth but also for reducing the frequency of recurrent chronic inflammation in skin tissue.
Humans ; Skin Diseases/immunology* ; Memory T Cells/immunology* ; Animals ; Vitiligo/immunology* ; Psoriasis/immunology* ; Immunologic Memory

OBJECTIVES: To elucidate the underlying mechanisms of macrophage-mediated inflammation and tissue injury in diabetic foot ulcer (DFU). METHODS: Skin tissue samples were collected from patients with DFU and with non-DFU. A total of 79 272 high-quality cell transcriptomes were obtained using single-cell RNA sequencing. An unbiased clustering approach was employed to identify cell subpopulations. Seurat functions were used to identify differentially expressed genes between DFU and non-DFU groups, and gene ontology (GO) enrichment analysis was used to reveal gene function. Furthermore, cell-cell communication network construction and ligand-receptor interaction analysis were performed to reveal the mechanisms underlying cellular interactions and signaling regulation in the DFU microenvironment from multiple perspectives. RESULTS: The results revealed a significant expansion of myeloid cells in DFU tissues, alongside a marked reduction in structural cells such as endothelial cells, epithelial cells, and smooth muscle cells. Major cell types underwent functional reprogramming, characterized by immune activation and impaired tissue remodeling. Specifically, macrophages in DFU skin tissues exhibited a shift toward a pro-inflammatory M1 phenotype, with upregulation of genes associated with inflammation and oxidative stress. Cell communication analysis further demonstrated that M1 macrophages served as both primary signal receivers and influencers in the COMPLEMENT pathway mediated communication network, and as key signal senders and mediators in the secreted phosphoprotein 1 (SPP1) pathway mediated communication network, actively shaping the inflammatory microenvironment. Key ligand-receptor interactions driving macrophage signaling were identified, including C3-(ITGAM+ITGB2) and SPP1-CD44. CONCLUSIONS This study establishes a comprehensive single-cell atlas of DFU, revealing the role of macrophage-driven cellular networks in chronic inflammation and impaired healing. These findings may offer potential novel therapeutic targets for DFU treatment.
Humans ; Macrophages/immunology* ; Diabetic Foot/pathology* ; Single-Cell Analysis ; Transcriptome ; Gene Expression Profiling ; Inflammation ; Skin ; Cell Communication ; Signal Transduction ; Cellular Reprogramming

Allergy and Immunology ; Ambulatory Care ; Autoimmune Diseases/therapy* ; COVID-19 ; Communicable Disease Control ; Connective Tissue Diseases/therapy* ; Delivery of Health Care/methods* ; Dermatology ; Humans ; Immunosuppressive Agents/therapeutic use* ; Patient Selection ; SARS-CoV-2 ; Singapore ; Skin Diseases, Vesiculobullous/therapy* ; Telemedicine/methods* ; Tertiary Care Centers ; Vasculitis/therapy*

The aim of this study was to investigate the expression of MHCⅠ gene in different tissues of Rana dybowskii under the stress of Aeromonas hydrophila (Ah), and to provide evidence for revealing the anti-infective immune response mechanism of amphibians. The experimental animal model of Aeromonas hydrophila infection was first constructed, and the pathological changes were observed by HE staining. The MHCⅠ gene α1+α2 peptide binding region of Rana dybowskii was cloned by RT-PCR and analyzed by bioinformatics. Real-time PCR was used to detect the transcription level of MHCⅠ in different tissues under Ah stress. After Ah infection, the skin, liver and muscle tissues showed signs of cell structure disappearance and texture disorder. The MHCⅠ gene α1+α2 peptide binding region fragment was 494 bp, encoding 164 amino acids, and homology with amphibians. Above 77%, the homology with mammals was as low as 14.96%, indicating that the α1+α2 region of MHC gene was less conserved among different species. The results of real-time PCR show that the liver, spleen and kidney of the experimental group were under Ah stress. The transcript levels of MHCⅠ gene in skin and muscle tissues were higher than those in the control group at 72 h, but the time to peak of each tissue was different (P<0.01), indicating that the response time of MHCⅠ gene in different tissues was different under Ah stress. This study provides a reference for further exploring the immune function of MHC molecules in anti-infection.
Aeromonas hydrophila ; Animals ; Gene Expression Profiling ; Gene Expression Regulation ; immunology ; Gram-Negative Bacterial Infections ; immunology ; Liver ; metabolism ; Ranidae ; genetics ; immunology ; microbiology ; Skin ; metabolism

PURPOSE: Although mild to moderate asthma is much more common, the morbidity and mortality of severe asthma are much higher. This study was performed to identify and analyze the clinical characteristics of severe asthma in Korea. METHODS: We registered patients with severe refractory asthma into the Severe Asthma Registry supported by the Severe Asthma Work Group of the Korean Academy of Asthma, Allergy and Clinical Immunology. Patients were enrolled since 2010 from the 15 university hospitals nationwide in Korea. Severe asthma was defined according to modified European Respiratory Society/American Thoracic Society criteria. Information on demographics, medical history, pulmonary function tests and skin prick tests was collected; the clinical characteristics of severe asthmatics were analyzed from the collected data. RESULTS: A total of 489 patients were enrolled with a mean age of 62.3; 45% are male. Sixty percent of patients received Global Initiative for Asthma step 4 treatment, and 30% received step 5 treatment. The most common comorbidities were allergic rhinitis (58.7%). Aspirin hypersensitivity was observed in 14.0%. Approximately half (53.9%) are non-smokers. Atopy was proven in 38.5% of the patients. Regarding asthma medications, inhaled corticosteroids and long-acting β-agonist combination inhalers were most commonly prescribed (96.5%), followed by leukotriene antagonists (71.0%). A recombinant anti-immunoglobulin E monoclonal antibody (omalizumab) has been used in 1.8% of the patients. The mean forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1) and FEV1/FVC were 78.7%, 67.5% and 67.9% of predicted values, respectively. The mean Asthma Control Test and quality of life questionnaire scores were 16.5 out of 25 and 59.5 out of 85, respectively. CONCLUSIONS: The baseline characteristics of severe asthma patients in the Korea Severe Asthma Registry were analyzed and reported for the first time. With this cohort, further prospective studies should be performed to search for ways to improve management of severe refractory asthma.
Adrenal Cortex Hormones ; Adult* ; Allergy and Immunology ; Aspirin ; Asthma* ; Cohort Studies ; Comorbidity ; Demography ; Forced Expiratory Volume ; Hospitals, University ; Humans ; Hypersensitivity ; Korea* ; Leukotriene Antagonists ; Male ; Mortality ; Nebulizers and Vaporizers ; Prospective Studies ; Quality of Life ; Respiratory Function Tests ; Rhinitis, Allergic ; Skin ; Vital Capacity

BACKGROUND: As a potent pro-inflammatory cytokine of the interleukin (IL)-1 family, IL-18 was elevated in early active and progressive plaque-type psoriatic lesions and that serum or plasma levels of IL-18 correlated with the Psoriasis Area and Severity Index (PASI). Although results from previous studies have established that IL-18 may aggravate psoriatic inflammation, the mechanisms of this process remain unknown. In this study, IL-18 knock out (KO) mice and wild-type (WT) mice were used to investigate the effects of IL-18 within a mouse model of psoriasis. METHODS: WT and IL-18 KO mice were divided into four groups, including imiquimod (IMQ)-treated IL-18 KO group (n = 11) and WT group (n = 13) as well as their respectively gene-matched control mice (receiving vaseline; n = 12). PASI scores were used to evaluate psoriatic lesions in IMQ-treated mice. Pathological features and dermal cellular infiltration were investigated by hematoxylin and eosin staining. The levels of psoriasis-related cytokines including IL-23, IL-17, IL-12, IL-1β, IFNγ, IL-15, IL-27, and IL-4 were tested by real-time polymerase chain reaction (PCR). The protein level of IL-1β, IL-27, CXCL1, and Ly6 g were investigated by immunohistochemistry (IHC). RESULTS: Acanthosis (98.46 ± 14.12 vs. 222.68 ± 71.10 μm, P < 0.01) and dermal cell infiltration (572.25 ± 47.45 vs. 762.47 ± 59.59 cells/field, P < 0.01) were significantly milder in IMQ-induced IL-18 KO mice compared with that in WT mice. IMQ-induced IL-18 KO mice manifested larger areas of Munro microabscesses (11,467.83 ± 5112.09 vs. 4093.19 ± 2591.88 μm, P < 0.01) and scales (100,935.24 ± 41,167.77 vs. 41,604.41 ± 14,184.10 μm, P < 0.01) as compared with WT mice. In skin lesions of IL-18 KO mice, the expressions of IL-1β, IL-4, and IL-27 were all significantly upregulated but IL-17 was decreased. Histologically, strong positive signals of Ly6g were observed within the epidermis of IL-18 KO mice but expressions of CXCL1 were decreased. CONCLUSIONS IL-18 may exacerbate prominent inflammation and influence pathological features in IMQ-induced mouse model of psoriasis. IL-18 may upregulate pro-inflammatory cytokines and reduce protective cytokines, thus aggravating psoriatic inflammation. In addition, IL-18 may be involved in the formation of Munro microabscesses and scales.
Animals ; Chemokine CXCL1 ; metabolism ; Cytokines ; metabolism ; Disease Models, Animal ; Imiquimod ; toxicity ; Interleukin-17 ; metabolism ; Interleukin-18 ; metabolism ; Mice ; Mice, Knockout ; Psoriasis ; chemically induced ; genetics ; metabolism ; Skin ; immunology ; metabolism

BACKGROUND: Recent studies have reported that glucosamine (GlcN) showed therapeutic effects in allergic diseases such as asthma and rhinitis, and its mechanisms include the suppression of T helper type 2 immune responses and the nuclear factor-κB pathway. OBJECTIVE: We aimed to investigate the effect of GlcN on atopic dermatitis (AD) in an animal model. METHODS: Twenty-five BALB/c mice were divided into five groups (groups A~E). Group A was the phosphate-buffered saline (PBS)-treated group without AD induction. Group B was the PBS control group with AD induction. Groups C to E were the AD induction groups, which were treated with three different doses of GlcN (10 mg, 20 mg, and 40 mg, respectively). Histopathological examination was performed after GlcN administration. Interleukin (IL)-4, IL-13, and IL-17 cytokine levels were measured by enzyme-linked immunosorbent assay using skin biopsy specimens. Serum total immunoglobulin E (IgE) concentrations were measured before and after administration with GlcN or PBS. RESULTS: Clinical dermatitis scores decreased with increasing GlcN dose (p<0.001). Concentrations of tissue IL-13 and IL-17 decreased after GlcN administration (each group: p=0.002 and p<0.001, respectively), but the concentrations of tissue IL-4 did not show differences across groups. Serum IgE levels tended to be lower after GlcN administration (p=0.004). Histopathological scores were not significantly different among groups B~E (p=0.394). CONCLUSION: GlcN improved AD symptoms and decreased tissue IL-13, IL-17, and serum total IgE levels in an animal model.
Allergy and Immunology ; Animals ; Anti-Allergic Agents ; Asthma ; Biopsy ; Dermatitis ; Dermatitis, Atopic ; Enzyme-Linked Immunosorbent Assay ; Glucosamine ; Immunoglobulin E ; Immunoglobulins ; Interleukin-13 ; Interleukin-17 ; Interleukin-4 ; Interleukins ; Mice ; Models, Animal ; Rhinitis ; Skin ; Therapeutic Uses

Aged ; Biopsy ; methods ; Diagnosis, Differential ; Erythema ; diagnosis ; etiology ; Extremities ; pathology ; Fever ; complications ; Humans ; Immunoglobulin A ; analysis ; Male ; Purpura ; diagnosis ; etiology ; Skin ; diagnostic imaging ; pathology ; Vasculitis ; complications ; immunology

BACKGROUND: We developed skin prick test (SPT) reagents for common inhalant allergens that reflected the real exposure in Korea. The study aim was to evaluate diagnostic usefulness and allergen potency of our inhalant SPT reagents in comparison with commercial products. METHODS: We produced eight common inhalant allergen SPT reagents using total extract (Prolagen): Dermatophagoides farinae, Dermatophagoides pteronyssinus, oak, ragweed, mugwort, Humulus japonicus pollens, as well as cat and dog allergens. We compared the newly developed reagents with three commercially available SPT reagents (Allergopharma, Hollister-Stier, Lofarma). We measured total protein concentrations, sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE), major allergen concentration, and biological allergen potencies measured by immunoglobulin E (IgE) immunoblotting and ImmunoCAP inhibition test. RESULTS: Diagnostic values of these SPT reagents were expressed as positivity rate and concordance rate of the results from ImmunoCAP allergen-specific IgE test in 94 allergic patients. In vitro analysis showed marked differences in protein concentrations, SDS-PAGE features, major allergen concentrations, and biological allergen potencies of four different SPT reagents. In vivo analysis showed that positive rates and concordance rates of Prolagen® SPT reagents were similar compared to the three commercial SPT reagents. CONCLUSION: The newly developed Prolagen® inhalant SPT reagents are not inferior to the commercially available SPT reagents in allergy diagnosis.
Allergens ; Allergy and Immunology ; Ambrosia ; Animals ; Artemisia ; Cats ; Dermatophagoides farinae ; Dermatophagoides pteronyssinus ; Diagnosis ; Dogs ; Electrophoresis ; Electrophoresis, Polyacrylamide Gel ; Humans ; Humulus ; Hypersensitivity ; Immunoblotting ; Immunoglobulin E ; Immunoglobulins ; In Vitro Techniques* ; Indicators and Reagents* ; Korea ; Methods* ; Pollen ; Skin* ; Sodium

PURPOSE: There is an unmet need for the treatment of moderate-to-severe atopic dermatitis (AD), leading to variation in management strategies. To investigate distinct features and treatment modalities according to physicians' specialties, we collected data on the current treatment approach to moderate-to-severe AD among allergists, pediatric allergists and dermatologists in Korea. METHODS: This questionnaire-based study was administered to physicians from the Korean Academy of Asthma, Allergy and Clinical Immunology (KAAACI), Korean Academy of Pediatric Allergy and Respiratory Disease (KAPARD), and Korean Atopic Dermatitis Association (KADA). RESULTS: A total of 93 physicians participated in the study; 64.5% were pediatric allergists and 31.2% were dermatologists. The major patient age groups were “less than 5 years” for 100% of pediatric allergists and “6–12 years old” for 38% of dermatologists. The proportion of patients with moderate-to-severe AD was higher for dermatologists and allergists compared to pediatric allergists. Physicians agreed on the necessity of education including demonstration of basic skin care and application of topical therapies (88.2%), nutritional consultation (83.9%) and psychological counseling (75.3%). However, less than half were able to educate and counsel their patients in real practice. There were noticeable differences in first-line treatment among physician groups. For pediatric allergists, the order of preferred systemic treatment was wet wrap therapy, systemic corticosteroids and oral cyclosporin. Dermatologists ranked cyclosporin, phototherapy, and systemic corticosteroids as first-line treatment regimens. Major reported barriers to proper management were steroid phobia, unproven complementary and alternative medicine, lack of education, and the unreasonable insurance system. CONCLUSIONS: Our findings suggest there are distinct differences in moderate-to-severe AD treatment according to physicians' specialties. Medical policy changes along with governmental supports are required in order to implement the ideal approach in real practice. For moderate-to-severe AD, a consensus on the approach to optimal management should be reached for the best outcomes, based on further randomized controlled trials.
Adrenal Cortex Hormones ; Allergy and Immunology ; Asthma ; Complementary Therapies ; Consensus ; Counseling ; Cyclosporine ; Dermatitis, Atopic* ; Education ; Humans ; Hypersensitivity ; Insurance ; Korea* ; Phobic Disorders ; Phototherapy ; Skin Care