Distorted Frequency and Functionality of Natural Killer Cells in Pemphigus Vulgaris: A Potential Therapeutic Target.

Pemphigus vulgaris (PV) is a rare autoimmune disorder where autoantibodies target the desmosomal proteins resulting in blistering of oral mucosa and skin. While the pathogenesis of PV is mainly mediated by the adaptive immune system, key players of innate immunity are also emerging. This study outlines the phenotypic as well as functional attributes of NK cells in PV. Through in-depth analysis using flow cytometry we identified an increase in the frequency of CD56+ CD3- NK cells and their subtypes in periphery. Along with this there is an increased frequency of IFNγ+ CD56bright CD16dim NK cells. mRNA expression of sorted NK cells for differentially expressed genes, particularly key transcription factors such as T-bet and EOMES, as well as surface receptors like NKG2D and KIR2D, and the cytokine IFNγ, displayed significant upregulation. A significant activation of NK cells was seen in the disease state. The levels of perforin and IFNγ were significantly elevated in the culture supernatants of patients. Additionally, a significantly higher cytotoxicity of NK cells in PV was observed. In lesioned tissues of PV, NK related markers were significantly increased. Lastly, we observed NK cells using confocal microscopy in the tissue biopsies of patients which showed significant infiltration of CD56+ CD3- NK cells at the lesional sites. This study aimed to shed light on the pivotal role of NK cells in the immunopathology of PV, offering a thorough understanding of their behavior and changes in expression which might help in contributing to the development of novel therapeutics.

Comparison of the Clinical Efficacy of Rituximab Infusion and Dexamethasone-Cyclophosphamide Pulse Therapy and Their Effect on Serum Th1, Th2, and Th17 Cytokines in Pemphigus Vulgaris-A Prospective, Nonrandomized, Comparative Pilot Study.

Background: Rituximab infusion and dexamethasone-cyclophosphamide pulse (DCP) are the two most popular regimens used in pemphigus vulgaris (PV) in India. Objective: The present study compared the clinical efficacy of rituximab and DCP in Indian PV patients and their effects on serum Th1,2, and 17 cytokine levels. Materials and Methods: A total of 37 patients received DCP (Group A, n = 22) or rituximab (Group B, rheumatoid arthritis protocol (n = 15)) as per patients' preference. They were monitored for clinical response, adverse events (AEs), changes in serum anti-desmoglein-1,3 antibody titers and Th1,2 and 17 cytokine levels at baseline and weeks 20 and 52. Results: The proportion of patients attaining disease control, remission, and relapse in groups A and B were 82% and 93%; 73% and 93%; and 27% and 50%, respectively, after a median duration of 2 months each for disease control; 4 and 4.5 months for remission; and 5 and 7 months for relapse post remission. The musculoskeletal AEs were the highest in the two groups. Significant and comparable decreases in anti-dsg1 and 3 titers from baseline to weeks 20 and 52 were observed in both groups. Th1 and Th17 cytokine levels decreased, while Th2 cytokines increased post-treatment in both groups. However, no correlation was found between change in body surface area of involvement by PV and anti-dsg titers and cytokine levels before and after therapy in both groups. Conclusion: Comparable clinical efficacy between DCP and rituximab was observed.

Clinical and immunological predictors of post-rituximab paradoxical pemphigus flare: A prospective cohort study.

Background Paradoxical flare of pemphigus following rituximab infusion has been reported previously, however, its incidence or risk factors have not been studied in detail. Objectives To evaluate the clinical and immunological predictors associated with post-rituximab paradoxical pemphigus flare. Materials and Methods This was a prospective cohort study including adult patients with pemphigus vulgaris or foliaceus who were treated with rituximab. Patients were administered 1000 mg of intravenous rituximab on days 0 and 14 (Rheumatoid arthritis (RA) protocol), with or without oral prednisolone and/or conventional immunosuppressive agents. Baseline clinical and immunological predictors of post-rituximab pemphigus flares were assessed. Results Fifty patients (mean age 40.44 ± 12.36 years) with a mean pemphigus disease area index (PDAI) score of 27.8 ± 15.48 were administered rituximab. Post-rituximab flare occurred in 10 (20%) patients after a mean of 14.1 ± 4.33 days after the first rituximab infusion. The mean baseline PDAI score (36.4 ± 11.7 vs. 25.6 ± 15.7, P = 0.02) and serum anti-Dsg1 levels (1216.8 ± 850.1 vs. 592 ± 562.12 RU/mL, P = 0.03) were statistically significantly higher in patients experiencing a flare. Using ROC-curve analysis, a PDAI score of 328 (OR 8.3, 95% CI 1.5-44.7) was 80% sensitive and 67.5% specific in predicting post-rituximab flare, while serum anti-Dsg1 level of 31137.78 RU/ml had a sensitivity of 60% and specificity of 85%. There was no significant difference in terms of affected body surface area, type of pemphigus, starting prednisolone dose, oral immunosuppressive adjuvant, serum anti-Dsg3, serum anti-AchRM3, and peripheral CD19+ B cell population. Limitations Our study is limited by a relatively small sample size. Immunological factors were not evaluated at the time of pemphigus flare. Though these unexpected pemphigus flares are likely to be associated with rituximab infusion, the possibility of spontaneous disease exacerbation cannot be entirely excluded. Conclusions Patients with more severe pemphigus or high serum anti-Dsg1 are at risk of post-rituximab paradoxical flare, and may benefit from rituximab administration under close monitoring.

Dominance and improved survivability of human γδT17 cell subset aggravates the immunopathogenesis of pemphigus vulgaris.

Human γδ T cells are highly enriched in epithelial cell-dominated compartments like skin. Nonetheless, their function in the pathogenesis of pemphigus vulgaris (PV), an autoimmune skin disorder, is lacking. Therefore, we investigated the functional expression of human γδT cell subsets along with their homing chemokine receptor-ligand and inflammatory cytokines in the immunopathogenesis of PV. Estimation of the frequency of γδT cell subsets by flow cytometry revealed four major subsets of γδ T cells (γδT1, γδT2, γδT17, γδTreg) in both control and PV circulation. The elevated frequency of γδT17 cells producing IL17 and expressing CCR6 receptor suggests their inflammatory and migratory potential in PV. In vitro culture of γδ T cells from patients showed increased mRNA expression of inflammatory cytokines IL17, RORγt, IL23, IL1, and co-stimulatory markers, CD27 and CD70. These findings correlated the role of IL1 and IL23 cytokines that alleviate the Th17 population in PV. Cytotoxic activities of γδ T cells were higher and inflammatory γδT17 cells were localized in the skin of PV whereas γδTreg cells associated TGFß and FOXP3 were lowered. Hyperinflammatory phenotype of the γδT17 cell subset and its migratory potential might be aiding in the pathogenesis of PV, whereas γδTreg cells fail to suppress these inflammatory responses. Hence, γδT17 cell-associated markers can be targeted for identifying novel therapeutics in PV.

An Open-Label Non-Randomized Preliminary Noninferiority Study Comparing Home-Based Handheld Narrow-Band UVB Comb Device with Standard Hospital-Based Whole-Body Narrow-Band UVB Therapy in Localized Vitiligo.

Background: Narrow-band ultraviolet B (NB-UVB) is the standard therapy for vitiligo. Objective: The objective of this study is to compare the safety and clinical efficacy of a handheld NB-UVB comb device with the standard whole-body NB-UVB therapy in localized stable vitiligo. Materials and Methods: Thirty-one vitiligo patients were allocated to either daily therapy with a home-based handheld comb device (group A, n = 17) or thrice-weekly hospital-based whole-body NB-UVB therapy (group B, n = 14) for 4 months, based on their preference. The primary and secondary outcomes were assessed at each follow-up, and appropriate statistical tools were used for analysis. Results: Of the 31 patients enrolled, 26 patients (study groups A/B: 15/11) completed the study. Primary outcome: Median percentage repigmentation of the representative patch in groups A and B were 51.35% and 63.85%, respectively (P = 0.64). The median size reduction of the representative patch in both groups was statistically significant (P < 0.05). The mean difference between "per protocol analysis" and "intention to treat" showed noninferiority. Secondary outcomes: Both groups were comparable on Lund and Browder score, patient global assessment and investigator global assessment scores, adverse events, color match, and change in the quality of life. The comparison group had a significantly greater number of missed sessions (P = 0.02). The majority of patients had a "good" response in both groups. Conclusion: Handheld NB-UVB comb device daily with a fixed dose of fluence was found to be noninferior with better compliance to standard whole-body NB-UVB therapy.