Faculty Bibliography

Psoriatic arthritis (PsA) is part of a group of closely related clinical phenotypes ('psoriatic disease') that is defined by shared molecular pathogenesis resulting in excessive, prolonged inflammation in the various tissues affected, such as the skin, the entheses or the joints. Psoriatic disease comprises a set of specific drivers that promote an aberrant immune response and the consequent development of chronic disease that necessitates therapeutic intervention. These drivers include genetic, biomechanical, metabolic and microbial factors that facilitate a robust and continuous mobilization, trafficking and homing of immune cells into the target tissues. The role of genetic variants involved in the immune response, the contribution of mechanical factors triggering an exaggerated inflammatory response (mechanoinflammation), the impact of adipose tissue and altered lipid metabolism and the influence of intestinal dysbiosis in the disease process are discussed. Furthermore, the role of key cytokines, such as IL-23, IL-17 and TNF, in orchestrating the various phases of the inflammatory disease process and as therapeutic targets in PsA is reviewed. Finally, the nature and the mechanisms of inflammatory tissue responses inherent to PsA are summarized.

The second basic science session at the Group for Research and Assessment of Psoriasis and Psoriatic Arthritis (GRAPPA) annual meeting focused on 2 recent publications that have increased our understanding of the pathogenesis of psoriatic arthritis (PsA). Data from the first publication, presented by Prof. Erik Lubberts, showed that interleukin (IL)-17A is produced by CD4+ and not CD8+ T cells in PsA synovial fluid following T cell receptor activation. These findings contrast with previously published data, which had suggested that CD8+ T cells are a prominent source of IL-17A. In further experiments, they showed that when CD8+ T cells were stimulated with paramethoxyamphetamine/ionomycin, relatively high levels of IL-17A were detected. Prof. Jose Scher presented work on the role of the microbiome in PsA and more specifically, on pharmacomicrobiomics. He demonstrated the baseline collection of genomes and genes from the microbiota community (the metagenome) can be used as predictor for future treatment response in early rheumatoid arthritis and also likely in PsA.

At the 2021 Group for Research and Assessment of Psoriasis and Psoriatic Arthritis (GRAPPA) annual meeting, a summary of the research conducted by the recipients of the 2020 GRAPPA Research Awards was presented by the awardees. The summary of the 4 presentations is provided here.

OBJECTIVE:To evaluate seroreactivity and disease flares after COVID-19 vaccination in a multi-ethnic/racial cohort of patients with systemic lupus erythematosus (SLE). METHODS:90 SLE patients and 20 healthy controls receiving a complete COVID-19 vaccine regimen were included. IgG seroreactivity to the SARS-CoV-2 spike receptor-binding domain (RBD) and SARS-CoV-2 microneutralization were used to evaluate B cell responses; IFN-γ production to assess T cell responses was measured by ELISpot. Disease activity was measured by the hybrid SLE disease activity index (SLEDAI) and flares were assigned by the SELENA/SLEDAI flare index. RESULTS:Overall, fully vaccinated SLE patients produced significantly lower IgG antibodies against SARS-CoV-2 spike RBD than controls. Twenty-six SLE patients (28.8%) generated an IgG response below that of the lowest control (<100 units/ml). In logistic regression analyses, the use of any immunosuppressant or prednisone and a normal anti-dsDNA level prior to vaccination associated with decreased vaccine responses. IgG seroreactivity to the SARS-CoV-2 Spike RBD strongly correlated with the SARS-CoV-2 microneutralization titers and antigen-specific IFN-γ production determined by ELISpot. In a subset of patients with poor antibody responses, IFN-γ production was likewise diminished. Pre-/post-vaccination SLEDAI scores were similar. Only 11.4% of patients had a post-vaccination flare; 1.3% were severe. CONCLUSION/CONCLUSIONS:In a multi-ethnic/racial study of SLE patients 29% had a low response to the COVID-19 vaccine which was associated with being on immunosuppression. Reassuringly, disease flares were rare. While minimal protective levels remain unknown, these data suggest protocol development is needed to assess efficacy of booster vaccination.

Background: Despite their impressive efficacy in phase 3 trials, biologic agents for psoriasis (PsO) may lose efficacy over time. The factors associated with loss of efficacy have yet to be fully elucidated. Objective: We aimed to identify factors associated with PsO patients using multiple biologics in comparison to patients who used 1 biologic. We also reviewed the literature comparing the survival of different biologic agents for PsO. Methods: We examined clinical data from 222 psoriasis patients at the University of California San Francisco, of whom 51 reported use of 3 or more biologics and of whom 171 reported use of only a single biologic agent at the time of enrollment into a research database from 2006-2020. This study was IRB-approved at UCSF (#10-02830) and all subjects provided written informed consent. We performed univariate and multivariate regression analysis to identify significant demographic features, clinical features, and co-morbidities associated with multi-biologic use. We performed a literature review of studies comparing psoriasis biologic survival at 1, 2, and 5 years and factors associated with single biologic failure. Results: In univariate analysis, duration of PsO, initial presentation of PsO on the gluteal cleft, erythrodermic psoriasis, and acne were associated with using 3 or more biologics. In multivariate analysis, duration of PsO, erythrodermic psoriasis, and acne remained significant. Our review of biologic survival revealed differences according to biologic class. Conclusion: We identified novel factors associated with multi-biologic use in PsO. Further studies in this area are needed to achieve a precision medicine approach.

OBJECTIVE:To examine the association of biologic therapy use for psoriasis with incident psoriatic arthritis (PsA) diagnosis. METHODS:A retrospective cohort study was conducted in the OptumInsights Electronic Health Record Database between 2006 and 2017 among patients with psoriasis between the ages of 16 and 90 initiating a therapy for psoriasis (oral, biologic or phototherapy). The incidence of PsA was calculated within each therapy group. Multivariable Cox models were used to calculate the HR for biologic versus oral or phototherapy using biologics as a time-varying exposure and next in a propensity score-matched cohort. RESULTS:Among 1 93 709 patients with psoriasis without PsA, 14 569 biologic and 20 321 cumulative oral therapy and phototherapy initiations were identified. Mean age was lower among biologic initiators compared with oral/phototherapy initiators (45.9 vs 49.8). The incidence of PsA regardless of therapy exposure was 9.75 per 1000 person-years compared with 77.26 among biologic users, 61.99 among oral therapy users, 26.11 among phototherapy users and 5.85 among those without a prescription for one of the target therapies. Using a multivariable adjustment approach with time-varying exposure, adjusted HR (95% CI) for biologic users was 4.48 (4.23 to 4.75) compared with oral or phototherapy users. After propensity score matching, the HR (95% CI) was 2.14 (2.00 to 2.28). CONCLUSIONS:In this retrospective cohort study, biologic use was associated with the development of PsA among patients with psoriasis. This may be related to confounding by indication and protopathic bias. Prospective studies are needed to address this important question.

Cutaneous T cell lymphoma (CTCL) is a heterogeneous group of mature T cell neoplasms characterized by the accumulation of clonal malignant CD4+ T cells in the skin. The most common variant of CTCL, Mycosis Fungoides, is confined to the skin in early stages but can be accompanied by extracutaneous dissemination of malignant T cells to the blood and lymph nodes in advanced stages of disease. Sézary Syndrome, a leukemic form of disease is characterized by significant blood involvement. Little is known about the transcriptional and genomic relationship between skin and blood residing malignant T cells in CTCL. To identify and interrogate malignant clones in matched skin and blood from leukemic MF and SS patients, we combine T cell receptor clonotyping, with quantification of gene expression and cell surface markers at the single cell level. Our data reveals clonal evolution at a transcriptional and genetic level within the malignant populations of individual patients. We highlight highly consistent transcriptional signatures delineating skin-derived and blood-derived malignant T cells. Analysis of these two populations suggests that environmental cues, along with genetic aberrations, contribute to transcriptional profiles of malignant T cells. Our findings indicate that the skin microenvironment in CTCL promotes a transcriptional response supporting rapid malignant expansion, as opposed to the quiescent state observed in the blood, potentially influencing efficacy of therapies. These results provide insight into tissue-specific characteristics of cancerous cells and underscore the need to address the patients' individual malignant profiles at the time of therapy to eliminate all sub-clones.