Evaluation of Psoriasis Area and Severity Index Thresholds as Proxies for Systemic Inflammation on an Individual Patient Level

Associations of novel complete blood count-derived inflammatory markers with psoriasis: a systematic review and meta-analysis

Psoriasis is an immune-mediated disorder which primarily affects skin and has systemic inflammatory involvement. Neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), systemic immune-inflammation index (SII), and monocyte-to-lymphocyte ratio (MLR) are novel complete blood count (CBC)-derived markers which can reflect systemic inflammation. This study aimed to systematically investigate the associations of NLR, PLR, SII, and MLR with psoriasis. This study was performed in compliance with the Preferred Reporting Items for Systematic Reviews and Meta-analyses statement. A comprehensive search of Pubmed, Embase, Scopus, and Google Scholar was conducted for relevant studies. Observational studies evaluating the correlations of NLR, PLR, SII, or MLR with psoriasis were included. The primary outcomes were the associations of these inflammatory markers with the presence and severity of psoriasis. The random-effect model was applied for meta-analysis. 36 studies comprising 4794 psoriasis patients and 55,121 individuals in total were included in the meta-analysis. All inflammatory markers were significantly increased in psoriasis groups compared to healthy controls (NLR: MD = 0.59, 95% CI: 0.47-0.7; PLR: MD = 15.53, 95% CI: 8.48-22.58; SII: MD = 111.58, 95% CI: 61.49-161.68; MLR: MD = 0.034, 95% CI: 0.021-0.048; all p < 0.001). Between-group mean differences in NLR and PLR were positively correlated with the mean scores of Psoriasis Area Severity Index (NLR: p = 0.041; PLR: p = 0.021). NLR, PLR, SII, and MLR are associated with the presence of psoriasis. NLR and PLR serve as significant indicators of psoriasis severity. These novel CBC-derived markers constitute potential targets in the screening and monitoring of psoriasis.

Evaluation of the inflammatory parameters as potential biomarkers of systemic inflammation extent and the disease severity in psoriasis patients

The disease severity of psoriasis is mainly assessed subjectively via  psoriasis area and severity index (PASI) and body surface area (BSA), while an optimal measure of cutaneous response, may overlook systemic inflammation in psoriasis patients. The neutrophil to lymphocyte ratio (NLR), platelet to lymphocyte ratio (PLR), monocyte to lymphocyte ratio (MLR), monocyte to high density lipoprotein ratio (MHR), and systemic immune-inflammation index (SII) exhibit notable associations with the inflammation severity in multiple diseases. The aim of this retrospective study was to explore the associations between inflammatory parameters and the skin lesions' severity of psoriasis. After analysis, we found that patients with psoriasis had higher NLR, MLR, PLR, MHR, and SII levels compared to the control group. At baseline, the parameters of NLR (r = 0.124, P = 0.003), MLR (r = 0.153, P < 0.001), MHR (r = 0.217, P < 0.001) and SII (r = 0.141, P = 0.001) had a positive correlation with PASI in psoriasis patients. At the same time, we analyzed the patients who received different systemic therapy. We observed a significant decrease in NLR, PLR, MLR, and SII in psoriasis patients after treatment. Notably, TNF-α inhibitors and IL-17A inhibitors subgroups showed a more significant reduction than IL-23/IL-12/23 inhibitors and MTX medication. Additionally, we found the change of NLR (r = 0.194, P < 0.001), PLR (r = 0.104, P = 0.014), MLR (r = 0.191, P < 0.001), MHR (r = 0.106, P = 0.012), and SII (r = 0.228, P < 0.001) had a positive correlation with the change of PASI in psoriasis patients. In conclusion, this study suggests that NLR, MLR, and SII may serve as useful biomarkers for assessing systemic inflammation extent and disease severity in psoriasis patients.

A simple tool for evaluation of inflammation in psoriasis: Neutrophil-to-lymphocyte and platelet-to-lymphocyte ratio as markers in psoriasis patients and related murine models of psoriasis-like skin disease

Objective parameters to quantify psoriatic inflammation are needed for interdisciplinary patient care, as well as preclinical experimental models. This study evaluates neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) in psoriasis patients and five murine models of psoriasis-like skin disease based on topical imiquimod application and overexpression of IL-17A under different promotors. We performed a single-center prospective observational study in a German population, investigating psoriasis patients prior to, 4 weeks, and 16 weeks post begin of systemic anti-inflammatory therapy. Psoriasis area and severity index (PASI), blood count, and C-reactive protein (CRP) levels were attained at each timepoint. Additionally, five murine models of psoriasis-like skin disease involving five distinct experimental procedures differing in time of disease-onset and severity were investigated regarding PLR and NLR. Of 43 recruited psoriasis patients, 34 patients were followed up to 16 weeks. The cohort was 69.77% male, showing a median age of 32.0 years (range 19.0-67.0; IQR 26). The median PASI decreased from 16.35 (8.0-50.0; 10.20) to 1.6 (0-10.3; 2.56) after 16 weeks of systemic therapy. Spearman's correlation showed statistically significant positive correlation for NLR with PASI (rs = 0.27, p = 0.006), however not for PLR. NLR, but not PLR, was significantly associated with PASI in a multiple linear regression analysis including age, sex, psoriasis arthritis, and smoking. In the murine models of psoriasis-like skin disease, both NLR and PLR were significantly increased in the acute-severe models compared to controls (p < 0.001, p = 0.005, and p = 0.02, respectively), demonstrating gradually less increased values from severe-acute to mild-late-onset psoriatic phenotype. NLR was significantly associated with PASI in psoriatic patients as well as psoriatic phenotype in different murine psoriasis models. Our data warrants investigation of NLR in psoriasis patients and preclinical psoriasis models as an objective biomarker of psoriatic skin inflammation. KEY MESSAGES : NLR, but not PLR, showed a statistically significant positive correlation with Psoriasis Area and Severity Index (PASI) in our human psoriasis cohort. Both NLR and PLR were significantly increased in murine psoriasis models compared to matched controls, with gradually less increased values from severe-acute to mild-late-onset psoriatic phenotype. NLR may represent an easily available, cheap, and objective parameter to monitor psoriatic inflammation in both clinical patient routine, as well as preclinical experimental murine models.

Association of Complete Blood Cell Count-Derived Inflammatory Biomarkers with Psoriasis and Mortality

Background and Aim

Psoriasis is a persistent inflammatory disorder that affects 3% of the population and is associated with cardiovascular diseases. Therefore, this study aimed to investigate the correlations between complete blood cell count (CBC)-derived inflammatory biomarkers, psoriasis prevalence, and all-cause mortality.

Methods

Data were obtained from the National Health and Nutrition Examination Survey (NHANES) spanning 2003-2006 and 2009-2014. Mortality data up to December 31, 2019 were obtained using the National Death Index. The following CBC-derived inflammatory biomarkers were examined: neutrophil/lymphocyte ratio (NLR), neutrophil/(white blood cells - neutrophils) ratio (dNLR), monocyte count/lymphocyte ratio (MLR), (neutrophil + monocyte)/lymphocyte ratio (NMLR), platelet/lymphocyte ratio (PLR), and systemic inflammatory response index (SIRI). Weighted logistic and Cox regression analyses were used to calculate odds ratios, hazard ratios, and the corresponding 95% confidence intervals. Additionally, the prognostic value of the inflammatory indicators was assessed and ranked using the random survival forest approach.

Results

In total, data from 21,431 participants with average age of 45.02 ± 0.27 years (49.51% male) were included in the study, among which 600 participants were positive for psoriasis (prevalence rate, 2.80%). Additionally, 79 all-cause deaths were recorded during a median follow-up period of 8.83 (6.67-11.00) years. Moreover, NLR, dNLR, NMLR, PLR, and SIRI were positively associated with the prevalence of psoriasis. Furthermore, MLR, NMLR, and SIRI were positively correlated with all-cause mortality in patients with psoriasis, with NMLR being the most valuable predictor of all-cause mortality.

Conclusion

CBC-derived inflammatory biomarkers were associated with psoriasis prevalence, NMLR, SIRI, and MLR values were associated with all-cause mortality in patients with psoriasis. Overall, assessment of these CBC-derived indicators may serve as a simple method for screening high-risk individuals among patients with psoriasis.

Finding Gene Regulatory Networks in Psoriasis: Application of a Tree-Based Machine Learning Approach

Psoriasis is a chronic inflammatory skin disorder. Although it has been studied extensively, the molecular mechanisms driving the disease remain unclear. In this study, we utilized a tree-based machine learning approach to explore the gene regulatory networks underlying psoriasis. We then validated the regulators and their networks in an independent cohort. We identified some key regulators of psoriasis, which are candidates to serve as potential drug targets and disease severity biomarkers. According to the gene regulatory network that we identified, we suggest that interferon signaling represents a key pathway of psoriatic inflammation.