Neutrophil-to-lymphocyte ratio and platelet-to-lymphocyte ratio in psoriasis: a systematic review and meta-analysis

Psoriasis is a chronic, inflammatory skin disorder characterized by well-demarcated erythematous lesions with surface scaling. The disease is underpinned by a dysregulated immune response with a shift in the balance of neutrophils, lymphocytes and platelets. We sought to evaluate the novel systemic inflammatory markers, neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR), as psoriatic indicators. Pubmed, Web of Science and Scopus were systematically searched for relevant studies. Twenty-four studies consisting of a total of 2,275 psoriatic patients (1,301 males and 974 females) and 2,334 healthy controls (1,401 males and 933 females) were identified for inclusion in the quantitative analysis. The NLR and PLR were found to be significantly increased in psoriatic patients [standardized mean difference (SMD) = 0.68, 95% CI 0.56-0.80, p < 0.01, and SMD = 0.37, 95% CI 0.14-0.60, p < 0.01, respectively]. However, no association between the NLR and PLR with psoriasis severity was detected (p = 0.93, and p = 0.83, respectively). In conclusion, the NLR and PLR are simple and cost-effective markers of psoriatic presence, but their value as severity markers requires further study.