# Understanding the Intricate Pathophysiology of Psoriasis and Related Skin Disorders
## 4 Sporiasis and Associated Dermatologic Disorders
Since SLE is more prevalent in women, the coexistence of psoriasis and SLE affects women more often as well, with a 1:5.8 ratio versus 1.3:1 in patients with psoriasis but without LE [34]. As compared with SLE, association of chronic cutaneous LE, such as LE profundus, has been rarely reported in association with psoriasis [35]. Several similarities have been observed between psoriasis and SLE, including genetic, epigenetic, and pathogenic factors. The shared pathmechanisms include innate immunity, type I interferon, plasmacytoid dendritic cells, neutrophil extracellular traps, and Th1/Th17-type cytokines [1]. IL-17, IL-22, and IL-23, produced by Th17 cells, have been shown to play a major role in maintaining chronic inflammation in both psoriasis and SLE, and an upregulated Th17 immunologic response may explain the association between both conditions, as well as provide a therapeutic target for management of concomitant psoriasis and SLE [36]. Genome-wide association studies have found that SLE and psoriasis share common genetic susceptibility loci, such as MHC genes, and non-MHC, such as PTPN22, STAT4, and TNIP1. Recent case-control differential analysis by national scholars has identified NFKBIA and IL28 RA as common susceptibility genes for psoriasis and SLE. These findings support the potential co-occurrence of psoriasis and SLE [37]. Moreover, LL37, an endogenous antimicrobial peptide, has been implicated in both SLE and psoriasis. LL37 triggers IFN-\(\alpha\) production in plasmacytoid dendritic cells, and SLE patients had circulating T-cells responding to LL37, which correlated with anti-LL37 antibodies and disease activity. Compared with psoriasis, LL37-specific T-cells in SLE displayed a T-follicular helper-like phenotype, implicating a pathogenic role in SLE [38]. Cases of SLE following PsA or vice versa are uncommon. Due to the complexity of autoimmune diseases and the rarity of such cases, comprehensive global data on the \begin{table}
\begin{tabular}{p{113.8 pt} p{113.8 pt}} \hline \hline
**Hypothesis** & **Observations** \\ \hline \multirow{4}{*}{Plasminogen Activation Hypothesis} & The activation of the plasminogen system has been suggested as a factor in the acantholysis observed in pemphigus. Elevated levels of tissue plasminogen activator have been noted in psoriatic skin lesions, potentially linking the two conditions. \\ \cline{2-3}  & The human leukocyte antigen (HLA) DRB1 alleles are involved in both psoriasis and pemphigus foliaceus. A shared HLA genotype may lead to abnormal T lymphocyte activation, resulting in the manifestation of lesions characteristic of both diseases. \\ \hline \multirow{4}{*}{Decreased Suppressor T Lymphrocyte Function} & This reduction of suppressor T-lymphocyte function can lead to increased activity of the humoral immune system and the production of autoantibodies, contributing to the pathogenesis of both conditions. \\ \cline{2-3}  & The pathogenesis of psoriasis involves both auto-inflammation and autoimmunity. It has been established that auto-inflammatory diseases can be linked with autoimmune disorders. Elevated levels of IL-19, common in auto-inflammatory conditions, may activate adaptive immunity and thus trigger autoimmune responses. \\ \hline \multirow{4}{*}{Role of NLRP1 Inflammasome} & Variations in the NLRP1 gene, which encodes proteins involved in the inflammasome, have been associated with increased susceptibility to both psoriasis and pemphigus foliaceus. This genetic variation could represent a common pathogenic mechanism underlying both diseases. \\ \cline{2-3}  & Variations in the NLRP1 gene, which encodes proteins involved in the inflammasome, have been associated with increased susceptibility to both psoriasis and pemphigus foliaceus. This genetic variation could represent a common pathogenic mechanism underlying both diseases. \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Hypotheses explaining the co-occurrence of psoriasis and pemphigus foliaceus. co-occurrence of these conditions is limited.