The Role of Serum Th1, Th2, and Th17 Cytokines in Patients with Alopecia Areata: Clinical Implications

Abstract

Alopecia areata is a type of non-scarring hair loss. The dysregulation of numerous systemic Th1 (IL-2, IFN-γ, TNF, IL-12, and IL-18), Th2 (IL-4, IL-5, IL-6, IL-9, IL-10, IL-13, IL-17E, IL-31 and IL-33) and Th17 (IL-17, IL-17F, IL-21, IL-22, IL-23 and TGF-β) cytokines was observed in patients with alopecia areata. Positive correlations between the severity of alopecia areata and an increased serum level of various cytokines including IL-2, TNF, IL-12, IL-17, and IL-17E were reported in the literature. An increased serum level of numerous cytokines, such as IL-2, IL-6, TNF, IL-12, IL-17E, and IL-22, was described as positively correlated with the duration of the disease. Moreover, it was shown that increased pre-treatment serum level of IL-12 was a positive, while increased serum levels of IL-4 and IL-13 were negative prognostic markers for the efficacy of diphenylcyclopropenone. In conclusion, alopecia areata is associated with the dysregulation of systemic Th1, Th2 and Th17 cytokines with their role in the pathogenesis, clinical manifestations and prognosis of the disease. Available data indicate the most significant role of serum IL-2, TNF, IL-12, IL-17, and IL-17E as markers of disease activity. The serum levels IL-4, IL-12 and IL-13 may be useful as potential predictors of diphenylcyclopropenone efficacy.

Evaluation of the serum C‐reactive protein–albumin ratio and its relationship with disease severity IN alopecia areata: A prospective case–control study

“…13 High correlations have been reported between serum IL-2, IL-6, TNF, IL-12, IL-17 E, and IL-22 levels and disease duration and severity in AA patients. 5,14 CRP is a positive acute phase reactant synthesized by hepatocytes. CRP production is stimulated by proinflammatory cytokines such as IL-6, IL-1β, and TNFα.…”

No increased risk of alopecia in ankylosing spondylitis patients: A population‐based cohort study in Taiwan

“…Elevation of certain cytokines in circulation occurs in AS patients, such as IL‐12, IL‐17, IL‐22, and IL‐23 25–31 . Likewise, elevation of IL‐12, IL‐22, and IL‐23 is found in patients with alopecia areata 7,8,32,33 . Though the increase in circulatory cytokine level may enhance one's systemic inflammatory response and overall immunity, this may not imply a direct association between AS and alopecia, especially alopecia areata, according to the understanding of our study results.…”

“…[25][26][27][28][29][30][31] Likewise, elevation of IL-12, IL-22, and IL-23 is found in patients with alopecia areata. 7,8,32,33 Though the increase in circulatory cytokine level may enhance one's systemic inflammatory response and overall immunity, this may not imply a direct association between AS and alopecia, especially alopecia areata, according to the understanding of our study results. To date, no adequate evidence supports a higher risk of alopecia in AS patients because of the systemically increased inflammatory reaction, which appears to be consistent with our findings.…”

Long-Term Efficacy of Dupilumab in Alopecia Areata

“…The pathogenesis of AA and other autoimmune conditions has been classically described as Th1/Th17-mediated. However, key studies have shown that this may be an oversimplification, and that autoimmune conditions can also involve the Th2 pathway [ 8 ]. Furthermore, more complex crosstalk between the Th1, 2, and 17 pathways seem to be at play.…”