Gene Expression Analysis of Inflammatory Cytokines in Korean Psoriatic Patients

BACKGROUND Although phenotypic heterogeneity of psoriasis is suggested by the alternate activation of either T-helper (Th)1-related or Th17-related cytokines, little is known about the mRNA levels of inflammatory cytokines. OBJECTIVE To investigate whether there is differential expression of Th1-related and Th17-related inflammatory cytokine genes 1) between psoriatic patients and healthy controls, and 2) between patients with different psoriasis phenotypes. METHODS Twenty-five patients with psoriasis (10 with guttate psoriasis and 15 with plaque psoriasis) and 5 healthy volunteers were enrolled in this study. The mRNA levels of circulating cytokines (interleukin [IL]-2, IL-12p40, interferon-γ, IL-17A, IL-22, and IL-23R) were measured by real-time reverse transcription polymerase chain reaction. RESULTS The comparison between psoriatic and healthy control samples revealed that IL-12p40, IL-17A, and IL-22 mRNA levels were significantly higher (approximately 4∼6 folds) in the patients with psoriasis. The mRNA levels of these six cytokines in the blood did not differ between the guttate and plaque psoriasis groups. CONCLUSION We found that the mRNA levels of blood inflammatory cytokines (IL-12p40, IL-17A, and IL-22) were significantly elevated in patients with psoriasis compared to the levels in healthy controls, but they did not significantly differ between patients with guttate and plaque type psoriasis.