Mechanistic Study of Indigo Naturalis in Treating Psoriasis
Condition: Psoriasis Vulgaris
MeSH terms: Psoriasis
Study type: Interventional
Phase: Phase 2

Summary: 
      The potential effect of indigo naturalis on the immune system is unknown. The investigators
      hypothesize that the therapeutic effect of indigo naturalis in psoriasis may involve
      inhibiting the activation of Th1 and Th17 cells that produce pro-inflammatory cytokines,
      thereby regulating the hyperplasia of epidermis induced by Th1/Th17 related cytokines.
    

Detailed description: 
      Psoriasis is a chronic inflammatory dermatosis induced by altered interactions between the
      immune system and skin and characterized by hyperplasia of the epidermis (acanthosis),
      infiltration of leukocytes into both the dermis and epidermis, and dilation and growth of
      blood vessels. Our previous studies have shown that topical application of indigo naturalis
      significantly improves psoriatic symptoms and demonstrated that the anti-psoriatic effects of
      indigo naturalis are mediated by promoting differentiation and inhibiting proliferation of
      epidermal keratinocytes. However, the potential effect of indigo naturalis on the immune
      system is unknown.

      Currently, growing evidence demonstrates that activated T cells are the primary modulators in
      the pathogenesis of psoriasis and psoriasis is believed to be a mixed Th1/Th17 disease with
      strong IL-17 and interferon-γ (IFN-γ) signatures. The identification of elevated levels of
      IFN-γ, tumor necrosis factor (TNF-α), IL-12, IL-17 and IL 22 in cutaneous lesions and in the
      serum of psoriatic patients supports the theory that these Th1/Th17-related cytokines
      directly or indirectly act on keratinocytes leading to their activation and
      hyperproliferation. The investigators suppose the therapeutic effect of indigo naturalis in
      psoriasis may involve inhibiting the activation of Th1 and Th17 cells that produce
      pro-inflammatory cytokines, thereby regulating the hyperplasia of epidermis induced by
      Th1/Th17 related cytokines.

      The aim of this study is:

        1. To investigate whether the effect of indigo naturalis in improving psoriatic symptoms is
           associated with the function of Th1/Th17 cells expressing IFN-γ and IL-17 in peripheral
           blood of patients with psoriasis before and after therapy.

        2. To investigate whether the effect of indigo naturalis in improving psoriatic symptoms is
           associated with the production of pro-inflammatory cytokines in peripheral blood of
           patients with psoriasis before and after therapy.

        3. To investigate whether the effect of indigo naturalis in improving psoriatic symptoms is
           associated with histopathological change in psoriatic lesions and whether these
           pathological changes are different from the change in inflammatory and immune reactions
           in patients with psoriasis.

        4. To investigate the effects of Th1/Th17-related cytokines and immunological factors in
           patients with indigo naturalis treatment on epidermal keratinocytes.

        5. To detect the effect of indigo naturalis on the function of releasing cytokines (IFN-γ,
           IL-17, and IL-23, etc.) from monocytes in patients with psoriasis.

        6. To analyze the concentration of indirubin in peripheral blood and to clarify whether the
           effect of indigo naturalis in improving psoriatic symptoms is: (A) a systemic effect
           that affects the metabolism and immune system through absorption and transdermal
           delivery into body. (B) a direct effect on the epidermal keratinocytes alone.
    

Intervention name(s): Indigo naturalis extract in oil ointment
Intervention type(s): Drug
Intervention description(s): Apply 0.5 g of INEO ointment per 10 x 10 cm psoriasis lesion twice daily.
Other intervention name(s): INEO ointment
Intervention model: Single Group Assignment
Masking: None (Open Label)
Primary purpose: Treatment
Keywords: Indigo naturalis, indirubin, Th1 cells, Th17 cells