From the Guidelines

The Reishi and Shiitake mushroom blend has no established effect on autoimmune disorders.

There is no direct evidence in the provided studies to support the use of a Reishi and Shiitake mushroom blend in the management of autoimmune disorders.
The studies primarily focus on the management of immune checkpoint blockade dysimmune toxicities and the use of cancer immunotherapy in patients with pre-existing autoimmune diseases 1.
Glucocorticoids and DMARDs are commonly used to manage flares of autoimmune diseases in patients undergoing cancer immunotherapy, with the goal of keeping the immunosuppressive regimen at the lowest dose possible 1.
Patients with pre-existing autoimmune diseases may experience flares or immune-related adverse events when treated with cancer immunotherapy, but these are often manageable without discontinuing treatment 1.
The decision to use cancer immunotherapy in patients with pre-existing autoimmune diseases should be made on a case-by-case basis, taking into account the potential benefits and risks, and with close monitoring by a multidisciplinary team 1.

From the Research

The current evidence suggests that a blend of Reishi and Shiitake mushrooms may have immunomodulatory effects, which could potentially impact autoimmune disorders 2, 3, 4.
A study on the synergistic immuno-modulatory activity of a medicinal mushroom formulation consisting of Reishi, Shiitake, and Maitake found that the combination of these mushrooms had a lower EC50 value in TNF-α expression from LPS-stimulated macrophages, suggesting a potential synergistic effect 2.
Another study reviewed the biochemical changes induced by different mushroom compounds, including Reishi and Shiitake, and found that they have immunomodulatory and anti-tumor effects, particularly through the action of glucans and specific proteins 3.
A study on the immune-enhancing effects of Maitake and Shiitake extracts found that the combination of these mushrooms had a significant stimulatory effect on defense reactions, including phagocytosis, NK cell activity, and secretion of IL-6, IL-12, and IFN-γ 5.
Reishi extract has been shown to have immunostimulatory and anticancer effects in clinical studies, and has been used as an adjuvant addition to standard cancer treatment in Japan and China 4.

The combination of Reishi and Shiitake mushrooms may have a synergistic immuno-modulatory effect 2.
Reishi and Shiitake mushrooms have immunomodulatory and anti-tumor effects, particularly through the action of glucans and specific proteins 3.
The combination of Maitake and Shiitake extracts has a significant stimulatory effect on defense reactions 5.
Reishi extract has been shown to have immunostimulatory and anticancer effects in clinical studies 4.

The immunomodulatory effects of Reishi and Shiitake mushrooms are thought to be mediated by the action of glucans and specific proteins, which can stimulate the immune system and induce the production of cytokines such as IL-6, IL-12, and IFN-γ 2, 3, 5.
The anticancer effects of Reishi extract are thought to be mediated by the induction of apoptosis and the inhibition of cell proliferation 4.