Immunomodulatory effects of silymarin in patients with β-thalassemia major.

OBJECTIVE

Silymarin, a flavonolignan complex isolated from milk thistle, is a cytoprotective, antioxidant, and hepatoprotective agent. The present study was designed to investigate the immunomodulatory effects of orally administered silymarin in patients with β-thalassemia major.

METHODS

The immunomodulatory effects of silymarin were investigated in a 12-week clinical trial in two groups of patients. In combined therapy group (n=25), patients continued desferrioxamine at the dose of 40mg/kg/day and Legalon® tablets (420mg daily) were added to desferrioxamine. In silymarin group (n=5), patients who were unable or unwilling to use desferrioxamine received only silymarin. Immunological tests were assessed at the beginning and the end of the trial.

RESULTS

No differences were detected between treatment groups regarding the percentage of lymphocyte subsets, concentration of serum immunoglobulins, complement levels, or T cell proliferation in vitro. Serum tumor necrosis factor (TNF-α) levels were significantly decreased in both groups, whereas the serum levels of neopterin significantly decreased in both groups after silymarin therapy. The analysis of cell culture supernatants of activated T cells showed increased production of interferon gamma (IFNγ) and interleukin (IL)-4 after silymarin treatment in both groups.

CONCLUSION

Silymarin stimulates cell-mediated immune response in β-thalassemia major, possibly through a direct action on cytokine-producing mononuclear cells. Because of its immunostimulatory, antioxidant, and iron-chelating activities, silymarin could be a good candidate in the therapy of chronic iron overload in combination with routine iron chelators in clinical use like desferrioxamine.

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