A review on immunomodulatory response of homoeopathic medicines through cytokine induction as evidenced inin vivo andin vitro studies

Background: This review discusses the importance of inter-individual variations in Homoeopathy and role of immune modulation through cytokine induction behind these variations in symptoms. Objectives: To analyse the effects of homoeopathic drugs in modulation of cytokine synthesis to find the individualised immunological mechanisms of these drugs. Methods: The PubMed database was searched for studies which analysed effects of homoeopathic medicines on cytokine synthesis. Full texts of shortlisted studies after scrutiny of abstracts, were analysed for study design, homoeopathic medicines used, cytokines analysed and results. Results: The PubMed search yielded 21 studies. After analysis of abstracts of 21 studies, 10 were shortlisted, which included 7 in vivo and 2 in vitro studies. One study had both in vivo and in vitro interventions. Majority of in vivo studies used rat and exposure to immunological challenge before administration of homoeopathic medicine. The cytokines studied were interleukin (IL)-1α, IL-1β, interferon-gamma, tumour necrosis factor alpha, IL-2, IL-4, IL-5, IL-6, IL-10 and IL-12. The two in vitro studies evaluated effects of Saussurea lappa and Mercurius solubilis on lymphocytes and macrophage culture, respectively. Out of 10 studies analysed, 8 showed homoeopathic medicines can modulate cytokine synthesis either by increasing or decreasing the cytokine synthesis, in a statistically significant manner. Conclusion: The studies were heterogeneous regarding the antigenic challenge given to stimulate immune cells and only 50% of studies clearly mentioned random allocation of animals in groups. Though majority of studies showed that homoeopathic medicines can modulate cytokine synthesis, the mechanism of cytokine modulation remained unexplored.