Faecal microbiome transfer - Dr John Campbell, Dr Robert Clancy

The Covid pandemic drew attention to the distinctive system of mucosal immunity and its limited interplay with systemic immunity with which we were more familiar. The pandemic coincided with a period of fifty years from the recognition of a communicating mucosal immune system. John Bienenstock called this “The Common Mucosal Immune System” (CMS). Lessons relevant to Covid on the relevance of mucosal immunity to both the pathogenesis of disease and vaccination strategies were slowly learnt. Early in the pandemic, protracted changes in the intestinal microbiota were noted that correlated with the progress and severity of infection, and later were linked to development of post-Covid syndrome. The purpose of this review is to pull together through the lens of Covid-19 how a viral infection of the respiratory mucosal space connects with systemic immunity on one hand, and mucosa-related microbiota on the other, within a single integrated mucosal system, to create a carpet of protection. Infection within this unified system can induce changes in balance between microbiota and the relevant local immune response at distant mucosal sites, which in turn, can impact the outcome of the inciting infection in either a deleterious or beneficial manner. Within the broader framework that includes systemic immunity, outcomes of both infection and vaccination, reflect a controlled balance determined by downregulation via suppressor T cells seeded from mucosal sites of infection. The integrity of this comprehensive system has been queried based on regional differences. Such a view fails to recognise mechanisms of critical outcomes of Covid and its management, and opportunities for innovative therapeutic intervention. Variations throughout the mucosal apparatus such as “offsite” generation of airway immunity in the gut and differences in microbial characteristics of microbiomes, reflect adaptation to local influences without compromising the essential qualities of a global mucosal protection system: communication, integration, and cooperation. A central unifying factor for a “Mucosal Immune Microbiome Protection System” or MIMPS, is the idea that a single set of gut-associated lymphoid tissues characterised by specialised M cells, samples appropriate microbiome to generate global mucosal immune defence.

https://www.youtube.com/watch?v=nWMjz-TvFq0