Probiotics as mainstream allergy therapy?

Probiotics, live microorganisms which confer a health benefit on the host when administered in adequate amounts,1 continue their impressive march from the fringes of scientific propriety to potential mainstream therapy. Claims for their efficacy, from the time of Metchnikoff and Nissle onwards, have sometimes appeared unfeasibly broad, with suggested benefits ranging from increased longevity to prevention of cancer and immunomodulation.1 Remarkably, the earliest patient known to have shown resolution of eczema with probiotics was Adolf Hitler, whose symptoms of irritable bowel syndrome also abated when treated with Mutaflor (Escherichia coli Nissle 1917) by the extravagantly quackish Theodor Morell, after dysbiosis was diagnosed by Nissle.2 With over 1¼ million internet pages, many commercially driven, probiotics remain big hitters in the alternative medicine arena. In contrast to many inhabitants of the fringe scene, they do however have a record of properly conducted trials confirming efficacy in specific areas – notably infectious diarrhoea and urogenital infection – and a burgeoning portfolio of basic scientific studies, which have led to the remarkably rapid introduction into human trials of transgenic probiotics, engineered to pump out immunosuppressive cytokines.3–5 No other therapeutic modality spans the divide between internet voodoo and cutting edge high tech in this way.

One very topical question is whether probiotics may have a role in the prevention or treatment of allergies, by providing appropriate exposures to the nascent immune system for generation of tolerance.6 A possible benefit in primary prevention of allergy was suggested by a study of perinatal administration of Lactobacillus GG (LGG) to at risk infants, showing reduction of eczema to age 4, but without effect upon overall atopy or IgE responses.7 Less well characterised reduction of allergies to age 20 was …