Intradermal administration of a killed Mycobacterium vaccae suspension (SRL 172) is associated with improvement in atopic dermatitis in children withmoderate-to-severe disease

Background: Although a doubling in the prevalence of atopic disease, includ ing atopic dermatitis, in the Western world over the last few generations h as been paralleled by a marked reduction in infectious diseases, especially tuberculosis, it is unclear whether this increase in atopy is causally rel ated to reduced exposure to mycobacteria. Objectives: The aim of this study was to determine whether administration o f mycobacterial antigens to atopic individuals might ameliorate their disea se. Methods: Forty-one children aged 5 to 18 years with moderate-to-severe atop ic dermatitis were enrolled in a randomized, double-blind, placebo-controll ed trial, where they were given either one intradermal injection of killed Mycobacterium vaccae (SRL 172) or buffer solution (placebo). Changes in ski n surface area affected by dermatitis and dermatitis severity score were as sessed before treatment and at 1 and 3 months after treatment. Results: Children treated with SRL 172 showed a mean 48% (95% CI, 32%-65%) reduction in surface area affected by dermatitis compared with a mean 4% (9 5% CI, -29% to 22%) reduction for the placebo group (P < .001) and a median 68% (interquartile range, 46%-85%) reduction in dermatitis severity score compared with 18% (interquartile range, -2% to 34%) for the placebo group ( P < .01) at 3 months after treatment. There were no untoward effects of the treatment, apart from a local reaction in 13 of the 21 children, which occ urred 1 month after SRL 172 administration and settled spontaneously. Conclusion: SRL 172 was associated with an improvement in the severity of t he dermatitis in children with moderate-to-severe disease.