In the study by Gianotti et al. [23], treatment with different doses of two probiotics, Bifidobacterium longum and Lactobacillus johnsonii, led, in a dose dependent way, to a decrease of pathogenic microorganisms, both in colonic mucosa and faecal samples, and an increase in CD3+, CD4+, and CD8+ T lymphocytes, suggesting a better protection of probiotic treated patients against possible infections. The gene discussed is CD4; the disease is infection.