Supporting a role for other members of the microbiome, like Gram-negative bacteria, in the pathogenesis of acne, results showed that lipopolysaccharides (LPS; a Gram-negative bacteria-derived stimulus signaling through the TLR4 pathway) were also able to induce the expression of cytokines and chemokines, such as interleukin-6 (IL-6) and C-X-C Motif Chemokine Ligand 8 (CXCL-8) in sebocytes [10], which were detected also in in vivo sebaceous glands of acne samples [4, 7, 28]. The gene discussed is TLR4; the disease is acne.