The high L/D lactic acid ratio in vagina is related to the increase of extracellular matrix metalloproteinase inducer (EMMPRIN) and matrix metalloproteinase-8 (MMP-8), which are known to alter the tight junctions in the endocervical epithelium, making the female genital tract susceptible to infections [102, 103]. The gene discussed is BSG; the disease is infection.