– The deteriorated periodontal health conditions of smoking patients can be attributed, in part, to a lowering of the host’s defense due to a decrease in the quantity of Igs in salivary fluid, despite the fact that there is little evidence that the salivary Igs have a protective action against periodontitis, and that the whole saliva examined cannot result in toto from the salivary glands. The gene discussed is CUBN; the disease is periodontitis.