Subjects with AD presented:> no differences in the control of periodontal destruction, IgG to PeD bacteria, and cytokine levels > presence of PeD bacteria only in periodontium > higher IgG to PeD bacteria in CSF than in serum> lower Aβ1–42 and higher t-tau levels in the CSF > association of CSF levels of t-tau with both serum levels of anti-Pg IgG and MCP1/CCL2Local production of IgG to PeD bacteria in the CSF may occur in demented patients, but there was no association with AD. The gene discussed is CCL2; the disease is Alzheimer disease.