32 untreated CIDP patients and 15 controls underwent clinical scoring, nerve-conduction studies (NCS), IL-18 genotyping (rs187238, rs1946518, rs1946519), serum cytokine profiling (IL-2, tumor necrosis factor α (TNF-α), IL-18), and SCFA quantification in stool, serum, and cerebrospinal fluid (CSF). The gene discussed is IL18; the disease is chronic inflammatory demyelinating polyradiculoneuropathy.