IL6 and chronic inflammatory demyelinating polyradiculoneuropathy: Elevated cytokine and pro-inflammatory molecule levels in serum or cerebrospinal fluid (CSF) have also been related to CIDP, i.a., in plasma IL-12, IL-17, IL-5, IL-6, growth arrest specific 6, MMP-2 and cathepsin B with low levels of cystatin C in CSF.