Creatine Kinase is an enzyme found in skeletal and heart muscle. Elevated serum levels of it are a marker for muscle damage. As far as I can see from a PubMed search this has not been linked to Peripheral Neuropathy.

Your IgA (a type of antibody) level is slightly high. Antibodies are made by plasma cells - what "polyclonal" means is that more than one clone of plasma cells is involved in your case. The "kappa and lambda" confirms this. IgA, like all antibodies, is made from H chains (alpha in this case) and L chains (kappa or lambda) - some of your plasma cell clones are making IgA with kappa L chains, others are making IgA with lambda L chains.