Evolving Immunologic Perspectives in Chronic Inflammatory Demyelinating Polyneuropathy

Chronic inflammatory demyelinating polyneuropathy (CIDP) is the commonest chronic idiopathic dysimmune neuropathy. Pathophysiologic processes involve both cellular and humoral immunity. There are various known forms of CIDP, likely caused by varying mechanisms. CIDP in its different forms is a treatable disorder in the majority of patients. The diagnosis of CIDP is clinical, supported routinely by electrophysiology. Cerebrospinal fluid analysis may be helpful. Routine immunology currently rarely adds to the diagnostic process but may contribute to the identification of an associated monoclonal gammopathy with or without hematologic malignancy and the consideration of alternative diagnoses, such as POEMS syndrome, anti-myelin associated glycoprotein (MAG) neuropathy or chronic ataxic neuropathy, with ophthalmoplegia, M-protein, cold aglutinins and disialosyl antibodies (CANOMAD). The search for antibodies specific to CIDP has been unsuccessful for many years. Recently, antibodies to paranodal proteins have been identified in a minority of patients with severe CIDP phenotypes, often unresponsive to first-line therapies. In conjunction with reports of high rates of antibody responses to neural structures in CIDP, this entertains the hope that more discoveries are to come. Although still arguably for only a small minority of patients, in view of current knowledge, such progress will enable earlier accurate diagnosis with direct management implications but only if the important, unfortunately and infrequently discussed issues of immunologic technique, test reliability and reproducibility are adequately tackled.