Anti-Ri has been reported in serum and cerebrospinal fluid (CSF) of patients who present typically with a subacute neurological disorder involving the brainstem, cerebellum, and spinal cord. This antigen is also found in a rare disorder known as opsoclonus/myoclonus syndrome.
Anti-Ri is the least common of the paraneoplastic autoantibodies. Detection of Anti-Ri antibody in serum or spinal fluid identifies an otherwise unexplained neurological disorder as autoimmune and paraneoplastic.
A negative result does not rule out cancer. Anti-Ri antibodies are seldom detected in patients with breast carcinoma who do not have neurological dysfunction.
References:
Mitchell AN, Bakhos CT, Zimmerman EA. Anti-Ri-associated paraneoplastic brainstem cerebellar syndrome with coexisting limbic encephalitis in a patient with mixed large cell neuroendocrine lung carcinoma. J Clin Neurosci. 2015 Feb;22(2):421-3. doi: 10.1016/j.jocn.2014.06.103. Epub 2014 Oct 13. PMID: 25443085.
Luque, F.A., Furneaux, H.M., Ferziger, R., Rosenblum, M.K., Wray, S.H., Schold, S.C., Jr., Glantz, M.J., Jaeckle, K.A., Biran, H., Lesser, M., Paulsen, W.A., River, M.E. and Posner, J.B. (1991), Anti-Ri: An antibody associated with paraneoplastic opsoclonus and breast cancer. Ann Neurol., 29: 241-251. https://doi.org/10.1002/ana.410290303
Anti-Ri (IgM)
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