Hodgkin lymphoma cell lines and tissues express mGluR5: a potential link to Ophelia syndrome and paraneoplastic neurological disease

Ophelia syndrome is characterized by the coincidence of severe neuropsychiatric symptoms, classical Hodgkin lymphoma, and the presence of antibodies to the metabotropic glutamate 5 receptor (mGluR5). Little is known about the pathogenetic link between these symptoms and the role anti-mGluR5-antibodies play. We investigated lymphoma tissue from patients with Ophelia syndrome and with isolated classical Hodgkin lymphoma by quantitative immunocytochemistry for mGluR5-expression. Further, we studied the L-1236, L-428, L-540, SUP-HD1, KM-H2, and HDLM-2 classical Hodgkin lymphoma cell lines by FACS and Western blot for mGluR5-expression, and by transcriptome analysis. mGluR5 surface expression differed significantly in terms of receptor density, distribution pattern, and percentage of positive cells. Highest levels were found in the L-1236 line. RNA-sequencing revealed more than 800 genes that were higher expressed in L-1236 in comparison to classical Hodgkin lymphoma-controls. High mGluR5-expression was associated with upregulation of PI3K/AKT and MAPK pathways and of downstream targets (e.g. EGR1) known to be involved in classical Hodgkin lymphoma progression. Finally, mGluR5 expression was increased in the classical Hodgkin lymphoma-tissue of our Ophelia syndrome patient in contrast to five classical Hodgkin lymphoma-patients without autoimmune encephalitis. Given the association of encephalitis and classical Hodgkin’s lymphoma in Ophelia syndrome, it is possible that mGluR5-expression on classical Hodgkin lymphoma cells not only drives tumor progression, but may also trigger anti-mGluR5 encephalitis already before classical Hodgkin lymphoma-manifestation. Comparative gene expression profiling analysis of RNA-seq data for 6 classical Hodgkin Lymphoma cell lines: L-1236, L-428, L-540, SUP-HD1, KM-H2, HDLM-2