Histological Subtypes Drive Distinct Prognostic Immune Signatures in Classical Hodgkin Lymphoma

SIMPLE SUMMARY: Classical Hodgkin lymphoma (cHL) is a highly curable disease, with about 80% of patients cured using standard first-line chemotherapy. However, outcomes for relapsed/refractory patients remain unfavorable and there is a critical lack of predictive biomarkers for early identification of these patients who may benefit from new therapeutic strategies. Here we evaluated the dynamic expression of 586 immune-related genes in a cohort of 42 cHL patients using NanoString technology. We identified a 19-gene immune signature predictive of relapse at the time of diagnosis, which was found to be strongly dependent on histological subtype. Moreover, comparative analyses between paired diagnostic/relapsed biopsies of nodular sclerosis cHL showed 118 differentially expressed genes, highlighting an immune contexture shift at relapse not found in mixed-cellularity cases. Overall, these results strongly suggest that the predictive value of immune signature in cHL is influenced by histological subtype, a criterion that should be considered when assessing new immunotherapy strategies. ABSTRACT: Despite the success of standard front-line chemotherapy, 20% of classical Hodgkin lymphoma (cHL) patients still relapse or have refractory disease (r/r), and a subset of them die due to disease progression. There is a critical lack of predictive factors for early identification of those r/r patients who may benefit from new therapeutic strategies. This study aimed to evaluate the dynamic expression of 586 immune-related genes in a cohort of 42 cHL patients including 30 r/r cHL after first-line chemotherapy. Gene expression profiling (GEP) using NanoString technology identified a 19-gene immune signature at diagnosis predictive of cHL relapse, but dependent on histological subtypes. Genes related to tumor survival were found upregulated while genes related to B-lineage were downregulated at diagnosis in r/r nodular sclerosis cHL. In contrast to the mixed-cellularity subtype, comparative GEP analyses between paired diagnosis/relapse biopsies of nodular sclerosis cHL showed 118 differentially expressed genes, supporting an immune contexture switch at relapse with upregulation of immunosuppressive cytokines, such as LGALS1 and TGFB1, and downregulation of the T-cell co-stimulatory receptor ICOS. These results indicate that the predictive value of immune signature in cHL is strongly influenced by histological subtype which should be considered when assessing new immunotherapy target strategies.