Kristiina Karihtala1,2, Suvi-Katri Leivonen1,2, Teijo Pellinen3, Oscar Brück4, Marja-Liisa Karjalainen-Lindsberg5, Satu Mustjoki4, Sirpa Leppä1,2
1 Research Program Unit, Faculty of Medicine, University of Helsinki, Helsinki, Finland, 2 Department of Oncology, Comprehensive Cancer Center, Helsinki University Hospital, Helsinki, Finland, 3 Institute for Molecular Medicine Finland (FIMM), Helsinki, Finland, 4 Hematology Research Unit Helsinki, Department of Clinical Chemistry and Hematology, University of Helsinki, Helsinki, Finland, 5 Department of Pathology, Helsinki University Hospital, Helsinki, Finland
Background: Emerging evidence indicates that tumor microenvironment and immune escape have a major impact on the pathogenesis of classical Hodgkin lymphoma (cHL). We hypothesized that quantification of immunity and immune escape in the tumor tissue would identify biological factors that could be used to predict outcome after standard chemotherapy.
Patients and Methods: We profiled the expression of 730 immune response genes of 88 newly diagnosed cHLs utilizing the Nanostring platform, and used multiplex immunohistochemistry (mIHC) to profile a tissue microarray of 134 cHLs for the immune cell phenotypes (CD3+, CD4+, CD8+, FoxP3+ and IDO+). Membranous HLA-ABC, HLA-DR, and beta 2 microglobulin were determined by IHC.
Results: In the whole cohort the male/female ratio was 46%/54%, and the median age 30 years (range 16–83). Thirty-two (24%) patients were 45 years or older, 105 (78%) had nodular sclerosis subtype and 76 (57%) stage IIB-IV disease. After a median follow-up of 54 months (range 7 to 229), recurrence free survival (RFS), disease specific survival (DSS) and overall survival (OS) rates at five years were 78%, 93% and 90%, respectively.
We identified a gene signature enriched for T-cell markers differentially expressed between the cHL patients. Low expression of the signature and high expression of PD1 and IDO1 genes were predictors of poor outcome in patients 45 years or older. In contrast, the impact of low T-cell signature on the survival of younger patients was favorable. The gene expression correlated with the quantities of CD3+ (rho = 0.384, p < 0.001), CD4+ (rho = 0.319, p = 0.004), CD8+ (rho = 0.796, p < 0.001), FoxP3+ (rho = 0.583, p < 0.001), and IDO+ (rho = 0.745, p < 0.001) cell subsets. Furthermore, the amount of cytotoxic (CD3+CD8+) T cells was higher in HLA-ABC (p = 0.010) and beta 2 microglobulin membrane-positive cases (p < 0.001). Neither the proportion of all CD3+ T cells, CD3+CD4+ T helper cells, cytotoxic T cells, nor the loss of HLA complexes were associated with survival. However, higher percentage of IDO+CD3+ cells was a predictor of poor outcome in patients 45 years or older with regards to RFS (p = 0.019), DSS (p = 0.017), and OS (p = 0.009). Conversely, in patients < 45 years, increased proportion of regulatory T (CD3+CD4+FoxP3+) cells associated with poor OS (p = 0.025) and DSS (p = 0.025).
Conclusion: Our data illustrate age dependent impact of local intratumoral immunity on the outcome of cHL patients treated with standard chemotherapy.