Programmed cell death protein-1 (PD-1)-expression in the microenvironment of classical Hodgkin lymphoma at relapse during anti-PD-1-treatment

Abstract

Inhibition of the immunoregulatory programmed cell death-protein-1 (PD-1)/PD-ligand (PD-L)-pathway by PD-1 blocking antibodies has resulted in high response rates in patients with relapsed/refractory (r/r) classical Hodgkin lymphoma (cHL). Nevertheless, the majority of r/r cHL patients relapse on anti-PD-1 treatment. To address the unsolved question of mechanisms of resistance to anti-PD-1 blockade in cHL we retrospectively examined sequential biopsies of nine r/r cHL-patients with progressive disease or relapse during anti-PD-1 treatment. We found a striking increase of PD-1-positive T-cells in four and a slight increase in the other cases with progressive disease during anti-PD-1 treatment, whereas a strong PD-L1 expression on Hodgkin-and Reed Sternberg cells (HRSC) prior to anti-PD-1 blockade and at relapse/progression was detected. The observation from our case series indicates that upregulation of PD-1 on T-cells in the microenvironment (ME) contributes the development of resistance. This hypothesis needs to be further explored by analysis of larger patient cohorts.Classical HL is characterized by rare HRSC, which are embedded in an anergic inflammatory cellular ME.1 Constitutional and high expression of PD-L1 by HRSC indicates a role of PD-1/PD-L1 interaction in cHL. 2-5Inhibition of PD-1/PD-L1 interaction by anti-PD1 blockade has shown impressive response rates in r/r cHL. Although durable responses to anti-PD-1 treatment have been documented, the majority of patients eventually relapse. [4][5][6] To address the important, but so far unsolved issue of mechanisms of resistance to PD-1 blockade, we retrospectively assessed sequential biopsies of r/r cHL patients developing progressive disease (PD) or relapse on anti-PD-1 treatment with regard to microenvironmental changes and PD-1 as well as PD-L1 expression.In nine cHL patients' formalin fixed paraffin embedded biopsy specimen prior to and a second biopsy at relapse/progression under anti-PD-1-treatment were available including three patients with three available biopsies (two patients with two biopsies before and one patient with two biopsies under anti-PD-1-treatment). All patients gave their informed consent for this study which had been approved by our local ethics committee.Biopsy specimens were stained for CD30, CD15, EBER or LMP1, CD20, and CD3 to characterize HRSC and to confirm the diagnosis using established protocols ( were performed on a Leica-Bond automated stainer to characterize the ME and to quantify PD-1-and PD-L1-expression. The total number of PD-1, PD-L1, CD8 and CD4 positive microenvironmental cells was counted by two expert pathologists in three high-power fields (HPF, 1000-fold magnification using oil immersion) and the average value was used for further analysis (table 1 supplements The time interval between the most recent application of the anti-PD-1-antibody and the biopsy at progressive disease or relapse ranged from 6 days to 6 months with seven of eight sequential biopsies being taken within 6 weeks after documentation of PD.B...

Programmed cell death protein-1 (PD1) expression in the microenvironment of classical Hodgkin lymphoma is similar between favorable and adverse outcome and does not enrich over serial relapses with conventional chemotherapy

“…We read with interest the recent paper published in Haematologica by Sasse et al examining programmed cell death protein -1 (PD1) expression in paired pretreatment/relapse samples for patients receiving PD1 inhibitor therapy in classical Hodgkin lymphoma (CHL). 1 Although the authors comment on an increase in PD1 + lymphocyte numbers in cases relapsing after PD1 inhibitor therapy, this difference did not reach statistical significance. The possibility that PD1 + lymphocytes might be enriched post PD1 inhibitor therapy is interesting, and raises a number of questions.…”

Therapeutic targets and microenvironment in sequential biopsies of classical Hodgkin lymphoma at diagnosis and relapse

“…Finally, spatial organization of cell types in combination with their abundance has been shown to provide relevant insight into the interaction between HRSC and the microenvironment in vivo [29]. Of note, our method of immunohistochemistry in fact is able to detect variability in PD1 expression as we have shown recently in patients suffering from a relapse after anti-PD1 treatment [12].…”

“…Moreover, it is currently not known whether therapeutic targets like PD-L1/ PD1 and CD30 change under conventional chemotherapy and which biopsies need to be assessed if the status should be assessed for targeted treatment at relapse. In fact, we recently showed that the number of PD1-positive cells increased in patients relapsing after/under anti-PD1 treatment [12]. We thus analyzed multiple biopsy specimens from cHL patients and compared histological subtype, immunophenotype, and microenvironment at diagnosis and at relapse to understand which tissue needs to be analyzed when assessing the presence of therapeutic targets CD30, PD1, and PD-L1 or prognostic biomarker such as the macrophage content in cHL.…”

Advances in targeted therapy for malignant lymphoma

“…[349][350][351][352] In addition, checkpoint inhibitors combined with CAR-T therapy, epigenetic modulators, radiotherapy, and BTK inhibitors have shown striking efficacy in refractory lymphoma. [353][354][355] PD-1/PD-L1 Programmed cell death-1 (PD-1, also known as CD279) is a member of the immunoglobulin superfamily and functions as an important immune checkpoint that suppresses excessive immune responses. 6 PD-1 is mainly expressed on activated T cells and a small number of B cells, NK cells, activated monocytes, and dendritic cells but is not expressed on naïve T cells.…”