Incidence of B-cell Malignancies in Patients with Lung Cancer Receiving PD-1 Blockade Therapy

Purpose: Many patients with various cancer types have received immune checkpoint inhibitors (ICI) worldwide since their approval, and novel unexpected complications from their long-term use are apparent. We identified some cases of B-cell lymphoma occurring during PD-1 blockade therapy as such unexpected complications. In this study, we aimed to evaluate the incidence of hematologic malignancies in patients with lung cancer receiving PD-1 blockade therapy and to elucidate the mechanisms underlying the progression of these malignancies.
Experimental Design: We performed IHC staining on the clinical samples from patients with B-cell lymphoma that developed during PD-1 blockade therapy and analyzed large-scale real-world datasets. We further investigated the underlying mechanisms through in vitro and in vivo experiments.
Results: A higher incidence of B-cell malignancies has been observed in patients with lung cancer treated with PD-1 blockade therapies based on large-scale real-world data analyses (n = 15,670). The identified lymphomas had a large amount of CD4+ T follicular helper (TFH) cell infiltration. In addition, PD-1 blockade activated PD-1+ TFH cells, which promoted lymphoma proliferation via the IL4/IL4R, IL21/IL21R, and CD40L/CD40 axes. Notably, the lymphomas exhibited high expression of IL4R, IL21R, and CD40.
Conclusions: Our findings highlight the need for careful monitoring and consideration of the potential B-cell malignancy complications in clinical settings in which ICIs are used.