Study design and patients
We designed a multicenter retrospective study to evaluate the efficacy of anti-PD1 therapy on HBV + non-liver cancer patients by comparing with their HBV- counterparts. This study was approved by IRB at the Southwest Hospital, AMU (ID: KY2021112). Total 84 eligible non-liver cancer patients (35 HBV + patients and 49 matched HBV- patients) were enrolled from database of the Southwest Hospital, Xinqiao Hospital and the Third Affiliated Hospital, CQMU from 2018 to 2021.
The 35 HBV + patients are HBsAg-positive (35; 100%) and HBcAb-positive (33; 94.3%). Furthermore, HBV-DNA was detected in all the 35 HBV + patients, indicating HBV was active in these patients (Supplementary Table 1). Clinical data of each patient, including age, gender, cancer types, metastasis, medical history and therapy history, were collected. HBV + patients and HBV- patients had matched for tumor types, with lung carcinoma, digestive system carcinoma, nasopharyngeal carcinoma, urogenital neoplasms, melanoma and esophageal carcinoma. The 49 HBV- non-liver cancer patients were selected to match the 35 HBV + non-liver cancer patients for cancer types, age, and gender, namely the features of HBV- patients were similar to that of HBV + patients (Supplementary Table 1–3).
Anti-PD1 therapy
Overall, 28 out of 35 HBV + non-liver cancer patients received anti-PD1 combination therapy (anti-PD1 plus chemotherapy), while the other 9 patients received anti-PD1 monotherapy. The anti-PD1 antibodies in this study include Toripalimab, Sintilimab, Pembrolizumab, Camrelizumab, Nivolumab, and Tislelizumab. Similarly, 39 out of the 49 HBV- cancer patients received anti-PD1 combination therapy, while the other 10 patients received anti-PD1 monotherapy (Supplementary Table 1–3).
The enrolled patients had no immune-related adverse event (irAE) or low grade (1 grade or 2 grade) irAEs during and after anti-PD1 therapy, except three 3-grade irAEs, namely maculopapular rash in a HBV + patient, cardiotoxicity in a HBV- patient and interstitial pneumonia in a HBV- patient. None of patient died of irAEs or developed HBV-associated disease (Supplementary Table 1–3). Overall, irAEs in HBV + non-liver cancer patients are not significantly different from that in their HBV- counterparts, consistent with recent reports that anti-PD1 therapy is safe for treatment of HBV + non-liver cancer patients31,32,36.
Single cell RNA-seq (scRNA-seq) library and sequencing
We performed scRNA-seq to blood samples of three ESCC patients. This study was approved by IRB at the Southwest Hospital, AMU (ID: KY2021112). All individuals signed an informed consent form approved by the IRBs when the patient was enrolled. Patients receive treatment according to clinical routine. The scRNA-seq library preparing and data were analyzed similar to our previous studies37–39.
Approximately 5ml blood sample was phlebotomized from each of the three ESCC patients pre-and post-treatment, and was transported to the lab in EDTA anticoagulant tube (WEGO, Blood Collection Tube with Vacuum for Single Use, EDTA-K2). Centrifuging the blood sample in condition of 1750rpm around 8min to collect the white blood cells. Lymphocyte Separation Medium (Human) (TBD, LTS1077) was added to substratum cell precipitation to obtain PBMCs after centrifugating at 1950rpm for 20 min and washed in 0.04% BSA of PBS (Gibco PBS pH7.4 basic 1x, 8121456) for twice with centrifuging at 1000rpm for 5min. Trypan blue (Beyotime Trypan blue 10ml, C360I-2) staining was used to check the cell viable. The single cell RNA sequencing libraries of PBMCs were generated using Chromium Next GEM Single Cell 3’ Reagent Kit v3.1 from 10X genomics. In brief, 20000 cells were loaded into each channel of the 10x Chromium controller to generate single cell GEMs. Single cell RNA-seq libraries were prepared using the Chromium Single Cell 3’ Gel Bead and Library Kit (10x Genomics), according to manufacturer instructions. Sequencing libraries were loaded at 2.4 pM on an Illumina NovaSeq 6000 with 2 × 75 paired-end kits.
Single cell RNA-seq data process
In brief, we mapped the reads to human reference genome GRCh38 and aggregated the gene expression matrixes using Cell Ranger (V.5.0.0). We constituted a Seurat object from the raw expression matrixes for Seurat analysis. Seurat package (V.3.2.3)40 and Harmony package (V.1.0)41 were used for the following analysis. Genes expressed in < 20 cells were filtered out. Low quality cells were filtered out if they met the criteria: (1) < 200 features number; (2) < 800 UMI number; or (3) > 15% mitochondrial genome UMIs. We further normalized the gene expression matrix using NormalizeData function. We identified the top 3,000 high variable genes using FindVariableFeatures function and further scaled the gene expression matrix using ScaleData function. We conducted principal component analysis (PCA) for linear dimension reduction using RunPCA function and the top 30 PCs were used for further analysis. The RunHarmony function in Harmony package was used to remove batch effect in our data. Finally, Uniform Manifold Approximation and Projection for Dimension Reduction (UMAP) were conducted using RunUMAP function.
Clustering and identification of cell subsets
The clusters were inferred using FindNeighbors and FindClusters functions based on the normalized gene expression matrix. We identified 17 clusters that were annotated according to their specific expression of classic markers, including 9 T cell subsets (CD3D), 2 natural killer cell (NK) subsets (KLRF1), 2 monocyte subsets (FCN1), 2 B cell subsets (CD19), mDC (CLEC10A) and plasma cell (MZB1) (Supplementary Fig. S1B). The 2 NK cell subsets are NCAM1bright NK and NCAM1dim NK. The 2 B cell subsets are naïve B cells (BN) (TCL1A+) and memory B cells (BM) (CD27+). The 2 monocyte subsets are classic monocyte (cMo) (CD14+) and non-classical Monocyte (ncMo) (FCGR3A+). The 9 T cell subsets are CD4+ Naïve T cells (CD4+ TN) (CD4+ CCR7+), CD8+ Naïve T cells (CD8+ TN) (CD8+ CCR7+), CD4+ memory T cells (CD4+ TM) (CD4+ SELLlo CCR7lo), CD8+ memory T cells (CD8+ TM) (CD8+ SELLlo CCR7lo), CD4+ effector T cells (CD4+ TEFF) (CD4+ GZMA+ GZMB+), CD8+ effector T cells (CD8+ TEFF) (CD8+ GZMA+ GZMB+), CD4+ regulatory T cells (CD4+ Treg) (CD4+ FOXP3+), γδT (TRDC+ TRGC1+) and mucosal-associated invariant T cell (MAIT) (ZBTB16+ SLC4A10+) (Supplementary Fig. S2B).
Comparison of population size and differential expression genes (DEGs)
We calculated the population change index (PopIndex) of each cell subset to measure the relative change of population size after anti-PD1 therapy. The PopIndex was defined as PopIndex=(Fpost-Fpre)/Fpre, where Fpre is the fraction of a cell subset in PBMCs before anti-PD1 treatment, and Fpost is the fraction of the same cell subset in PBMCs after anti-PD1 treatment. A positive value of PopIndex indicates the population size increase after anti-PD1 treatment, and a negative value index population size decrease after anti-PD1 treatment.
FindMarkers function was used to find differential expression genes between cell subsets. The differential expression genes with bonferroni-adjusted p-values < 0.05 and average log (fold-change) (avg_logFC) > 0.2 were kept for further analyses.
Comparison of functional features for each cell subset pre-and post anti-PD1 therapy
In order to evaluate the changes of functional features of each cell subset pre-and post anti-PD1 therapy, we calculate cytotoxicity score, exhaustion score, major histocompatibility complex (MHC)-I score and MHC-II score of each cell using AddModuleScore function. The cytotoxicity score was calculated based on 12 cytotoxicity-associated genes: PRF1, IFNG, GNLY, NKG7, GZMB, GZMA, GZMH, KLRK1, KLRB1, KLRD1, CTSW and CST7. The exhaustion score was calculated based on 6 exhaustion-associated genes: LAG3, TIGIT, PDCD1, CTLA4, HAVCR2 and TOX. MHC-I score was calculated based on 9 MHC-I-associated genes: HLA-A, HLA-B, HLA-C PSMB8, PSMB9, TAP1, TAP2, TAPBP and B2M. MHC-II score was calculated based on 11 MHC-II-associated genes: HLA-DRA, HLA-DRB1, HLA-DRB5, HLA-DPA1, HLA-DPB1, HLA-DQA1, HLA-DQA2, HLA-DQB1, HLA-DQB2, HLA-DMA and HLA-DMB.
DATA AND CODE AVAILABILITY
The sequencing data has been deposited in Genome Sequence Archive in BIG Data Center under accession number HRA002492. Code used for analysis is available upon request.