Fig. 2: Circulating CD4⁺ T effector memory cell frequency predicts hepatitis after Nivolumab plus Ipilimumab treatment.

a Peripheral blood samples were collected from melanoma patients with metastatic disease receiving αPD-1/αCTLA-4 therapy immediately before administration of the first dose (n = 89). Leucocyte subsets differentially represented in patients with or without hepatitis were identified in a randomly assigned training set (B.H.-corrected t-tests; n = 44; m = 50; FDR = 0.25). Red dots indicate significantly differently represented subsets. Example gating strategies for analysis of flow cytometry data are provided as Supplementary Figs. 2–8. b CD4⁺ T_EM % in training set patients with or without treatment-related hepatitis (n = 44; M.W.). Median values are indicated by a red line. c CD4⁺ T_EM % in validation set patients with or without treatment-related hepatitis (n = 45; M.W.). d ROC analysis of CD4⁺ T_EM % as a discriminatory marker for treatment-related hepatitis in the validation set (n = 45). e Comparison of the bimodal distribution of CD4⁺ T_EM % in patients with unresectable metastatic disease (n = 107) and the normal distribution (n = 49; K2 = 2.79; p = 0.248) of CD4⁺ T_EM % in patients with completely resected tumours. A cut-off of CD4⁺ T_EM ≥ 21% was set (indicated by a dashed red line) below which 99% of completely resected tumour cases should fall. Four pink points represent CD4⁺ T_EM^≥21% patients with metastatic disease who were electively treated with αPD-1 monotherapy. f In the validation set, 68.9% patients were correctly classified using a cut-off of CD4⁺ T_EM ≥ 21 %, whereas 55.6% were correctly classified under the no-information model (n = 45; F.E.). g CD4⁺ T_EM ≥ 21 % is not a marker of predisposition to αPD-1/αCTLA-4-related colitis (n = 89; F.E.). h CD4⁺ T_EM^≥21% patients did not experience more severe hepatitis than CD4⁺ T_EM^<21% patients (n = 38; F.E.). Dashed red line indicates a cut-off of CD4⁺ T_EM ≥ 21%. i Time-to-first presentation of hepatitis was not different between CD4⁺ T_EM^≥21% (n = 12) and T_EM^<21% (n = 26) patients (log-rank). j Twelve of 12 patients with unresectable metastatic melanoma and CD4⁺ T_EM ≥ 21% developed hepatitis after αPD-1/αCTLA-4 dual therapy. By contrast, 3 of 4 CD4⁺ T_EM^≥21% patients treated with αPD-1 monotherapy did not develop hepatitis (F.E.; p = 0.007).