PMC8481808_01
Results of the abdominal CT throughout the course of treatment. (A) Large area of mixed density in the right middle and lower abdomen when the patient was diagnosed with PTLD. (B) Before the anti-CD19-CAR T cell combined with PD-1 inhibitor therapy, he was refractory to all the combined chemotherapies. (C, D). One and 2 months after the combination therapy, CT scan showed a significantly smaller abdominal mass.
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Computed tomography (CT) of the abdomen revealed a large area of mixed density in the right middle and lower abdomen (Figure 1A). However, the patient was refractory to all these combined chemotherapies (Figure 1B) and was therefore diagnosed with refractory PTLD. The CT scan showed a significantly smaller abdominal mass than before (Figures 1C, D). During maintenance therapy (PD-1 inhibitors and tacrolimus 1 mg/day for 3 weeks), we observed a continued reduction in tumor volume (Figure 1).
Monitoring the course of anti-CD19-CAR T cell combined with PD-1 inhibitor therapy. (A) Flowchart of combination and maintenance therapy. (B) The expression level of PD-1 in CD3+ T cells in peripheral blood detected by FCM declined to less than 2%. (C) The expression level of the anti-CD19-CAR gene remained more than 10 times higher than the baseline level before therapy. (D) The patient had a persistent deficiency of B lymphocytes in his peripheral blood.
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Autologous humanized anti-CD19-CAR T cells were infused on day 0 (2 x 106 cells/kg) in December 2020 (Figure 2A). The DNA expression level of the anti-CD19-CAR gene detected by quantitative PCR reached its peak at 14500 copies/ng gDNA on day 14. The expression level of PD-1 in CD3+ T cells in peripheral blood detected by FCM declined to less than 2% during the combination therapy (Figure 2B). Subsequently, his renal function gradually declined (Figure 2A). The expression level of the anti-CD19-CAR gene detected 16 weeks after cell infusion remained more than 10 times higher than the baseline level before therapy (Figure 2C). The expression level of PD-1 in the peripheral blood remained below 3% throughout this period. The patient exhibited persistent B-lymphocyte deficiency in his peripheral blood (Figure 2D).