Clinical course of protracted cytopenia after CD19 CAR-T therapy. (A) Timeline of the absolute neutrophil count (per microliter; left y-axis) and platelet count (×10⁹/L; right y-axis) from start of lymphodepletion (day −5) until the day of death (day 165). Significant clinical events are superimposed above the graph. (B) Radiographic evidence of partial response and eventual relapse in ¹⁸fluorodeoxyglucose positron emission tomographic/computed tomographic imaging across 4 time points. Abdominal lymphoma masses are depicted on transverse cross-sections. (C) BM biopsy findings 1 month after CAR infusion with immunohistochemical (IHC) staining for Ki-67 proliferation index and PD-L1 (left) and 3 months after CAR infusion (right, IHC for CD8⁺ and CD57⁺ T cells). Magnification of microscopy is 10×. (D) Dynamics of serum inflammatory markers from day 5 until day 30 after CAR T-cell infusion. CRP (blue) and ferritin (red) are depicted (left). Procalcitonin (purple) and interleukin-6 (green) are depicted on the right. (E) Overview of downregulated (left, red) and upregulated (right, blue) serum inflammatory markers. Protein levels are expressed in normalized protein expression (NPX) units, derived from Ct values. As NPX is expressed in a log₂ scale, a 1-NPX difference translates into a doubling of protein concentration. (F) Flow cytometric analysis depicting the absolute number of CAR⁺ T cells (CD3⁺, CD3⁺/CD8^-, CD3⁺/CD8⁺) over time.