Relapsed/Refractory Peripheral T-Cell Lymphoma-Associated Hemophagocytic Lymphohistiocytosis With UNC13D and CD27 Germline Mutations

Abstract

Hemophagocytic lymphohistiocytosis (HLH) is a severe hyperinflammatory disease characterized by familial and acquired forms. Here, we present the case of a 26-year-old male patient with relapsed/refractory peripheral T-cell lymphoma and concurrent HLH. Whole-exon sequencing revealed germline mutations associated with HLH, including those in critical genes such as CD27 and UNC13D and other germline heterozygous variants (NOTCH2, NOTCH3, IL2RA, TYK2, AGL, CFD, and F13A1). CD107a analyses consistently demonstrated impaired degranulation of cytotoxic T-lymphocytes and natural killer (NK) cells. Examination of the patient's family pedigree revealed that his father and mother harbored UNC13D and CD27 mutations, respectively; his brother carried the same CD27 heterozygous mutation. However, none of them manifested the disease. Despite the missense mutation of CD27 (c.779C>T; p.Pro260Leu) lacking previous documentation in databases, comprehensive analysis suggested non-pathogenic mutations in the CD27 variant, indicating minimal impact on T- and NK-cell functions. These results ultimately supported the option of hematopoietic stem cell transplantation (HSCT) as a successful curative therapeutic approach. As of this report, the patient has remained free of lymphoma and quiescent HLH 15.2 months post-HSCT. This study underscores the efficacy of genetic tests in identifying significant mutations and confirming their etiologies, providing an early basis for treatment decisions and the selection of suitable transplant donors.

Keywords: CD27; UNC13D; hematopoietic stem cell transplantation; hemophagocytic lymphohistiocytosis.

Figure 1.

(A) Degranulation of CD56+ natural killer (NK) cells and CD8+ CTL in the CD107a analysis. CD107a expression on cell surfaces was analyzed using flow cytometry in resting cells (left dot plot diagrams) and subsequent to 48 h stimulation with IL-2 of NK cells, and phytohemagglutinin (PHA)/IL-2 of CD8+ T cells (right dot plot diagrams), respectively. (B) Clinical evaluation by positron emission tomography/computed tomography imaging. (C) Ferritin levels and Epstein–Barr virus-DNA copies throughout treatment courses. APC-A: allophycocyanin-area; CHOP: cyclophosphamide, doxorubicin, vincristine, and prednisolone; CTL: cytotoxic T-lymphocytes; EBV: epstein–Barr virus; E-POCH: etoposide, prednisolone, vincristine, cyclophosphamide, doxorubicin; E-SHAP: etoposide, methylprednisolone, cytarabine, and cisplatin; GDP: gemcitabine, dexamethasone, and cisplatin; HSCT: hematopoietic stem cell transplantation; IL-2: interleukin 2; NK: natural killer; PE-A: phycoerythrin-area; PEG: pegaspargase.

Figure 2.

(A) Specific information on the mutated genes detected by the whole-exon sequencing. (B) Structure of the human UNC13D (left panel) and CD27 (right panel) domain highlighting the primary mutated sites. (C) Whole-exon sequencing pedigree analysis of the patient and his family members. dbSNP: The Single Nucleotide Polymorphism Database; pLDDT: per-residue Local Distance Difference Test. ^aVPS13B mutation in the patient is inherited from his mother.

Figure 3.

(A) Overlay of AlphaFold structures for WT (green model) and mutated CD27 (blue model). (B) CD27 surface expression on T cells from healthy controls (left panel) and donors (right panel). (C–E) Flow cytometry analysis of natural killer cell activity (C), granzyme B (D), and perforin (E) in patients with HLH. Left panels show the isotype control (ISO). CTL: cytotoxic T-lymphocytes; HLH: hemophagocytic lymphohistiocytosis; NK: natural killer; SSC: side scatter; WT, wild type; 7-AAD, 7-aminoactinomycin D. Note. The Annexin V conjugate with the label is used in Flow Cytometry to facilitate the rapid and early detection of cell surface changes associated with apoptosis.