case_images: PMC10771736_01
case_images: (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.
case_images: 10.1177_09636897231221887-fig1.jpg
case_images: PMC10771736_01_10.1177_09636897231221887-fig1.jpg
case_images: fig1-09636897231221887
case_images: HLH functional studies indicated impaired degranulation of NK (Delta CD107a 0%) and CTL (Delta MFI 2.1) in CD107a analysis (Fig. 1A), along with normal NK-cell activity (18.66%) and perforin expression in NK and CTL. Positron emission tomography/computed tomography (PET/CT) unveiled generalized and multiple enlarged lymphoma nodes, coupled with hypermetabolism and splenomegaly, indicative of lymphoma infiltration (Fig. 1B). A follow-up PET/CT examination after chemotherapy revealed generally ameliorated lesions, indicative of partial remission (PR) of lymphoma (Fig. 1B). The detailed treatment course is summarized in Fig. 1C. PET/CT at 5 months after transplantation confirmed complete remission of disease (Fig. 1B).
case_images: (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.
case_images: 10.1177_09636897231221887-fig2.jpg
case_images: PMC10771736_01_10.1177_09636897231221887-fig2.jpg
case_images: fig2-09636897231221887
case_images: AGL, F13A1, CFD, CD27, and UNC13D, which were further confirmed by Sanger sequencing (Fig. 2A and Supplemental Table S2). Although UNC13D and CD27 are known HLH-predisposing genes, a novel germline missense mutation was detected in CD27 (c.779C>T, p.Pro260Leu) (Fig. 2B). His father and mother were found to harbor UNC13D and CD27 mutations, respectively, and his older brother (HLA-identical, 10/10) carried part of the germline mutations inherited from his parents, including the same CD27 missense mutation (Fig. 2C and Supplemental Table S2).
case_images: (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.
case_images: 10.1177_09636897231221887-fig3.jpg
case_images: PMC10771736_01_10.1177_09636897231221887-fig3.jpg
case_images: fig3-09636897231221887
case_images: To provide further insights, we used AlphaFold 2 to speculate on the structure of this mutation, revealing a predicted structure closely resembling the wild-type structure (Fig. 3A). Flow cytometry demonstrated that the expression of CD27 was similar to that in the normal control (Fig. 3B). B and perforin expression levels in his brother were all within normal ranges (Fig. 3C-E). Based on the aforementioned results, we hypothesized that the germline CD27 variant does not adversely affect the T-cell function, making his brother a suitable candidate for allo-HSCT.