PMC10368518_01
Graphical representation of some important laboratory parameters and treatment. (a) Haemoglobin and platelet count, (b) liver enzymes, (c) ferritin and (d) EBV viral load. ALT, alanine transaminase; AST, aspartate transamine; EBV, Epstein-Barr virus; GGT, gamma-glutamyl transferase; R, rituximab.
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There was elevation of liver enzymes: aspartate aminotransferase (AST) of 527 U L-1 (0-45 U L-1), alanine aminotransferase (ALT) of 1188 U L-1 (0-55 U L-1) and gamma-glutamyl transferase (GGT) of 132 U L-1 (0-60 U L-1) (Figure 1b).
Morphology and immunohistochemistry of bone marrow biopsy. (a) Haemophagocytosis, one metamyelocyte within a histiocyte (*), (b) erythrophagocytosis (arrow), (c) CD3-staining indicative of prominent T cells of intermediate size with occasional large cells (arrow) and (d) CD163-staining demonstrating increased histiocytes. Immunohistochemistry method: Formalin-fixed, paraffin-embedded bone marrow trephine processed on automated Ventana BenchMark ULTRA  platform with CD3 and CD163 monoclonal antibodies and presence identified by ultraView Universal DAB Detection Kit .
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CD25 (sCD25) (30 625 pg mL-1; < 2678 pg mL-1), reduced fibrinogen (1.05 g L-1; 1.5-4.0 g L-1) and presence of haemophagocytosis in the bone marrow (Figure 2). Collectively, her H score was 258, indicating a > 99% probability of HLH.
Flow cytometry. Immunophenotyping of bone marrow, indicating lymphocytes (blue) with aberrant CD8+ T cells (red) expressing CD2 (d), dim to negative CD5 (e), dim CD7 (f) and TRBC1 expression (i). Flow cytometry method: Bone marrow aspirate sample is lysed, washed, reconstituted in RPMI medium and incubated with monoclonal antibodies (CD45, CD3, CD2, CD5, CD7, CD16/56 and TRBC1) tagged with fluorescent dyes. Data were acquired through BD FACSCanto II  flow cytometer and analysed on Beckman Coulter Kaluza C software. The gating strategy identifies lymphocytes by CD45 and side scatter (a) followed by gating CD3 against CD4+ T cells (b) and CD8+ T cells (c), T-cell surface markers on these CD4+ and CD8+ T cells; CD2 (d), CD5 (e), CD7 (f), CD16/56 (g) and TRBC1 on CD3+ CD4+ T cells (h) and CD3+ CD8+ T cells (i).
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