Clonal CD8+ T Lymphocytic Proliferation and Karyotypical Abnormalities in an EBV Associated Hemophagocytic Lymphohistiocytosis

Figure 2

Immunophenotypic features of atypical lymphoid infiltrates. (a)–(h) Flow cytometry analysis of bone marrow showed most of lymphoid infiltrates were CD3+ (a and e), CD2+ (f), CD8+ (b) positive T cells with few CD4+ (b) T cells, and rare CD20+ (a) B cells. These T cells have bright HLA-DR (c) and CD38 (d) expression. Loss of CD5 (g) and CD7 (h) in T cells was evident. (i)–(n) Immunohistochemical stains of bone marrow showed a prominent CD3+ (i) and CD8+ (j) T cell infiltration. These T cells are positive for cytotoxic markers perforin (k), granzyme B (l), and TIA-1 (m) and negative for CD56 (n). (o) In situ hybridization of EBER showed diffuse EBER positive cells in the bone marrow biopsy. (p) Double immunohistochemical stains of CD3 (red) and EBV-LMP (brown) demonstrated colocalization of EBV and CD3.

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