PT  - JOURNAL ARTICLE
AU  - Lin, Ming-Tsan
AU  - Chang, Hui-Mei
AU  - Huang, Chang-Jen
AU  - Chen, Woan-Ling
AU  - Lin, Chi-Yung
AU  - Lin, Ching-Yang
AU  - Chuang, Shih-Sung
TI  - Massive expansion of EBV+ monoclonal T cells with CD5 down regulation in EBV-associated haemophagocytic lymphohistiocytosis
AID  - 10.1136/jcp.2005.034371
DP  - 2007 Jan 01
TA  - Journal of Clinical Pathology
PG  - 101--103
VI  - 60
IP  - 1
4099  - http://jcp.bmj.com/content/60/1/101.short
4100  - http://jcp.bmj.com/content/60/1/101.full
SO  - J Clin Pathol2007 Jan 01; 60
AB  - Haemophagocytic lymphohistiocytosis (HLH) comprises primary and secondary forms; the secondary form is most commonly triggered by the Epstein–Barr virus (EBV; EBV-HLH). Patients with EBV-HLH usually exhibit oligoclonal or monoclonal T cell proliferation, which may mimic T cell lymphoproliferative disorder (T-LPD). This article reports on EBV-HLH in a 17-month-old girl with an extreme surge of reactive T lymphocytosis (absolute count 167×109/l) with CD5 down regulation. Bone marrow aspirate and trephine contained florid haemophagocytosis and massive infiltration of CD3+ Epstein–Barr virus-encoded RNA+ lymphocytes, as seen by double labelling. These lymphocytes were monoclonal for EBV and T cell receptor γ chain gene rearrangement. The patient responded dramatically to intravenous immunoglobulin, interferon α2b, ganciclovir and prednisolone, suggesting restoration of her immune system and eradication of the clonal T cells through these immunoregulatory agents. Thus, careful clinicopathological correlation is warranted in the interpretation of immunophenotyping and clonality data in T cell proliferation in association with EBV-HLH to avoid erroneous diagnosis of T-LPD.