RESUMEN
Chronic active Epstein-Barr virus infection (CAEBV) is a lymphoproliferative disorder characterized by the clonal proliferation of EBV-infected T or NK cells and is related to severe systemic inflammation. This study aims to investigate STAT3 to elucidate the mechanism underlying the CAEBV development. We determined that STAT3 was constitutively activated in EBV-positive T- or NK-cell lines. We also determined that STAT3 was activated in the peripheral blood mononuclear cells (PBMCs) containing EBV-infected clonally proliferating T or NK cells in six of seven patients with CAEBV. We conducted direct sequencing of the STAT3 Src homology 2 (SH2) domain, which has previously been reported to be mutated in T- or NK-cell neoplasms. No mutation was detected in the STAT3 SH2 domain in patients with CAEBV. Next, we investigated the effects of ruxolitinib, an inhibitor of both JAK1 and JAK2, which phosphorylates and activates STAT3. Ruxolitinib suppressed the phosphorylation of STAT3 in EBV-positive T- or NK-cell lines. Ruxolitinib also decreased the viable cell number of EBV-positive T- or NK-cell lines and PBMCs from patients with CAEBV. Furthermore, ruxolitinib suppressed the production of inflammatory cytokines in the cell lines and CAEBV patient-derived cells. In conclusion, constitutively activated STAT3, which promotes survival and cytokine production, could be a therapeutic target for CAEBV.
RESUMEN
Epstein-Barr virus-positive T/NK-cell lymphoproliferative diseases (EBV-T/NK-LPDs) include several overlapping EBV-related conditions with variably aggressive courses. For prognostic categorization, we retrospectively analyzed 42 EBV-T/NK-LPD cases. Male (79% [33/42]), young (≤40 years; 83% [35/42]) patients and T-cell lineage (81% [34/42]; CD8/CD4 = 1.8) were predominant. Clinicopathologically, three systemic and one cutaneous category were developed: hemophagocytic lymphohistiocytosis (HLH; 26% [11/42]), chronic active EBV infection (CAEBV; 31% [13/42]), systemic unclassifiable disease (24% [10/42]), and hydroa vacciniforme/hydroa vacciniforme-like lymphoma (HV/HVL; 19% [8/42]). Prognostically, cutaneous disease (HV/HVL) was better than systemic disease (p = 0.014; median, 285 vs. 10 months). In systemic diseases, HLH was worst (p = 0.002; 3[HLH] vs. 4[unclassifiable] vs. not reached [CAEBV]). Univariate survival analysis (n = 42) revealed cytopenia (≥one lineage; p < 0.001), onset age (>40 years; p = 0.001), T-cell lineage (p = 0.041), hemophagocytic histiocytes (p = 0.031), elevated lactate dehydrogenase (p = 0.020), and liver dysfunction (p = 0.023) predicted shorter survival. In multivariate analysis, T-cell lineage (p = 0.025 [HR =11.3]) and cytopenia (p = 0.028 [HR =5.4]) were independent prognostic factors. Therefore, EBV-T/NK-LPD could be classified into four prognostic categories.