The patient was a 27-year-old woman with no relevant medical history or family history. In June 2016, she presented at our hospital for 4 months of intermittent fever with 3 and half months of fatigue and dark-colored urine. The patient developed fever (38.5  C) 4 months ago with no apparent cause. The fever type was irregular; it was accompanied by myalgia and occasional headache. She denied any history of chills, pharyngalgia, cough, and expectoration, abdominal pain, diarrhea, localized joint pain, or rash. The patient was prescribed anti-infection therapy for 4 days in a local hospital because of increased white blood cell (WBC) counts and neutrophils. However, her body temperature persisted in the range of 38.5  C to 39.1  C. About 3 and half months ago, the patient was referred to the superior central hospital owing to development of anorexia, fatigue, and dark-colored urine. Results of lab investigations were as follows: serum alanine aminotransferase (ALT) 1187 U/L; serum aspartate transaminase (AST) 1243.7 U/L; total bilirubin (TBIL) 165.4 mumol/L, direct bilirubin (DBIL) 92.2 mumol/L. She tested negative for antigen and antibody markers of hepatotropic hepatitis A-E virus with the exception of hepatitis B surface antibody, and undetectable for viral nucleic acid. She received glycyrrhizin remedies for hepato-protection and to lower transaminase levels, and cefoperazone-sulbactam antibiotic therapy for about 1 month; however, there was no improvement in clinical manifestations. About 2 and half months ago, the patient was transferred to another local hospital for specialized infectious diseases. Liver biochemistry tests showed ALT 374 U/L, AST 164 U/L, TBIL 84.2 mumol/L, DBIL 57.3 mumol/L. Besides, her anti-streptolysin "O" was 201 U/mL, rheumatoid factor was 156.2 IU/mL, and C-reaction protein (CRP) level was 1.9 mg/L. EBV- capsid antigen (CA)-IgM, cytomegalovirus (CMV)-IgM, rubella virus-IgM, toxoplasmosis-IgM, herpes simplex virus 2-IgM, as well as Widal, Weil-Felix test, and Brucella agglutination test were all negative. The anti-extractable nuclear antigen antibodies were all negative. Liver biopsy was performed and then the diagnosis of DILI was considered based on liver pathology (Fig. 1). The patient received symptomatic treatment along with methylprednisolone (starting at 28 mg/day and reduced by 4 mg per week). The patient's temperature and liver function were restored during treatment. However, there was recurrence of fever after 1 week of methylprednisolone withdrawal. When she came to our hospital, she was still febrile (temperature 39.5  C); however, the general physical examination was unremarkable.
At admission, the results of blood tests were: WBC 3.95 x 109/L; platelet 142.00 x 109/L; plasma prothrombin time 13.5 s; and fibrinogen 1.86 g/L. Liver biochemistry tests were: ALT 1577 U/L; AST 2354 U/L; TBIL 80.5 mumol/L; DBIL 51.2 mumol/L; albumin 33 g/L; alkaline phosphatase 468 U/L; gamma-glutamyl transferase 215 U/L; lactate dehydrogenase (LDH) 1032 U/L; triglycerides 2.67 mmol/L; erythrocyte sedimentation rate 27 mm/h; procalcitonin 0.06 ng/mL; and CRP 8.80 mg/L. Tuberculin skin test, anti-tuberculosis (TB) antibody, T-Spot TB test, as well as (1,3)-beta-D-Glucan and Galactomannan tests were all negative. A series of blood, urine, stool, and marrow culture were repeatedly negative. CMV DNA level was <500 copies/mL; Multi-tumor markers were all within normal range. However, EBV DNA level was 2.837 x 104 copies/mL. The EBV antibody spectrum showed EBV-CA-IgG (+), EBV nuclear antigen (EBNA)1-IgG (+), and EBV-early antigen (EA)-IgG (+). T cell subsets: clusters of differentiation (CD)3+ 21.05%, CD3+CD4+ 8.83%, CD3+CD8+ 11.53% and CD4/CD8 0.77. On ultrasound, the size of spleen was 12.0 cm x 5.6 cm; however, there was no hepatomegaly or lymphadenectasis in neck, armpits, mediastinum, or along the abdominal blood vessels.
After admission, the patient received symptomatic treatment and antiviral therapy with a combination of acyclovir and Foscarnet Sodium. Thymosin alpha 1 and methylprednisolone were prescribed to regulate immunity and as an adjuvant to antiviral therapy. The patient's liver biochemical profile recovered to normal range while intermittent fever continued to persist. Furthermore, an increase in EBV DNA level was also noted (4 weeks after admission: 3.01 x 104 copies/mL; 6 weeks after admission: 1.32 x 107 copies/mL). Bone marrow immunophenotyping for hematological malignancy by flow cytometry with CD45/side scatter (SSC) gating and normal cells as internal reference showed that: lymphocytes (LYs) accounted for about 31.8% of nucleated cells, of which CD3-CD56+ NK cells accounted for about 79.8% and the cells were CD2, CD38, CD56, CD94 positive, and CD7 negative (Fig. 2). Repeat evaluation of the pathologic section of the liver (borrowed from the local hospital) showed mildly expanded hepatic sinusoids with beaded arrangement of LYs; severe lymphocytic infiltration in portal tracts, mixed with occasional atypical LY with dark cytoplasm, prominent nucleoli, and vacuolar nucleus (Fig. 1). EBER-1 probe in situ hybrids of hepatic pathologic section (+). One month after admission, the patient developed hematochezia but colonoscopy showed no abnormality. At this time, blood tests showed WBC 6.54 x 109/L (neutrophils 2.13 x 109/L; LYs 3.84 x 109/L), red blood cell 3.80 x 1012/L, hemoglobin 106.60 g/L, platelet 234 x 109/L; plasma prothrombin time 12.8 s; prothrombin activity 82.00%; international normalized ratio 1.14; fibrinogen 1.03 g/L; and D-dimer 0.89 mg/L. The bleeding resolved after symptomatic treatment. Two months after admission, the patient passed soy urine. Urine test showed red blood cells 67.3/muL and occult blood (+++). The symptoms improved after hemostatic therapy; laboratory tests showed plasma fibrinogen level of 0.77 g/L and ferritin >1200 mg/L. sCD25 in serum was 20312 pg/mL (Ref 400-2700 pg/mL). Based on the above results, the patient received treatment with etoposide and dexamethasone for diagnosis of EBV associated HLH; subsequently, her temperature, liver biochemical profile and blood lipids were restored to normal range. Repeat flow cytometry of bone marrow showed that 11.01% bone marrow cells exhibited an abnormal phenotype of mature NK cells, which accounted for 17.17% of nucleated cells and 64.13% of LYs; the cells were CD56, CD2, CD7dim, CD8dim, CD161, CD94bri, CD159a positive, and CD3, CD4, CD5, CD16, CD159c, CD158b, CD158a/h, Ki67, CD30, CD57, CD10, T cell receptor (TCR) ab, TCRrd, CD158e, CD117 negative; granzyme B positive rate was 91.51% and perforin positive rate was 93.83%; bone marrow chromosome karyotyping: 46, XX [20]; gene rearrangements of IgH and TCRgamma/delta were negative. Bone marrow cytomorphologic features: 3 cell-lineage of erythrocyte, granulocyte and thrombocyte in bone marrow showed active proliferation with toxic change in some granulocytes. The proportion of LYs was within the normal range; occasionally, atypical LYs characterized by dense chromatin and purple-red particles in cytoplasm. The mononuclear-macrophage showed active proliferation and phagocytic red blood cells, platelet fragments, and coarse particles were scattered within the cytoplasm. Bone marrow pathology showed clusters or cord-shaped cells distributed in hematopoietic tissues, with large cell volume and deep nuclear staining. Reticular fiber staining: myelofibrosis-1 (Fig. 3). According to these results, the patient was eventually diagnosed as a case of EBV associated NK cell lymphoma accompanied by HLH. In September 8, 2016, the patient received the first course of revised EPOCH chemotherapy with etoposide (100 mg/d, d1-5), dexamethasone (7.5 mg/d, d1-5; 5 mg/d, d6-14), cyclophosphamide (0.8 g/d, d1-2), and pegaspargase (3750 u/d, tid, d1-2). Fifteen days later, the patient developed hematochezia again; colonoscopy showed that the location of gastrointestinal hemorrhage was in cecum and ascending colon. Unfortunately, the patient died of gastrointestinal hemorrhage and multiple organ failure.