School of Medicine

Diagnosis and Clinical Course

Her blood bank testing was consistent with a cold autoantibody causing autoimmune hemolysis. This was likely self-resolving upon presentation at the ER given the weaker reactivity and panreactivity only seen with the 4^oC testing. Given her history of recent flu-like illness without significant respiratory symptoms and a clinically significant cold auto antibody causing hemolysis which appears to be likely transient and resolving, Epstein-Barr viral (EBV) infection was suggested as a possible cause of both her anemia and hepatitis during discussion of her case between transfusion medicine and the Hematology/Oncology team.

EBV IgM testing was performed and was very strongly positive at >160 U/mL (>43.9 is considered positive).

Although her liver biopsy was performed due to high initial suspicion for autoimmune hepatitis, it showed markedly active hepatitis consistent with EBV hepatitis. The microscopic description includes: The liver biopsy contains an active hepatitis, with extensive lobular inflammation in the sinusoids. There is patchy portal inflammation, composed of lymphocytes and a few plasma cells. The cells in the sinusoids are a mixture of small lymphocytes and larger, more atypical forms. There is individual hepatocyte necrosis scattered throughout the lobules. The sinusoidal pattern of inflammation suggests the possibility of EBV-related hepatitis (acute infectious hepatitis)  which is confirmed by a positive in-situ hybridization stain (EBER) in scattered cells in the sinusoids. The degree of interface activity and, particularly, the number of plasma cells in the infiltrate are less than is expected in a typical case of untreated autoimmune hepatitis.

The patient was given a clinical diagnosis of EBV hepatitis which was treated by providing supportive care only and the autoimmune hemolytic anemia (AIHA) was treated with oral steroids. Her anemia and liver function improved over the next five days, and she was discharged on tapering steroids.

Outpatient follow-up with internal medicine and the Hematology/Oncology team over the subsequent 2-3 months revealed complete resolution of her hepatitis and anemia.

Discussion

EBV, a member of the herpesvirus family, is known to infect oropharyngeal epithelial cells and B lymphocytes, leading to an expansion of cytotoxic CD8+ T lymphocytes and subsequent atypical lymphocytosis. A vast majority, approximately 90% to 95%, of the global population carries EBV antibodies, indicating past exposure. Primary EBV infection is common in young children and often goes unnoticed. However, in adolescents, symptomatic EBV infection frequently occurs, typically presenting as infectious mononucleosis with symptoms like tonsillitis, cervical lymphadenopathy, and fever.

While splenomegaly is observed in about half of infectious mononucleosis cases, hepatomegaly is less common, occurring in roughly 14% of patients. In more than 90% of EBV-related mononucleosis cases, there is some level of liver involvement. Typically, this manifests as mild and transient elevations in liver enzyme levels (2–3 times the upper limit of normal). Severe liver involvement is rare, with jaundice occurring in less than 5% of patients. However, severe, or fatal hepatitis from EBV infection can be observed, particularly in immunocompromised individuals.

Laboratory findings that support EBV infection include lymphocytosis with numerous atypical lymphocytes. Heterophile antibodies are typically associated with EBV in adolescents and adults but have limited specificity and sensitivity. In early disease stages, most patients with primary EBV infections will have detectable immunoglobulin M (IgM) antibodies to EBV viral capsule antigen (VCA), which usually disappear within 4 to 6 weeks. Immunoglobulin G (IgG) antibodies to VCA appear in the initial month of illness, while IgG antibodies against Epstein-Barr nuclear antigen 1 (EBNA-1) typically emerge during the convalescence stage.

While up to 60% of patients with infectious mononucleosis develop cold auto antibodies, the occurrence of clinically significant hemolytic anemia is rare. Cold autoantibodies are mostly IgM antibodies generated against common antigens found on red blood cells and are frequently encountered during blood bank antibody screening. These antibodies typically cause agglutination at low temperatures only making them unlikely to cause hemolysis in vivo, but those capable of reacting at body temperature may cause complement activation and subsequent hemolysis. Cold-type autoimmune hemolytic anemia (AIHA) is most commonly linked to lymphoid malignancies but can occasionally be triggered by infections, primarily mycoplasma pneumoniae and infectious mononucleosis (IMN). The diagnosis of cold-type AIHA due to IMN is confirmed by high levels of cold auto antibodies, a positive direct antiglobulin test (typically IgG negative/C3 positive), and serological evidence indicating recent IMN infection. The presence of red cell aggregates on a peripheral blood smear may be seen when cold auto antibodies are especially strong. Autoimmune antibody production, such as antinuclear antibodies or anti–smooth muscle antibodies, can also be associated with EBV possibly due to cross-reactivity between EBV proteins and autoantigens.

Autoantibodies tend to cause panreactivity upon red blood cells (RBC) antibody screening due to their specificity for common RBC antigens with cold autos most commonly reacting strongest or only at the IS or 4^oC phases. While the vast majority of cold autoantibodies are not clinically significant and do not cause hemolysis those which also react at 37^oC or AHG phases are more likely to be clinically significant and capable of causing hemolysis. Because they often cause panreactivity, cold autoantibodies must be removed or neutralized so that alloantibodies can be identified or excluded. Those which only react at IS or 4^oC can often be neutralized using prewarmed techniques where all components of testing are maintained at body temperature (37^oC) throughout testing. They can also be physically removed by adsorption using either rabbit erythrocyte stroma (RESt) or the patient’s own RBCs (if they have not been recently transfused); this is often necessary if they react at 37^oC or AHG since prewarming is less likely to be effective.

Transfusions are uncommonly required in patients with cold AIHA since severe anemia is unusual especially in cases not associated with lymphoid malignancies. When necessary, they may be complicated by a lack of crossmatch compatibility due to the panreactive nature of the antibodies. It is particularly important to withhold transfusion until the antibody screening workup is complete and alloantibodies are identified or completely excluded since patients with auto antibodies are more likely to also harbor alloantibodies. Although crossmatch incompatible blood may be required (often referred to as least incompatible in the setting of auto antibodies), transfusions in this setting assuming alloantibodies have been identified or excluded are considered low risk for acute hemolysis although they may occasionally increase the patient’s autoimmune hemolysis of their own and transfused cells due to immune stimulation (so-called fueling the fire). Therefore, AIHA is a clinical situation where utilizing the typical hemoglobin cutoff of <7g/dL is often discouraged, and patients should be transfused based on acute symptoms of anemia and not strictly due to their hemoglobin level.

Regarding histopathology, EBV hepatitis is primarily diagnosed clinically, but a liver biopsy may be recommended if the clinical presentation is unusual or if laboratory findings are ambiguous. As in our case it is often done because primary suspicion is for autoimmune hepatitis. Various histopathologic features can be observed in EBV hepatitis, with the most characteristic being a diffuse lymphocytic sinusoidal infiltrate resembling a "string of beads" pattern. The portal tracts often show expansion due to lymphocytic infiltrates including occasional plasma cells, neutrophils, and eosinophils. Large, atypical lymphocytes are commonly present. While hepatocytes may exhibit mild changes like swelling, vacuolation, and steatosis with focal apoptosis, the overall liver architecture remains mostly intact.

Treatment for EBV hepatitis is usually supportive as it is generally self-limiting. Steroids and antiviral medications may be used in some cases, such as for our patient where treatment commenced with solumedrol, resulting in symptom improvement and resolution of anemia of the patient.

Autoimmune hepatitis: Autoimmune hepatitis can be distinguished by the lack of positive EBV serologies, elevated IgG levels, and the presence of other autoantibodies. In contrast, EBV hepatitis lacks prominent plasma cells, and the liver architecture remains largely intact.

Lymphoproliferative disorders: Can mimic EBV hepatitis on histological grounds, particularly hepatosplenic T-cell lymphoma, which primarily involves the liver sinuses. Differentiating the two entities often requires clinical and immunohistochemical assessments.

Drug-induced liver injury: Should always be considered in the differential diagnosis of EBV hepatitis. This diagnosis can be challenging due to the diverse histologic features of drug-induced liver injury, which can resemble various primary liver diseases. Phenytoin hepatotoxicity is most likely to cause sinusoidal lymphocytosis such as that associated with EBV hepatitis.  Laboratory evidence of EBV infection and EBER may be useful in this situation, along with a careful review of the patient's medications.

 

References:

1. Schechter S, Lamps L. Epstein-Barr Virus Hepatitis: A Review of Clinicopathologic Features and Differential Diagnosis. Arch Pathol Lab Med. 2018 Oct;142(10):1191-1195. Doi: 10.5858/arpa.2018-0208-RA. PMID: 30281361.
2. Dematapitiya C, Perera C, Chinthaka W, Senanayaka S, Tennakoon D, Ameer A, Ranasinghe D, Warriyapperuma U, Weerarathna S, Satharasinghe R. Cold type autoimmune hemolytic anemia- a rare manifestation of infectious mononucleosis; serum ferritin as an important biomarker. BMC Infect Dis. 2019 Jan 18;19(1):68. Doi: 10.1186/s12879-019-3722-z. PMID: 30658594; PMCID: PMC6339345.

 

 

Board Type Review Questions:

1. What histological changes are observed in the liver tissue during EBV hepatitis?

a. Diffuse lymphocytic sinusoidal infiltrate, with portal tracts expansion due to lymphocytic infiltrates predominantly plasma cells. Overall liver architecture remains mostly intact. 
b. Diffuse lymphocytic sinusoidal infiltrate, with portal tracts expansion due to lymphocytic infiltrates. Large, atypical lymphocytes are commonly present. Overall liver architecture remains mostly intact. 
c.Diffuse lymphocytic sinusoidal infiltrate, with portal tracts expansion due to lymphocytic infiltrates predominantly plasma cells. Overall liver architecture is completely disrupted.

2. What is the most common pattern of reactivity upon antibody screening for a clinically significant cold auto antibody?

a. Panreactivity at IS or 4^oC only.
b. Patchy reactivity at IS and/or AHG with panreactivity only seen at 4^o C
c. Panreactivity at all phases which is strongest at the AHG phase.
d. Panreactivity at all phases which is strongest at the IS phase.
e. Panreactivity at AHG only