What Is Known
- Epstein Barr virus is a human herpes virus that children are exposed to most typically before entering university.
- Primary Epstein Barr virus infection is associated with potentially fatal complications.
- Epstein Barr virus is associated with lymphoma in patients with IBD treated with thiopurines.
- Pediatric patients with inflammatory bowel disease are presently not screened routinely for Epstein Barr virus status.
What Is New
- More than half of pediatric patients with Epstein Barr virus have not been exposed to Epstein Barr virus especially in thiopurine-exposed children.
- Asymptomatic screening of patients with inflammatory bowel disease for Epstein Barr virus can help clinicians decide if a child is at risk for developing primary Epstein Barr virus infection, which is of concern in thiopurine treated patients.
- We propose that physicians should screen for Epstein Barr virus before initiating thiopurines irrespective of sex.
The Epstein Barr virus (EBV) is a human herpes virus that infects more than 90% of the world's population and persists throughout life in resting memory B cells where it induces B-cell proliferation (1). Although prevalent in adults, only 20% to 25% of children in developed countries will have acquired EBV by the age of 5 (2). A Scottish study found that 75% of students entering university were seropositive and half of the seronegative students converted while at university (3). A study from Canada reported that the prevalence of EBV seropositivity in a population with IBD in patients of 18 to 25 years was similar to the population rate, and in patients above 25 years reached close to 100% (4).
Positive viral capsid antigen (VCA) immunoglobulin (Ig)M with negative VCA IgG serology indicates an acute primary infection, whereas negative or positive IgM serology with positive IgG, early antigen and Epstein Barr nuclear antigen serology could indicate individuals at risk for EBV reactivation (5). The clinical spectrum of primary infection ranges from asymptomatic forms to overt infectious mononucleosis. After the primary phase, EBV infects B lymphocytes and leads to a lifelong, asymptomatic, latent infection that is usually controlled by the virus-specific, cell-mediated cytotoxicity of an immunocompetent host by means of natural killer cells, CD4+, and CD8+ T cells. A breakdown in this surveillance, such as that described in organ or bone marrow transplant recipients and in patients on immunosuppression, can be responsible for an uncontrolled proliferation of infected lymphocytes that have been transformed by the virus (1).
Because of the preferential affinity of the EBV virus for B cells, the most common result of infected B cells malignant transformation is B-cell lymphomas (6). Other more familiar EBV-associated lymphoproliferative disorders (LPD) include Hodgkin and Burkitt lymphoma and posttransplant lymphoproliferative disease. Interestingly, because of the escalating list of EBV-associated human cancers in 1997, the WHO classified EBV as a carcinogenic agent (7).
The relevance of these EBV repercussions lies in the fact that the therapies we use in managing patients with IBD, thiopurines in particular, may play an important role in this malignant transformation. The IBD literature has shown that thiopurines, particularly in men above the age of 65, were associated with a 5-fold increased risk of LPD (8,9). Of the 23 cases of LPD reported in the CESAME cohort, just above 40% stained positive for EBV. The association of EBV and lymphoma in IBD is not a new concept; notably, a Dutch nationwide study reported a strong relation between EBV-positive lymphoma and thiopurine use, particularly in patients younger than 50 years (10). Beyond lymphoma, hemaphagocytic lymphohistiocytosis has been described in pediatric patients diagnosed with primary EBV infection on thiopurines (11). Three of the original 7 malignant LPDs reported from the phase 4 post marketing DEVELOP registry were hemaphagocytic histiocytois, Hodgkin lymphoma, and malignant lymphohistiocytosis. All of the 7 malignancies, including these, occurred on thiopurine monotherapy or in combination with anti-tumor necrosis factor (TNF) therapy, and none on anti-TNF monotherapy (12).
If, indeed, there is a relation between EBV and lymphoma risk in thiopurine-treated patients with IBD, then understanding the seroprevalence of EBV infection in the at-risk pediatric age group is warranted. Hradsky et al (13) recently reported that EBV positivity was associated with thiopurine use compared with a nonthiopurine-based strategy. It is unclear whether patients were positive at start of therapy or converted while on therapy.
Given that risks associated with EBV may rest more so with primary infection, it is unclear whether physicians should preemptively check EBV status before initiating IBD therapy, and specifically when planning on a thiopurine-based strategy. In this study, we describe the EBV status within a pediatric cohort with IBD and examine the timing of this status documentation as it relates to therapy.
The Electronic Privacy Information Center data warehouse at Mount Sinai Medical Center, New York, was queried for all patients with IBD of 25 years or younger seen at the Pediatric IBD Center from January 1, 2013 to June 30, 2015. A total of 688 patients were identified and their medical records were reviewed. Among those with EBV status documentation, only those with at minimum a VCA IgG recorded were included. This retrospective study was approved by the institutional review board of the Mount Sinai School of Medicine.
VCA IgM, IgG, early antigen, and Epstein Barr nuclear antigen, when available, were recorded on all subjects. The setting of EBV testing was classified as either suspicion of active EBV infection or for screening purposes in asymptomatic patients. Those asymptomatic patients being screened for EBV were then further divided into those whose EBV status was documented preemptively, meaning before starting IBD therapy, or tested while on therapy. Pertinent demographic and disease-specific data were collected at the time of EBV status assessment that included sex, age, duration of disease, and treatment class, including duration of treatment. Complete blood counts and differentials were recorded.
Descriptive statistics were employed. In the asymptomatic screening group, frequency of prior exposure—VCA IgG positive—was calculated. The age, sex, and therapeutic class were described for patients with and without the history of prior exposure. These same factors were examined in those suspected of active infection. EBV status was specifically examined within the group of patients managed on thiopurines. t test was used to compare between 2 groups when applicable. Within those with documented active EBV infection, neutrophil and lymphocyte counts were compared between initiation of thiopurine therapy, time of positive VCA IgM, and 6 months post infection.
Of the 688 patients identified from the data warehouse, only 150 (22%) had EBV IgG status documented in the electronic medical record. The majority (76%) of patients had Crohns disease and 62% were of male sex. The mean age at diagnosis was 13 years and the mean age at time of EBV assessment was 14 years. Treatments at the time of EBV status documentation are detailed in Table 1. One hundred twenty-four patients (83%) were screened for prior EBV exposure and 26 (17%) were suspected of active infection. VCA IgG was positive in 61 of the 150 (41%) analyzed subjects.
Of the 124 asymptomatic patients screened for EBV, 64 (52%) were assessed before initiating IBD treatment, and the remainder while already on treatment. Table 2 outlines VCA IgG status for each therapeutic cohort. The mean (SD) time from diagnosis to EBV status assessment was 2.0 ± 2.2 years, and 50 (40%) of these patients were VCA IgG positive. Among the cohort of patients with IgG seropositive, more than half were above 15 years and only 6 patients (12%) were younger than 10 years (Fig. 1). Fifteen percent of patients 18 years or older were IgG negative, compared to 20% of patients between the ages of 15 and 17. The mean (SD) age of patients with IgG positive was no different than that of patients with IgG negative (14.3 ± 3.8 years vs 13.9 ± 3.7 years, P = 0.21).
Within the overall thiopurine-treated cohort, 53 (77%) were screened for prior EBV exposure with 27 (51%) assessed before initiating treatment and the remainder while already on treatment. VCA IgG was negative in 58% of these patients with 61% being boys. Sixty-three percent of the thiopurine-treated patients assessed before therapy initiation were IgG negative. The mean (SD) age of thiopurine-treated patients with IgG positive was no greater than that of patients with IgG negative (15.0 ± 4.4 years vs 14.4 ± 3.8 years, P = 0.18).
Suspicious for EBV Infection
Of the 26 patients that were assessed for active EBV infection, 10 (38%) were IgM positive. Of the 16 patients without evidence of active infection (IgM negative), the majority (69%) were also IgG seronegative. The mean (SD) age of patients with active infection was 15 ± 4.4 years. Among this cohort of patients with IgM seropositive, 1 (10%) patient was of 7 years or younger, 2 (20%) were between 10 and 12 years, 1 (10%) was between 13 and 14 years, 3(30%) patients were between 15 and 17 years, and 3(30%) were 18 years or older. Eight (80%) of the patients with VCA IgM positive were on thiopurines, either as monotherapy (n = 6) or in combination with anti-TNF therapy (n = 2). The mean time (SD) between initiation of thiopurine therapy and documented positive VCA IgM serology was 2.02 ± 1.5 years. Mean neutrophil counts decreased by 65% between the initiation of thiopurine therapy and the time of EBV IgM positivity, and subsequently increased by 75% at 6 months postdocumented positive IgM serology. No significant changes in mean lymphocyte counts between these time points were observed.
The influence of EBV status on IBD treatment decisions is an emerging but still controversial concept. Only 22% of our pediatric patients with IBD had EBV status documented in the electronic medical record when reviewed during a 24-month period. The majority of patients were not tested for presumed infection but more so in the face of asymptomatic screening. In our screening cohort, 60% were EBV naïve. Perhaps, more meaningful is that 63% of patients initiating thiopurine therapy had not been exposed to EBV. The emphasis on this group is influenced by teachings from the transplant field, which remind us that primary EBV infection in children is a risk factor for posttransplant LPD. Organ recipients younger than 18 years at time of transplantation are believed to have a 2-to 4-fold greater risk of developing post-transplant lymphoproliferative disorder than adults, (14–16) and patients with negative EBV serostatus carry a 10- to 76-fold greater risk when compared with their seropositive counterparts (17–20).
When T-cell surveillance is impaired, there is enhanced EBV latent gene expression, which drives the proliferation of EBV-infected B cells and LPD risk. LPDs, in general, are rare in patients with IBD. Lymphoma, however, has become the most concerning LPD both for patients and physicians. The most referenced data comes from the Cancers Et Surrisque Associé aux Maladies inflammatoires intestinales En France (CESAME) cohort of almost 20,000 patients, which reported that present thiopurine therapy had a hazard ratio of close to 5 for the development of an LPD (8). This must, however, be put into perspective because they demonstrated that the overall risk remains small, estimated to result in 1 additional lymphoma for every 300 to 1400 years of thiopurine treatment. One thing that cannot be debated is that EBV was implicated in most of the cases of lymphoma. Although the CESAME study focused on an older cohort of patients, our initial data from the inflammatory bowel disease multicenter, prospective, long-term registry of pediatric patients registry followed 5000 pediatric patients with IBD, and this data suggests that malignancy and EBV-related LPDs are associated with thiopurine use in the pediatric population as well (12). The updated incidence data will provide more information on whether this trend continued.
Given EBV exposure occurs in the majority of individuals in childhood or as a young adult, the pediatric age group is most vulnerable to repercussions of primary infection. This concern may be limited to strategies that include thiopurine treatment. Thus, this begs the question as to whether EBV status should be known at diagnosis or at minimum before initiating thiopurine therapy either alone or in combination. In our cohort, 80% of patients with acute EBV infection were on monotherapy with thiopurines and 20% on combination therapy with thiopurines and anti-TNF therapy. The European Crohn's and Colitis Organization guidelines last updated in 2013 states that screening for EBV infection before initiation of immunomodulator therapy should be considered (21). Present pediatric guidelines or algorithms do not comment on EBV screening before thiopurine initiatiation, and as more data surfaces, this may be the direction the field will head but this still remains to be seen. The question of sex remains at the forefront of our clinical decision trees because it relates to thiopurines, in particular in combination with anti-TNF therapies, given the male predominance of hepatosplenic T-cell lymphoma (22). This is thought not to be an EBV-related malignancy, and unlike EBV-related lymphomas, for example, sex, may matter. This remains to be seen because not all hepatosplenic T-cell lymphoma are males, but the common denominator is thiopurine past or present exposure.
There is also debate as to whether patients considered to be doing well on thiopurines and EBV naïve should discontinue thiopurines and be changed to another therapy given the small increased risk of malignancy and risk of primary EBV infection. The majority of our patients did get primary infection manifested as infectious mononucleosis on thiopurines accompanied by a drop in neutrophils. The CESAME study did report that the risk of non-Hodgkin lymphoma does revert back to baseline similar to the unexposed population in individuals who discontinue thiopurines (8). This was not the case for skin cancers in patients exposed to thiopurines because the risk was still increased despite discontinuation (23).
The limitation of this study is its retrospective cross-sectional design at a single center, which may not allow us to generalize EBV status to other pediatric populations with IBD. Moreover, patients may have had their EBV serologies measured at an outside laboratory and the results were not transferred to their electronic medical record, which could underestimate the frequency of patients checked for EBV in our overall cohort. Because we only reported on those patients in whom EBV status was known, we were, however, able to accurately report on the prevalence of exposed versus naïve patients. In those EBV positive patients determined whilst on therapy, we were unable to determine if they were positive prior to initiation of therapy; this is particularly relevant in the thiopurine group.
Our data suggest that the majority of patients initiating thiopurines in the pediatric age group are likely EBV naïve. The question on whether this information changes physician's behavior merits further exploration, and a prospective longitudinal study will help understand the change in EBV status over time and whether screening is indeed warranted.
1. Wistinghausen B, Gross TG, Bollard C. Post-transplant lymphoproliferative disease in pediatric solid organ transplant recipients. Pediatr Hematol Oncol
2. Epstein MA. Reflections on Epstein-Barr virus
: some recently resolved old uncertainties. J Infect
3. Crawford DH, Macsween KF, Higgins CD, et al. A cohort study among university students: identification of risk factors for Epstein-Barr virus
seroconversion and infectious mononucleosis
. Clin Infect Dis
4. Linton MS, Kroeker K, Fedorak D, et al. Prevalence of Epstein-Barr Virus
in a population of patients with inflammatory bowel disease: a prospective cohort study. Aliment Pharmacol Ther
5. De Paschale M, Clerici P. Serological diagnosis of Epstein-Barr virus
infection: problems and solutions. World J Virol
6. Saha A, Robertson ES. Epstein-Barr virus
-associated B-cell lymphomas: pathogenesis and clinical outcomes. Clin Cancer Res
7. Delecluse HJ, Feederle R, O'Sullivan B, et al. Epstein Barr virus-associated tumours: an update for the attention of the working pathologist. J Clin Pathol
8. Beaugerie L, Brousse N, Bouvier AM, et al. Lymphoproliferative disorders
in patients receiving thiopurines for inflammatory bowel disease: a prospective observational cohort study. Lancet
9. Kandiel A, Fraser AG, Korelitz BI, et al. Increased risk of lymphoma
among inflammatory bowel disease patients treated with azathioprine and 6-mercaptopurine. Gut
10. Vos AC, Bakkal N, Minnee RC, et al. Risk of malignant lymphoma
in patients with inflammatory bowel diseases: a Dutch nationwide study. Inflamm Bowel Dis
11. Biank VF, Sheth MK, Talano J, et al. Association of Crohn's disease, thiopurines and primary epstein-barr virus
infection with hemophagocytic lymphohistiocytosis. J Pediatr
12. Colletti RB, Cucchiara S, Dubinsky M, et al. 833 malignancies in children receiving infliximab and other inflammatory bowel disease therapies: an inflammatory bowel disease multicenter, prospective, long-term registry of pediatric patients (develop) registry data. Gastroenterol
13. Hradsky O, Copova I, Zarubova K, et al. Seroprevalence of Epstein-Barr virus
, cytomegalovirus, and polyomavirus in children with inflammatory bowel disease. Dig Dis Sci
14. Mynarek M, Schober T, Behrends U, et al. Posttransplant lymphoproliferative disease after pediatric solid organ transplantation. Clin Dev Immunol
2013; 2013:814973Epub 2013 Sep 24.
15. Dharnidharka VR, Lamb KE, Gregg JA, et al. Associations between EBV serostatus and organ transplant type in PTLD risk: an analysis of the SRTR National Registry Data in the United States. Am J Transplant
16. Dharnidharka VR, Tejani AH, Ho PL, et al. Post-transplant lymphoproliferative disorder in the United States: young Caucasian males are at highest risk. Am J Transplant
17. Preiksaitis JK, Keay S. Diagnosis and management of posttransplant lymphoproliferative disorder in solid-organ transplant recipients. Clin Infect Dis
18. Walker RC, Marshall WF, Strickler JG, et al. Pretransplantation assessment of the risk of lymphoproliferative disorder. Clin Infect Dis
19. Swinnen LJ, Costanzo-Nordin MR, Fisher SG, et al. Increased incidence of lymphoproliferative disorder after immunosuppression with the monoclonal antibody OKT3 in cardiac-transplant recipients. N Engl J Med
20. Preiksaitis JK, Cockfield SM. Epstein-Barr virus
and lymphoproliferative disorders
after transplantation. Transplant infections. 1998; Philadelphia: Lippincott-Raven Publishers, 245–263.
21. Rahier JF, Magro F, Abreu C, et al. Second European evidence-based consensus on the prevention, diagnosis and management of opportunistic infections in inflammatory bowel disease. J Crohns Colitis
22. Kotylar DS, Osterman MT, Diamond RH, et al. A systematic review of factors that contribute to hepatosplenic T-cell lymphoma
in patients with inflammatory bowel disease. Clin Gastroenterol Hepatol
23. Peyrin-Biroulet L, Khosrotehrani K, Carrat F, et al. Increased risk for nonmelanoma skin cancers in patients who receive thiopurines for inflammatory bowel disease. Gastroenterology
Keywords:© 2016 by European Society for Pediatric Gastroenterology, Hepatology, and Nutrition and North American Society for Pediatric Gastroenterology,
Epstein-Barr virus; infectious mononucleosis; lymphoma; lymphoproliferative disorders