Effect of Pharmacogenomic Testing for Drug-Gene Interactions on Medication Selection and Remission of Symptoms in Major Depressive Disorder: The PRIME Care Randomized Clinical Trial.

Importance: Selecting effective antidepressants for the treatment of major depressive disorder (MDD) is an imprecise practice, with remission rates of about 30% at the initial treatment. Objective: To determine whether pharmacogenomic testing affects antidepressant medication selection and whether such testing leads to better clinical outcomes. Design, Setting, and Participants: A pragmatic, randomized clinical trial that compared treatment guided by pharmacogenomic testing vs usual care. Participants included 676 clinicians and 1944 patients. Participants were enrolled from 22 Department of Veterans Affairs medical centers from July 2017 through February 2021, with follow-up ending November 2021. Eligible patients were those with MDD who were initiating or switching treatment with a single antidepressant. Exclusion criteria included an active substance use disorder, mania, psychosis, or concurrent treatment with a specified list of medications. Interventions: Results from a commercial pharmacogenomic test were given to clinicians in the pharmacogenomic-guided group (n = 966). The comparison group received usual care and access to pharmacogenomic results after 24 weeks (n = 978). Main Outcomes and Measures: The co-primary outcomes were the proportion of prescriptions with a predicted drug-gene interaction written in the 30 days after randomization and remission of depressive symptoms as measured by the Patient Health Questionnaire-9 (PHQ-9) (remission was defined as PHQ-9 ≤ 5). Remission was analyzed as a repeated measure across 24 weeks by blinded raters. Results: Among 1944 patients who were randomized (mean age, 48 years; 491 women [25%]), 1541 (79%) completed the 24-week assessment. The estimated risks for receiving an antidepressant with none, moderate, and substantial drug-gene interactions for the pharmacogenomic-guided group were 59.3%, 30.0%, and 10.7% compared with 25.7%, 54.6%, and 19.7% in the usual care group. The pharmacogenomic-guided group was more likely to receive a medication with a lower potential drug-gene interaction for no drug-gene vs moderate/substantial interaction (odds ratio [OR], 4.32 [95% CI, 3.47 to 5.39]; P < .001) and no/moderate vs substantial interaction (OR, 2.08 [95% CI, 1.52 to 2.84]; P = .005) (P < .001 for overall comparison). Remission rates over 24 weeks were higher among patients whose care was guided by pharmacogenomic testing than those in usual care (OR, 1.28 [95% CI, 1.05 to 1.57]; P = .02; risk difference, 2.8% [95% CI, 0.6% to 5.1%]) but were not significantly higher at week 24 when 130 patients in the pharmacogenomic-guided group and 126 patients in the usual care group were in remission (estimated risk difference, 1.5% [95% CI, -2.4% to 5.3%]; P = .45). Conclusions and Relevance: Among patients with MDD, provision of pharmacogenomic testing for drug-gene interactions reduced prescription of medications with predicted drug-gene interactions compared with usual care. Provision of test results had small nonpersistent effects on symptom remission. Trial Registration: ClinicalTrials.gov Identifier: NCT03170362.

Implementation of large-scale laboratory-based detection of COVID-19 in the Veterans Health Administration, March 2020 - February 2021.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) presented numerous operational challenges to healthcare delivery networks responsible for implementing large scale detection of Coronavirus Disease 2019 (COVID-19), the infection caused by SARS-CoV-2. We describe testing performance, review data quality metrics, and summarize experiences during the scale up of laboratory-based detection of COVID-19 in the Veterans Health Administration, the largest healthcare system in the United States. During March 2020 to February 2021, we observed rapid increase in testing volume, decreases in test turnaround time, improvements in testing of hospitalized persons, changes in test positivity, and varying utilization of different tests. Though performance metrics improved over time, surges challenged testing capacity and data quality remained suboptimal. Future planning efforts should focus on fortifying supply chains for consumables and equipment repair, optimizing distribution of testing workload across laboratories, and improving informatics to accurately monitor operations and intent for testing during a public health emergency.

VA-Wide, Multicenter Verification Study of the Cepheid Xpert SARS-CoV-2 Assay.

Early in the Severe Acute Respiratory Syndrome Coronavirus 2 pandemic, there was a progressive increase in diagnostic demands that developed within a relatively short period of time. On February 4, 2020, the Secretary of Health and Human Services issued the Emergency Use Authorization for in vitro diagnostics assays for the Severe Acute Respiratory Syndrome Coronavirus 2 virus. Subsequently, multiple assays were approved under the Emergency Use Authorization, including the Cepheid Xpert SARS-CoV-2 assay. Presented here is a description of the nationally coordinated verification study of the Cepheid assay that was performed within the Veteran's Affairs Health System. This coordinated study helped to expedite the verification process for a majority of the Veteran's Affairs system labs, preserved precious system resources, and highlighted the power of a national medical system in response to an emergency.

Veterans Affairs Pharmacogenomic Testing for Veterans (PHASER) clinical program.

In 2019, the Veterans Affairs (VA), the largest integrated US healthcare system, started the Pharmacogenomic Testing for Veterans (PHASER) clinical program that provides multi-gene pharmacogenomic (PGx) testing for up to 250,000 veterans at approximately 50 sites. PHASER is staggering program initiation at sites over a 5-year period from 2019 to 2023, as opposed to simultaneous initiation at all sites, to facilitate iterative program quality improvements through Plan-Do-Study-Act cycles. Current resources in the PGx field have not focused on multisite, remote implementation of panel-based PGx testing. In addition to bringing large scale PGx testing to veterans, the PHASER program is developing a roadmap to maximize uptake and optimize the use of PGx to improve drug response outcomes.

Alanine Aminotransferase Results Differ by Analyzer Manufacturer in a National Integrated Health Setting, 2012-2017.

CONTEXT.­: Disease guidelines specify universal alanine aminotransferase (ALT) thresholds for clinical decision-making, yet the effect of variability among ALT analyzers remains unclear. OBJECTIVE.­: To compare ALT results from different analyzers from 2012-2017. DESIGN.­: Veterans Health Administration (VHA) laboratories perform external ALT proficiency testing using standardized College of American Pathologists (CAP) samples in analyzers by 5 manufacturers. In this operational analysis, we evaluated 22 950 ALT values from 80 independent CAP samples tested at 223 laboratories. Using mixed effects modeling, we estimated the association between analyzer manufacturer and CAP outcome, adjusting for manufacturer, facility, and calendar year. We performed subgroup analyses on CAP samples with overall means near clinical guideline-specified thresholds, including less than 50 U/L (n = 10) and less than 35 U/L (n = 5). RESULTS.­: The VHA used Abbott Laboratories (n = 3175; 14%), Beckman Coulter Diagnostics (n = 8723; 38%), Roche Diagnostics (n = 2595; 11%), Siemens Healthineers USA (n = 5713; 25%), and Vitros/Ortho Clinical Diagnostics (n = 2744; 12%) analyzers. The CAP samples (n = 80 samples, n = 22 950 tests) covered a wide range of mean ALT values (21-268 U/L). The average difference in mean ALT value per sample between the highest-reading and lowest-reading manufacturers was 15.4 U/L (SD = 1.8) for the 10 samples with mean ALT less than 50 U/L, and it was 10.4 U/L (SD = 3.6) overall (n = 80). In linear mixed effects modeling, we found statistically significant differences in ALT values between the different manufacturers in each year. CONCLUSIONS.­: We found statistically and clinically meaningful differences between analyzers across the ALT spectrum in each year, including at ALT levels lower than 50 U/L and lower than 35 U/L. Universal ALT thresholds should be avoided as a trigger for clinical action until differences between analyzers can be resolved.

Projected Prevalence of Actionable Pharmacogenetic Variants and Level A Drugs Prescribed Among US Veterans Health Administration Pharmacy Users.

Importance: Implementation of pharmacogenetic testing to guide drug prescribing has potential to improve drug response and prevent adverse events. Robust data exist for more than 30 gene-drug pairs linking genotype to drug response phenotypes; however, it is unclear which pharmacogenetic tests, if implemented, would provide the greatest utility for a given patient population. Objectives: To project the proportion of veterans in the US Veterans Health Administration (VHA) with actionable pharmacogenetic variants and evaluate how testing might be associated with prescribing decisions. Design, Setting, and Participants: This cross-sectional study included veterans who used national VHA pharmacy services from October 1, 2011, to September 30, 2017. Data analyses began April 26, 2018, and were completed February 6, 2019. Exposures: Receipt of level A drugs based on VHA pharmacy dispensing records. Main Outcomes and Measures: Projected prevalence of actionable pharmacogenetic variants among VHA pharmacy users based on variant frequencies from the 1000 Genomes Project and veteran demographic characteristics; incident number of level A prescriptions, and proportion of new level A drug recipients projected to carry an actionable pharmacogenetic variant. Results: During the study, 7 769 359 veterans (mean [SD] age, 58.1 [17.8] years; 7 021 504 [90.4%] men) used VHA pharmacy services. It was projected that 99% of VHA pharmacy users would carry at least 1 actionable pharmacogenetic variant. Among VHA pharmacy users, 4 259 153 (54.8%) received at least 1 level A drug with 1 188 124 (15.3%) receiving 2 drugs, and 912 189 (11.7%) receiving 3 or more drugs. The most common incident prescriptions during the study were tramadol (923 671 new recipients), simvastatin (533 928 new recipients), citalopram (266 952 new recipients), and warfarin (205 177 new recipients). Gene-drug interactions projected to have substantial clinical impacts in the VHA population include the interaction of SLCO1B1 with simvastatin (1 988 956 veterans [25.6%]), CYP2D6 with tramadol (318 544 veterans [4.1%]), and CYP2C9 or VKORC1 with warfarin (7 163 349 veterans [92.2%]). Conclusions and Relevance: Clinically important pharmacogenetic variants are highly prevalent in the VHA population. Almost all veterans would carry an actionable variant, and more than half of the population had been exposed to a drug affected by these variants. These results suggest that pharmacogenetic testing has the potential to affect pharmacotherapy decisions for commonly prescribed outpatient medications for many veterans.

Laboratory practices for identification and reporting of carbapenem-resistant Enterobacteriaceae in Department of Veterans Affairs facilities.

Laboratory identification of carbapenem-resistant Enterobacteriaceae (CRE) is a key step in controlling its spread. Our survey showed that most Veterans Affairs laboratories follow VA guidelines for initial CRE identification, whereas 55.0% use PCR to confirm carbapenemase production. Most respondents were knowledgeable about CRE guidelines. Barriers included staffing, training, and financial resources.

Clinical Impact of 21-Gene Recurrence Score Test Within the Veterans Health Administration: Utilization and Receipt of Guideline-Concordant Care.

INTRODUCTION: Ensuring guideline-concordant cancer care is a Department of Veterans Affairs (VA) priority, especially as the number of breast cancer patients at VA medical centers (VAMCs) grows. We assessed the utilization and clinical impact of the 21-gene Recurrence Score test, which predicts 10-year risk of breast cancer recurrence and the likelihood of chemotherapy benefit, on veterans newly diagnosed with breast cancer. PATIENTS AND METHODS: We conducted a retrospective cohort study using 2011-2012 VA Central Cancer Registry, chart review, and laboratory test data. Independent variables assessed included patient and site-of-care characteristics. The outcome of interest was whether newly diagnosed, eligible (node negative, hormone-receptor positive, human epidermal growth factor receptor 2 [HER2] negative) veterans underwent the 21-gene test. We performed descriptive statistics on all patients and multivariate logistic regression to determine associations. We correlated treatments received with test results. RESULTS: Among 328 eligible veterans, 82 (25%) had the 21-gene test; 100 eligible veterans (30%) sought care at a VAMC where no tests were ordered. Receiving care at a VAMC that had women's health services (odds ratio [OR], 1.84, 95% confidence interval [CI], 1.05-3.22) and having tumor characteristics meeting the National Comprehensive Cancer Network 2010 test criteria (OR, 3.06, 95% CI, 1.69-5.57) were positive predictors of testing; increasing age (OR, 0.93, 95% CI, 0.91-0.96 per year) and fee-based care (OR, 0.46, 95% CI, 0.26-0.82) were negative predictors. The majority of tested patients received guideline-concordant care. CONCLUSION: Site of care and tumor characteristics were important predictors of test uptake. Facilitating delivery of guideline-concordant cancer care requires improved laboratory informatics and clinical decision support.

VHA Practice Guideline Recommendations for Diffuse Gliomas.

Although histology still plays a critical role in diagnosing diffuse gliomas, additional ancillary testing is an essential tool for VA pathology laboratories.

Clinical decisions surrounding genomic and proteomic testing among United States veterans treated for lung cancer within the Veterans Health Administration.

BACKGROUND: Current clinical guidelines recommend epidermal growth factor receptor (EGFR) mutational testing in patients with metastatic non-small cell lung cancer (NSCLC) to predict the benefit of the tyrosine kinase inhibitor erlotinib as first-line treatment. Proteomic (VeriStrat) testing is recommended for patients with EGFR negative or unknown status when erlotinib is being considered. Departure from this clinical algorithm can increase costs and may result in worse outcomes. We examined EGFR and proteomic testing among patients with NSCLC within the Department of Veterans Affairs (VA). We explored adherence to guidelines and the impact of test results on treatment decisions and cost of care. METHODS: Proteomic and EGFR test results from 2013 to 2015 were merged with VA electronic health records and pharmacy data. Chart reviews were conducted. Cases were categorized based on the appropriateness of testing and treatment. RESULTS: Of the 69 patients with NSCLC who underwent proteomic testing, 33 (48%) were EGFR-negative and 36 (52%) did not have documented EGFR status. We analyzed 138 clinical decisions surrounding EGFR/proteomic testing and erlotinib treatment. Most decisions (105, or 76%) were concordant with clinical practice guidelines. However, for 24 (17%) decisions documentation of testing or justification of treatment was inadequate, and 9 (7%) decisions represented clear departures from guidelines. CONCLUSION: EGFR testing, the least expensive clinical intervention analyzed in this study, was significantly underutilized or undocumented. The records of more than half of the patients lacked information on EGFR status. Our analysis illustrated several clinical scenarios where the timing of proteomic testing and erlotinib diverged from the recommended algorithm, resulting in excessive costs of care with no documented improvements in health outcomes.

The Challenges of Precision Medicine and New Advances in Molecular Diagnostic Testing in Hematolymphoid Malignancies: Impact on the VHA.

The Hematopathology Molecular Genetics subcommittee presents recommendations for molecular diagnostic testing in acute myeloid leukemia, myeloproliferative neoplasms, myelodysplastic syndrome, and lymphomas and for the development of an interfacility consultation service.

BRCA testing within the Department of Veterans Affairs: concordance with clinical practice guidelines.

Guideline-concordant cancer care is a priority within the Department of Veterans Affairs (VA). In 2009, the VA expanded its capacity to treat breast cancer patients within VA medical centers (VAMCs). We sought to determine whether male and female Veterans diagnosed with breast cancer received BRCA testing as recommended by the National Comprehensive Cancer Network (NCCN) guidelines on Genetic/Familial High-Risk Assessment in Breast and Ovarian Cancer (v. 1.2010-1.2012). Using the 2011-2012 VA Central Cancer Registry and BRCA test orders from Myriad Genetics, we conducted a retrospective study. The outcome variable was a recommendation for genetic counseling or BRCA testing, determined by chart review. Independent variables expected to predict testing included region, site of care, and patient characteristics. We performed descriptive analysis of all patients and conducted multivariable logistic regression on patients who sought care at VAMCs that offered BRCA testing. Of the 462 Veterans who met NCCN testing criteria, 126 (27 %) received guideline-concordant care, either a referral for counseling or actual testing. No BRCA testing was recommended in 49 (50 %) VAMCs that provide cancer treatment. Surprisingly, patients with second primary breast cancer were less likely to be referred/tested (OR 0.39; CI 0.17, 0.89; p = 0.025). For patients under age 51, a yearly increase in age decreased likelihood of referral or testing (OR 0.85; CI 0.76, 0.94; p < 0.001). There were no differences in testing by race. In conclusion, there was significant underutilization and lack of access to BRCA testing for Veterans diagnosed with breast cancer. Our research suggests the need for clinical decision support tools to facilitate delivery of guideline-concordant cancer care and improve Veteran access to BRCA testing.

The stress-regulated transcription factor CHOP promotes hepatic inflammatory gene expression, fibrosis, and oncogenesis.

Viral hepatitis, obesity, and alcoholism all represent major risk factors for hepatocellular carcinoma (HCC). Although these conditions also lead to integrated stress response (ISR) or unfolded protein response (UPR) activation, the extent to which these stress pathways influence the pathogenesis of HCC has not been tested. Here we provide multiple lines of evidence demonstrating that the ISR-regulated transcription factor CHOP promotes liver cancer. We show that CHOP expression is up-regulated in liver tumors in human HCC and two mouse models thereof. Chop-null mice are resistant to chemical hepatocarcinogenesis, and these mice exhibit attenuation of both apoptosis and cellular proliferation. Chop-null mice are also resistant to fibrosis, which is a key risk factor for HCC. Global gene expression profiling suggests that deletion of CHOP reduces the levels of basal inflammatory signaling in the liver. Our results are consistent with a model whereby CHOP contributes to hepatic carcinogenesis by promoting inflammation, fibrosis, cell death, and compensatory proliferation. They implicate CHOP as a common contributing factor in the development of HCC in a variety of chronic liver diseases.

ANA (+) ANCA (+) systemic vasculitis associated with the use of minocycline: case-based review.

Minocycline is a synthetic tetracycline-derived antibiotic with significant anti-inflammatory properties that may benefit patients with rheumatoid arthritis. Surprisingly, chronic exposure to minocycline can also cause a breach in immunologic tolerance resulting in a variety of autoimmune syndromes such as drug-induced lupus or autoimmune hepatitis. Vasculitis, most commonly resembling cutaneous polyarteritis nodosa, has also been seen in patients taking this drug. Herein, we present a case of biopsy-proven systemic vasculitis presenting as an ANA (+) ANCA (+) polyarteritis nodosa-like syndrome in a male patient who was taking minocycline for his acne for approximately 2 years. Patient initially presented with constitutional symptoms such as profound weight loss and fatigue, along with myalgias, oligoarticular arthritis, and livedo reticularis. About 2 months later, he developed a severe left testicular pain. Biopsy showed vasculitis complicated with the infarction of the left testis. Angiography revealed microaneurysms in the renal and splenic circulation. Stopping the offending drug, along with the short course of prednisone and hydroxychloroquine, resulted in prompt resolution of his symptoms. We additionally present a comprehensive review of biopsy-proven cases of vasculitis associated with chronic minocycline treatment focusing on its pathogenesis and clinical manifestations.

Congenital pancytopenia and absence of B lymphocytes in a neonate with a mutation in the Ikaros gene.

BACKGROUND: Congenital pancytopenia is a rare and often lethal condition. Current knowledge of lymphoid and hematopoietic development in mice, as well as understanding regulators of human hematopoiesis, have led to the recent discovery of genetic causes of bone marrow failure disorders. However, in the absence of mutations of specific genes or a distinct clinical phenotype, many cases of aplastic anemia are labeled as idiopathic, while congenital immune deficiencies are described as combined immune deficiency. PROCEDURE: We describe the case of a 33-week gestation age male with severe polyhydramnios, hydrops, and ascites who was noted to be pancytopenic at birth. Bone marrow examination revealed a hypocellular marrow with absent myelopoiesis. An immune workup demonstrated profound B lymphopenia, near absent NK cells, and normal T cell number. Due to the similarity of the patient's phenotype with the IKAROS knockout mouse, studies were performed on bone marrow and peripheral blood to assess a potential pathogenic role of Ikaros. RESULTS: DNA studies revealed a point mutation in one allele of the IKAROS gene, resulting in an amino acid substitution in the DNA-binding zinc finger domain. Functional studies demonstrated that the observed mutation decreased Ikaros DNA-binding affinity, and immunofluorescence microscopy revealed aberrant Ikaros pericentromeric localization. CONCLUSIONS: Our report describes a novel case of congenital pancytopenia associated with mutation of the IKAROS gene. Furthermore, these data suggest a critical role of IKAROS in human hematopoiesis and immune development.

Hepatitis C virus infection and hepatic stellate cell activation downregulate miR-29: miR-29 overexpression reduces hepatitis C viral abundance in culture.

BACKGROUND: Chronic hepatitis C virus (HCV)-induced liver fibrosis involves upregulation of transforming growth factor (TGF)-ß and subsequent hepatic stellate cell (HSC) activation. MicroRNAs (miRNAs) regulate HCV infection and HSC activation. METHODS: TaqMan miRNA profiling identified 12 miRNA families differentially expressed between chronically HCV-infected human livers and uninfected controls. To identify pathways affected by miRNAs, we developed a new algorithm (pathway analysis of conserved targets), based on the probability of conserved targeting. RESULTS: This analysis suggested a role for miR-29 during HCV infection. Of interest, miR-29 was downregulated in most HCV-infected patients. miR-29 regulates expression of extracellular matrix proteins. In culture, HCV infection downregulated miR-29, and miR-29 overexpression reduced HCV RNA abundance. miR-29 also appears to play a role in HSCs. Hepatocytes and HSCs contribute similar amounts of miR-29 to whole liver. Both activation of primary HSCs and TGF-ß treatment of immortalized HSCs downregulated miR-29. miR-29 overexpression in LX-2 cells decreased collagen expression and modestly decreased proliferation. miR-29 downregulation by HCV may derepress extracellular matrix synthesis during HSC activation. CONCLUSIONS: HCV infection downregulates miR-29 in hepatocytes and may potentiate collagen synthesis by reducing miR-29 levels in activated HSCs. Treatment with miR-29 mimics in vivo might inhibit HCV while reducing fibrosis.

Correlation between microRNA expression levels and clinical parameters associated with chronic hepatitis C viral infection in humans.

MicroRNAs (miRNAs) are small RNAs that regulate gene expression pathways. Previous studies have shown interactions between hepatitis C virus (HCV) and host miRNAs. We measured miR-122 and miR-21 levels in HCV-infected human liver biopsies relative to uninfected human livers and correlated these with clinical patient data. miR-122 is required for HCV replication in vitro, and miR-21 is involved in cellular proliferation and tumorigenesis. We found that miR-21 expression correlated with viral load, fibrosis and serum liver transaminase levels. miR-122 expression inversely correlated with fibrosis, liver transaminase levels and patient age. miR-21 was induced ∼twofold, and miR-122 was downregulated on infection of cultured cells with the HCV J6/JFH infectious clone, thus establishing a link to HCV. To further examine the relationship between fibrosis and the levels of miR-21 and miR-122, we measured their expression levels in a mouse carbon tetrachloride fibrosis model. As in the HCV-infected patient samples, fibrotic stage positively correlated with miR-21 and negatively correlated with miR-122 levels. Transforming growth factor ß (TGF-ß) is a critical mediator of fibrogenesis. We identified SMAD7 as a novel miR-21 target. SMAD7 is a negative regulator of TGF-ß signaling, and its expression is induced by TGF-ß. To confirm the relationship between miR-21 and the TGF-ß signaling pathway, we measured the effect of miR-21 on a TGF-ß-responsive reporter. We found that miR-21 enhanced TGF-ß signaling, further supporting a relationship between miR-21 and fibrosis. We suggest a model in which miR-21 targeting of SMAD7 could increase TGF-ß signaling, leading to increased fibrogenesis.

Down-regulation of heme oxygenase-1 by hepatitis C virus infection in vivo and by the in vitro expression of hepatitis C core protein.

Antioxidant enzymes, including heme oxygenase (HO)-1, are an important line of defense against oxidant-mediated liver injury. Because hepatitis C virus (HCV) infection appears to increase the production of oxidants, we evaluated levels of antioxidant enzymes and HO-1 in liver-biopsy samples from HCV-infected patients by immunoblot and semiquantitative reverse-transcriptase polymerase chain reaction. In HCV-infected liver samples, levels of immunoreactive HO-1 and HO-1 mRNA were >4-fold lower than levels in control samples, but levels of superoxide dismutase and catalase were unaffected. Immunohistochemical results confirmed the decreased expression of HO-1 in hepatocytes from liver samples from HCV-infected patients but not in those from patients with other chronic liver diseases. The expression of HO-1 was also reduced in cell lines that stably express HCV core protein, which suggests that core gene products are capable of regulating the expression of HO-1.

Burkitt s lymphoma variant of post-transplant lymphoproliferative disease (PTLD).

The occurrence of posttransplant lymphoproliferative disorder (PTLD) in solid organ allograft recipients can be quite varied in clinical presentation, histopathological characteristics and frequency. A variety of lymphomas can develop as a PTLD although some types appear infrequently and remain poorly understood in this clinical setting. In this report, we describe two cases of Burkitt s lymphoma presenting as a PTLD following liver transplantation. The recipients were 12 and 44 years of age and displayed gastrointestinal involvement by the tumors several years following transplant. The tumors displayed the typical histological features of Burkitt s lymphoma and were markedly positive for EBV. The tumors displayed similar immunophenotypic characteristics by flow cytometry and had rearrangements of the immunoglobulin J-H heavy chain. The tumors required aggressive chemotherapy and a cessation of immunosuppressive therapy. This report demonstrates that Burkitt s type lymphomas can develop in the posttransplant setting and that these tumors contain morphologic, cytofluorographic and molecular features identical to Burkitt s lymphomas that occur in non-transplant patients. Our experience is that these PTLD- Burkitt s lymphomas behave aggressively and require intensive chemotherapeutic intervention.