Acute and Chronic Changes in Gene Expression After CMV DNAemia in Kidney Transplant Recipients

Cytomegalovirus (CMV) viremia continues to cause significant morbidity and mortality in kidney transplant patients with clinical complications including organ rejection and death. Whole blood gene expression dynamics in CMV viremic patients from onset of DNAemia through convalescence has not been well studied to date in humans. To evaluate how CMV infection impacts whole blood leukocyte gene expression over time, we evaluated a matched cohort of 62 kidney transplant recipients with and without CMV DNAemia using blood samples collected at multiple time points during the 12-month period after transplant. While transcriptomic differences were minimal at baseline between DNAemic and non-DNAemic patients, hundreds of genes were differentially expressed at the long-term timepoint, including genes enriching for pathways important for macrophages, interferon, and IL-8 signaling. Amongst patients with CMV DNAemia, the greatest amount of transcriptomic change occurred between baseline and 1-week post-DNAemia, with increase in pathways for interferon signaling and cytotoxic T cell function. Time-course gene set analysis of these differentially expressed genes revealed that most of the enriched pathways had a significant time-trend. While many pathways that were significantly down- or upregulated at 1 week returned to baseline-like levels, we noted that several pathways important in adaptive and innate cell function remained upregulated at the long-term timepoint after resolution of CMV DNAemia. Differential expression analysis and time-course gene set analysis revealed the dynamics of genes and pathways involved in the immune response to CMV DNAemia in kidney transplant patients. Understanding transcriptional changes caused by CMV DNAemia may identify the mechanism behind patient vulnerability to CMV reactivation and increased risk of rejection in transplant recipients and suggest protective strategies to counter the negative immunologic impact of CMV. These findings provide a framework to identify immune correlates for risk assessment and guiding need for extending antiviral prophylaxis.

944. CMV Peak Viral Load, Recurrence, Duration, and Outcomes in Kidney Transplant Recipients

Background Cytomegalovirus (CMV) infection continues to cause morbidity in kidney transplant recipients, despite prophylaxis and pre-emptive therapy. Predictors of poor outcomes remain incompletely characterized. We questioned whether markers of CMV replication (CMV peak viral load, recurrent episodes, or duration of CMV DNAemia) are associated with adverse outcomes in the current era. Methods We studied 605 people who underwent kidney transplant at Johns Hopkins University (2010 – 2018). Mean follow-up was 45.5 months. The average age was 51.85 years and 39.7% were female. Donor-seropositive, recipient seronegative (D+/R-) patients received valganciclovir 900 mg/day for 6 months, while R+ patients received valganciclovir 450 mg/day for 3 months. CMV recurrence was defined as CMV DNAemia after two undetectable CMV PCR’s. Outcomes of acute rejection, graft failure, and death were evaluated in univariate analysis; p values were calculated by Fisher’s exact test. Results Peak CMV viral load was not associated with any outcomes (Table 1). There was a trend of increased graft failure in people who had long duration ( >6 month) DNAemia (Table 2). More than two episodes of CMV reactivation was associated with graft failure and rejection (Table 3). Conclusion CMV reactivation is associated with kidney rejection and failure in univariate models. Multivariate analyses and longitudinal modeling will provide increased data upon which to better instruct preventative strategies. Acknowledgments Funding for the research study was provided by Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc., Kenilworth, NJ, USA Disclosures Robin K. Avery, MD, Aicuris (Grant/Research Support)Astellas (Grant/Research Support)Chimerix (Research Grant or Support)Merck (Grant/Research Support)Oxford Immunotec (Grant/Research Support)Qiagen (Grant/Research Support)Takeda/Shire (Grant/Research Support) Yuexin Tang, PhD, JnJ (Other Financial or Material Support, Spouse’s employment)Merck & Co., Inc. (Employee, Shareholder) Kieren Marr, MD, Merck (Grant/Research Support, Advisor or Review Panel member)

924. Cytomegalovirus (CMV) Retinitis during Maintenance Chemotherapy for Acute Lymphoblastic Leukemia

Background Acute leukemia patients are at risk for cytomegalovirus (CMV) retinitis following hematopoietic stem cell transplantation, though the disease can also occur in non-transplant adult leukemia patients. Emerging data suggest a shift to pediatric-inspired chemotherapy regimens in adults with acute lymphoblastic leukemia (ALL) can lead to increasing cytopenias and impaired functional immunity, placing these patients at risk for this opportunistic infection. Here we describe a case of CMV retinitis in an ALL patient following a lower-intensity regimen during maintenance chemotherapy. Methods Chart review. Results A 55-year-old male with ALL presented to his optometrist with complaints of visual changes including “fogginess” and “floaters”. The patient had completed 8 cycles of dose-adjusted etoposide, prednisone, vincristine, cyclophosphamide, doxorubicin, and rituximab (EPOCH-R) and achieved complete remission. He had been on maintenance chemotherapy with 6-mercaptopurine, vincristine, methotrexate, and prednisone (POMP) for 2 months at the time of symptom onset. He was referred to his local ophthalmologist who had concerns for bilateral, zone 1 CMV retinitis based on fundoscopic exam (Figure 1). Vitreous aspiration was performed and CMV DNA PCR returned positive at 1.6 million IUs/ml. Peripheral blood CMV DNA PCR was also positive at 1133 IU/ml. He was started on combination therapy with intravitreal ganciclovir injections and oral valganciclovir 900 mg twice daily (Figure 2). The patient received 14 intravitreal injections with resultant stability of his eye exam, though he remained on induction valganciclovir for 5 months due to persistent blood CMV DNAemia. Letermovir was added to help suppress his peripheral CMV DNAemia and he attained partial vision recovery. Figure 1. Fundoscopic images Conclusion CMV retinitis is an uncommon and highly morbid infection that can occur during maintenance chemotherapy in adult non-transplant ALL patients. Early identification of the disease is imperative as delay can result in blindness or further systemic CMV disease. Treatment is challenging, involving systemic and intravitreal antiviral therapy, serial ophthalmologic exams, serum CMV monitoring, and close coordination with the treating hematologist. Disclosures Michael Boeckh, MD PhD, AlloVir (Consultant)Ansun Biopharma (Grant/Research Support)Astellas (Grant/Research Support)EvrysBio (Consultant, Other Financial or Material Support, Options to acquire equity, but have not exercised them)Gilead Sciences (Consultant, Grant/Research Support)GlaxoSmithKline (Consultant)Helocyte (Consultant, Other Financial or Material Support, Options to acquire equity, but have not exercised them)Janssen (Grant/Research Support)Kyorin (Consultant)Merck (Consultant, Grant/Research Support)Moderna (Consultant)Symbio (Consultant)Takeda (formerly known as Shire) (Consultant, Grant/Research Support)VirBio (Consultant, Grant/Research Support) Ryan Cassaday, MD, Amgen (Grant/Research Support, Advisor or Review Panel member)Kite/Gilead (Grant/Research Support, Advisor or Review Panel member)Merck (Grant/Research Support)Pfizer (Grant/Research Support, Advisor or Review Panel member)Seagen (Other Financial or Material Support, Spouse is employee and hold stock)Vanda Pharmaceuticals (Grant/Research Support)

Comparison of Humoral and Cellular CMV Immunity in Patients Awaiting Kidney Transplantation

Chronic kidney disease may alter antiviral T cell immunity. In the current study, we assessed in 63 patients prior to kidney transplantation how humoral and cellular immunity against cytomegalovirus (CMV) correlated using an interferon (IFN)-γ ELISpot (T-Track® CMV, Mikrogen, Neuried, Germany). The cohort comprised 24 patients with negative and 39 with positive CMV IgG. Whereas none of the patients with negative CMV IgG showed detectable responses to the T-Track® CMV, 26 out of 39 patients with positive CMV IgG had positive ELISpot responses. The median response to CMV pp65 in the CMV seronegative group was 0 spot forming units (SFU) per 200,000 PBMC (range 0–1) and in the seropositive group 43 SFU (range 0–750). Thus, 13 out of 39 patients with positive CMV serostatus (33%) had undetectable T cell immunity and may be at an increased risk of CMV reactivation. CMV pp65-specific ELISpot responses were 29.3-fold higher in seropositive patients with vs. without dialysis and 5.6-fold higher in patients with vs. without immunosuppressive therapy, but patients with dialysis and immunosuppressive therapy showed, as expected, lower responses to phytohemagglutinin, the positive control. This finding may be caused by (subclinical) CMV-DNAemia and a “booster” of CMV-specific T cells.

The TLR9 2848C/T Polymorphism Is Associated with the CMV DNAemia among HIV/CMV Co-Infected Patients

Toll-like receptors (TLRs) recognize pathogen-associated molecular patterns and are essential components of the host’s innate immune response. The aim of this study was to determine the TLR9 genotype frequency and investigate the association between TLR9 polymorphisms and cytomegalovirus (CMV) DNAemia in human immunodeficiency virus (HIV)/CMV co-infected patients. A total of 205 HIV/CMV co-infected adults were screened for the presence of the four TLR9 polymorphisms (−1237T/C, −1486T/C, 1174G/A, and 2848C/T) by using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Mutation presented in at least one allele of the TLR9 2848C/T single nucleotide polymorphism (SNP) was associated with the occurrence of CMV DNAemia among HIV-infected patients with CMV co-infection (p = 0.004). The level of CMV DNA was higher in patients who were homozygous recessive or heterozygous for the 2848C/T polymorphism compared with those who had a wild-type genotype for this polymorphism (p = 0.005). Mutation detected in at least one allele of this SNP was also associated with a lower interferon type β (IFN-β) concentration (p = 0.048), while no relationships between TLR9 −1237T/C, −1486T/C, and 1174G/A SNPs and CMV DNAemia were observed. Our findings suggest that the mutation present in at least one allele of the TLR9 2848C/T SNP may be associated with the active CMV infection in HIV/CMV co-infected subjects.

Th1/17 Cells Infiltrate Murine Cytomegalovirus-Infected Renal Allografts via Virus-Induced CCL20 and Promote Th1 Cells through IL-17A.

Cytomegalovirus (CMV) infection is associated with renal allograft failure by unknown mechanisms. In a murine renal transplant model, murine CMV (MCMV) induces intragraft infiltration of Th17 cells co-expressing Th1 cytokines, IFN-γ and TNF-α, but only a minority of intragraft Th17 cells are specific for MCMV antigens. Instead, MCMV promotes viral antigen-independent Th17 cell recruitment via CCL20-CCR6 and CXCL10-CXCR3 interactions. Th17 cells correlate directly with Th1 cell frequencies and inversely with Tregs in MCMV infected grafts. Pharmacologic inhibition of IL-17A reduces intragraft Th17 cells and neutrophils, increases Tregs, and reduces total but not MCMV-specific Th1 cells. Among a clinical renal transplant cohort with acute rejection, patients with CMV DNAemia had significantly higher serum IL-17A quantities compared to those without CMV DNAemia. Together, these findings indicate that CMV infection upregulates Th17 cell activity during acute rejection and suggests that inhibition of IL-17A may ameliorate CMV-associated allograft injury without impairing antiviral Th1 cells.

Association between Antiviral Prophylaxis and Cytomegalovirus and Epstein–Barr Virus DNAemia in Pediatric Recipients of Allogeneic Hematopoietic Stem Cell Transplant

Background: Epstein–Barr virus (EBV) and cytomegalovirus (CMV) infections can have serious consequences during the period of aplasia and lymphopenia following hematopoietic stem cell transplantation (HSCT). Large pediatric cohort studies examining the effect of antiviral prophylaxis against these viruses are scarce. The present study aimed to analyse the potential effect of antiviral prophylaxis (acyclovir and famciclovir) on active post-transplant EBV and CMV infection in a pediatric cohort of allogeneic HSCT recipients. Methods: We used data from the TREASuRE cohort, consisting of 156 patients who had a first allogeneic HSCT, enrolled in four pediatric centers in Canada between July 2013 and March 2017. Follow-up was performed from the time of transplant up to 100 days post-transplant. Adjusted hazard ratio (HR) with 95% confidence intervals (CI) for the association between antiviral prophylaxis with acyclovir and/or famciclovir and EBV and CMV DNAemia was estimated using multivariate Cox regression models. Results: The post-transplant cumulative incidence of EBV and CMV DNAemia at 100 days of follow-up were, respectively, 34.5% (95% CI: 27.6–42.6) and 19.9% (95% CI: 14.5–27.1). For acyclovir, the adjusted hazard ratio (HR) for CMV and EBV DNAemia was 0.55 (95% CI: 0.24–1.26) and 1.41 (95% CI: 0.63–3.14), respectively. For famciclovir, the adjusted HR were 0.82 (95% CI: 0.30–2.29) and 0.79 (95% CI: 0.36–1.72) for CMV and EBV DNAemia, respectively. Conclusion: The antivirals famciclovir and acyclovir did not reduce the risk of post-transplant CMV and EBV DNAemia among HSCT recipients in our pediatric population.

#50: Cytomegalovirus Retinitis Among Pediatric Hematopoietic Stem Cell and Solid Organ Transplantation Recipients: A Contemporary Review

Background Cytomegalovirus infection can cause significant morbidity and mortality after transplantation. Cytomegalovirus retinitis (CMVR) can be a major complication of tissue invasive CMV disease in transplant recipients. There are little data regarding the contemporary incidence and outcomes of CMVR among pediatric transplant recipients. Methods We performed a retrospective cohort analysis of allogeneic hematopoietic (allo-HCT) and solid organ transplant (SOT) recipients who received medical care at Nationwide Children’s Hospital (NCH) from 1/1/10–11/30/20 and had a diagnosis of CMVR to describe the incidence, timing post-transplant, ocular manifestations, management, and outcomes. Basic demographic and clinical data, pre-transplant donor/recipient CMV serostatus, and post-transplant CMV infection data were collected. Graft-specific CMV surveillance and prophylaxis strategies were performed according to NCH hospital guidelines. During the study period, quantitative plasma CMV PCR assays included copies/mL (2010–2013) and WHO international standard IU/mL (2013–2020). Results During the 10-year study period, 347 patients underwent allo-HCT (N=214) or SOT (N=133; heart N=46, liver N=36, kidney N= 52; 1 patient had concomitant kidney and liver transplantation); median age was 8.6 years [range 0.1–25.9] and 198 (56.5%) were male. In total, 98 patients had CMV DNAemia post-transplant, and CMVR was diagnosed in 3 (HCT=2, SOT=1), for an overall CMVR incidence of 0.86% among all transplant recipients and occurring in 3% of patients with CMV DNAemia. No CMVR was diagnosed in patients without CMV DNAemia. An ophthalmologic examination was performed in 58 (59%) of patients with any DNAemia compared with 67 (27%) of patients without DNAemia. CMVR was diagnosed on funduscopic examination a median of 183 days [range 34–512] post-transplant based on visual symptomatology (N=2) or by routine eye screening prompted by DNAemia (N=1). CMV DNAemia at the time of CMVR was 1,463 copies/mL, 3,000, and 14,204 IU/mL; all patients had prolonged (>3 months) CMV detection before CMVR. One SOT recipient had concomitant pathology confirming CMV gastrointestinal tract disease. Two of the 3 CMVR cases occurred in the setting of genotypic UL94 CMV resistance mutations (A594V, H520Q)(Figure 1). Two patients were already receiving CMV antiviral therapy (maribavir N=1; valganciclovir=1) at the time of CMVR diagnosis. After the CMVR diagnosis, all patients were prescribed systemic foscarnet. Adjunctive therapies included concurrent intravitreal antiviral therapy (ganciclovir N=1; foscarnet N=1) and adoptive immunotherapy with CMV antiviral specific T-cells (N=1, HCT). Improvement of ocular symptoms occurred in 2 patients at 15 and 20 days after starting targeted CMV antiviral therapy; one patient developed permanently impaired vision. Conclusion CMVR remains as an important complication in transplant recipients. Although CMVR incidence was low in our cohort of transplant recipients, it occurred most frequently in cases of CMV resistance, prolonged DNAemia, and led to permanent visual impairment in 1 of 3 patients. The development of resistant CMV may have a role in the occurrence, progression, and severity of CMVR. Additional pediatric-specific data are needed to better characterize CMVR and inform optimal prevention strategies.

CMV-Specific Cell-Mediated Immunity in Immunocompetent Adults with Primary CMV Infection: A Case Series and Review of the Literature

Cytomegalovirus-specific cell-mediated immunity (CMV-CMI) in actively infected healthy immunocompetent hosts has been poorly investigated. Conversely, correlates of maternal protective immunity for the fetus after primary infection in pregnancy continue to be studied. The kinetics and magnitude of CMV-specific CMI in immunocompetent primary CMV-infected adults are described. A literature review on CMV-CMI in primarily infected pregnant women and its correlation to the risk of vertical virus transmission is included. Immunological measurements after infection were performed by enzyme-linked ImmunoSPOT assay enumerating IFN-γ secreting CMV-specific T cells, at a single cell level, upon in vitro stimulation with viral antigens. Simultaneously, serological and virological profiles of infected patients were investigated. Patients displayed mild-to-moderate clinical and laboratory profiles for infection, and all showed positive EliSpot results in the early stage of infection (<20 days after onset). The virus-CMI was strong in the majority of patients (58.8%) in which the lowest CMV-DNAemia levels (<300 copies/mL) were detected. Significantly higher viral loads were observed in patients with weak CMV-CMI at the same time-point post-infection (up to 15,104 copies/mL; p < 0.001). T cell response magnitudes to IE-1 and pp65-UL83 peptides were overlapping and stable over time. In these case series, the early presence of CMV-CMI was probably pivotal in controlling viral replication and led to spontaneous viral clearance.

Letermovir for Cytomegalovirus Prophylaxis in Lung Transplant Patients with Valganciclovir-Induced Leukopenia

Cytomegalovirus (CMV) prophylaxis with valganciclovir is the standard of practice in most transplant centers, but treatment-related leukopenia can limit valganciclovir’s use. Therefore, we evaluated letermovir, a novel antiviral agent recently approved for use in hematopoietic cell transplant patients as CMV prophylaxis, in lung transplant recipients unable to tolerate valganciclovir due to severe leukopenia. We performed a retrospective analysis of all lung transplant patients at our center who received letermovir for CMV prophylaxis between 1 December 2018 and 1 January 2020. A repeated measures mixed model was used to analyze white blood cell (WBC) trends, and descriptive statistics were used to analyze secondary endpoints, including CMV DNAemia, renal function, immunosuppression dosing, and allograft function. Seventeen patients were administered letermovir during the study period due to valganciclovir-induced leukopenia (median WBC nadir 1.1 K/uL, range <0.30–2.19 K/uL). Median WBC improvement was noted in 15 (88.2%) patients after starting letermovir. Breakthrough CMV DNAemia necessitating treatment occurred in two patients, with one of the two cases being due to patient noncompliance. CMV resistance to letermovir was detected in two patients, necessitating a change to an alternative agent in one of these patients. No major side effects were reported in any patient. Letermovir is a generally safe and effective alternative for CMV prophylaxis in lung transplant recipients unable to tolerate valganciclovir due to leukopenia.