Ajit P. Limaye

Ganciclovir-resistant cytomegalovirus in organ transplant recipients

Ganciclovir-resistant (GanR) cytomegalovirus (CMV) is an emerging clinical problem in organ transplant recipients, particularly recipients of kidney and pancreas and lung transplants. GanR CMV, a late posttransplantation complication, is observed predominantly among CMV-seronegative recipients of organs from seropositive donors, especially among recipients receiving intensive immunosuppression and having prolonged exposure to ganciclovir. Given the limitations of current diagnostic methods, if GanR CMV is clinically suspected, empirical treatment with intravenously administered foscarnet should be used in conjunction with reductions in immunosuppressive therapy and possibly CMV hyperimmune globulin. Better diagnostic tools and newer, less-toxic antiviral agents with different mechanisms of action are urgently needed to decrease the morbidity associated with this complication in organ transplant recipients.

Longitudinal Assessment of Cytomegalovirus (CMV)—Specific Immune Responses in Liver Transplant Recipients at High Risk for Late CMV Disease

Cytomegalovirus (CMV)-seronegative recipients (R(-)) of a liver transplant from CMV-positive donors (D(+)) are at high risk for developing late CMV disease after discontinuation of antiviral prophylaxis. Levels of viremia and CMV-specific interferon (IFN)- gamma -producing CD4(+) and IFN- gamma -producing CD8(+) T cell responses were prospectively measured from discontinuation of antiviral prophylaxis until 1 year after transplantation in 17 consecutive D(+)/R(-) patients. CMV loads of >1000 copies/mL were strongly associated with CMV disease in the 6 symptomatic patients. Despite immunosuppression, broadly diverse T cells specific for CMV lysate or peptide libraries spanning pp65 and immediate early (IE) 1 immunodominant CMV antigens developed in all patients. A vigorous CD8(+) T cell response to pp65 and IE1 antigens characterized the D(+)/R(-) cohort. Unexpectedly, none of these responses were predictive of CMV disease or viremia. No significant lymphopenia or functional impairment of CMV-specific T cells was detected in the symptomatic patients, whose morbidity was resolved after antiviral treatment while measurable CMV immunity was maintained during the 1-year observation period.

Association of hepatic iron overload with invasive fungal infection in liver transplant recipients

Invasive fungal infection is a serious complication of orthotopic liver transplantation, but its risk factors remain incompletely defined. Iron overload has already been associated with increased risk of fungal infections, but it has not yet been assessed as a risk factor in liver transplantation. We retrospectively studied a cohort of 153 consecutive patients who underwent their first liver transplantation at a single center and who survived at least 7 days after transplantation. The association between various pretransplant patient characteristics, including hepatic explant iron and risk of invasive fungal infections, was analyzed by univariate and multivariate models. Iron in the hepatic explant was assessed by Perls Prussian blue stain by a pathologist blinded to clinical outcome. During the first year after transplantation, 28 of 153 patients developed a total of 31 invasive fungal infections, of which 21 (68%) were caused by Candida, 7 (23%) by Aspergillus, 2 (6%) by Cryptococcus, and 1 (3%) by Saccharomyces. Stainable iron in the hepatic explant was found in 48 patients (31%). Stainable iron in the hepatic explant was found to be strongly and independently associated with posttransplantation fungal infections in multivariate analysis (hazard ratio 3.09; 95% confidence interval 1.45‐6.56; P = 0.003). Hepatic iron overload is strongly and independently associated with posttransplantation invasive fungal infections. Studies to confirm this finding in other centers and define the mechanism are warranted. Liver Transpl 12:1799‐1804, 2006.

Programmed death-1 expression in liver transplant recipients as a prognostic indicator of cytomegalovirus disease

Immunological parameters that distinguish solid-organ transplant (SOT) recipients at risk for life-threatening cytomegalovirus (CMV) disease are being actively pursued to aid posttransplant management. A candidate marker is programmed death (PD)-1 receptor, whose overexpression has been associated with disease progression during persistent viral infections. To determine whether levels of this negative regulator of T cell activity are altered in SOT recipients with symptoms of CMV disease, a comparative PD-1 expression analysis was done in healthy, CMV-positive individuals and in liver transplant recipients. PD-1 levels were measured among the total population of CD8(+) and CD8(+) T cells binding to CMV-specific major histocompatibility complex class I tetramers. Minimal PD-1 expression was found in the healthy, CMV-positive cohort, and symptomatic SOT recipients had significantly higher PD-1 levels. PD-1 up-regulation was significantly associated with incipient and overt CMV disease and with viremia. Our findings suggest that PD-1 could be developed as a prognostic tool to predict CMV disease and guide therapeutic interventions.

Programmed death-1 receptor and interleukin-10 in liver transplant recipients at high risk for late cytomegalovirus disease

A. Krishnan, W. Zhou, S.F. Lacey, A.P. Limaye, D.J. Diamond, C. La Rosa. Programmed death‐1 receptor and interleukin‐10 in liver transplant recipients at high risk for late cytomegalovirus disease.u2028Transpl Infect Dis 2010: 12: 363–370. All rights reserved

Primary response against cytomegalovirus during antiviral prophylaxis with valganciclovir, in solid organ transplant recipients

Antiviral prophylaxis has proved successful for prevention of cytomegalovirus (CMV) disease in solid organ transplant (SOT) patients; though emerging data suggest that antiviral agents interfere with immunity, and may inhibit immune priming. In this context, we investigated levels and phenotype of primary CMV‐specific immune responses that developed during antiviral prophylaxis in a cohort of CMV seronegative recipients (R−) of a SOT from a seropositive donor (D+). We longitudinally monitored CMV viral load, antibodies and levels of the negative immuno‐modulator IL‐10. PBMC were stimulated with CMV‐specific peptide libraries to measure CD137 activation marker on CMV‐specific T‐cells and levels of PD‐1 receptor, which is over expressed on exhausted T‐cells. Unexpectedly, the majority (13/18) of D+R− patients who developed a primary CMV response showed early post‐transplant CMV‐specific responses, though levels of PD‐1 on CMV‐specific T‐cells remained elevated throughout prophylaxis. A strong inverse association was found between levels of plasma IL‐10 and CMV‐specific cellular immune responses. Our study suggests that during prophylaxis, subclinical CMV infection might have occurred in the D+R− patients, and primary CMV‐specific responses were detected early post‐transplant when levels of plasma IL‐10 were low. Extended prophylaxis or antiviral treatment did not appear to suppress CMV‐specific antibodies or T‐cells, which, however, showed exhaustion phenotypes.

Infection control strategies that successfully controlled an outbreak of Mycobacterium abscessus at a cystic fibrosis center

BACKGROUNDnMycobacterium abscessus infection in patients with cystic fibrosis (CF) can result in accelerated clinical decline and the potential for direct or indirect transmission between patients has been recently demonstrated. Data on the outcomes of M abscessus outbreaks and the efficacy of specific infection control procedures in patients with CF remain limited. This study provides follow-up from an outbreak of pulmonary M abscessus in our center, highlighting outcomes and strategies that appear to have prevented further spread of the organism.nnnMETHODSnData from our adult CF center (1989-2015) were analyzed, including chart reviews of all patients with positive mycobacterial sputum cultures, cultures from environment surfaces, and epidemiologic evaluation of infected patients. Following an M abscessus outbreak in 2009, infection control policies were intensified based on CF guidelines and surveillance data were collected and reviewed.nnnRESULTSnFive cases of M abscessus were involved in the outbreak; 3 patients died during follow-up. An environment search failed to reveal an intermediary source of transmission between patients. After implementation of infection control measures composed of staff/patient education, environment sterilization, and patient isolation, no new cases were detected.nnnCONCLUSIONSnDirect or indirect patient-to-patient transmission of M abscessus is a threat in the CF population. A multifaceted infection control strategy based on CF guidelines was effective in halting transmission in our center.

Rapid Detection of Human Cytomegalovirus UL97 and UL54 Mutations Directly from Patient Samples

ABSTRACT Human cytomegalovirus (CMV) is a significant contributor to morbidity and mortality in immunocompromised patients, particularly in the transplant setting. The availability of anti-CMV drugs has improved treatment, but drug resistance is an emerging problem. Here, we describe an improved, rapid, sequencing-based assay for the two genes in CMV where drug resistance occurs, the UL97 and UL54 genes. This assay is performed in 96-well format with a single master mix and provides clinical results within 2 days. It sequences codons 440 to 645 in the UL97 gene and codons 255 to 1028 in the UL54 gene with a limit of detection of 240 IU/ml. With this assay, we tested 43 specimens that had previously been tested for UL97 drug resistance and identified 3 with UL54 mutations. One of these patients had no concurrent UL97 mutation, pointing toward the need for an assay that facilitates dual UL97/UL54 gene testing for complete resistance profiling.

Are we underestimating the quality of aviremic hepatitis C-positive kidneys? Time to reconsider

Kidney Donor Risk Index (KDRI) introduced in 2009 included hepatitis C serologic but not viremic status of the donors. With nucleic acid amplification testing (NAT) now being mandatory, further evaluation of these donors is possible. We conducted a retrospective matched case‐control analysis of adult deceased donor kidney transplants performed between December 5, 2014 to December 31, 2016 with the KDRI score and hepatitis C virus antibody (HCV Ab) and NAT testing status obtained from the United Network for Organ Sharing database. The 205 aviremic HCV Ab+ NAT ‐ kidney transplants were compared to KDRI matched control kidneys that were HCV Ab–NAT‐. The aviremic HCV kidneys were recovered from donors who were significantly younger, more likely to be white, and less likely to have hypertension and diabetes. The majority of the recipients of the aviremic HCV kidneys when compared to matched controls were HCV positive: 90.2% vs 4.3%. The recipients were significantly older, were on dialysis for a shorter time, and were transplanted sooner. The graft survival of aviremic HCV kidneys was similar (P < .08). If the HCV status of the aviremic kidneys was assumed to be negative, 122 more kidneys could have been allocated to patients with estimated posttransplant survival <20. Seven kidneys would no longer have Kidney Donor Profile Index >85%. Further policies might consider these findings to appropriately allocate these kidneys.

Unintended Consequences in Use of Increased Risk Donor Kidneys in the New Kidney Allocation Era

BACKGROUNDnThe new kidney allocation system (KAS) intends to allocate the top 20% of kidneys to younger recipients with longer life expectancy. We hypothesized that the new KAS would lead to greater allocation of Public Health Service (PHS) increased-risk donor organs to younger recipients.nnnMETHODSnAnalyses of the Organ Procurement and Transplantation Network data of patients who underwent primary deceased kidney transplantation were performed in pre- and post-KAS periods.nnnRESULTSnThe allocation of PHS increased-risk kidney allografts in various age groups changed significantly after implementation of the new KAS, with an increased proportion of younger individuals receiving increased-risk kidneys (7% vs 10% in age group 20-29 y and 13% vs 18% in age group 30-39 y before and after KAS, respectively; Pxa0< .0001). This trend was reversed in recipients 50-59 years old, with 31% in the pre-KAS period compared with 26% after KAS (Pxa0< .0001).nnnCONCLUSIONSnThe new KAS resulted in a substantial increase in allocation of PHS increased-risk kidneys to candidates in younger age groups. Because increased-risk kidneys are generally underutilized, future efforts to optimize the utilization of these organs should target younger recipients and their providers.