Cytomegalovirus infection after intestinal transplantation in children

Clinical characteristics and outcomes in CMV infection in intestinal transplant recipients: A single-center experience

BACKGROUND

Cytomegalovirus (CMV) infection is one of the most common posttransplantation infections and has been associated with increased rejection and mortality. Data in intestinal transplants recipients are limited.

METHODS

This is a single-center, retrospective cohort study of all intestinal transplants performed between January 1, 2009, and August 31, 2020. We included recipients of all ages who were at risk of CMV infection. To identify the risk factors, we conducted at first univariate and multivariate analysis. For the multivariate analysis, we developed a logistic regression model based on the result of univariate analysis.

RESULTS

Ninety five patients with a median age of 32 (interquartile range [IQR] 4, 50) were included. CMV donor seropositive/recipient seronegative were 17 (17.9%). Overall, 22.1% of the recipients developed CMV infection at a median time of 155 (IQR 28-254) days from transplant, including 4 CMV syndrome and 6 CMV end-organ disease. Overall, 90.4%, (19/21) developed DNAemia while on prophylaxis. Median peak viral load and time to negativity was 16 000 (IQR 1034-43 892) IU/mL and 56 (IQR 49-109) days, respectively. (Val)ganciclovir and foscarnet were utilized in 17 (80.9%) and 1 (4.76%) recipients, respectively. Recurrences of CMV DNAemia and graft rejection were observed in three and six recipients, respectively. Younger age was identified as a risk factor (p = .032, odds ratio 0.97, 95% confidence interval 0.95-0.99) to develop CMV DNAemia.

CONCLUSION

A significant proportion of intestinal transplant recipients developed CMV infection while on prophylaxis. Better methods such as CMV cell mediated immunity guided prophylaxis should be used to prevent infections in this population.

The Third International Consensus Guidelines on the Management of Cytomegalovirus in Solid-organ Transplantation

Despite recent advances, cytomegalovirus (CMV) infections remain one of the most common complications affecting solid organ transplant recipients, conveying higher risks of complications, graft loss, morbidity, and mortality. Research in the field and development of prior consensus guidelines supported by The Transplantation Society has allowed a more standardized approach to CMV management. An international multidisciplinary panel of experts was convened to expand and revise evidence and expert opinion-based consensus guidelines on CMV management including prevention, treatment, diagnostics, immunology, drug resistance, and pediatric issues. Highlights include advances in molecular and immunologic diagnostics, improved understanding of diagnostic thresholds, optimized methods of prevention, advances in the use of novel antiviral therapies and certain immunosuppressive agents, and more savvy approaches to treatment resistant/refractory disease. The following report summarizes the updated recommendations.

Pediatric intestinal transplantation

The field of intestinal transplantation has experienced dramatic growth since the first reported cases 3 decades ago. Improvements in operative technique, donor assessment and immunosuppressive protocols have afforded children who suffer from life-threatening complications of intestinal failure a chance at long-term survival. As experience has grown, newer diseases, with more systemic manifestations have arisen as potential indications for transplant. After discussing the historical developments of intestinal transplant as a backdrop, this review focuses on the specific pre-operative indications for transplant as well as the great success that intestinal rehabilitation has witnessed over the past decade. A detailed discussion of evolution of immunosuppressive strategies is followed a general review of the common infectious complications experienced by children after intestinal transplant as well as the current long- and short-term results, including a section on new research on the quality of life in this challenging population of patients.

Intestinal Transplantation in Pediatric Patients

Intestine transplantation has evolved into a feasible alternative for children with permanent intestinal failure and life-threatening complications related to total parenteral nutrition. Although the first transplantations were done nearly 40 years ago, long-term survival has only been achieved in the last decade. Nearly 700 intestinal transplantations have been performed internationally since 1985, with an overall patient survival of greater than 50%. Improvements in patient selection, medical management, and assessment and treatment for rejection and infection have contributed to the increased survival. This article will discuss current results and medical management strategies for this innovative type of transplantation for children with end-stage short gut syndrome.

Is There a Role for Living Donor Intestine Transplants?

The use of living donors with intestinal transplantation is controversial because it may not significantly improve candidate access to organs when intestine-only grafts are needed, and may involve excessive donor risk when combined liver-intestine grafts are required. Although limited data are available for comparison at this time, graft and patient survival rates for intestinal transplantations using living donors are no different than for deceased donor transplantations. Potential benefits that may be provided to the intestine transplant recipient through the use of living donors include better HLA matching, shorter ischemia times, better bowel preparation, and better opportunities for introducing immunomodulatory strategies. Conversely, living intestine donors are at risk for mortality, significant morbidity, financial loss, and psychologic trauma. The long-term outcomes of living intestine donors have not yet been reported. Ultimately, these data are essential before the wider use of living donors can be advocated for intestinal transplantation.

Risks and Epidemiology of Infections After Intestinal Transplantation

Intestinal transplantation has become a well-accepted and successful procedure to save the lives of patients suffering from intestinal failure and who have developed life-threatening complications of parenteral nutrition. Advances in all aspects of care, from the role of multidisciplinary intestinal rehabilitation services prior to transplant to the development strategies for early recognition of infectious sequelae and even the increasing availability of preventive strategies, have led to improved outcomes and a dramatic decline in infection-associated morbidity and mortality in children undergoing intestinal transplantation. Improvements in surgical techniques and immunosuppressive regimens have been essential components in these improvements, reducing risk of infection through reduction of technical complications and more optimal immunosuppression regimens. In addition, the development of molecular tools for early recognition of viral pathogens and an understanding of the timing and risks for infection have allowed for earlier and more successful treatments. Despite these improvements, infectious sequelae remain an important problem in this population, and additional efforts are needed to further minimize the risk of infectious sequelae in those children requiring this procedure.

Cytotoxic T-lymphocyte antigen 4 gene polymorphism influences the incidence of symptomatic human cytomegalovirus infection after renal transplantation

BACKGROUND

The role of CTLA4 gene polymorphisms in T-cell-mediated immunity in association with human cytomegalovirus (HCMV) infection after transplantation is poorly understood. In the present study, we have made an attempt to investigate the impact of CTLA4 single nucleotide polymorphisms (SNPs) (rs231775, rs5742909, rs11571317, rs16840252, rs4553808, rs3087243) and dinucleotide (AT)n repeat polymorphism on the incidence of symptomatic HCMV infection (disease) among 270 renal allograft recipients.

MATERIALS AND METHODS

Genotyping of CTLA4 SNPs was performed by a PCR, followed by a restriction fragment length polymorphism assay. The detection of the dinucleotide (AT)n repeat polymorphism was carried out by PCR-polyacrylamide gel electrophoresis.

RESULTS

An almost three-fold increased risk was observed for the incidence of symptomatic HCMV infection in mutant genotype carriers of rs231775 and rs3087243 SNPs under additive and recessive models, respectively. The mutant haplotype carriers of six studied SNPs (rs231775, rs5742909, rs11571317, rs16840252, rs4553808 and rs3087243) showed an almost two-fold higher risk for symptomatic HCMV cases, whereas wild-type haplotype combinations of these six SNPs showed a protective effect. Subsequently, no correlation was observed in the promoter region SNPs of CTLA4, namely, rs5742909, rs11571317, rs16840252 and rs4553808 in symptomatic HCMV cases at the genotypic/allelic level. Survival analysis showed that the mutant genotypes of rs231775 and rs3087243 SNPs were associated with the lowest HCMV disease-free survival compared with heterozygous and wild genotypes. The crude and adjusted hazard ratios showed an almost three-fold and 2.5-fold increased risk in univariate and multivariate Cox regression models, respectively, for HCMV disease-free survival against mutant genotypes of rs231775 and rs3087243 SNPs. CTLA4 dinucleotide (AT)n repeat analysis showed that the smaller allele (102 bp) was associated with a protective effect, whereas the longer (110 and 116 bp) alleles showed a susceptible effect for symptomatic HCMV cases.

CONCLUSION

These results suggested that CTLA4 variants might be involved in the clinical manifestation of HCMV diseases.

Adenovirus disease in six small bowel, kidney and heart transplant recipients; pathology and clinical outcome

Adenoviruses are emerging as important viral pathogens in hematopoietic stem cell and solid organ transplant recipients, impacting morbidity, graft survival, and even mortality. The risk seems to be highest in allogeneic hematopoietic stem cell transplant recipients as well as heart, lung, and small bowel transplant recipients. Most of the adenovirus diseases develop in the first 6 months after transplantation, particularly in pediatric patients. Among abdominal organ recipients, small bowel grafts are most frequently affected, presumably due to the presence of a virus reservoir in the mucosa-associated lymphoid tissue. Management of these infections may be difficult and includes the reduction of immunosuppression, whenever possible, combined with antiviral therapy, if necessary. Therefore, an awareness of the pathology associated with such infections is important in order to allow early detection and specific treatment. We reviewed six transplant recipients (small bowel, kidney, and heart) with adenovirus graft involvement from two institutions. We sought to compare the diagnostic morphology and the clinical and laboratory findings. The histopathologic features of an adenovirus infection of the renal graft and one native kidney in a heart transplant recipient included a vaguely granulomatous mixed inflammatory infiltrate associated with rare cells showing a cytopathic effect (smudgy nuclei). A lymphocytic infiltrate, simulating T cell rejection, with admixture of eosinophils was also seen. In the small bowel grafts, there was a focal mixed inflammatory infiltrate with associated necrosis in addition to cytopathic effects. In the heart, allograft adenovirus infection was silent with no evidence of inflammatory changes. Immunohistochemical stain for adenovirus was positive in all grafts and in one native kidney. All patients were subsequently cleared of adenovirus infection, as evidenced by follow-up biopsies, with no loss of the grafts. Adenovirus infection can involve allografts as well as native organs in solid organ transplant recipients. Infection is associated with variable necrosis and acute inflammation, in addition to a rejection-like infiltrate. Hematuria in non-renal solid organ transplant recipients may be associated with adenovirus nephritis and clinically silent graft involvement. Prompt diagnosis (aided by immunohistochemistry (IHC) and serology), with specific treatment, can prevent graft loss.

The current state of intestine transplantation: indications, techniques, outcomes and challenges

Intestine transplantation is the least common form of organ transplantation in the United States and often deemed one of the most difficult. Patient and graft survival have historically trailed well behind other organ transplants. Over the past 5-10 years registry reports and single center series have demonstrated improvements to patient survival after intestinal transplantation that now match patient survival for those without life-threatening complications on parenteral nutrition. For various reasons including improvements in medical care of patients with intestinal failure and difficulty accessing transplant care, the actual number of intestine transplants has declined by 25% over the past 6 years. In light of the small numbers of intestine transplants, many physicians and the lay public are often unaware that this is a therapeutic option. The aim of this review is to describe the current indications, outcomes and advances in the field of intestine transplantation and to explore concerns over future access to this important and life-saving therapy.

Clinical utility of viral load in management of cytomegalovirus infection after solid organ transplantation

The negative impact of cytomegalovirus (CMV) infection on transplant outcomes warrants efforts toward improving its prevention, diagnosis, and treatment. During the last 2 decades, significant breakthroughs in diagnostic virology have facilitated remarkable improvements in CMV disease management. During this period, CMV nucleic acid amplification testing (NAT) evolved to become one of the most commonly performed tests in clinical virology laboratories. NAT provides a means for rapid and sensitive diagnosis of CMV infection in transplant recipients. Viral quantification also introduced several principles of CMV disease management. Specifically, viral load has been utilized (i) for prognostication of CMV disease, (ii) to guide preemptive therapy, (iii) to assess the efficacy of antiviral treatment, (iv) to guide the duration of treatment, and (v) to indicate the risk of clinical relapse or antiviral drug resistance. However, there remain important limitations that require further optimization, including the interassay variability in viral load reporting, which has limited the generation of standardized viral load thresholds for various clinical indications. The recent introduction of an international reference standard should advance the major goal of uniform viral load reporting and interpretation. However, it has also become apparent that other aspects of NAT should be standardized, including sample selection, nucleic acid extraction, amplification, detection, and calibration, among others. This review article synthesizes the vast amount of information on CMV NAT and provides a timely review of the clinical utility of viral load testing in the management of CMV in solid organ transplant recipients. Current limitations are highlighted, and avenues for further research are suggested to optimize the clinical application of NAT in the management of CMV after transplantation.

Clinical practice guidelines--Nursing management for pediatric patients with small bowel or multivisceral transplant

PURPOSE

Small bowel or multivisceral transplant is a relatively new treatment for irreversible intestinal damage, and no published practice guidelines exist. The purpose of this article is to report evidence regarding the best plan of care to achieve adequate nutrition and appropriate development for children.

DESIGN AND METHODS

An integrative review was conducted with 54 articles related to management of this transplant population. A nine-member nursing team integrated the findings.

PRACTICE IMPLICATIONS

This resulting guideline represents the best research and best practices on which to base staff education and competency validations to manage this medically fragile patient population.

Updated international consensus guidelines on the management of cytomegalovirus in solid-organ transplantation

Cytomegalovirus (CMV) continues to be one of the most common infections after solid-organ transplantation, resulting in significant morbidity, graft loss, and adverse outcomes. Management of CMV varies considerably among transplant centers but has been become more standardized by publication of consensus guidelines by the Infectious Diseases Section of The Transplantation Society. An international panel of experts was reconvened in October 2012 to revise and expand evidence and expert opinion-based consensus guidelines on CMV management, including diagnostics, immunology, prevention, treatment, drug resistance, and pediatric issues. The following report summarizes the recommendations.

Cytomegalovirus colitis in a 10 year-old girl after kidney transplantation

BACKGROUND

Cytomegalovirus is an important infection in kidney Transplantation. Isolation of the CMV virus or detection of its proteins or nucleic acid in any body fluid or tissue specimen is defined as "CMV infection".

CASE PRESENTATION

A 10-year-old girl was admitted frequently for vomiting and colicky watery diarrhea starting one month after renal transplantation from a non-relative living donor. Cr, BUN, serum electrolytes and also liver function tests were normal. Anti CMV IgM titer was negative before and after transplantation. On colonoscopy large aphthous like lesions were detected in the colon. CMV PCR of the lesion was strongly positive (>2000 copies/ml). The patient received Ganciclovir.

CONCLUSION

Usually CMV infected patients present with renal dysfunction after renal transplantation but other organ involvements must not be ignored. We report a patient presenting only with intestinal signs and symptoms of CMV infection.

Small-Bowel Allograft Biopsies in the Management of Small-Intestinal and Multivisceral Transplant Recipients: Histopathologic Review and Clinical Correlations

Context.—Intestinal transplant has become a standard treatment option in the management of patients with irreversible intestinal failure. The histologic evaluation of small-bowel allograft biopsy specimens plays a central role in assessing the integrity of the graft. It is essential for the management of acute cellular and chronic rejection; detection of infections, particularly with respect to specific viruses (cytomegalovirus, adenovirus, Epstein-Barr virus); and immunosuppression-related lymphoproliferative disease.

Objective.—To provide a comprehensive review of the literature and illustrate key histologic findings in small-bowel biopsy specimen evaluation of patients with small-bowel or multivisceral transplants.

Data Sources.—Literature review using PubMed (US National Library of Medicine) and data obtained from national and international transplant registries in addition to case material at Columbia University, Presbyterian Hospital, and Mount Sinai Medical Center, New York, New York.

Conclusions.—Key to the success of small-bowel transplantation and multivisceral transplantation are the close monitoring and appropriate clinical management of patients in the posttransplant period, requiring coordinated input from all members of the transplant team with the integration of clinical, laboratory, and histopathologic parameters.

Incidence, risk factors, and outcomes associated with cytomegalovirus disease in small bowel transplant recipients

Despite improved prophylaxis, monitoring, and more efficient immunosuppression, CMV infection remains a common opportunistic infection in transplant recipients. We assessed the incidence of CMV disease in pediatric SBT recipients, the timing of CMV disease after transplantation, and its impact on patient outcome. The medical records of 98 SBT recipients were reviewed. We performed descriptive analysis, regression analysis, and Kaplan-Meier curves to determine the time-to-event after transplantation. Fifty-three percent patients were male and 47% female, with a mean age of 38.3 months. Thirty-five percent of patients received prophylactic VGC, 55% GCV, 10% a combination of GCV/VGC, and 99% CMV immunoglobulins. A total of 24.5% recipients were CMV D+/R- (CMV serostatus donor positive/recipient negative). Seven (c. 7%) patients developed CMV disease. CMV disease was associated with 2.5 times (0.52-12.1; p = 0.25) higher rate of CMV mismatch and 11.1 times (1.3-95.9; p = 0.03) higher risk of death. CMV prophylaxis increased time-to-death (p = 0.074). Time-to-CMV disease was shorter in patients with enteritis (p < 0.0001), and CMV disease was associated with shorter time-to-death after transplantation (p = 0.001). CMV disease in SBT recipients was associated with an 11-fold mortality increase and a fourfold faster time-to-death. Time-to-death was significantly shorter with CMV enteritis.

Pediatric intestinal and multivisceral transplantation: a new challenge for the pediatric intensivist

INTRODUCTION

With increasing survival rates, intestinal transplantation (ITx) and multivisceral transplantation have reached the mainstream of medical care. Pediatric candidates for ITx often suffer from severe multisystem impairments that pose challenges to the medical team. These patients frequently require intensive care preoperatively and have unique intensive care needs postoperatively.

METHODS

We reviewed the literature on intensive care of pediatric intestinal transplantation as well as our own experience. This review is not aimed only at pediatric intensivists from ITx centers; these patients frequently require ICU care at other institutions.

RESULTS

Preoperative management focuses on optimization of organ function, minimizing ventilator-induced lung injury, preventing excessive edema yet maintaining adequate organ perfusion, preventing and controlling sepsis and bleeding from varices at enterocutaneous interfaces, and optimizing nutritional support. The goal is to extend life in stable condition to the point of transplantation. Postoperative care focuses on optimizing perfusion of the mesenteric circulation by maintaining intravascular volume, minimizing hypercoagulability, and providing adequate oxygen delivery. Careful monitoring of the stoma and its output and correction of electrolyte imbalances that may require renal replacement therapy is critical, as are monitoring for and aggressively treating infections, which often present with only subtle clinical clues. Signs of intestinal rejection may be non-specific, and early differentiation from other causes of intestinal dysfunction is important. Understanding of the expanding armamentarium of immunosuppressive agents and their side-effects is required.

CONCLUSIONS

As outcomes of ITx improve, transplant teams accept patients with higher pre-operative morbidity and at higher risk for complications. Many ITx patients would benefit from earlier referral for transplant evaluation before severe liver disease, recurrent central venous catheter-related sepsis and venous thromboses develop.

La greffe intestinale

Even though surgical techniques for isolated intestine, liver-intestine, and multivisceral transplantations were developed in the 1960's, very few patients were transplanted before 1990 because initial immunosuppression regimens were insufficient, making intestine transplantation impossible. Intestine transplantation resulted in death in most patients within days or months. The discouraging results of the first clinical trials were due to technical complications, sepsis, and the failure of conventional immunosuppression to control rejection. By 1990 the development of tacrolimus-based immunosuppression and improved surgical techniques, the increased array of potent immunosuppressive medications, infection prophylaxis, and suitable patient selection helped improve actuarial graft and patient survival rates for all types of intestine transplantation. The aims of this review are to describe the current status of intestine transplantation including the underlying diseases and conditions that may be indications for intestine transplantation, to identify patient populations for this indication, to provide key steps for patient evaluation, to summarize current recommendations for immunosuppression, to list the most common postoperative complications, and to discuss the international experience of small bowel transplantation compiled and analyzed by the International Intestine Transplant Registry since 1985.

Intestinal transplantation: current status

Intestine transplant is indicated for patients with intestinal failure who are unable to be weaned from parenteral nutrition (PN). Long-term PN, although life sustaining in many patients, can be associated with life-threatening complications including PN-associated liver disease (PNALD). Most patients are not considered for intestine transplant until they have developed severe PNALD and also need a liver transplant. Overall outcomes with intestinal transplantation are steadily improving, and current 1-year patient survivals for intestine-only transplants are now similar to those for liver transplant. Intestinal transplantation should be considered earlier in intestinal failure patients who are at high risk for developing PNALD and other life-threatening complications.

Is there a role for living donor intestine transplants?

The use of living donors with intestinal transplantation is controversial because it may not significantly improve candidate access to organs when intestine-only grafts are needed, and may involve excessive donor risk when combined liver-intestine grafts are required. Although limited data are available for comparison at this time, graft and patient survival rates for intestinal transplantations using living donors are no different than for deceased donor transplantations. Potential benefits that may be provided to the intestine transplant recipient through the use of living donors include better HLA matching, shorter ischemia times, better bowel preparation, and better opportunities for introducing immunomodulatory strategies. Conversely, living intestine donors are at risk for mortality, significant morbidity, financial loss, and psychologic trauma. The long-term outcomes of living intestine donors have not yet been reported. Ultimately, these data are essential before the wider use of living donors can be advocated for intestinal transplantation.

Evolutionary experience with immunosuppression in pediatric intestinal transplantation

BACKGROUND/PURPOSE

Intestinal transplantation has developed to become the standard of care for patients with irreversible intestinal failure who are not responding to total parenteral nutrition. Once considered experimental, it has taken time and much effort for the procedure to become a clinical reality, with final acceptance primarily because of the vastly improved outcomes. Advances and novel modifications in immunosuppression have been at the forefront of these improvements. The authors review their evolutionary experience with intestinal transplantation, particularly relating changes in immunosuppression protocols to improved outcomes.

METHODS

From July 1990 to December 2003, 122 children received 129 intestinal containing allografts (70 liver/intestine, 42 isolated intestine, 17 multivisceral). Mean age was 5.3 +/- 5.2 years, and 55% were boys. Indications for transplantation were mostly short gut syndrome. The allografts were cadaveric, ABO identical (except one), with no immunomodulation. Bone marrow augmentation was used in 29% of the recipients since 1995. T-cell lymphoctytotoxic crossmatch was positive in 24% cases. Immunosuppression protocols can be divided into 3 categories: (i) maintenance tacrolimus and steroids (n = 52, 1990-1995, 1997-1998); (ii) addition of induction therapy with cyclophosphamide (n = 16, 1995-1997) then daclizumab (n = 24, 1998-2001). A third immunosuppressive agent was added in either group where increased immunosuppression was indicated; (iii) pretreatment/induction with antilymphocyte conditioning and steroid-free posttransplantation tacrolimus monotherapy (n = 37, 2002-2003). In this later group, if clinically stable at 60 to 90 days posttransplantation, and no recent rejection, the tacrolimus was weaned by decreasing frequency of dosing.

RESULTS

The overall Kaplan-Meier patient/graft survival was 81%/76% at 1 year, 62%/60% at 3 years, and 61%/51% at 5 years. Survival continues to improve, with 1-year patient/graft survival being 71%/62%, 77%/75%, and 100%/100% for groups (i), (ii), and (iii), respectively. Acute intestinal allograft rejection has decreased markedly in group (iii). The rate of infectious diseases, such as cytomegalovirus and Epstein-Barr virus, is lowest in group (iii). Graft-versus-host disease has not significantly increased with the latest protocol. Most importantly, the overall level of immunosuppression requirements has decreased markedly, with most patients in group (iii) being on monotherapy. Of these, most had their monotherapy weaned down to spaced doses, something never systematically attempted or achieved in pediatric intestinal transplantation.

CONCLUSIONS

Intestinal transplantation has progressed markedly over the last 13 years. Although there have been modifications in all aspects of the procedure, the story of intestinal transplantation has been the evolution of successful immunosuppression regimens. Our latest pretreatment/induction conditioning and posttransplantation monotherapy strategy improves graft acceptance and lowers subsequent immunosuppression dosing requirements. It is expected this will overcome many of the complications related to the previously high immunosuppression requirements. Minimization of immunosuppression with avoidance of steroid therapy offers profound long-term benefits, especially in the pediatric population. The patients still remain challenging and complex in every aspect; however, these advances offer significant hope to both patients and caregivers alike.

CMV, EBV, HHV6, and HHV7 infections after intestinal transplantation without specific antiviral prophylaxis

PURPOSE

To analyze the incidence and relevance of viral infections after intestinal transplantation (ITx) without specific antiviral prophylaxis.

METHODS

Eleven patients (median age 34 years; range 26 to 58 years) who underwent ITx received no CMV/EBV prophylaxis but rather preemptive treatment. Viral monitoring for CMV or EBV polymerase chain reactions (PCR) in peripheral blood and graft biopsies, for HHV6-, and HHV7-PCR; for adeno-/rotavirus antigen and serology was performed based on clinical indications.

RESULTS

Median time under risk was 19 months (range 2 to 39). CMV: The donor (D)-to-recipient (R) status prior to ITx was: D+/R+ (4); D+/R- (3); D-/R- (2); D-/R+ (2). Eight patients showed no positive CMV-PCR. Three episodes of tissue invasive CMV disease occurred in two patients. There were two asymptomatic CMV infections but no episodes of CMV disease. None of the R(-) recipients developed CMV infection or enteritis irrespective of the donor status. EBV: Four patients experienced six episodes of transient significant EBV-viremia. Two patients developed EBV enteritis concurrently with CMV enteritis during acute rejection. There were no PTLD. CMV and EBV enteritis only occurred during or immediately after steroid and OKT3 therapy. None of the patients developed significant HHV6 and HHV7 infection or viremia. There was one episode of adeno- and rotavirus enteritis.

CONCLUSIONS

Despite witholding specific antiviral prophylaxis against CMV and EBV, we observed no such infections in 60% to 80% of patients. Donor-recipient matching regarding CMV was not predictive for the occurrence of CMV-related complications. HHV6 and HHV7 have not contributed to posttransplant morbidity.

Infectious complications in pediatric solid organ transplantation

Transplantation has emerged as one of the remarkable achievements of the latter half of the twentieth century for treatment of many end-stage organ disorders. Survival in pediatric solid organ transplantation continues to improve as strategies for immunosuppression, prevention and treatment of infectious complications progress. This article presents the summaries of the common and opportunistic pathogens that cause infectious complications for the pediatric transplant recipient. In addition, an approach to the pediatric transplant patient who presents with specific symptoms suggestive of infection is provided.

Isolated intestinal transplantation: proof of clinical efficacy

BACKGROUND AND AIMS

Isolated intestinal transplantation has been limited by poor patient and graft survival. If high survival could be achieved and if parenteral nutrition-associated liver disease were reversible, this procedure could be more widely applied, with early liver dysfunction indicating the need for transplant evaluation.

METHODS

Twenty-six patients who had failed parenteral nutrition received 28 isolated intestinal transplants. We analyzed patient and graft survival, the effect of sirolimus on the severity and frequency of rejection, and the reversibility of liver dysfunction after transplant.

RESULTS

Three-year actuarial patient and primary graft survival were 88% and 71%, respectively. Two patients underwent successful retransplants. Twenty-two patients are alive at a mean of 21+/-15 (median 18; range 3-51) months. Actuarial survival with freedom from parenteral support is 81% at 3 years (21 of 26 patients). Actuarial freedom from parenteral support among survivors is 95.5% at 3 years (21 of 22 patients). Early rejection was less frequent with sirolimus (34% vs. 70% without sirolimus) (P=0.007). Moderate and severe rejection was less frequent with sirolimus (1/11 episodes vs. 9/17 episodes without sirolimus) (P=0.05). No grafts were lost after introduction of sirolimus. In all four patients with advanced liver dysfunction, fibrosis and cholestasis regressed within 1 year.

CONCLUSIONS

High patient survival and parenteral nutrition-free survival can be achieved after isolated intestinal transplantation. Sirolimus treatment has eliminated graft loss. Parenteral nutrition-associated liver disease is reversible with intestinal transplantation. Refractory liver dysfunction in patients receiving parenteral nutrition should prompt consideration for isolated intestinal transplantation.

Exfoliative rejection after intestinal transplantation in children

BACKGROUND

Graft rejection is the most significant cause of allograft failure after intestinal transplantation (ITx). Severity can vary and is based on histologic criteria, the most extreme form being exfoliation of the mucosa. We present the characteristics and outcome of children who developed exfoliative rejection (ER) after ITx.

METHODS

Between June 1990 and March 2002, 88 patients received 92 ITx which included isolated small bowel (SB, n = 26), combined liver-small bowel (LSB, n = 54), and multivisceral MV n = 12) allografts performed under tacrolimus and steroid immunosuppresson. ER was diagnosed by endoscopy and confirmed by biopsy.

RESULTS

Thirteen (15%) of 88 patients developed 15 episodes of ER in 15 intestinal allografts, and included SB (n = 8), LSB (n = 5), and MV (n = 2). Time to ER after ITx ranged from 9 days to 45.5 months (median 22 days). Eight episodes of ER developed within 1 month after ITx. Ten episodes of ER were exacerbations of prior rejection. Five episodes occurred abruptly. All but one received OKT3. Fourteen of 15 allografts were lost; six patients underwent allograft enterectomy acutely as a salvage operation because of ER. The remainder of the allografts were either removed or lost to patient death as a consequence to infection or chronic rejection after resolution of ER. Retransplantation was performed in three patients, with subsequent recurrence of ER in two retransplanted allografts. Inclusion of a liver allograft was a protective factor toward decreasing the incidence of ER. The results of cross-matching, inclusion of a colonic segment, and simultaneous bone marrow infusion did not affect the incidence of ER. Infectious complications included post-transplant lymphoproliferative disease (n = 4), cytomegalovirus (n = 5), and adenovirus infection (n = 2).

CONCLUSIONS

Exfoliative rejection is associated with a high morbidity and mortality after ITx. Strategies to improve survival may include up front anti-lymphocyte antibody therapy and, when fail to respond promptly and satisfactorily, early intestinal allograft removal.

Calicivirus enteritis in an intestinal transplant recipient

Protracted diarrhea of uncertain etiology is a significant problem following intestinal transplantation. We report an infant who developed severe secretory diarrhea 178 days after intestinal transplantation that persisted for more than 120 days. Repeated allograft biopsies demonstrated only nonspecific inflammation. Enzyme immunoassay (for rotavirus), culture, and reverse transcription polymerase chain reaction [calicivirus (Norwalk-like virus)] were used to identify the allograft viral infection. A heavy density of calicivirus RNA nucleotide sequences (genogroup II, strain Miami Beach) was isolated from the jejunal and ileal allograft. Following a reduction in immunosuppressive therapy, diarrhea and enteritis remitted in association with the disappearance of all calicivirus RNA sequences. Calicivirus may cause severe allograft dysfunction in intestinal transplant recipients.

Pediatric intestinal transplantation: historical notes, principles and controversies

The development in technique and immunosuppressive management of the last 12 yr have made intestinal transplantation an effective treatment for children with intestinal failure. The information provided in this review support such a conclusion, but was more clearly validated by the March 2001 Medicare Report which provided a national coverage decision of the Social Security Act for intestinal transplantation. As of May 2001, there were 55 centers world-wide which have performed 696 intestinal transplants in 656 patients. (Intestinal Transplant Registry, http://www.lhsc.on.ca/itr) the majority of recipients have been children, and there has been a greater need for liver replacement in conjunction with the allograft intestine because of a higher incidence of TPN-induced cholestatic liver disease in children. Though overall long-term survival is approximately 50%, similar advances in surgical, clinical and immunosuppressive management since 1995 have improved patient survival to more than 70% in most experienced programs. Over 80% of survivors are enjoying nutrition-supporting intestinal function. The major causes of graft loss and patient demise continues to be rejection and infection. Tacrolimus remains the mainstay of immunosuppressive therapy. Further experience other induction protocols utilizing rapamycin and daclizumab, as well graft pretreatment protocols may further enhance results in the future.

Intestinal transplantation in pediatric patients

Intestine transplantation has evolved into a feasible alternative for children with permanent intestinal failure and life-threatening complications related to total parenteral nutrition. Although the first transplantations were done nearly 40 years ago, long-term survival has only been achieved in the last decade. Nearly 700 intestinal transplantations have been performed internationally since 1985, with an overall patient survival of greater than 50%. Improvements in patient selection, medical management, and assessment and treatment for rejection and infection have contributed to the increased survival. This article will discuss current results and medical management strategies for this innovative type of transplantation for children with end-stage short gut syndrome.

Clinical intestinal transplantation: a decade of experience at a single center

OBJECTIVE

To assess the long-term efficacy of intestinal transplantation under tacrolimus-based immunosuppression and the therapeutic benefit of newly developed adjunct immunosuppressants and management strategies.

SUMMARY BACKGROUND DATA

With the advent of tacrolimus in 1990, transplantation of the intestine began to emerge as therapy for intestinal failure. However, a high risk of rejection, with the consequent need for acute and chronic high-dose immunosuppression, has inhibited its widespread application.

METHODS

During an 11-year period, divided into two segments by a 1-year moratorium in 1994, 155 patients received 165 intestinal allografts under immunosuppression based on tacrolimus and prednisone: 65 intestine alone, 75 liver and intestine, and 25 multivisceral. For the transplantations since the moratorium (n = 99), an adjunct immunosuppressant (cyclophosphamide or daclizumab) was used for 74 transplantations, adjunct donor bone marrow was given in 39, and the intestine of 11 allografts was irradiated with a single dose of 750 cGy.

RESULTS

The actuarial survival rate for the total population was 75% at 1 year, 54% at 5 years, and 42% at 10 years. Recipients of liver plus intestine had the best long-term prognosis and the lowest risk of graft loss from rejection (P =.001). Since 1994, survival rates have improved. Techniques for early detection of Epstein-Barr and cytomegaloviral infections, bone marrow augmentation, the adjunct use of the interleukin-2 antagonist daclizumab, and most recently allograft irradiation may have contributed to the better results.

CONCLUSION

The survival rates after intestinal transplantation have cumulatively improved during the past decade. With the management strategies currently under evaluation, intestinal transplant procedures have the potential to become the standard of care for patients with end-stage intestinal failure.

Intestinal transplantation for children with short bowel syndrome

Intestinal transplantation has emerged as a feasible alternative in the treatment of children with short gut syndrome. The challenges in the management of these patients include maintaining a tight balance between the degree of immunosuppression necessary to prevent graft-versus-host disease and rejection. At the same time, this amount of immunosuppression is associated with a high risk for lymphoproliferative disorders and intestinal-derived sepsis. Current 3-year patient and graft survival rates are 55% and 50%, respectively. The indications, morbidity, and timing for referral are discussed.

Intestinal transplantation in children

Intestinal transplantation has emerged in the last decade as a lifesaving procedure for patients with intestinal failure who are suffering from complications arising from the administration of total parenteral nutrition. Indications for transplantation include irreversible liver injury and loss of vascular access. At least 50 children in the United States may benefit from intestinal transplantation every year. In this article, indications, pre- and postoperative management, and outcomes of intestinal transplantation in children are discussed.

Intestinal transplantation

Increasing experience with intestinal transplantation has led to the refinement of techniques to detect and treat rejection and infectious complications. Improved outcome has led to a broadening of the indications for intestinal transplantation, particularly solitary intestinal transplantation.

Clinical intestinal transplantation: new perspectives and immunologic considerations

BACKGROUND

Although tacrolimus-based immunosuppression has made intestinal transplantation feasible, the risk of the requisite chronic high-dose treatment has inhibited the widespread use of these procedures. We have examined our 1990-1997 experience to determine whether immunomodulatory strategies to improve outlook could be added to drug treatment.

STUDY DESIGN

Ninety-eight consecutive patients (59 children, 39 adults) with a panoply of indications received 104 allografts under tacrolimus-based immunosuppression: intestine only (n = 37); liver and intestine (n = 50); or multivisceral (n = 17). Of the last 42 patients, 20 received unmodified adjunct donor bone marrow cells; the other 22 were contemporaneous control patients.

RESULTS

With a mean followup of 32 +/- 26 months (range, 1-86 months), 12 recipients (3 intestine only, 9 composite grafts) are alive with good nutrition beyond the 5-year milestone. Forty-seven (48%) of the total group survive bearing grafts that provide full (91%) or partial (9%) nutrition. Actuarial patient survival at 1 and 5 years (72% and 48%, respectively) was similar with isolated intestinal and composite graft recipients, but the loss rate of grafts from rejection was highest with intestine alone. The best results were in patients between 2 and 18 years of age (68% at 5 years). Adjunct bone marrow did not significantly affect the incidence of graft rejection, B-cell lymphoma, or the rate or severity of graft-versus-host disease.

CONCLUSIONS

These results demonstrate that longterm rehabilitation similar to that with the other kinds of organ allografts is achievable with all three kinds of intestinal transplant procedures, that the morbidity and mortality is still too high for their widespread application, and that the liver is significantly but marginally protective of concomitantly engrafted intestine. Although none of the endpoints were markedly altered by donor leukocyte augmentation (and chimerism) with bone marrow, establishment of the safety of this adjunct procedure opens the way to further immune modulation strategies that can be added to the augmentation protocol.

Current status of intestinal transplantation in children

PURPOSE

A clinical trial of intestinal transplantation (Itx) under tacrolimus and prednisone immunosuppression was initiated in June 1990 in children with irreversible intestinal failure and who were dependent on total parenteral nutrition (TPN).

METHODS

Fifty-five patients (28 girls, 27 boys) with a median age of 3.2 years (range, 0.5 to 18 years) received 58 intestinal transplants that included isolated small bowel (SB) (n = 17), liver SB (LSB) (n=33), and multivisceral (MV) (n=8) allografts. Nine patients also received bone marrow infusion, and there were 20 colonic allografts. Azathioprine, cyclophosphamide, or mycophenolate mofetil were used in different phases of the series. Indications for Itx included: gastroschisis (n=14), volvulus (n=13), necrotizing enterocolitis (n=6), intestinal atresia (n=8), chronic intestinal pseudoobstruction (n=5), Hirschsprung's disease (n=4), microvillus inclusion disease (n=3), multiple polyposis (n=1), and trauma [n=1).

RESULTS

Currently, 30 patients are alive (patient survival, 55%; graft survival, 52%). Twenty-nine children with functioning grafts are living at home and off TPN, with a mean follow-up of 962 (range, 75 to 2,424) days. Immunologic complications have included liver allograft rejection (n=18), intestinal allograft rejection (n=52), posttransplant lymphoproliferative disease (n=16), cytomegalovirus (n=16) and graft-versus-host disease (n=4). A combination of associated complications included intestinal perforation (n=4), biliary leak (n=3), bile duct stenosis (n=1), intestinal leak (n=6), dehiscence with evisceration (n=4), hepatic artery thrombosis (n=3), bleeding (n=9), portal vein stenosis (n=1), intraabdominal abscess (n=11), and chylous ascites (n=4). Graft loss occurred as a result of rejection (n=8), infection (n=12), technical complications (n=8), and complications of TPN after graft removal (n=3). There were four retransplants (SB, n=1; LSB n=3).

CONCLUSIONS

Intestinal transplantation is a valid therapeutic option for patients with intestinal failure suffering complications of TPN. The complex clinical and immunologic course of these patients is reflected in a higher complication rate as well as patient and graft loss than seen after heart, liver, and kidney transplantation, although better than after lung transplantation.