Tecnologías e investigación de trasplantes

HLA-E, HLA-G, and major histocompatibility complex class I-related chain A and B (MICA and MICB) proteins belong to human non-classical Major Histocompatibility Complex (MHC) class Ib molecules. These molecules are well known as powerful modulators of the immune response. The majority of the mentioned proteins interact exclusively with receptors from the CD94/NKG2 c-type lectin family. The peptide-presenting HLA-E molecule is recognized by the NKG2A or NKG2C receptor, triggering a signal cascade leading to inhibition or activation of immune cell activity, respectively. Another member of this family is the NKG2D receptor that interacts with the MICA/B proteins, transducing signals that result in activation of immune cells.

This article discusses the current knowledge in regard to the genetic properties and physiological functions of the molecules HLA-E and MICA/B as well as the CD94/NKG2 receptors in the context of the potential role of the signaling pathways they constitute in the outcome of hematopoietic stem cell transplantation. Furthermore, the possible role of HLA-G, also a member of the non-classical MHC class Ib family, is considered.

Introduction: Infections are frequent causes of morbidity and mortality after liver transplantation and a major cause of decomposition in cirrhotic patients awaiting liver transplantation. Cirrhotic patients with poor oral health status may present increased susceptibility to systemic infections in the pre and/or post-operative liver transplantation period.

Objective: To compare oral health status of liver transplantation patients with chronic viral hepatitis carriers.

Methods: This prospective, concurrent study included 66 patients, 45 males (68.2%), observed from January, 2010 to December, 2011. Out of these 66 patients, 18 (27%) were waiting for liver transplantation and 48 (73%) were non-cirrhotic hepatitis patients: 16 (24%) were Hepatitis C Virus carriers, 17 (26%) Hepatitis B Virus carriers and 15 (23%) non-HCV and non-HBV hepatitis. All patients were evaluated at the Stomatology Service from Federal University of Bahia. Oral health status evaluation was performed according to WHO Standards.

Results: Forty-seven patients (71.2%) experienced reduced salivary flow. Patients in the liver transplantation group had more gingivitis (p=0.04), periodontitis (p=0.04) and a slightly higher DMFT (Decayed, Missing and Filled Teeth) mean (19.11) when compared with those with less severe liver disease. However, when comparing the liver transplantation group with non-cirrhotic HCV carriers, there was no statistical significance.

Conclusion: Liver transplantation patients have poorer oral health than patients with less severe hepatitis. Hepatitis C carriers also present severe periodontal disease, requiring stomatological preventive and curative intervention.

BK virus is a ubiquitous human virus with a peak incidence of primary infection in children 2-5 years of age and a seroprevalence rate of greater than 60-90% among the adult population worldwide. Following primary infection, BK virus preferentially establishes latency within the genitourinary tract and frequently reactivates in the setting of immunosuppression. In renal transplant recipients, BK virus is associated with a range of clinical syndromes including asymptomatic viruria with or without viremia, ureteral stenosis and obstruction, interstitial nephritis, and BK allograft nephropathy (BKN). BKN most commonly presents with an asymptomatic rise in serum creatinine between 2 to 60 months after engraftment (median 9 months). A definitive diagnosis requires an allograft biopsy. Over the last two decades, BKN has been recognized as an important cause of allograft dysfunction and graft loss in kidney transplant recipients. Nonetheless, there is currently no standardized protocol for the management of BK viremia or established BKN. In this article, a brief overview of the literature on the various treatment strategies for BK-associated clinical spectrum is presented followed by the authors’ suggested approach for posttransplant screening and monitoring for BK virus replication. Suggested treatment strategies are also discussed.

Objectives: Historically, patients with lower urinary tract dysfunction (LUTD) were considered poor candidates for renal transplantation (RT). We aimed to review our experience with this procedure for its safety and efficacy.

Methods: We reviewed the case records of patients with LUTD who underwent RT at our center. Graft and patient survival were analyzed.

Results: Out of 2053 RTs, 26 (1.2%) patients had LUTD as the primary cause of end-stage renal disease (ESRD). All patients underwent cystourethroscopy prior to transplantation, had abnormal bladders and all underwent bladder augmentation. Only 16 (61.5%) patients had urodynamic (UDN) evaluation prior to transplantation. Pretransplantation augmentation cystoplasty (AC) was performed in 24 (92.3%) patients, and post-RT in two (7.7%). Mitrofanoff channel was made in 25 (96.1%) patients using appendix in 14 (56%) patients and native ureter in 11 (44%). Double-J (DJ) stents were placed in all patients peroperatively. All patients developed 156 episodes of urinary tract infections (UTIs), with an average of 6 UTIs/ patient. All patients except three are maintaining their graft function within acceptable limits. We observed 100% patient and graft survival rates in this series.

Conclusions: In conclusion, RT combined with AC is a feasible option for patients with LUTD with good results in the medium term and should be explored in selected patients.

Kidney transplantation is the best treatment for chronic renal failure patient (CRF), because in this treatment the patient will have normal life and also it is more cost effective than other methods for treatment of CRF. One of the major problems with the kidney transplantation is shortage of the kidney donor. Besides deceased donor, live kidney donors (related and unrelated) are selected for solving the problem of kidney donor shortage. Two approaches are used for removing kidney from live donors including: open nephrectomy and laparoscopic nephrectomy. The short stay at hospital is mentioned as one of the advantages of laparoscopic donor nephrectomy that is a factor for increasing live donor volunteer. At our center, we studied the issue: how long is the time of hospital stay of the kidney donor who has been operated as open nephrectomy and is it different with that reported for laparoscopic donor nephrectomy?

Methods: The time of hospital stay of 326 kidney donors (35 females, 291 males) post operation have been studied as retrospectively at kidney transplant center of Imam Reza hospital from 2005 to 2011.

Results: In 326 kidney donors, 48 donors after second day of operation, 276 donors after third day of operation, one donor after eight day of operation, and one donor after sixth day of operation had been discharged from the hospital, for all the kidney donors the operation had been done through trans flank incision and retroperitoneal and without the rib resection.

Conclusion: In this study, considering the hospital staying time of open nephrectomy donors, it is understood that nearly one hundred percent of donors had been discharged from the hospital until third day of operation so it seems that the hospital stay of the open nephrectomy donors are comparable with the reported time for hospital stay of laparoscopic nephrectomy donors.