Implications of Resident Memory T Cells for Transplantation.

Recent studies have established resident memory T cells (TRM ) as the dominant memory lymphocyte population surveying most nonlymphoid tissues. Unlike other memory T cell lineages, TRM do not recirculate through blood and are permanently confined to their tissue of residence. TRM orchestrate local immune responses and have been shown to accelerate local pathogen control in many experimental infection models. Here we briefly summarize recent advances in TRM differentiation, maintenance, and their protective function. While little is known, we have speculated on the potential implications of TRM for transplantation biology. Areas of emphasis include the role of passenger TRM in controlling latent viral recrudescence in donor organs, donor TRM as a source of graft-versus-host disease, the ability of TRM to potently induce inflammation through sensing and alarm functions, and differentiation of host T cells into TRM in response to local cues inside the allograft. Further investigation of TRM in the context of transplantation might identify therapeutic targets to prolong graft survival.

Differential regulation of miR-21 and miR-146a by Epstein-Barr virus-encoded EBNA2.

The discovery of microRNA (miR) represents a novel paradigm in RNA-based regulation of gene expression and their dysregulation has become a hallmark of many a tumor. In virally associated cancers, the host-pathogen interaction could involve alteration in miR expression. Epstein-Barr virus (EBV)-encoded EBNA2 is indispensable for the capacity of the virus to transform B cells in vitro. Here, we studied how it affects cellular miRs. Extensive miR profiling of the virus-infected and EBNA2-transfected B lymphoma cells revealed that oncomiR miR-21 is positively regulated by this viral protein. Conversely, Burkitt's lymphoma (BL) cell lines infected with EBNA2 lacking P3HR1 strain did not show any increase in miR-21. EBNA2 increased phosphorylation of AKT and this was directly correlated with increased miR-21. In contrast, miR-146a was downregulated by EBNA2 in B lymphoma cells. Low miR-146a expression correlates with an elevated level of IRAK1 and type I interferon in EBNA2 transfectants. Taken together, the present data suggest that EBNA2 might contribute to EBV-induced B-cell transformation by altering miR expression and in particular by increasing oncomiR-like miR-21 and by affecting the antiviral responses of the innate immune system through downregulation of its key regulator miR-146a.

Epstein-Barr virus encoded LMP1 downregulates TCL1 oncogene through miR-29b.

Epstein-Barr virus (EBV) encoded latent membrane protein 1 (LMP1) is noted for its transforming potential. Yet, it also acts as a cytostatic and growth-relenting factor in Burkitt's lymphoma (BL) cells. The underlying molecular mechanisms of the growth inhibitory property of LMP1 have remained largely unknown. In this study, we show that LMP1 negatively regulates a major oncogene, TCL1, in diffuse large B-cell lymphoma (DLBCL) and BL cells. MicroRNA (miR) profiling of LMP1 transfectants showed that among others, miR-29b, is upregulated. LMP1 diminished TCL1 by inducing miR-29b through C-terminus activation region 1 (CTAR1) and CTAR2. miR-29b locked nucleic acid (LNA) antisense oligonucleotide transfection into LMP1-expressing cells reduced miR-29b expression and consequently reconstituted TCL1, suggesting that LMP1 negatively regulates TCL1 through miR-29b upregulation. The miR-29b increase by LMP1 was due to an increase in the cluster pri-miR-29b1-a transcription, derived from human chromosome 7. Using pharmacological inhibitors, we found that p38 mitogen-activated protein kinase-activating function of LMP1 is important for this effect. The ability of LMP1 to negatively regulate TCL1 through miR-29b might underlie its B-cell lymphoma growth antagonistic property. As LMP1 is also important for B-cell transformation, we suggest that the functional dichotomy of this viral protein may depend on a combination of levels of its expression, lineage and differentiation of the target cells and regulation of miRs, which then directs the outcome of the cellular response.

Abdominal wall recurrences after colorectal resection for cancer: results of the Italian registry of laparoscopic colorectal surgery.

PURPOSE: The purpose of the present study was to evaluate prospectively the abdominal wall recurrence rate after laparoscopic resection for colorectal cancer, to analyze the impact of the learning curve on abdominal wall recurrence, and to assess the outcome of those patients. METHODS: The Italian Registry of Laparoscopic Colorectal Surgery database was analyzed to obtain data on cancer patients with abdominal wall recurrence, concomitant local or distant metastases, and interval between initial surgery and diagnosis of trocar site or minilaparotomy recurrences. The records of the initial procedures and the technique of specimen removal were reviewed. RESULTS: From January 1992 to July 2000, 2,583 patients (1,753 cases of carcinomas and 830 cases of benign diseases) were recorded. The malignant lesions were located on the right colon in 19 percent, the left colon in 48.8 percent, and rectum in 32.2 percent. Sixteen patients with histologic evidence of colorectal adenocarcinoma recurrences at the abdominal wall were observed (0.9 percent). Ten patients presented an advanced stage (III for 7 patients and IV for 3 patients). Eleven cases occurred during the learning curve period (the first 50 consecutive cases). The median survival time after abdominal wall recurrence diagnosis was 16 (range, 12-60) months. By July 2000 only two patients were alive. CONCLUSIONS: The results of the Italian prospective Registry of Laparoscopic Colorectal Surgery confirm that the incidence of abdominal wall recurrences is similar to that reported in open studies (<1 percent). Most abdominal wall recurrences occurred in the learning curve period, suggesting that surgical experience may play a role in the development of this outcome. The prognosis of these patients is very poor.

Laparoscopic treatment of gastric stromal tumors.

BACKGROUND: The laparoscopic resection of gastric stromal tumors (GST) is being performed with increased frequency. METHODS: Between November 1993 and October 1998, nine consecutive patients with benign and low-grade gastric stromal tumors underwent laparoscopic resection using intraoperative endoscopy. For lesions located on the anterior wall (three cases), a direct approach was utilized. Lesions located on the posterior wall were resected via a transgastric approach (four cases) or through a small opening on the omentum or on the gastrocolic ligament (two cases). Excision of the lesions was performed manually by means of electrocautery and scissors in eight cases; the gastric incisions were closed by manual running suture. An endoscopic stapler device was used in one case only. RESULTS: All patients were successfully treated laparoscopically; there were no conversions to open surgery. Operative time ranged from 75 to 120 min. There was one bleeding from the suture line of the gastric wall postoperatively that was treated conservatively. The average postoperative hospital stay was 4 days (range, 2-6). CONCLUSIONS: In light of the results reported in the literature and on the basis of the present work, it seems that laparoscopic resection of GST should be considered as the treatment of choice. Wedge resection of anterior wall lesions is generally performed. The treatment of posterior wall lesions is still controversial. In our opinion the direct approach should be reserved for lesions located on the posterior wall of the body, which can be easily reached through the greater omentum, while the transgastric approach should be preferred for lesions located on the fundus and antrum. Manual excision allows a tailored operation; hand-sewn sutures are always feasible, and they are cheaper than stapled ones.

360 degrees laparoscopic fundoplication with tension-free hiatoplasty in the treatment of symptomatic gastroesophageal reflux disease.

BACKGROUND: Since laparoscopic Nissen fundoplication was first described by Cuschieri in 1989 and later by Dallemagne in 1991, this procedure has been widely employed for the treatment of symptomatic gastroesophageal reflux disease (GERD) and/or hiatal hernia. However, a relatively high incidence (7-11%) of intrathoracic Nissen valve migration/paraesophageal hernia following laparoscopic fundoplication has recently been reported. METHODS: Between November 1992 and August 1995, 65 consecutive patients with severe GERD and/or hiatal hernia underwent laparoscopic 360 degrees fundoplication. In nine of these 65 (13.8%) patients, an intrathoracic Nissen valve migration had occurred within 4 months. Six of these patients were symptomatic and were again submitted to the laparoscopic intervention. Videotapes of both the first and second operation were reviewed. In all cases, it was apparent that, at the first operation, closure by stitches of the hiatus was under tension, and at the second operation, the muscle fibers of the right crus were disrupted, probably due to the tension between the suture margins during the inspiratory movements of the diaphragm. These findings prompted us to perform an effective tension-free closure of the hiatus. A polypropylene mesh (3 x 4 cm) was placed on the hiatus behind the esophagus and fixed with eight metallic agraphes (2 + 2 on the superior edge and 2 + 2 on the lateral sides of the right and left cruses). RESULTS: Between August 1995 and February 1998, the technique, complete with 360 degrees fundoplication, was used for 67 patients with GERD. At mean follow-up of 22.5 months (range, 1-30), there was no evidence of postoperative paraesophageal hernia or complications related to the use of the mesh. CONCLUSIONS: This tension-free hiatoplasty seems to be an effective solution to prevent postoperative paraesophageal hernia in patients undergoing antireflux laparoscopic surgery. However, longer follow-up is still needed.

Laparoscopic direct supragastric left adrenalectomy.

BACKGROUND: In this paper a novel laparoscopic approach to the left adrenal gland by the transabdominal anterior route is presented. This approach avoids an extensive viscera dissection to gain access to the left adrenal gland. METHODS: The first step of the procedure is the division of the gastrophrenic ligament and the section of 1 or 2 short gastric vessels in order to mobilize the gastric fundus. The gastric fundus is then pulled down, allowing a wide exposure of the left crus of the diaphragm, the perirenal fat, and the superior edge of the pancreatic body. The diaphragmatic-adrenal channel runs on the left crus, crosses the middle adrenal artery, and, usually, joins the left adrenal vein before its junction with the left renal vein. By pulling on the diaphragmatic vein, exposure of the adrenal vein is facilitated. The adrenal vein is then isolated and divided between clips. Using the monopolar electrocautery to control arteries and small veins, the mobilization of the gland is then completed. The adrenal gland is then placed in a plastic bag to prevent cell spillage and removed through an enlarged umbilical incision. RESULTS: During a 20-month period, 6 consecutive patients with left adrenal gland neoplasms have been operated on with the above mentioned original approach. The diameter of the adrenal mass ranged from 3 cm to 6 cm. No conversion to open surgery or complications have been registered. The mean operative time was 126 minutes. The mean length of hospitalization was 4.1 days (range 3 to 6). CONCLUSIONS: This approach offers a complete visualization of the left adrenal gland, avoiding mobilization of the spleen, pancreatic tail, and left flexure of the colon, and allows an early and easy control of the left adrenal vein so adrenalectomy can be safely performed.

Management of abdominal lymphoproliferative diseases in the era of laparoscopy.

BACKGROUND: The treatment of lymphoproliferative diseases requires extensive histological, immunohistochemical, and cytogenetic diagnosis. The aim of this study was to analyze the results of 66 laparoscopic procedures in the diagnosis, staging, and restaging of hematological malignancies localized in the abdominal cavity. METHODS: Between July 1993 and March 1998, 64 consecutive patients (28 male and 36 female; mean age 46.6 years, range 7 to 69) with diagnosed or suspected lymphoproliferative diseases were referred for primary diagnosis or reassessment and for staging/restaging. RESULTS: Sixty-two out of 66 procedures (93.9%) were completed laparoscopically. CONCLUSIONS: The minimally invasive approach, in the management of lymphoproliferative diseases, is able not only to provide an adequate specimen for proper diagnostic techniques, but also, when compared with open surgery, to offer a large number of advantages.

"Tension-free" hiatoplasty, gastrophrenic anchorage, and 360 degrees fundoplication in the laparoscopic treatment of paraesophageal hernia.

In our initial experience of four cases from March to November 1994, large paraesophageal hernias were repaired by conventional primary closure of the hiatus with interrupted, nonabsorbable sutures, adding a 360 degrees fundoplication. In all four cases the hernia recurred. Subsequently, we modified the procedure. The technique and results are described. From March 1995 to May 1998, 12 patients with paraesophageal hernia (4 following a previous Nissen procedure) underwent elective laparoscopic repair. In all patients a "tension-free" hiatoplasty and a floppy 360 degrees fundoplication were performed. The hiatal defect was repaired with a polypropylene mesh, fixed to the diaphragm by staples. A gastrophrenic anchorage procedure was added in the eight patients undergoing surgery for the first time, utilizing the peritoneum of the hernia sac. There were no conversions to open surgery or intraoperative complications. Two patients developed postoperative pleural effusion, which was treated medically. Mean hospital stay was 5 days. Three patients developed postoperative transient dysphagia to solid food that lasted 10 days. At a mean follow-up of 22.7 months (range 1-40), all patients are asymptomatic without dysphagia, reflux, or hernia recurrence. Laparoscopic "tension-free" hiatoplasty, 360 degrees fundoplication, and anterior gastrophrenic anchorage are effective in the treatment of large paraesophageal hernias.

Laparoscopic colorectal resection. A multicenter Italian study.

BACKGROUND: The aim of the present study was to evaluate retrospectively the experience of six surgical units currently performing laparoscopic colorectal surgery. METHODS: From November 1991 to January 1994, 200 patients (103 male, 97 female; mean age 62.5 years) were candidates for, and received, laparoscopic colorectal resection for benign (54) or malignant (196) lesions. All the units excluded patients with locally advanced organ tumors and all cases with suspected perforation and ascites. One center submitted to laparoscopic resection only stage I and IV adenocarcinoma. All surgeons considered obesity a relative contraindication. The following data were analyzed: indications, conversion rate to open surgery, operative time, morbidity and mortality, resumption of gastrointestinal function, number of lymph nodes harvested, hospital stay. RESULTS: Twenty-one out of 200 patients were converted to open surgery (10.5%); 37 patients had a complete laparoscopic procedure (17.1%); 137 had an assisted resection (68.5%); and the remaining 5 patients had a facilitated resection. The mean operative time was 208 min (90-480) for assisted resection and 275 min (54-550) for complete laparoscopic resection. The mortality rate was 1.7%; the overall morbidity was 19.6% (major complications 11.2%). All patients quickly became ambulatory and showed a prompt resumption of gastrointestinal functions, and less postoperative pain if compared with converted cases. The average number of lymph nodes was 12.1 (range 1-32). The mean hospital stay was 8.6 days (range 5-14.5). The mean follow-up was 16 months (range 6-24). The recurrence rate 11.7%. CONCLUSIONS: Laparoscopy seems to offer the possibility of minimally invasive treatment, but long-term follow-up is needed to evaluate the efficacy of laparoscopic surgery in the treatment of colorectal cancer.

Minimally invasive approach in Mirizzi's syndrome.

During a 4-year period (November 1990-September 1994), 1152 patients underwent laparoscopic cholecystectomy (LC). In five (0.4%) patients a cholecysto-choledochal fistula (Mirizzi's syndrome type II) was diagnosed and a minimally invasive treatment (endoscopy-laparoscopy-interventional radiology) was attempted. The first two cases were converted to open surgery probably because of severe anatomical distortion and inadequate confidence in performing a laparoscopic choledochal repair. The last three patients were successfully treated by minimally invasive procedures. These data indicate that a minimally invasive treatment can be safely attempted through a multi-disciplinary approach in Mirizzi's syndrome.