Innate immune activation by tissue injury and cell death in the setting of hematopoietic stem cell transplantation

Allogeneic hematopoietic stem cell transplantation (Allo-HSCT) with donor lymphocyte infusion is the mainstay of treatment for many types of hematological malignancies, but the therapeutic effect and prevention of relapse is complicated by donor T-cell recognition and attack of host tissue in a process known as graft-versus-host disease (GvHD). Cytotoxic myeloablative conditioning regimens used prior to Allo-HSCT result in the release of endogenous innate immune activators that are increasingly recognized for their role in creating a pro-inflammatory milieu. This increased inflammatory state promotes allogeneic T-cell activation and the induction and perpetuation of GvHD. Here, we review the processes of cellular response to injury and cell death that are relevant following Allo-HSCT and present the current evidence for a causative role of a variety of endogenous innate immune activators in the mediation of sterile inflammation following Allo-HSCT. Finally, we discuss the potential therapeutic strategies that target the endogenous pathways of innate immune activation to decrease the incidence and severity of GvHD following Allo-HSCT.

Complete thymectomy in adult rats with non-invasive endotracheal intubation

Thymectomy in neonatal rodents is an established and reliable procedure for immunological studies. However, in adult rats, complications of hemorrhage and pneumothorax from pleural disruption can result in a significant mortality rate. This protocol is a simple method of rat thymectomy that utilizes a mini-sternotomy and endotracheal intubation. Intubation is accomplished with a non-invasive and easily reproducible method and allows for positive pressure ventilation to prevent pneumothorax and a controlled airway that allows sufficient time for careful thymus dissection to minimize pleural disruption. A 1.5 cm sternal incision decreases contact with mediastinal vessels and pleura, while still providing full visualization of the thymus. Following exposure of the mediastinum, the thymus is removed by blunt dissection under magnification. The pleural space is then sealed by suture closure of the pre-tracheal muscles followed by the application of surgical glue. The thorax is then closed by suture closure of the sternum, followed by suture closure of the skin. All thymectomies were complete as evidenced by immunohistochemical (IHC) staining of mediastinal tissue, and absence of naïve T-cells by flow cytometry, and the procedure had a 96% survival rate. This method is suitable when complete thymectomy with minimal complications is desired for further immunological studies in athymic adult rats.

Renal outcomes of simultaneous liver-kidney transplantation compared to liver transplant alone for candidates with renal dysfunction

It is unclear whether a concomitant kidney transplant grants survival benefit to liver transplant (LT) candidates with renal dysfunction (RD). We retrospectively studied LT candidates without RD (n = 714) and LT candidates with RD who underwent either liver transplant alone (RD-LTA; n = 103) or simultaneous liver-kidney transplant (RD-SLKT; n = 68). RD was defined as renal replacement therapy (RRT) requirement or modification of diet in renal disease (MDRD)-glomerular filtration rate (GFR) <25 mL/min/1.73 m(2) . RD-LTAs had worse one-yr post-transplant survival compared to RD-SLKTs (79.6% vs. 91.2%, p = 0.05). However, RD-LTA recipients more often had hepatitis C (60.2% vs. 41.2%, p = 0.004) and more severe liver disease (MELD 37.9 ± 8.1 vs. 32.7 ± 9.1, p = 0.0001). Twenty RD-LTA recipients died in the first post-transplant year. Evaluation of the cause and timing of death relative to native renal recovery revealed that only four RD-LTA recipients might have derived survival benefit from RD-SLKT. Overall, 87% of RD-LTA patients recovered renal function within one month of transplant. One yr after RD-LTA or RD-SLKT, serum creatinine (1.5 ± 1.2 mg/dL vs. 1.4 ± 0.5 mg/dL, p = 0.63) and prevalence of stage 4 or 5 chronic kidney disease (CKD; 5.9% vs. 6.8%, p = 0.11) were comparable. Our series provides little evidence that RD-SLKT would have yielded substantial short-term survival benefit to RD-LTA recipients.

Liver transplantation in an adolescent with acute liver failure from acute lymphoblastic leukemia

The most common identifiable causes of acute liver failure in pediatric patients are infection, drug toxicity, metabolic disease, and autoimmune processes. In many cases, the etiology of acute liver failure cannot be determined. Acute leukemia is an extremely rare cause of acute liver failure, and liver transplantation has traditionally been contraindicated in this setting. We report a case of acute liver failure in a previously healthy 15-yr-old male from pre-B-cell acute lymphoblastic leukemia. He underwent liver transplantation before the diagnosis was established, and has subsequently received chemotherapy for pre-B-cell acute lymphoblastic leukemia. He is currently alive 31 months post-transplantation. The published literature describing acute lymphoblastic leukemia as a cause of acute liver failure is reviewed.

Upregulation of IL-1β, IL-6, and CCL-2 by a novel mouse model of pancreatic ischemia-reperfusion injury

BACKGROUND

Little is known about the immunologic events surrounding pancreatic ischemia-reperfusion injury (IRI) because of a lack of established experimental models. The purpose of this study was to develop a mouse model for pancreatic IRI to serve as a basis for the immunologic characterization of pancreatic organ damage at transplantation.

METHODS

Reversible ischemia was surgically induced by vascular isolation of the distal pancreas for 0, 10, 20, or 30 min. Mice receiving laparotomy without clamping served as sham-operated controls. After reperfusion, mice were serially assayed for biochemical and histologic evidence of inflammation, proinflammatory cytokine and chemokine production, and inflammatory gene upregulation.

RESULTS

After induction of pancreatic IRI, serum amylase and lactate dehydrogenase peaked at 6 hr and returned to baseline by 120 hr after injury in all groups. Mice undergoing 30 min of IRI demonstrated the greatest biochemical evidence of inflammation. Histologic scoring similarly demonstrated marked inflammation in mice subjected to 30-min IRI compared with controls. Serum cytokine/chemokine analysis demonstrated significant upregulation of granulocyte colony-stimulating factor, interferon γ, tumor necrosis factor α, interleukin (IL)-2, IL-1β, IL-6, chemokine (C-C motif) ligand-2, chemokine (C-C motif) ligand-5, chemokine (C-X-C motif) ligand-1, and macrophage inflammatory protein 2. A similar upregulation of ccl2, il1b, il6, fos, hspa1a, hspd1, and cd14 gene expression was detected by real-time polymerase chain reaction analysis of pancreatic tissue.

CONCLUSIONS

This novel model of distal pancreatic IRI in the mouse demonstrates time-limited pancreatic inflammation and injury by histologic and biochemical indices. Inflammation may be, in part, a result of the immunologic effects of IL-1β, IL-6, and CCL-2. This model provides a method by which immunologic mechanisms of pancreatic IRI can be elucidated.

Posterior reversible encephalopathy syndrome independently associated with tacrolimus and sirolimus after multivisceral transplantation

Posterior reversible encephalopathy syndrome (PRES) is a small vessel microangiopathy of the cerebral vasculature that occurs in 0.5-5% of solid organ transplant recipients, most commonly associated with tacrolimus (Tac). Clinical manifestations include hypertension and neurologic symptoms. We report an adult multivisceral transplant recipient who experienced recurrent PRES initially associated with Tac and subsequently with sirolimus. A 49-year-old woman with short bowel syndrome underwent multivisceral transplantation due to total parenteral nutrition-related liver disease. She was initially maintained on Tac, mycophenalate mofetil (MMF) and prednisone. Three months after transplantation, she developed renal dysfunction, leading to a reduction in Tac and the addition of sirolimus. Eight months after transplantation, she developed PRES. Tac was discontinued and PRES resolved. Sirolimus was increased to maintain trough levels of 12-15 ng/mL. Fourteen months after transplant, she experienced recurrent PRES which resolved after discontinuing sirolimus. Currently 3 years posttransplant, she is maintained on cyclosporine, MMF and prednisone with no PRES recurrence. In addition to calcineurin inhibitors, sirolimus may also be associated with PRES after solid organ transplantation. Ours is the first report of sirolimus-associated PRES in the setting of multivisceral transplantation. Identifying a safe alternative immunosuppression regimen was challenging but ultimately successful.

Use of vascularized posterior rectus sheath allograft in pediatric multivisceral transplantation--report of two cases

Restoring abdominal wall cover and contour in children undergoing bowel and multivisceral transplantation is often challenging due to discrepancy in size between donor and recipient, poor musculature related to birth defects and loss of abdominal wall integrity from multiple surgeries. A recent innovation is the use of vascularized posterior rectus sheath to enable closure of abdomen. We describe the application of this technique in two pediatric multivisceral transplant recipients--one to buttress a lax abdominal wall in a 22-month-old child with megacystis microcolon intestinal hypoperistalsis syndrome and another to accommodate transplanted viscera in a 10-month child with short bowel secondary to gastoschisis and loss of domain. This is the first successful report of this procedure with long-term survival. The procedure has potential application to facilitate difficult abdominal closure in both adults and pediatric liver and multivisceral transplantation.

Derivation of non-infectious envelope proteins from virions isolated from plasma negative for HIV antibodies

Natural membrane-bound HIV-1 envelope proteins (mHIVenv) could be used to produce an effective subunit vaccine against HIV infection, akin to effective vaccination against HBV infection using the hepatitis B surface antigen. The quaternary structure of mHIVenv is postulated to elicit broadly neutralizing antibodies protective against HIV-1 transmission. The founder virus transmitted to infected individuals during acute HIV-1 infection is genetically homogeneous and restricted to CCR5-tropic phenotype. Therefore, isolates of plasma-derived HIV-1 (PHIV) from infected blood donors while negative for antibodies to HIV proteins were selected for expansion in primary lymphocytes as an optimized cell substrate (OCS). Virions in the culture supernatants were purified by removing contaminating microvesicles using immunomagnetic beads coated with anti-CD45. Membrane cholesterol was extracted from purified virions with beta-cyclodextrin to permeabilize them and expel p24, RT and viral RNA, and permit protease-free Benzonase to hydrolyze the residual viral/host DNA/RNA without loss of gp120. The resultant mHIVenv, containing gp120 bound to native gp41 in immunoreactive form, was free from infectivity in vitro in co-cultures with OCS and in vivo after inoculating SCID-hu Thy/Liv mice. These data should help development of mHIVenv as a virally safe immunogen and enable preparation of polyclonal hyper-immune globulins for immunoprophylaxis against HIV-1 infection.

Requirements for prolongation of allograft survival with regulatory T cell infusion in lymphosufficient hosts

BACKGROUND

For the clinical applicability of regulatory T cells (Tregs) in transplantation, it is critical to determine if donor antigen specificity is required for their immunosuppressive function. We developed an allospecific CD4(+) T cell receptor transgenic (TCR-tg) mouse as a source for large numbers of Tregs with defined allospecificity and tested whether they are more effective than polyclonal Tregs at suppressing allograft rejection.

MATERIALS AND METHODS

CD4(+)CD25(+)CD62L(hi) T cells were sorted from the spleen and peripheral lymph nodes of wild-type (WT-Tregs) and TCR-tg (Allo-Tregs) mice, and expanded using IL-2 and anti-CD3/anti-CD28 conjugated magnetic beads. Tregs were tested for their ability to suppress the proliferation and cytokine production of alloreactive CD4(+)CD25(-) T cells in mixed leukocyte assays. Syngeneic WT hosts were adoptively transferred 5 × 10(6) Tregs and transplanted with allogeneic hearts.

RESULTS

Using anti-CD3/anti-CD28 conjugated beads, Tregs were expanded in vitro 100-fold and maintained their suppressor phenotype and function. Allo-Tregs were 6-8 times more potent on a cell-for-cell basis than WT-Tregs in suppressing allospecific proliferation in vitro. Allo-Tregs were unable to suppress in the absence of allo-antigen. Adoptive transfer of expanded Allo-Tregs into WT recipients prolonged the graft survival in a F1 heart transplant model compared with WT-Treg or no treatment [20.0 ± 4.4 d (n = 6) versus 10.4 ± 1.2 (n = 8) and 9.7 ± 1.6 d (n = 6)].

CONCLUSIONS

Unlike polyclonal Tregs, allospecific Tregs are able to prolong allograft survival. However, large numbers of Allo-Tregs were unable to induce tolerance, suggesting that Treg therapy in immunocompetent recipients will require conditioning and/or additional immunomodulation for the induction of tolerance.

Living donor kidney transplant recipients and clinical trials: participation profiles and impact on post-transplant care

Many transplant physicians believe that transplant candidates who enroll in clinical trials may have better outcomes than those who do not enroll. We examined a 7-year cohort (1997-2003) of adult primary, non-HLA identical, living donor kidney transplant (LDKT) recipients to determine whether demographic characteristics predisposed to enrollment and whether participation affected posttransplant care intensity and/or allograft function. Overall, 146 of 512 (28.5%) LDKT recipients enrolled in clinical trials. LDKT recipients who were male and those who lived <100 miles from our transplant center were significantly more likely to participate. During the first post-transplant year, study patients (SPs) had more clinic visits (p < 0.0001) and more allograft biopsies (p = 0.024) compared to nonstudy patients (NSPs), but comparable numbers of hospital readmissions and allograft ultrasounds. SPs and NSPs did not differ in 1-year creatinine clearance, delta creatinine or rejection incidence. Overall graft and patient survival were comparable. We conclude that clinical trial participants were disproportionately male, had increased intensity of post-transplant care but comparable outcomes to nonparticipants.

End stage polycystic kidney disease: indications and timing of native nephrectomy relative to kidney transplantation

PURPOSE

We evaluated the indications for and outcome of pre-transplant, concomitant and post-transplant native nephrectomy in patients with end stage polycystic kidney disease (PCKD).

MATERIALS AND METHODS

The records of 32 patients were retrospectively reviewed using the electronic database at our institution.

RESULTS

Between January 1992 and December 2002, 171 patients with end stage PCKD received a kidney transplant at University of California-San Francisco. A total of 32 patients (18.7%) underwent pre-transplant (7, group 1), concomitant (16, group 2) or post-transplant (9, group 3) native nephrectomy. Of these patients 25 underwent bilateral nephrectomy. Median followup was 18 months. Indications for nephrectomy were hematuria, a renal mass and chronic pain in group 1, lack of space in group 2 and urinary tract infection in group 3. Mean operative time +/- SEM was 231 +/- 14, 370 +/- 24 and 208 +/- 14 minutes in groups 1 to 3, respectively (p = 0.001). Mean intraoperative blood loss was 533 +/- 105, 573 +/- 155 and 522 +/- 181 ml in groups 1 to 3, respectively (p not significant). Two group 2 patients required blood transfusions. Postoperative complications requiring surgical intervention included wound dehiscence in group 1 and abdominal bleeding in group 3. Mean hospital stay was comparable among groups 1 to 3 at 7 +/- 0.7, 8.6 +/- 1.2 and 6.3 +/- 0.6 days, respectively (p not significant). At 3 months mean serum creatinine was not significantly different between groups 2 and 3 at 1.3 +/- 0.1 and 1.5 +/- 0.2 mg/dl, respectively.

CONCLUSIONS

Unilateral or bilateral nephrectomy for PCKD at transplantation is safe in terms of postoperative patient morbidity and graft function. We perform concomitant native nephrectomy when indicated, preferably in recipients of living donor kidney transplants.

Optimizing Living Donor Kidney Graft Function by Donor-Recipient Pair Selection

BACKGROUND

With the rising prevalence of living donor kidney transplantations (LDKT), we increasingly encounter transplant candidates who present with multiple potential living donors. For a given candidate, it can be unclear which donor offers the best opportunity for optimal posttransplant graft function. This study was undertaken to determine the relative contributions of individual donor demographic factors on graft function following LDKT.

METHODS

All LDKT donor-recipient pairs between January 1, 1999 and December 31, 2002 entered into the Scientific Registry of Transplant Recipients (SRTR) were reviewed. Suboptimal one year graft function was defined as a serum creatinine (Cr) greater than 1.5 mg/dL.

RESULTS

Of 20,528 adult LDKTs performed, 8,603 donor-recipient pairs had complete donor, recipient, and one year graft function data. Over one third (36%) of all LDKTs had suboptimal one year graft function. Logistic regression identified simple recipient and donor characteristics associated with suboptimal one year graft function. Four recipient factors (age, gender, race, and size), three donor factors (age, gender, and size) and recipient-donor relatedness were used to derive an equation that predicts the risk of suboptimal one year graft function posed by each potential living donor for a given transplant candidate.

CONCLUSIONS

In the setting of multiple potential living kidney donors, this quantitative tool may facilitate the choice of the optimal donor.

Increased Rejection in Living Unrelated versus Living Related Kidney Transplants does not Affect Short-Term Function and Survival

BACKGROUND

At our institution, increased kidney donation from unrelated donors accounts for a steady rise in live donor kidney transplantation rates. We compared outcomes of living related (LRT) versus living unrelated kidney transplants (LURT) and analyzed the effect of early rejection upon graft survival.

METHODS

A retrospective analysis on 428 adult living donor kidney transplants was performed. Graft function and survival were compared between LRT and LURT and risk factors for 1-year rejection were defined by multivariate analysis.

RESULTS

Between 1/1/97 and 12/31/01, 308 LRT and 120 LURT were performed at the University of California San Francisco. Donor age and number of mismatches were significantly higher in the LURT group. Patient and graft survival were similar in both groups. After a median follow-up of 26 months, graft survival was 94.8% (LRT) versus 93.3% (LURT). Five-year serum creatinine levels were comparable in both populations. One-year rejection was higher in the LURT group (30% vs. 18.5%; P<0.01). Rejection was influenced by the number of human leukocyte antigen mismatches. Other independent risk factors for early rejection were poor initial graft function, donor age greater than 55 years, and recipient body mass index greater than 30. Patients with poor initial graft function and early rejection had a statistically greater incidence of subtherapeutic tacrolimus trough levels on postoperative day 7.

CONCLUSIONS

Despite a higher incidence of early rejection, LURT show similar function and survival compared with LRT. In high-risk patients receiving living unrelated renal transplants, consideration should be given to intensify initial immunosuppression to prevent early rejection episodes.

Early graft function after living donor kidney transplantation predicts rejection but not outcomes

Poor early graft function (EGF) after deceased donor kidney transplantation (DDKT) has been intensely studied. Much less is known about poor EGF after living donor kidney transplantation (LDKT). Data were collected on 469 LDKTs performed between 1/1/97 and 12/31/01 to determine risk factors for and outcomes associated with poor EGF, defined as either delayed or slow graft function (DGF or SGF). The incidence of DGF and SGF were 4.7% and 10.7%, respectively. Diabetic etiology (OR 2.22; p = 0.021) and warm ischemia time (WIT) (OR 1.05 per min increment; p = 0.0025) emerged as independently associated with poor EGF. Neither functional graft survival nor 1-year graft function differed among the EGF groups. However, DGF and SGF strongly predisposed to acute rejection (AR), which compromised functional graft survival (p = 0.0007) and 1-year graft function. Therefore, we conclude that diabetic etiology of renal disease and WIT are the dominant risk factors for poor EGF after LDKT. Poor EGF did not directly compromise functional graft survival but strongly predisposed to AR. We suggest that immunosuppression should be intensified in the poor EGF setting to maximize LDKT longevity, as AR does impair functional graft survival.

Congenital cleft spleen with CT scan appearance of high-grade splenic laceration after blunt abdominal trauma

The spiral computed tomography (CT) scan has made the diagnosis of traumatic injury increasingly rapid and accurate, especially in cases of solid parenchymal organ injury that follows blunt abdominal trauma. Nonetheless, this valuable method of diagnosis can be confounded when anatomical variances are encountered in the setting of concomitant associated injuries. We present here a case where a congenitally bi-lobed spleen was diagnosed by CT scan as an apparent high-grade splenic laceration, prompting emergent laparotomy.

Coagulopathy, marantic endocarditis, and cerebrovascular accidents as paraneoplastic features in medullary thyroid cancer--case report and review of the literature

Medullary thyroid cancers account for approximately 7% of primary thyroid malignancies and are often associated with paraneoplastic syndromes. We discuss the case of a 59-year-old man who presented with a hypercoagulable state, nonbacterial endocarditis, and recurrent strokes in the setting of widespread medullary thyroid cancer. The patient was anticoagulated and underwent thyroidectomy, modified radical neck dissection, and subsequent axillary lymphadenectomy. Despite no recurrent thromboembolic events, the patient ultimately succumbed to his disease 8 months after diagnosis and 6 months after initial thyroidectomy. This is the first report, to our knowledge, of this unique presentation in a patient with thyroid cancer. The literature pertaining to the diagnosis and management of hypercoagulability states in patients with cancer, in general, and thyroid cancer, in particular, is reviewed.

Novel microlaparoscopic technique for peritoneal dialysis catheter placement

We describe our technique of microlaparoscopic placement of continuous ambulatory peritoneal dialysis catheters. Visualization is achieved using a 2.7-mm microlaparoscope, and intra-abdominal manipulation, as well as catheter placement using the Seldinger technique, is accomplished through a single 5-mm port. The advantages of this method include accurate placement of the catheter, minimal patient morbidity, and immediate use of the catheter for peritoneal dialysis.

Laparoscopic treatment of acute mesenteric torsion

Acute torsion of the small bowel mesentery is a diagnostically challenging cause of acute abdominal pain, which most commonly afflicts pediatric patients with midgut malrotation. We describe a case of mesenteric torsion in an adult patient that had manifested as acute abdominal pain. The patient had a remote history of prior abdominal surgery, presenting on multiple occasions with undiagnosed acute intermittent abdominal pain. Diagnosis of mesenteric torsion was made by contrast enhanced CT and the ailment was successfully treated with laparoscopic surgery without recurrence.

Effect of adjacent histidine and cysteine residues on the spontaneous degradation of asparaginyl- and aspartyl-containing peptides

Aspartate and asparagine residues in polypeptides are subject to nonenzymatic reactions that lead to deamidation, isomerization, peptide bond cleavage and racemization. Much of this reactivity is due to the propensity for the initial formation of a cyclic succinimide intermediate. We have been interested in determining the effect of the side chains of neighboring histidine and cysteine residues in facilitating these reactions, particularly in the possibility that they can act as general acids and bases. In this study, we found little or no effect of histidine residues preceding an asparagine residue in hexapeptides derived from the sequence of adrenocorticotropic hormone, while a histidine residue preceding an aspartic acid residue was found to increase the rate of succinimide formation 8- to 11-fold. The presence of a histidine residue following either an asparagine or aspartic acid residue did not effect the rate of succinimide formation by peptide-bond nitrogen attack, but did increase the rate of the competing side-chain nitrogen attack leading to cleavage in the asparaginyl-containing peptide. We found that the effect of a cysteine residue following an asparagine or aspartic acid residue was in general similar to that of a serine residue, although the cleavage reaction appeared to be enhanced. These results suggest that His-Asp sequences may be particularly labile to spontaneous degradation in proteins and peptides, possibly owing to the ability of the histidine residue to facilitate succinimide formation by protonating the OH- leaving group on the side chain carboxylic acid of the aspartic acid residue.(ABSTRACT TRUNCATED AT 250 WORDS)