Donation after circulatory death: the current state and technical approaches to organ procurement.

PURPOSE OF REVIEW: In this review, we discuss the current state of donation after circulatory death (DCD). We define the DCD donor and describe the current protocols in management of the DCD patient. We then discuss current techniques in organ procurement of the lung and abdominal organs. RECENT FINDINGS: Although donation after brain death is preferable to DCD, recent data have demonstrated acceptable early outcomes in both thoracic and abdominal organ transplant. In spite of advancements in surgical techniques and organ preservation, much has yet to be learned to minimize warm ischemia time and reperfusion injury in the DCD population. SUMMARY: In light of the continually growing disparity between organ supply and demand, DCD has regained traction as a means to increase the donor pool.

Positioning ganglioside D3 as an immunotherapeutic target in lymphangioleiomyomatosis.

Tumors that develop in lymphangioleiomyomatosis (LAM) as a consequence of biallelic loss of TSC1 or TSC2 gene function express melanoma differentiation antigens. However, the percentage of LAM cells expressing these melanosomal antigens is limited. Here, we report the overexpression of ganglioside D3 (GD3) in LAM. GD3 is a tumor-associated antigen otherwise found in melanoma and neuroendocrine tumors; normal expression is largely restricted to neuronal cells in the brain. We also observed markedly reduced serum antibody titers to GD3, which may allow for a population of GD3-expressing LAM cells to expand within patients. This is supported by the demonstrated sensitivity of cultured LAM cells to complement mediated cytotoxicity via GD3 antibodies. GD3 can serve as a natural killer T (NKT) cell antigen when presented on CD1d molecules expressed on professional antigen-presenting cells. Although CD1d-expressing monocyte derivatives were present in situ, enhanced NKT-cell recruitment to LAM lung was not observed. Cultured LAM cells retained surface expression of GD3 over several passages and also expressed CD1d, implying that infiltrating NKT cells can be directly cytotoxic toward LAM lung lesions. Immunization with antibodies to GD3 may thus be therapeutic in LAM, and enhancement of existing NKT-cell infiltration may be effective to further improve antitumor responses. Overall, we hereby establish GD3 as a suitable target for immunotherapy of LAM.

TGF-ß converts apoptotic stimuli into the signal for Th9 differentiation.

Naturally arising CD4(+)CD25(+)FoxP3(+) regulatory T cells (nTregs) have an essential role in maintenance of immune homeostasis and peripheral tolerance. Previously, we reported that conventional CD4(+) and CD8(+) T cells undergo p53-induced CD28-dependent apoptosis (PICA) when stimulated with a combination of immobilized anti-CD3 and anti-CD28 Abs, whereas nTregs expand robustly under the same conditions, suggesting that there is a differential survival mechanism against PICA between conventional T cells and nTregs. In this study, we demonstrate that TGF-ß signaling is required for nTregs to survive PICA. Conversely, when an active form of exogenous TGF-ß is present, conventional T cells become resistant to PICA and undergo robust expansion instead of apoptosis, with reduction of the proapoptotic protein Bim and FoxO3a. A substantial fraction of PICA-resistant T cells expressed IL-9 (T(H)9 cells). Moreover, the presence of IL-6 along with TGF-ß led to the generation of T(H)17 cells from conventional T cells. Together, the data demonstrate a novel role for TGF-ß in the homeostasis of regulatory T cells and effector T cell differentiation and expansion.

Pin1 protein regulates Smad protein signaling and pulmonary fibrosis.

Interstitial pulmonary fibrosis is caused by the excess production of extracellular matrix (ECM) by Fb in response to TGF-ß1. Here, we show that the peptidyl-prolyl isomerase Pin1 modulates the production of many pro- and antifibrogenic cytokines and ECM. After acute, bleomycin injury, Pin1(-/-) mice showed reduced, pulmonary expression of collagens, tissue inhibitors of metalloproteinases, and fibrogenic cytokines but increased matrix metalloproteinases, compared with WT mice, despite similar levels of inflammation. In primary fibroblasts, Pin1 was required for TGF-ß-induced phosphorylation, nuclear translocation, and transcriptional activity of Smad3. In Pin1(-/-) cells, inhibitory Smad6 was found in the cytoplasm rather than nucleus. Smad6 knockdown in Pin1(-/-) fibroblasts restored TGF-ß-induced Smad3 activation, translocation, and target gene expression. Therefore, Pin1 is essential for normal Smad6 function and ECM production in response to injury or TGF-ß and thus may be an attractive therapeutic target to prevent excess scarring in diverse lung diseases.

Ontogeny and localization of the cells produce IL-2 in healthy animals.

IL-2 is a growth factor for activated T cells and is required for maintenance of naturally arising regulatory T cells (nTregs). Mice defective in IL-2/IL-2 receptor signaling pathways have impaired nTregs and suffer from lymphoproliferative disorders, suggesting that IL-2 is present and functional in healthy animals. However, the cellular source of IL-2 is currently unknown. To determine which cells produce IL-2 in healthy animals, we established mice carrying cre gene knock in at the il-2 locus (termed IL-2(cre)). When IL-2(cre) mice were crossed with EGFP reporter mice, EGFP was exclusively expressed by a fraction of CD4 T cells present in both lymphoid and non-lymphoid tissues. Live imaging of IL-2(cre) mice that carry the luciferase reporter showed concentrated localization of luciferase(+) cells in Peyer's patches. These cells were not observed in new born mice but appeared within 3days after birth. Reduction of antigen receptor repertoire by transgene expression reduced their number, indicating that recognition of environmental antigens is necessary for generation of these IL-2 producers in healthy animals. A substantial fraction of EGFP(+) cells also produce IL-10 and IFN-γ, a characteristic profile of type 1 regulatory T cells (Tr1). The data suggest that a group of Tr1 cells have addition roles in immune homeostasis by producing IL-2 along with other cytokines and help maintaining Tregs.

Pepsin concentrations are elevated in the bronchoalveolar lavage fluid of patients with idiopathic pulmonary fibrosis after lung transplantation.

BACKGROUND: Aspiration of gastroesophageal refluxate has been implicated in the pathogenesis of idiopathic pulmonary fibrosis (IPF) and the progression of bronchiolitis obliterans syndrome after lung transplantation. The goals of the present study were to identify lung transplant patients at the greatest risk of aspiration and to investigate the causative factors. MATERIALS AND METHODS: From September 2009 to November 2011, 252 bronchoalveolar lavage fluid (BALF) samples were collected from 100 lung transplant patients. The BALF pepsin concentrations and the results of transbronchial biopsy, esophageal function testing, barium swallow, and gastric emptying scan were compared among those with the most common end-stage lung diseases requiring lung transplantation: IPF, chronic obstructive pulmonary disease, cystic fibrosis, and α1-antitrypsin deficiency. RESULTS: Patients with IPF had higher BALF pepsin concentrations and a greater frequency of acute rejection than those with α1-antitrypsin deficiency, cystic fibrosis, or chronic obstructive pulmonary disease (P = 0.037). Moreover, the BALF pepsin concentrations correlated negatively with a lower esophageal sphincter pressure and distal esophageal amplitude; negatively with distal esophageal amplitude and positively with total esophageal acid time, longest reflux episode, and DeMeester score in those with chronic obstructive pulmonary disease; and negatively with the upright acid clearance time in those with IPF. CONCLUSIONS: Our results suggest that patients with IPF after lung transplantation are at increased risk of aspiration and a greater frequency of acute rejection episodes, and that the risk factors for aspiration might be different among those with the most common end-stage lung diseases who have undergone lung transplantation. These results support the role of evaluating the BALF for markers of aspiration in assessing lung transplant patients as candidates for antireflux surgery.

A current viewpoint of lymphangioleiomyomatosis supporting immunotherapeutic treatment options.

Lymphangioleiomyomatosis (LAM) leads to hyperproliferation of abnormal smooth muscle cells in the lungs, associated with diffuse pulmonary parenchymal cyst formation and progressive dyspnea on exertion. The disease targets women of child-bearing age. Complications include pneumothoraces and chylous pleural effusions. Ten-year survival is estimated at 70%, and lung transplantation remains the only validated treatment. It has been observed that LAM cells express markers associated with melanocytic differentiation, including gp100 and MART-1. Other melanocytic markers have also been observed. The same proteins are targeted by T cells infiltrating melanoma tumors as well as by T cells infiltrating autoimmune vitiligo skin, and these antigens are regarded as relatively immunogenic. Consequently, vaccines have been developed for melanoma targeting these and other immunogenic melanocyte differentiation proteins. Preliminary data showing susceptibility of LAM cells to melanoma derived T cells suggest that vaccines targeting melanosomal antigens can be successful in treating LAM.

Kv7 potassium channels in airway smooth muscle cells: signal transduction intermediates and pharmacological targets for bronchodilator therapy.

Expression and function of Kv7 (KCNQ) voltage-activated potassium channels in guinea pig and human airway smooth muscle cells (ASMCs) were investigated by quantitative reverse transcriptase polymerase chain reaction (qRT-PCR), patch-clamp electrophysiology, and precision-cut lung slices. qRT-PCR revealed expression of multiple KCNQ genes in both guinea pig and human ASMCs. Currents with electrophysiological and pharmacological characteristics of Kv7 currents were measured in freshly isolated guinea pig and human ASMCs. In guinea pig ASMCs, Kv7 currents were significantly suppressed by application of the bronchoconstrictor agonists methacholine (100 nM) or histamine (30 µM), but current amplitudes were restored by addition of a Kv7 channel activator, flupirtine (10 µM). Kv7 currents in guinea pig ASMCs were also significantly enhanced by another Kv7.2-7.5 channel activator, retigabine, and by celecoxib and 2,5-dimethyl celecoxib. In precision-cut human lung slices, constriction of airways by histamine was significantly reduced in the presence of flupirtine. Kv7 currents in both guinea pig and human ASMCs were inhibited by the Kv7 channel blocker XE991. In human lung slices, XE991 induced robust airway constriction, which was completely reversed by addition of the calcium channel blocker verapamil. These findings suggest that Kv7 channels in ASMCs play an essential role in the regulation of airway diameter and may be targeted pharmacologically to relieve airway hyperconstriction induced by elevated concentrations of bronchoconstrictor agonists.

Pulmonary immune changes early after laparoscopic antireflux surgery in lung transplant patients with gastroesophageal reflux disease.

BACKGROUND: The biologic mechanisms by which laparoscopic antireflux surgery (LARS) might influence the inflammatory process leading to bronchiolitis obliterans syndrome are unknown. We hypothesized that LARS alters the pulmonary immune profile in lung transplant patients with gastroesophageal reflux disease. METHODS: In 8 lung transplant patients with gastroesophageal reflux disease, we quantified and compared the pulmonary leukocyte differential and the concentration of inflammatory mediators in the bronchoalveolar lavage fluid (BALF) 4 weeks before LARS, 4 weeks after LARS, and 12 months after lung transplantation. Freedom from bronchiolitis obliterans syndrome (graded 1-3 according to the International Society of Heart and Lung Transplantation guidelines), forced expiratory volume in 1 second trends, and survival were also examined. RESULTS: At 4 weeks after LARS, the percentages of neutrophils and lymphocytes in the BALF were reduced (from 6.6% to 2.8%, P = 0.049, and from 10.4% to 2.4%, P = 0.163, respectively). The percentage of macrophages increased (from 74.8% to 94.6%, P = 0.077). Finally, the BALF concentration of myeloperoxide and interleukin-1ß tended to decrease (from 2109 to 1033 U/mg, P = 0.063, and from 4.1 to 0 pg/mg protein, P = 0.031, respectively), and the concentrations of interleukin-13 and interferon-γ tended to increase (from 7.6 to 30.4 pg/mg protein, P = 0.078 and from 0 to 159.5 pg/mg protein, P = 0.031, respectively). These trends were typically similar at 12 months after transplantation. At a mean follow-up of 19.7 months, the survival rate was 75% and the freedom from bronchiolitis obliterans syndrome was 75%. Overall, the forced expiratory volume in 1 second remained stable during the first year after transplantation. CONCLUSIONS: Our preliminary study has demonstrated that LARS can restore the physiologic balance of pulmonary leukocyte populations and that the BALF concentration of pro-inflammatory mediators is altered early after LARS. These results suggest that LARS could modulate the pulmonary inflammatory milieu in lung transplant patients with gastroesophageal reflux disease.

Comparison of sirolimus with azathioprine in a tacrolimus-based immunosuppressive regimen in lung transplantation.

RATIONALE: Lung transplantation has evolved into a life-saving therapy for select patients with end-stage lung diseases. However, long-term survival remains limited because of chronic rejection. Sirolimus is beneficial in preventing cardiac rejection and may decrease rejection after lung transplantation. OBJECTIVES: To determine the potential benefit versus risk of sirolimus in lung transplantation. METHODS: We conducted a multicenter randomized, open label controlled trial comparing sirolimus (SIR) with azathioprine (AZA) in a tacrolimus-based immunosuppressive regimen in lung transplantation. The primary end point was the incidence of acute rejection at 1 year after transplantation between the two study groups. MEASUREMENTS AND MAIN RESULTS: One hundred eighty-one patients were randomized to be included in this study. At 1 year after transplantation, there was no significant difference in the incidence of grade A acute rejection between the two study groups. Similarly, the incidence of chronic rejection and graft survival was no different between the two study groups. Cytomegalovirus infection was decreased in the SIR arm compared with the AZA arm (relative risk, 0.67 [95% confidence interval, 0.55, 0.82]; P < 0.01). There was a higher rate of adverse events leading to early discontinuation of SIR (64%) compared with AZA (49%) during the course of this study. CONCLUSIONS: Sirolimus, an mTOR inhibitor, did not decrease the incidence of acute rejection at 1 year compared with azathioprine in lung transplantation. These results differ from previous results in cardiac and renal transplantation and emphasize the need for multicenter randomized controlled trials in lung transplantation. Clinical trial registered with www.clinicaltrials.gov (NCT 00321906).

Laparoscopic antireflux surgery for gastroesophageal reflux disease after lung transplantation.

BACKGROUND: Although gastroesophageal reflux disease (GERD) is highly prevalent in lung transplantation, the pathophysiology of GERD in these patients is unknown. We hypothesize that the pathophysiology of GERD after lung transplantation differs from that of a control population, and that the 30-d morbidity and mortality of laparoscopic antireflux surgery (LARS) are equivalent in both populations. METHODS: We retrospectively compared the pathophysiology of GERD and the 30-d morbidity and mortality of 29 consecutive lung transplant patients with 23 consecutive patients without lung transplantation (control group), all of whom had LARS for GERD between November 2008 and May 2010. RESULTS: Both groups had a similar prevalence of endoscopic esophagitis and Barrett's esophagus , comparable manometric profiles, and similar prevalence of abnormal peristalsis. However, hiatal hernia was more common in controls than in lung transplant patients (57% versus 24%; P = 0.04). Lung transplant patients had a higher prevalence and severity of proximal GERD (65% versus 33%; P = 0.04). The 30-d morbidity and mortality following LARS were similar in both groups regardless of the higher surgical risk of lung transplants (median ASA class: 3 versus 2 for controls, P < 0.001). CONCLUSIONS: These results show that despite similar manometric profiles, lung transplant patients are more prone to proximal reflux than the general population with GERD; the prevalence of endoscopic esophagitis and Barrett's esophagus is the same in both groups of patients; a hiatal hernia is uncommon after lung transplantation; and the morbidity and mortality of LARS are the same for lung transplant patients as the general population with GERD.

Donation after cardiac death lung transplantation outcomes.

PURPOSE OF REVIEW: Lung transplantation is now a well established treatment option for several end-stage respiratory diseases. Survival after lung transplantation has significantly improved over the last decade. The primary limitation to increased utilization of lung transplantation remains donor scarcity. Suitable allografts have been procured from donors after determination of neurologic death and from donors after determination of cardiac death (DDCD or DCD). Historically, the first human lung transplantation performed, utilized an allograft procured after cardiovascular death, also referred to as nonheart-beating donor.The experience at University of Wisconsin in 1993 reintroduced DCD lung transplantation with the first successful clinical case. RECENT FINDINGS: A potential additional lung allograft source, DCD lung transplantation has been established with very acceptable outcomes observed by several centers. We provide the relevant background for the rationale of donor allograft expansion to include DCD lungs from controlled (Maastricht category III donors). SUMMARY: This review considers the available evidence for DCD lung transplantation and compares reported primary graft dysfunction rates and current survival data available.

Donation after circulatory death donors in lung transplantation.

Transplantation of any organ into a recipient requires a donor. Lung transplant has a long history of an inadequate number of suitable donors to meet demand, leading to deaths on the waiting list annually since national data was collected, and strict listing criteria. Before the Uniform Determination of Death Act (UDDA), passed in 1980, legally defined brain death in the U.S., all donors for lung transplant came from sudden death victims [uncontrolled Donation after Circulatory Death donors (uDCDs)] in the recipient's hospital emergency department. After passage of the UDDA, uDCDs were abandoned to Donation after Brain Death donors (DBDs)-perhaps prematurely. Compared to livers and kidneys, many DBDs have lungs that are unsuitable for transplant, due to aspiration pneumonia, neurogenic pulmonary edema, trauma, and the effects of brain death on lung function. Another group of donors has become available-patients with a devastating irrecoverable brain injury that do not meet criteria for brain death. If a decision is made by next-of-kin (NOK) to withdraw life support and allow death to occur by asphyxiation, with NOK consent, these individuals can have organs recovered if death occurs relatively quickly after cessation of mechanical ventilation and maintenance of their airway. These are known as controlled Donation after Circulatory Death donors (cDCDs). For a variety of reasons, in the U.S., lungs are recovered from cDCDs at a much lower rate than kidneys and livers. Ex-vivo lung perfusion (EVLP) in the last decade has had a modest impact on increasing the number of lungs for transplant from DBDs, but may have had a larger impact on lungs from cDCDs, and may be indispensable for safe transplantation of lungs from uDCDs. In the next decade, DCDs may have a substantial impact on the number of lung transplants performed in the U.S. and around the world.

IL-17-dependent cellular immunity to collagen type V predisposes to obliterative bronchiolitis in human lung transplants.

Bronchiolitis obliterans syndrome (BOS), a process of fibro-obliterative occlusion of the small airways in the transplanted lung, is the most common cause of lung transplant failure. We tested the role of cell-mediated immunity to collagen type V [col(V)] in this process. PBMC responses to col(II) and col(V) were monitored prospectively over a 7-year period. PBMCs from lung transplant recipients, but not from healthy controls or col(IV)-reactive Goodpasture's syndrome patients after renal transplant, were frequently col(V) reactive. Col(V)-specific responses were dependent on both CD4+ T cells and monocytes and required both IL-17 and the monokines TNF-alpha and IL-1beta. Strong col(V)-specific responses were associated with substantially increased incidence and severity of BOS. Incidences of acute rejection, HLA-DR mismatched transplants, and induction of HLA-specific antibodies in the transplant recipient were not as strongly associated with a risk of BOS. These data suggest that while alloimmunity initiates lung transplant rejection, de novo autoimmunity mediated by col(V)-specific Th17 cells and monocyte/macrophage accessory cells ultimately causes progressive airway obliteration.

Melanoma-associated antigen expression in lymphangioleiomyomatosis renders tumor cells susceptible to cytotoxic T cells.

The antibody HMB45 is used to diagnose lymphangioleiomyomatosis, a hyperproliferative disorder of lung smooth muscle cells with mutations in both alleles of either TSC1 or TSC2. A subset of these tumor cells expresses the melanoma-associated antigens gp100 and melanoma antigen recognized by T cells (MART-1). To explore the feasibility of targeting tumors in lymphangioleiomyomatosis by melanoma immunotherapy, we therefore assessed melanoma target antigen expression and existing immune infiltration of affected tissue compared with normal lung and melanoma as well as the susceptibility of cultured lymphangioleiomyomatosis cells to melanoma reactive cytotoxic T lymphocytes in vitro. Tumors expressed tyrosinase-related proteins 1 and 2 but not tyrosinase, in addition to gp100 and MART-1, and were densely infiltrated by macrophages, but not dendritic cells or T cell subsets. Although CD8(+) lymphocytes were sparse compared with melanoma, cells cultured from lymphangioleiomyomatosis tissue were susceptible to cytotoxic, gp100 reactive, and major histocompatibility complex class I restricted CD8(+) T cells in functional assays. Responder T cells selectively clustered and secreted interferon-gamma in response to HLA-matched melanocytes and cultured lymphangioleiomyomatosis cells. This reactivity exceeded that based on detectable gp100 expression; thus, tumor cells in lymphangioleiomyomatosis may process melanosomal antigens different from melanocytic cells. Therefore, boosting immune responses to gp100 in lymphangioleiomyomatosis may offer a highly desirable treatment option for this condition.

Th-17, monokines, collagen type V, and primary graft dysfunction in lung transplantation.

RATIONALE: The pathogenesis of primary graft dysfunction (PGD), a serious complication of lung transplantation, is poorly understood. Human studies and rodent models have shown that collagen type V (col[V]), stimulates IL-17-dependent cellular immunity after lung transplantation. OBJECTIVES: To determine whether patients with end-stage lung disease develop pretransplant col(V)-specific cellular immunity, and if so, the impact of this response on PGD. METHODS: Trans-vivo delayed-type hypersensitivity (TV-DTH) assays were used to evaluate memory T-cell responses to col(V) in 55 patients awaiting lung transplantation. Pa(O(2))/Fi(O(2)) index data were used to assess PGD. Univariate risk factor analysis was performed to identify variables associated with PGD. Rats immunized with col(V) or irrelevant antigen underwent lung isografting to determine if prior anti-col(V) immunity triggers PGD in the absence of alloreactivity. MEASUREMENTS AND MAIN RESULTS: We found that 58.8% (10/17) of patients with idiopathic pulmonary fibrosis, and 15.8% (6/38) of patients without idiopathic pulmonary fibrosis tested while on the wait list for a lung transplant were col(V) DTH positive. Col(V) reactivity was CD4(+) T-cell and monocyte mediated, and dependent on IL-17, IL-1beta, and tumor necrosis factor (TNF)-alpha. Pa(O(2))/Fi(O(2)) indices were impaired significantly 6-72 hours after transplantation in col(V)-reactive versus nonreactive patients. Univariate risk factor analysis identified only preoperative TV-DTH to col(V) and ischemic time as predictors of PGD. Finally, in a rat lung isograft model, col(V) sensitization resulted in significantly lower Pa(O(2))/Fi(O(2)), increased local TNF-alpha and IL-1beta production, and a moderate-to-severe bronchiolitis/vasculitis when compared with control isografts. CONCLUSIONS: The data suggest that activation of innate immunity by col(V)-specific Th-17 memory cells represents a novel pathway to PGD after lung transplantation.

Effect of annual influenza immunization on antibody response in lung transplant patients.

BACKGROUND: Influenza viral infections cause significant morbidity and mortality each season. Lung transplant patients may be at higher risk because of their underlying pathophysiology. Although annual immunization is the standard of care, its efficacy remains largely unproven. Previous studies showed poor antibody response to influenza vaccine in lung transplant patients, but no data on the antibody response in consecutive seasons have been published. METHODS: We studied antibody responses to influenza vaccine in 122 subjects: 66 lung transplant recipients, 28 control subjects, and 28 patients awaiting lung transplantation. We compared antibody response rates to individual viruses contained in influenza vaccines in consecutive years within the 3 groups. Serum antibody concentrations were measured at baseline and 2 to 4 weeks after vaccination by using the hemagglutination inhibition assay. Log-transformed antibody concentrations and incidence of serconversion and seroprotection were calculated. RESULTS: Median log-transformed antibody responses were similar in consecutive seasons in lung transplant subjects. Incidences of seroprotection and seroconversion did not differ between consecutive seasons in lung transplant recipients. CONCLUSIONS: Antibody responses were similar in consecutively measured years in lung transplant subjects. Annual influenza vaccination in lung transplant subjects produces similar immune responses in 2 consecutive years, indicating that these patients are not at significantly increased risk of vaccine failure.

Daclizumab to prevent rejection after cardiac transplantation.

BACKGROUND: Daclizumab, a humanized monoclonal antibody against the interleukin-2 receptor, reduced the risk of rejection without increasing the risk of infection among renal-transplant recipients and, in a single-center trial, among cardiac-transplant recipients. We conducted a multicenter, placebo-controlled, double-blind study to confirm these results in cardiac-transplant patients. METHODS: We randomly assigned 434 recipients of a first cardiac transplant treated with standard immunosuppression (cyclosporine, mycophenolate mofetil, and corticosteroids) to receive five doses of daclizumab or placebo. The primary end point was a composite of moderate or severe cellular rejection, hemodynamically significant graft dysfunction, a second transplantation, or death or loss to follow-up within six months. RESULTS: By six months, 104 of 218 patients in the placebo group had reached the primary end point, as compared with 77 of the 216 patients in the daclizumab group (47.7 percent vs. 35.6 percent, P=0.007), a 12.1 percent absolute risk reduction and a 25 percent relative reduction. The rate of rejection was lower in the daclizumab group than in the placebo group (41.3 percent vs. 25.5 percent). Among patients reaching the primary end point, the median time to the end point was almost three times as long in the daclizumab group as in the placebo group during the first 6 months (61 vs. 21 days) and at 1 year (96 vs. 26 days). More patients in the daclizumab group than in the placebo group died of infection (6 vs. 0) when they received concomitant cytolytic therapy. CONCLUSIONS: Daclizumab was efficacious as prophylaxis against acute cellular rejection after cardiac transplantation. Because of the excess risk of death, concurrent or anticipated use of cytolytic therapy with daclizumab should be avoided.

IL-17 producing gammadelta T cells are required for a controlled inflammatory response after bleomycin-induced lung injury.

BACKGROUND: gammadelta T cells play a key role in the regulation of inflammatory responses in epithelial tissue, and in adaptive immunity, as gammadelta T cell deficient mice have a severely impaired capacity to clear lung pathogens. gammadelta T cells regulate the initial inflammatory response to microbial invasion and thereby protect against tissue injury. Here we examined the response of gammadelta T cells to lung injury induced by bleomycin, in an effort to study the inflammatory response in the absence of any adaptive immune response to a pathogen. RESULTS: After lung injury by bleomycin, we localized the gammadelta T cells to the lung lesions. gammadelta T cells were the predominant source of IL-17 (as detected by flow cytometry and real-time PCR). Moreover, gammadelta T cell knockout mice showed a significant reduction in cellular infiltration into the airways, reduced expression of IL-6 in the lung, and a significant delay in epithelial repair. CONCLUSION: Mouse gammadelta T cells produce IL-17 in response to lung injury and are required for an organized inflammatory response and epithelial repair. The lack of gammadelta T cells correlates with increased inflammation and fibrosis.

T-cell responses to hepatitis B surface antigen in lung transplant recipients.

STUDY OBJECTIVE: To determine whether lung transplant recipients would have a less vigorous T-cell response to hepatitis B surface antigen (HBsAg) than that of patients awaiting lung transplantation and healthy subjects, we sought to measure and compare T-cell responses among these three groups. DESIGN: Prospective study. SETTING: Lung transplant clinic at a university hospital. SUBJECTS: Twelve lung transplant recipients, 12 patients awaiting lung transplantation, and 15 healthy subjects. All participants had received the hepatitis B vaccine series and had a documented antibody response to it. INTERVENTION: Blood samples were obtained from each participant. MEASUREMENTS AND MAIN RESULTS: Participants' sex, age, time since lung transplantation (if applicable), and time since hepatitis B immunization were recorded. Peripheral blood mononuclear cells were isolated from the participants' blood samples for the trans vivo delayed-type hypersensitivity (DTH) assay. These cells were mixed with saline, tetanus toxoid, or HBsAg and injected into the footpads of immunodeficient mice. Resultant swelling of the footpad was used as an index of human T-cell response. The healthy subjects were younger than the patients in both transplant groups. However, we found no significant difference in DTH response elicited by HBsAg among the healthy subjects, patients awaiting lung transplantation, and lung transplant recipients (mean +/- standard error [SE] 34.7 +/- 4.3, 32.1 +/- 3.1, and 33.5 +/- 4.0 x 10(-4) in., respectively, p>0.8) or when tetanus toxoid was used as a positive control (15.7 +/- 2.8, 22.8 +/- 6.5, and 21.7 +/- 3.9 x 10(-4) in., respectively, p>0.3). No correlation between age or time since immunization and DTH response was noted. CONCLUSION: Lung transplant recipients maintained a T-cell response to HBsAg that was similar in vigor to that of both patients awaiting transplantation and healthy subjects even though their antibody concentrations waned rapidly after transplantation. The role of these T cells as a correlate of protection from infection remains to be investigated.