Outcomes of elective and emergency surgical repair of incisional hernia: a comparative observational study.

PURPOSE: Incisional hernia (IH) is a common complication following abdominal surgery. Surgical repair of IH is associated with the alleviation of symptoms and improvement of quality of life. Operative intervention can pose a significant burden to the patient and healthcare facilities. This study aims to describe and compare outcomes of elective and emergency surgical repair of IH. METHODS: This study is a single-centre comparative retrospective study including patients who had repair of IH. Patients were divided into Group I (Emergency) and Group II (Elective), and a comparison was conducted between them. RESULTS: Two hundred sixty-two patients were identified with a mean age of 61.8 ± 14.2 years, of which 152 (58%) were females. The mean BMI was 31.6 ± 7.2 kg/m2. More than 58% had at least one comorbidity. 169 (64.5%) patients had an elective repair, and 93 (35.5%) had an emergency repair. Patients undergoing emergency repair were significantly older and had higher BMI, p = 0.031 and p = 0.002, respectively. The significant complication rate (Clavien-Dindo III and IV) was 9.54%. 30 and 90-day mortality rates were 2.3% (n = 6) and 2.68% (n = 7), respectively. In the emergency group, the overall complications, 30-day and 90-day mortality rates were significantly higher than in the elective group, p ≤ 0.001, 0.002 and 0.001, respectively. Overall, 42 (16.1%) developed wound complications, 25 (9.6%) experienced a recurrence, and 41 (15.71%) were readmitted within 90 days, without significant differences between the two groups. CONCLUSION: Patients who underwent emergency repair were significantly older and had a higher BMI than the elective cases. Emergency IH repair is associated with higher complication rates and mortality than elective repair.

Onset of the humoral immune response of layer chicks vaccinated in ovo with strain F Mycoplasma gallisepticum vaccine and evidence of male-biased mortality.

Previous trials in which layers were in ovo-vaccinated against strain F Mycoplasma gallisepticum (FMG) showed that nearly 50% of the birds produced IgM antibody against FMG at 6 wk of age (WOA). Standard FMG vaccination application at 9 or 10 woa, result in this percentage at approximately 15 woa. This study investigated when FMG in ovo-vaccinated birds initiate a humoral immune response prior to 6 wk, and if sex influences this response. Hy-Line W-36 embryonated eggs were either not vaccinated (controls) or in-ovo vaccinated with a 50 µL volume of a 10-6 dilution of Poulvac MycoF vaccine (Zoetis). For each treatment group, 384 straight-run chicks were reared. At hatch and at 2, 3, 5, 7, 14, 21, and 28 d post-hatch, 54 birds per treatment were individually weighed and a blood sample was collected for Mycoplasma gallisepticum (MG) IgM antibody detection. ELISA was run on blood samples at 14, 21, and 28 d to distinguish IgG antibody production. At each age, BW was not different between vaccinated and control chicks (all P > 0.19). Males, however, outweighed females starting at d 5 (P = 0.02). Mortality was 1.0% for the control birds and 12.2% for the FMG birds during the first 2 wk. The majority (72.3%) of the mortalities in the FMG group were male. The percentage of control and FMG in ovo-vaccinated birds with IgM antibody production was 0% and 1.9% on d 7, 0% and 31.5% on d 14, 1.9% and 55.9% on d 21, and 0% and 60.6% on d 28, respectively. IgG antibody production in the FMG in ovo-vaccinated birds was 0.0% at 14 d, 2.9% at 21 d, and 21.2% at 28 d of age. All control birds tested negative for FMG-IgG production. In conclusion, the earliest detection of MG antibodies after in ovo vaccination with live FMG occurred at 7 d. Male layer chickens were more susceptible to the effects of an in ovo FMG vaccine than females.

Factors influencing parentage ratio in canine dual-sired litters.

Breeding a bitch with two different sires during a single estrous cycle has the potential to facilitate rapid genetic gain and improve reproductive performance within a canine breeding colony. There is limited data regarding the factors that contribute to the success of dual-sired litters in domestic dogs, and only anecdotal evidence suggesting that these litters rarely produce offspring from more than one sire. The objective of this prospective clinical study was to investigate multiple factors that likely affect the success of dual-sired litters on whelping rate, litter size and parentage ratio. These factors include: timing of artificial insemination (AI), order of sires, number of AI's per cycle, semen type, sperm quality and age of sire and bitch. Data collected over a 10 year period from twenty-nine estrous cycles (28 individual bitches of 10 different breeds) were evaluated after an initial AI with frozen semen from the 'genetically desired' sire and followed up with a second AI with either fresh (n = 9) or frozen (n = 16) semen or natural mating (n = 4) from a different, 'back up', sire. DNA parentage of each pup born was determined by using a primary panel of 288 SNPs. The whelping rate and litter size from previous single sire inseminations per estrous cycle, in the same bitches, (n = 16) over 25 estrous cycles using either fresh (n = 4) or frozen-thawed (n = 21) semen, were analyzed as controls. Of the 29 dual-sired breedings, 26 bitches whelped (89.7%), and 8 litters (30.8%) were of mixed parentage. In the litters of mixed parentage after a dual-sired breeding, a greater proportion of the offspring were from the second sire than the first sire (73.0% and 27.0% respectively; P < 0.05). Interestingly, in litters where all pups were of single sire parentage after a dual-sired breeding, 50.0% of the offspring were by the first sire and 50.0% were by the second sire. For litters of mixed or single paternity produced by dual-sired breeding there was no difference in average litter size. However, on a per estrous cycle basis for each bitch the whelping rate (89.7% v. 76.0%.) and litter size (5.5 ± 2.5 v. 4.0 ± 2.78) of all dual-sired breedings were greater (P < 0.05) compared to previous single-sired breedings (controls) respectively. This study demonstrates that offspring of mixed parentage derived from dual-sired breedings may be achieved. Furthermore, insemination with semen from two different sires may increase the whelping rate and litter size, which is an important consideration when using genetically valuable, or older individuals with potentially reduced fertility.

Interindividual and intraindividual variability in adolescent sleep patterns across an entire school term: A pilot study.

OBJECTIVES: This study aimed to investigate sleep patterns in adolescent males over a 12-week period (a 10-week school term and pre and post term holidays). DESIGN: Intensive longitudinal design, with sleep data collected daily via actigraphy for 81 consecutive days. SETTING: Five Secondary Schools in Adelaide, South Australia. PARTICIPANTS: Convenience sample of 47 adolescent males aged 14 to 17 years. MEASUREMENTS: Daily sleep duration, bedtimes, rise times, and sleep efficiency were collected via actigraphy with all (except sleep efficiency) also measured by sleep diary. Mood was measured weekly with Depression Anxiety Stress Scale-21 (DASS-21) and weekly wellbeing with the Satisfaction with Life Scale (SWLS). Age, body mass index, self-reported mood, life satisfaction, and chronotype preference assessed at baseline (pre-term holiday week) were included as covariates. RESULTS: Dynamic Structural Equation Modeling indicated significant but small fixed-effect and random-effect auto-regressions for all sleep variables. Collectively, these findings demonstrate day-to-day fluctuations in sleep patterns, the magnitude of which varied between individuals. Age, morningness, and mood predicted some of the temporal dynamics in sleep over time but other factors (BMI, life satisfaction) were not associated with sleep dynamics. CONCLUSIONS: Using intensive longitudinal data, this study demonstrated inter-individual and intra-individual variation in sleep patterns over 81 consecutive days. These findings provide important and novel insights into the nature of adolescent sleep and require further examination in future studies.

Impact of Introduction of a Clinical Pathway for the Management of Pyelonephritis on Obstetric Patients: a Quality Improvement Project

Aim To determine whether the introduction of a clinical pathway for the treatment of pyelonephritis in obstetric patients would improve outcomes. Methods This was a retrospective study conducted in a maternity hospital using quantitative analysis methods. Patients who met laboratory and clinical criteria for pyelonephritis during data collection were included. Results The study included analysis of 23 patients pre-intervention and 19 post-intervention. Baseline and patient characteristics were similar for both groups. A statistically significant difference was seen in 3 of 7 outcome measures. Increased use of gentamicin (13% Vs 52% p=0.006), Increased number of renal ultrasounds (17% Vs 47%, p=0.04) and increased use of prophylaxis (21% Vs 68%, p=0.003). The proportion of patients receiving ≥ 10 days of IV antimicrobials decreased from 48% to 21% post-intervention (p=0.07). Discussion This study has shown that the introduction of a pathway for the treatment of pyelonephritis in pregnancy had a positive impact on several important clinical outcomes.

The treatment of achalasia patients with esophageal varices: an international study.

Background: Treatment options for achalasia include endoscopic and surgical techniques that carry the risk of esophageal bleeding and perforation. The rare coexistence of esophageal varices has only been anecdotally described and treatment is presumed to carry additional risk. Methods: Experience from physicians/surgeons treating this rare combination of disorders was sought through the International Manometry Working Group. Results: Fourteen patients with achalasia and varices from seven international centers were collected (mean age 61 ± 9 years). Five patients were treated with botulinum toxin injections (BTI), four had dilation, three received peroral endoscopic myotomy (POEM), one had POEM then dilation, and one patient underwent BTI followed by Heller's myotomy. Variceal eradication preceded achalasia treatment in three patients. All patients experienced a significant symptomatic improvement (median Eckardt score 7 vs 1; p < 0.0001) at 6 months follow-up, with treatment outcomes resembling those of 20 non-cirrhotic achalasia patients who underwent similar therapy. No patients had recorded complications of bleeding or perforation. Conclusion: This study shows an excellent short-term symptomatic response in patients with esophageal achalasia and varices and demonstrates that the therapeutic outcomes and complications, other than transient encephalopathy in both patients who had a portosystemic shunt, did not differ to disease-matched patients without varices.

Artificial intelligence for the real-time classification of intrapapillary capillary loop patterns in the endoscopic diagnosis of early oesophageal squamous cell carcinoma: A proof-of-concept study.

Background: Intrapapillary capillary loops (IPCLs) represent an endoscopically visible feature of early squamous cell neoplasia (ESCN) which correlate with invasion depth - an important factor in the success of curative endoscopic therapy. IPCLs visualised on magnification endoscopy with Narrow Band Imaging (ME-NBI) can be used to train convolutional neural networks (CNNs) to detect the presence and classify staging of ESCN lesions. Methods: A total of 7046 sequential high-definition ME-NBI images from 17 patients (10 ESCN, 7 normal) were used to train a CNN. IPCL patterns were classified by three expert endoscopists according to the Japanese Endoscopic Society classification. Normal IPCLs were defined as type A, abnormal as B1-3. Matched histology was obtained for all imaged areas. Results: This CNN differentiates abnormal from normal IPCL patterns with 93.7% accuracy (86.2% to 98.3%) and sensitivity and specificity for classifying abnormal IPCL patterns of 89.3% (78.1% to 100%) and 98% (92% to 99.7%), respectively. Our CNN operates in real time with diagnostic prediction times between 26.17 ms and 37.48 ms. Conclusion: Our novel and proof-of-concept application of computer-aided endoscopic diagnosis shows that a CNN can accurately classify IPCL patterns as normal or abnormal. This system could be used as an in vivo, real-time clinical decision support tool for endoscopists assessing and directing local therapy of ESCN.

Minichromosomal Maintenance Component Complex 5 (MCM5) as a Marker of Barrett's Esophagus-Related Neoplasia: A Feasibility Study.

BACKGROUND: The endoscopic detection of esophageal cancer is suboptimal in both patients referred with dyspeptic symptoms and those enrolled in Barrett's surveillance programs. MCM5 expression in cells collected from gastric fluid may be correlated with the presence of dysplasia or adenocarcinoma. Analysis of this biomarker may improve the detection of cancer. METHODS: Sixty-one patients were enrolled at a single UK referral center. From each patient, 5-10 ml of gastric fluid was aspirated endoscopically. Patients were categorized according to their histology, normal, non-dysplastic Barrett's (NDBE), high-grade dysplastic Barrett's (HGD), and esophageal adenocarcinoma (EAC). All histology was confirmed by Seattle protocol biopsies or endoscopic mucosal resection. Samples were centrifuged, and the cell pellet was lysed. MCM5 expression levels were quantified using a proprietary immunoassay. The mean MCM5 expression was compared between groups by Kruskal-Wallis test. ROC curves were also used to assess diagnostic utility. RESULTS: The mean expression of MCM5 increases as patients progress from a normal esophagus to NDBE, HGD, and EAC (14.4; 49.8; 112.3; and 154.1, respectively). There was a significant difference in the MCM5 expression of patients with a normal esophagus compared to those with EAC (p = 0.04). There was a trend toward higher MCM5 expression in patients with EAC compared to those with NDBE (p = 0.34). MCM5 expression was a fair discriminator (AUC 0.70 [95% CI 0.57-0.83]) between patients without neoplasia (normal and NDBE) and those with early neoplasia (HGD and EAC). CONCLUSION: MCM5 expression in gastric fluid samples can differentiate patients with a histologically normal esophagus compared to those with early adenocarcinoma. Larger, powered studies are needed to assess whether it can be used to differentiate those with HGD from NDBE.

The role of the neutrophil:lymphocyte ratio (NLR) and the CRP:albumin ratio (CAR) in predicting mortality following emergency laparotomy in the over 80 age group.

INTRODUCTION: Emergency laparotomy in the elderly is an increasingly common procedure which carries high morbidity and mortality. Risk prediction tools, although imperfect, can help guide management decisions. Novel markers of surgical outcomes may contribute to these scoring systems. The neutrophil:lymphocyte ratio (NLR) and CRP:albumin ratio (CAR) have been associated with outcomes in malignancy and sepsis. We assessed the use of ratio NLR and CAR as prognostic indicators in patients over the age of 80 undergoing emergency laparotomy. METHODS: A retrospective analysis of all patients over the age of 80 who underwent emergency laparotomy during a 3 year period was conducted. Pre and post-operative NLR and CAR were assessed in relation to outcome measures including inpatient, 30-day and 90-day mortality. Statistical analysis was conducted with Mann-Whitney U, receiver operating characteristics, Spearmans rank correlation coefficient and chi-squared tests. RESULTS: One hundred and thirty-six patients over the age of 80 underwent emergency laparotomy. Median age was 84 years (range 80-96 years). Overall inpatient mortality was 19.2%. Pre-operative and post-operative NLR and CAR were significantly raised in patients with sepsis v no sepsis (p < 0.05). Pre-operative NLR was significantly associated with inpatient (p = 0.046), 30-day (p = 0.02) and 90-day mortality (p = 0.01) in patients with visceral perforation. A pre-operative NLR value of greater than 8 was associated with significantly increased mortality (p = 0.016, AUC:0.78). CAR was not associated with mortality. CONCLUSION: Pre-operative NLR is associated with mortality in patients with visceral perforation undergoing emergency laparotomy. NLR > 8 is associated with a poorer outcome in this group of patients. CAR was not associated with mortality in over-80s undergoing emergency laparotomy.

Bladder cancer in renal allograft recipients: risk factors and outcomes.

BACKGROUND: Solid organ transplant recipients have an increased cancer risk owing to immunosuppression and oncogenic viral infections. We report on the incidence and types of bladder cancer in kidney transplant recipients in Ireland, describing possible additional risk factors and outcomes in these patients. METHODS: We identified kidney transplant recipients diagnosed with de novo bladder cancer between January 1, 1994, and July 31, 2012, by integrating data from the Irish National Cancer Registry and National Renal Transplant Registry. We calculated the standardized incidence ratio (SIR) and examined patient and tumor characteristics and 1-year survival rate. RESULTS: Fifteen patients were diagnosed with de novo bladder cancer during the study period, representing 0.48% of kidney transplant recipients. The SIR was 2.5 (95% CI, 1.4-4.2; P < .001). The mean interval between transplantation and diagnosis of bladder tumor was 8.6 years and mean age at time of diagnosis was 55.7 years. Sixty percent of patients were male. The tumor types were transitional cell carcinoma (9 patients), squamous cell carcinoma (3 patients), adenocarcinoma (1 patient), carcinoma in situ (1 patient), and diffuse large B-cell lymphoma (1 patient). Beside immunosuppression, risk factors associated with bladder cancer were urogenital disease (6 patients), cyclophosphamide exposure (2 patients), BK nephropathy (1 patient), analgesic nephropathy (1 patient), and extensive smoking (1 patient). Eight patients underwent radical cystectomy for invasive tumors, with resection of other pelvic organs in 7 patients. Mortality rate within the first year was 40%. CONCLUSION: Bladder cancer occurred more commonly in kidney transplant recipients with a predominance of aggressive tumors and a high mortality. In patients with preexisting risk factors such as urologic abnormalities and cyclophosphamide exposure careful assessment before transplantation and vigilant monitoring posttransplantation with a low threshold for cystoscopy may improve outcomes.

Organ donation following the circulatory determination of death (DCD): an audit of donation and outcomes following renal transplantation.

Organ Donation following the Circulatory determination of Death was introduced in Beaumont Hospital during 2011. The Intensive Care Society of Ireland formally endorsed a national DCD clinical practice guideline in 2012. This retrospective audit covers a 2-year period during which eleven patients were considered suitable for DCD and where consent was obtained. Nine patients died within the ninety-minute period following the withdrawal of life sustaining therapies and subsequently donated organs (82%). Eighteen kidneys were recovered and seventeen patients received renal transplants--one patient received a nephron-dosing dual renal transplant. Lungs were recovered on two occasions and one patient received a lung transplant. Heart valves were recovered on one occasion. To date sixteen of seventeen recipient patients have functioning renal transplants (94%). In conclusion, this model of deceased donation has proven acceptable to families, nursing and medical staff and the outcomes reported are consistent with international best practice.

Impact of Duodopa on Quality of Life in Advanced Parkinson's Disease: A UK Case Series.

Treatment options in advanced Parkinson's disease (PD) include subcutaneous apomorphine, pallidal or subthalamic nucleus Deep Brain Stimulation (DBS), or levodopa/carbidopa intestinal gel (LCIG/Duodopa). In this study, we describe the outcome of 12 PD patients with PD related complications started on LCIG, with respect to their quality of life measured by a disease specific validated scale-the PDQ39, together with diaries recording time spent "On," "Off," "Dyskinetic," or "Asleep." At the time of latest follow up, improvements were observed in both the PDQ39 Summary index as well as diary reports of PD symptom control following introduction of LCIG, supporting its use in well selected patients. The use of a trial period of LCIG via naso-jejunal administration allows objective evaluation of improvement in PD symptom control in advance of the placement of the more invasive percutaneous jejunostomy procedure. The decision to embark on LCIG, apomorphine or DBS should be supported by input from centres with experience of all 3 approaches. Since LCIG is an expensive option, development of the most appropriate future commissioning of this therapy in the absence of Class 1 evidence requires careful scrutiny of the outcomes of its use in a broad range of published series.

Home haemodialysis in Ireland.

BACKGROUND: A home haemodialysis programme (HHD) was established in Ireland in 2009 following studies suggesting better outcomes and a survival advantage when compared to conventional in-centre dialysis. AIM: The aim of this study was to assess the outcomes in patients commenced on the HHD programme. METHODS: Baseline characteristics, standard dialysis parameters, blood pressure control, antihypertensive usage, vascular access problems, hospitalisation rates and technical issues related to dialysis were analysed. RESULTS: Seventeen patients were followed over a 2-year period. Time spent travelling for dialysis-related treatments was reduced with time on dialysis per week increased. There was a trend towards lower blood pressure with nine patients, either discontinuing or having a reduction in antihypertensive medications. There were eight episodes of hospitalisation with the majority of complications related to vascular access. CONCLUSION: Home haemodialysis is a community-based therapy, offering an alternative to conventional in-centre haemodialysis in a select patient population.

Identification of distinct body mass index trajectories in Australian children.

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT: Recent studies have identified distinct trajectories of obesity development in children, but more research is required to further explore these trajectories. Several socio-demographic variables such as parental education and obesity are associated with these trajectories. WHAT THIS STUDY ADDS: This study further demonstrates that there are distinct trajectories of body mass index in children. The use of raw body mass index values is more sensitive to changes in body composition compared with body mass index categories (e.g. lean vs. overweight). Hence the present results provide a more detailed insight into development patterns of obesity. The socio-demographic predictors of the trajectories offer potential avenues for future obesity interventions. BACKGROUND: A limited number of studies have demonstrated that there may be distinct developmental trajectories of obesity during childhood. OBJECTIVE: To identify distinct trajectories of body mass index (BMI) in a large sample of Australian children. METHODS: Participants included 4601 children aged 4-5 years at baseline, who were followed up at ages 6-7 years, 8-9 years and 10-11 years. Height and weight were measured at each of these time points, and used to calculate BMI. Growth Mixture Modelling was used to identify the presence of distinct BMI trajectories. RESULTS: Four distinct trajectories were identified (i) High Risk Overweight; (ii) Early Onset Overweight; (iii) Later Onset Overweight and (iv) Healthy Weight. Further analyses indicated that factors such as parental overweight, parent education, parent smoking and child birth weight were significant predictors of these trajectories. CONCLUSION: These findings indicate that different patterns of BMI development exist in children, which may require tailored interventions.

Kisspeptide in the estrous mare: is it an appropriate ovulation-inducing agent?

Kisspeptides (KiSS) are a recently discovered family of neuropeptides with a central role in regulating the onset of reproductive function in all animals studied to date. We have established biological and physiological evidence for KiSS signaling in the mare. The objective of the current study was to evaluate the physiological and behavioral responses of mares repeatedly given the equine-specific kisspeptpin decapeptide (eKp-10, YRWNSFGLRY-NH(2)) in an effort to shorten the interovulatory period. Administration of eKp-10 (0.5 mg iv every 4 h) to mares beginning on Day 16 postovulation (Group 2) or in estrus (Group 3) did not shorten the mean ± SEM interovulatory interval compared with untreated (Group 1) controls (21.9 ± 1.2, 22 ± 1.2, and 21.5 ± 1.5 days in Groups 1 to 3, respectively; N = 6 per group), nor was there a significant difference in follicle diameter before ovulation among groups, nor number of days treated with eKp-10 for Groups 2 and 3. Mean daily concentrations of FSH, the preovulatory LH surge (timing, mean, and peak concentrations), and mean progesterone concentrations from the newly formed CL were not significantly different among groups. The initiation of treatment was negatively correlated with sexual receptivity (scored 0 to 5: no interest to strong interest) and serum estradiol concentrations, indicating that eKp-10 can significantly disrupt normal sexual receptivity in the estrous mare. This effect on sexual receptivity was short-lived (< 72 h) and the overall change in sexual receptivity score was not significantly different between Groups 2 and 3 (-1.2 ± 0.5 and -1.4 ± 0.4, respectively). However, the day of the cycle that treatment was initiated significant affected the decline in sexual receptivity score, such that the later in the cycle that treatment was initiated, the greater the estimated decrease in sexual receptivity. In conclusion, the linear hypothalamic-pituitary mechanism for KiSS described in other species was not appropriate for the horse and administration of eKp-10 in the seasonally estrous mare may have been outside of the hormone's normal physiological context.

Twenty-year survivors of kidney transplantation.

There have been few studies of patients with renal allografts functioning for more than 20 years. We sought to identify clinical factors associated with ultra long-term (>20 year) renal allograft survival and to describe the clinical features of these patients. We performed a retrospective analysis of the Irish Renal Transplant Database and included 1174 transplants in 1002 patients. There were 255 (21.74%) patients with graft function for 20 years or more. Multivariate analysis identified recipient age (HR 1.01, CI 1.01-1.02), gender (male HR 1.25, CI 1.08-1.45), acute rejection (HR 1.26, CI 1.09-1.45) and transplant type (living related donor vs. deceased donor) (HR 0.52, CI 0.40-0.66) as significantly associated with long-term graft loss. Median serum creatinine was 115 µmol/L. The 5-year graft survival in 20-year survivors was 74.7%. The mean age at death was 62.7 years (±10.6). The most common causes of death were cardiovascular disease and malignancy. The two major causes of graft loss were death (with function) and interstitial fibrosis/tubular atrophy. Comorbidities included skin cancer (36.1%), coronary heart disease (17.3%) and other malignancies (14.5%). This study identifies factors associated with long-term allograft survival and a high rate of morbidity and early mortality in long-term transplant recipients.

The role of costimulatory molecules in directing the functional differentiation of alloreactive T helper cells.

Costimulatory molecules are a heterogenous group of cell surface molecules that act to amplify or counteract the initial activating signals provided to T cells from the T cell receptor following its interaction with an antigen/major histocompatibility complex, thereby influencing T cell differentiation and fate. Although costimulation was previously thought to be indispensable for T cell activation at all stages of development, it is now known that the requirements for costimulation, and the costimulatory molecules involved, vary according to the stage of T cell differentiation. The ability to influence T cell fate is of paramount interest in the field of transplantation as we seek therapeutic options that inhibit detrimental alloimmune responses whilst simultaneously promoting allograft tolerance. As with many immune mechanisms, there is a degree of functional overlap between certain costimulatory molecules, whereas some have diametrically opposite effects on different T cell subsets despite sharing common ligands. This is a critical point when considering these molecules as therapeutic targets in transplantation, as blockade of a costimulatory pathway, although desirable in itself, may prevent the ligation of an essential regulatory coinhibitory molecule. This review discusses the T helper cell lineages pertinent to transplantation and the costimulatory molecules involved in their differentiation.

Ex vivo expansion of human Tregs by rabbit ATG is dependent on intact STAT3-signaling in CD4⁺ T cells and requires the presence of monocytes.

The addition of low, nondepleting doses of rabbit antithymocyte globulin (ATG) to human peripheral blood mononuclear cells has been shown to expand functional CD4(+) CD25(+) FoxP3(+) regulatory T cells (Tregs) in vitro. This report is the first to elucidate the exact cellular mechanisms of ATG-mediated Treg expansion. CD4(+) T cells require monocytes, but not other antigen presenting cell subsets, to be present in coculture to expand Tregs. However, T cells do not require direct cell-cell contact with monocytes, suggesting the importance of soluble factors. Moreover, ATG initially "reprograms" CD4(+) T cells, but not monocytes, and induces STAT3 and STAT5 signaling in CD4(+) cells. These reprogrammed CD4(+) T cells subsequently secrete GM-CSF and IL-10 only in case of intact STAT3 signaling, which in turn promote the generation of tolerogenic CD14(+) CD11c(+) dendritic cells characterized by enhanced IL-10 and decreased IL-12 production. Treg expansion following ATG treatment is accompanied by enhanced gene expression of both GM-CSF and Bcl-2, but not TGF-ß, in peripheral blood mononuclear cells. These results demonstrate that ex vivo expansion of human Tregs by ATG is due to its ability to reprogram CD4(+) T cells in a STAT3-dependent but TGF-ß-independent manner, leading to the generation of monocyte-derived dendritic cells with a tolerogenic cytokine profile.