MAIT cells in placental tissues and their reconstitution following allogeneic hematopoietic stem cell transplantation

The placenta is a temporary organ of human reproduction. Both the fetus and placenta are covered in a membrane of maternal origin, the decidua. After the 1st trimester, the fetus is supplied with oxygen and nutrients by maternal arterial blood that penetrates the decidua and fills the intervillous space of the placenta. Fetal blood vessels covered in a thin cell layer, the villi, protrude down into this intervillous blood (IVB), and gases and molecules are transported in and out of the fetal circulation. The maternal immune system recognizes fetal antigen as foreign, yet in the case of a successful pregnancy, it tolerates the fetus while still maintaining immunity against pathogens. Maternal immune cells come into contact with fetal antigen in the decidua and the intervillous space, and these immunological sites are referred to as the feto-maternal interface. Mucosal associated invariant T (MAIT) cells is a large subset of antigen-specific T cells. MAIT cells are activated by metabolites from the synthesis of vitamin B2 by certain species of bacteria and fungi, which are presented on the MHC class I related molecule (MR1). As humans cannot synthesize vitamin B2, MAIT cells can thus discern between self and non-self. In this thesis, we have studied the immune cell composition and function at the feto-maternal interface with special focus on MAIT cells. We also studied the reconstitution of MAIT cells in the conceptually interesting context of allogeneic hematopoietic cell transplantation (HCT). We found that IVB has a fundamentally different composition of immune cells compared to peripheral blood (PB) from the same donors. The IVB was enriched in MAIT cells, effector memory T cells and B cells. The MAIT cells in IVB had a more potent response when stimulating mixed mononuclear cell cultures with bacteria compared to PB. MR1 was readily expressed by fetal macrophages inside the villi. We compared immune cells isolated from the two different parts of the decidual membrane, the decidua basalis (DB) that covers the placenta from the maternal side, and the decidua parietalis (DP) that is attached to the edge of the placenta, and covers the fetus and amniotic fluid. DP contained more T cells and CD56high NK cells, whereas DB was enriched in MAIT cells, B cells, monocytes and CD56dim NK cells. Immune cells in DP had a higher expression of co-inhibitory markers such as PD-1, TIM-3 and LAG-3. In spite of this expression, MAIT cells, T cells and NK cells from both DP and DB were functional when stimulated with bacteria or PMA/Ionomycin. Non-pregnant women had a higher frequency of MAIT cells in PB compared to pregnant women at term. Using supernatants from placenta tissue explant cultures, we observed that MAIT cells and CD8+ effector T cells were selectively recruited in migration assays. When analyzing the chemokine and cytokine patterns in these supernatants and plasma samples from IVB, many similarities were seen. In contrast, the levels of chemokines in PB plasma was strikingly different compared to that of IVB plasma. Among these, macrophage migration inhibitory factor (MIF) was 182-fold higher in IVB compared to PB plasma. The frequency of MAIT cells in both IVB and DP correlated with levels of MIF in IVB. When blocking MIF together with CCL20 and CCL25, the migration of MAIT cells towards the placenta tissue explant supernatant was reduced. Using recombinant MIF protein, we could show that MIF attracted MAIT cells, probably by binding the chemokine receptor CXCR4. IVB contained a higher proportion of B cells compared to PB, and the IVB B cells were primarily of the mature/naïve phenotype. This subset of B cells was correlated with levels of CCL20 in IVB plasma. Mature/naïve B cells all expressed the receptor for CCL20, CCR6, and they had a higher median fluorescent intensity of CCR6 compared to immature B cells. Using the same migration assay as previously, we could see that placenta tissue explant supernatant attracted B cells. Lastly, we investigated the reconstitution of MAIT cells following HCT. MAIT cells did not start to increase in total number until two years after the transplantation, and as the non-MAIT T cells proliferated during this time, the relative proportion of MAIT cells remained at the same low levels during the observation period. When stimulating mixed mononuclear cells with bacteria, the MAIT cells from 2-6 months after HCT had an impaired interferon-γ response, whereas the response at 24 months was similar to that seen in healthy controls. Lastly, we showed that proliferating MAIT cells were more sensitive to common immunosuppressive drugs used in patients after HCT. In conclusion, the immunological constitution and function of IVB seems to be shaped by soluble factors secreted by placental tissue. IVB is a specialized immunological environment enriched in MAIT cells and other effector T cells, as well as mature B cells, and challenging IVB mononuclear cells with bacteria led to a more potent MAIT cell response. This points to that the placenta attracts certain subsets of immune cells in order to uphold immunity at the feto-maternal interface. MAIT cell reconstitution following HCT was impaired, both in terms of cell number, frequency and function. This could partly be explained by an increased sensitivity of dividing MAIT cells to common immunosuppressive drugs used after transplantation. The impaired MAIT cell reconstitution could partly be an explanation of the increased risk of infectious complications following HC

Ion counting efficiencies at the IGISOL facility

At the IGISOL-JYFLTRAP facility, fission mass yields can be studied at high precision. Fission fragments from a U target are passing through a Ni foil and entering a gas filled chamber. The collected fragments are guided through a mass separator to a Penning trap where their masses are identified. This simulation work focuses on how different fission fragment properties (mass, charge and energy) affect the stopping efficiency in the gas cell. In addition, different experimental parameters are varied (e. g. U and Ni thickness and He gas pressure) to study their impact on the stopping efficiency. The simulations were performed using the Geant4 package and the SRIM code. The main results suggest a small variation in the stopping efficiency as a function of mass, charge and kinetic energy. It is predicted that heavy fragments are stopped about 9% less efficiently than the light fragments. However it was found that the properties of the U, Ni and the He gas influences this behavior. Hence it could be possible to optimize the efficiency.Comment: 52 pages, 44 figure

Late-onset limb-girdle muscular dystrophy caused by GMPPB mutations

Mutations in GMPPB gene have been reported in patients with early-onset disease ranging from severe congenital muscular dystrophies to limb-girdle muscular dystrophy (LGMD) with mental retardation. More recently mutations in GMPPB have been identified with congenital myasthenic syndromes as well as milder phenotypes. We report two unrelated cases with LGMD that underwent clinical, histopathological and genetic studies. In both cases, we found identical compound heterozygous GMPPB mutations c.79G>C p.D27H and c.859C>T p.R287W, leading to a glycosylation defect of alpha-dystroglycan. The onset of muscle weakness was 30-40 years and the progression rate mild to moderate. Case 2 became wheelchair-bound at the age of 60. No cognitive or behavioral symptoms were noted. These cases provide further evidence that GMPPB mutations can also cause late-onset recessive LGMD with milder phenotypes than previously reported, and thus should be considered in the differential diagnosis of patients with adult-onset muscular dystrophies. (C) 2017 Elsevier B.V. All rights reserved.Peer reviewe

Effect of pancreatic and/or renal transplantation on diabetic autonomic neuropathy

Thirty-nine Type 1 (insulin-dependent) diabetic patients were studied prospectively after simultaneous pancreas and kidney (n=26) and kidney grafting alone (n=13) by measuring heart rate variation during various manoeuvers and answering a standardized questionnaire every 6 to 12 months post-transplant. While age, duration of diabetes, and serum creatinine (168.1±35.4 vs 132.7±17.7 mgrmol/l) were comparable, haemoglobin A1 levels were significantly lower (6.6±0.2 vs 8.5±0.3%; p<0.01) and the mean observation time longer (35±2 vs 25±3 months; p<0.05) in the pancreas recipients when compared with kidney transplanted patients. Heart rate variation during deep breathing, lying/standing and Valsalva manoeuver were very similar in both groups initially and did not improve during follow-up. However, there was a significant reduction in heart rate in the pancreas recipient group. Autonomic symptoms of the gastrointestinal and thermoregulatory system improved more in the pancreas grafted subjects, while hypoglycaemia unawareness deteriorated in the kidney recipients. This study suggests that long-term normoglycaemia by successful pancreatic grafting is able to halt the progression of autonomic dysfunction

Characterization of a Be(p,xn) neutron source for fission yields measurements

We report on measurements performed at The Svedberg Laboratory (TSL) to characterize a proton-neutron converter for independent fission yield studies at the IGISOL-JYFLTRAP facility (Jyv\"askyl\"a, Finland). A 30 MeV proton beam impinged on a 5 mm water-cooled Beryllium target. Two independent experimental techniques have been used to measure the neutron spectrum: a Time of Flight (TOF) system used to estimate the high-energy contribution, and a Bonner Sphere Spectrometer able to provide precise results from thermal energies up to 20 MeV. An overlap between the energy regions covered by the two systems will permit a cross-check of the results from the different techniques. In this paper, the measurement and analysis techniques will be presented together with some preliminary results.Comment: 3 pages, 3 figures, also submitted as proceedings of the International Conference on Nuclear Data for Science and Technology 201

Follow-up study of sensory-motor polyneuropathy in Type 1 (insulin-dependent) diabetic subjects after simultaneous pancreas and kidney transplantation and after graft rejection

The influence of successful simultaneous pancreas and kidney transplantation on peripheral polyneuropathy was investigated in 53 patients for a mean observation period of 40.3 months. Seventeen patients were followed-up for more than 3 years. Symptoms and signs were assessed every 6 months using a standard questionnaire, neurological examination and measurement of sensory and motor nerve conduction velocities. While symptoms of polyneuropathy improved (pain, paraesthesia, cramps, restless-legs) and nerve conduction velocity increased, there was no change of clinical signs (sensation, muscle-force, tendon-reflexes). Following kidney-graft-rejection there was a slight decrease of nerve conduction verlocity during the first year, which was not statistically significant. Following pancreas-graft rejection there was no change of nerve conduction velocity during the first year. Comparing the maximum nerve conduction velocity of the patients with pancreas-graft-rejection to the nerve conduction velocities of these patients at the end of the study, there was a statistically significant decrease of 6.5 m/s. In conclusion, we believe that strict normalization of glucose metabolism alters the progressive course of diabetic polyneuropathy. It may be stabilized or partly reversed after successful grafting even in long-term diabetic patients

Results of pancreas transplantation after steroid withdrawal under tacrolimus immunosuppression

Purpose. The results of steroid withdrawal in pancreas transplant recipients under tacrolimus immunosuppression were analyzed. Methods. From July 4, 1994 until April 30, 1998, 147 pancreas transplantations were performed in 141 patients, including 126 simultaneous pancreas-kidney transplantations, 13 pancreas after kidney transplantation, and 8 pancreas transplantations alone. Baseline immunosuppression consisted of tacrolimus and steroids without antilymphocyte induction. Twenty-three patients were excluded from analysis because of early graft loss in 17 cases, retransplantation in 5 cases, and simultaneous pancreas-kidney transplantation after heart transplantation in 1 patient. Results. With a mean follow-up of 2.8±1.1 years (range 1.0 to 4.8 years), complete steroid withdrawal was achieved in 58 (47%) patients with a mean time to steroid withdrawal of 15.2±8 months (range 4 to 40 months after transplantation). Of the entire cohort of 141 patients, overall 1-, 2-, and 4-year patient survival rates were 98%, 95.5%, and 86%, respectively. Overall 1-, 2-, and 4- year graft survival rates were 83%, 80%, and 71% (pancreas) and 95%, 91%, and 84% (kidney), respectively. Of the 124 patients analyzed for steroid withdrawal, 1-, 2-, and 4-year patient survival rates were 98%, 97%, and 92%, respectively. Overall 1-, 2-, and 4-year graft survival rates were 98%, 91.5%, 83% (pancreas) and 97%, 95%, and 91% (kidney). Patient, pancreas, and kidney survival rates at 1 year were 100%, 100%, and 98% (off steroids) versus 97%, 91%, and 96% (on steroids, all NS) and at 4 years were 100%, 94%, and 95% (off steroids) versus 78%, 68%, and 85% (on steroids, P=0.01, 0.002, and NS, respectively). The cumulative risk of rejection at the time of follow-up was 76% for patients on steroids versus 74% for patients off steroids (P=NS). Seven patients originally tapered off steroids were treated for subsequent rejection episodes, which were all steroid sensitive, and two of these seven patients are currently off steroids. Thirteen patients received antilymphocyte therapy for steroid-resistant rejection, five of whom are now off steroids. Tacrolimus trough levels were 9.3±2.4 ng/ml (off steroids) and 9.7±4.3 (on steroids, P=NS). Mean fasting glucose levels were 98±34 mg/dl (off steroids) and 110±41 mg/dl (on steroids, P=NS). Mean glycosylated hemoglobin levels were 5.2±0.9% (off steroids) and 6.2±2.1% (on steroids, P=0.02), and mean serum creatinine levels were 1.4±0.8 mg/dl (off steroids) and 1.7±1.0 mg/dl (on steroids, P=0.02). Conclusion. These data show for the first time that steroid withdrawal can be safely accomplished in pancreas transplant recipients maintained on tacrolimus-based immunosuppression. Steroid withdrawal is associated with excellent patient and graft survival with no increase in the cumulative risk of rejection