Recruiting refugees and migrants as potential hematopoietic stem cell donors to serve patients of comparable ethnicities with rare human leucocyte antigen patterns - The BluStar.NRW project in North Western Germany.

Currently, approximately 19 million people with a migration background live in Germany. The majority of those descend from regions where the population has a genetically different distribution of HLA antigens when compared to the HLA frequencies usually found in North Western Europe. In case of severe haematological disorders of these individuals, allogeneic stem cell transplantation may be the treatment of choice. However, finding appropriate histocompatible hematopoietic stem cell donors continues to be a major challenge. If no matching sibling donors are available, there are only few suitable donors with a similar genetic background available in international blood stem cell donor registries. The "BluStar.NRW" project aimed to recruit new blood and hematopoietic stem cell donors with a migration background and to noticeably increase the number of suitable donors for patients within this group. Since December 2017, a total number of 9100 blood and stem cell donors with a migration background were recruited and typed for this project. HLA typing for HLA-A, -B, -C, -DRB1, -DQB1, and -DPB1 was performed by Next Generation Sequencing. We assessed the proportion of rare alleles according to HLA frequency tables, as defined by a frequency of <1:1000. The rare HLA allele frequencies according to HLA frequency tables of the BluStar.NRW cohort were compared with a matched control donor cohort: Rare HLA-A, -B, -C, -DRB1 and -DQB1 alleles occurred three times more frequent than in the control group, but rare HLA-DPB1 alleles occurred more frequently in the control cohort. This difference was highly significant for all HLA alleles (p < 0.0001 for HLA-A, -B, -C, -DRB1, -DPB1; p = 0.0002 for HLA-DQB1). In addition, the distribution of rare alleles differed between the two groups. To date, 29 work-ups were initiated, 12 PBSC, one BM and three DLI were collected so far out of the BluStar.NRW cohort. The apheresis probability is twofold higher (0.18% vs. 0.07%) compared to the control group which clearly shows a serious medical need. However, 13 work-ups were cancelled in the BluStar.NRW donor cohort which represents an almost twice as higher cancellation rate (45% vs. 25%). This single registry analysis with a large sample cohort clearly indicates that hematopoietic stem cell donors with a migration background represent an adequate donor pool to serve patients of comparable ethnicity.

Anti-HLA alloantibodies of the IgA isotype in re-transplant candidates part II: Correlation with graft survival.

We reported previously on the widespread occurrence of anti-HLA alloantibodies of the IgA isotype (anti-HLA IgA) in the sera of solid-organ re-transplantation (re-tx) candidates (Arnold et al., ). Specifically focussing on kidney re-tx patients, we now extended our earlier findings by examining the impact of the presence and donor specificity of anti-HLA IgA on graft survival. We observed frequent concurrence of anti-HLA IgA and anti-HLA IgG in 27% of our multicenter collective of 694 kidney re-tx patients. This subgroup displayed significantly reduced graft survival as evidenced by the median time to first dialysis after transplantation (TTD 77 months) compared to patients carrying either anti-HLA IgG or IgA (TTD 102 and 94 months, respectively). In addition, donor specificity of anti-HLA IgA had a significant negative impact on graft survival (TTD 74 months) in our study. Taken together, our data strongly indicate that presence of anti-HLA IgA, in particular in conjunction with anti-HLA-IgG, in sera of kidney re-tx patients is associated with negative transplantation outcome.

Effect of ABO incompatibility on T-cell flow cytometry cross-match results prior to living donor kidney transplantation.

BACKGROUND: Due to its high sensitivity, the flow cytometry cross-match (FCXM) has been described as valuable tool for identifying an optimal donor. We here focused on the impact of ABO incompatibility on FCXM results. METHODS: We analyzed 29 ABO incompatible and 89 ABO compatible donor-recipient pairs (73 and 175 datasets, respectively) prior to living donor kidney transplantation. In all patients, lymphocytotoxic cross-matches for B and T cells were negative. RESULTS: Recipients with blood group O (A to O and B to O) displayed significantly (P < 0.05) higher T-FCXM results than those with blood group A and B (A to B, B to A and AB to A), respectively. Donor-specific T-FCXM responses (ΔMFI values) were significantly higher (P < 0.05) in ABO incompatible vs. compatible pairs (ABO incompatible recipients with blood group O: 32 ± 6; with blood group A: 19 ± 7; with blood group B: 7 ± 4; recipients with ABO compatibility: 3 ± 2, respectively, data represent mean ± SEM). Consistent with the T-FCXM results donor-specific isohemagglutinins (IgG titers) were significantly higher in recipients with blood group O vs. A, both prior to rituximab treatment and plasmapheresis/immune adsorption (P = 0.004) and immediately prior to transplantation, i.e., after rituximab and antibody-depleting therapies (P = 0.04). CONCLUSIONS: ABO incompatibility was associated with higher T-FCXM responses, especially in recipients with blood group O. This finding has major impact on the interpretation of flow cross-match results. Current cut-off values need to be reassessed in the ABO incompatible setting. © 2016 International Clinical Cytometry Society.

Primary central nervous system vasculitis and its mimicking diseases - clinical features, outcome, comorbidities and diagnostic results - A case control study.

OBJECTIVES: To compare clinical features and outcome, imaging characteristics, biopsy results and laboratory findings in a cohort of 69 patients with suspected or diagnosed primary central nervous system vasculitis (PCNSV) in adults; to identify risk factors and predictive features for PCNSV. PATIENTS AND METHODS: We performed a case-control-study including 69 patients referred with suspected PCNSV from whom 25 were confirmed by predetermined diagnostic criteria based on biopsy (72%) or angiography (28%). Forty-four patients turned out to have 15 distinct other diagnoses. Clinical and diagnostic data were compared between PCNSV and Non-PCNSV cohorts. RESULTS: Clinical presentation was not able to discriminate between PCNSV and its differential diagnoses. However, a worse clinical outcome was associated with PCNSV (p=0.005). Biopsy (p=0.004), contrast enhancement (p=0.000) or tumour-like mass lesion (p=0.008) in magnetic resonance imaging (MRI), intrathecal IgG increase (p=0.020), normal Duplex findings of cerebral arteries (p=0.022) and conventional angiography (p 0.010) were able to distinguish between the two cohorts. CONCLUSION: In a cohort of 69 patients with suspected PCNSV, a large number (64%) was misdiagnosed and partly received treatment, since mimicking diseases are very difficult to discriminate. Clinical presentation at manifestation does not help to differentiate PCNSV from its mimicking diseases. MRI and cerebrospinal fluid analysis are unlikely to be normal in PCNSV, though unspecific if pathological. Cerebral angiography and biopsy must complement other diagnostics when establishing the diagnosis in order to avoid misdiagnosis and mistreatment. CLINICAL TRIAL REGISTRATION: German clinical trials register: http://drks-neu.uniklinik-freiburg.de/drks_web/, Unique identifier: DRKS00005347.

Humoral and Cellular Responses to a Single Dose of Fendrix in Renal Transplant Recipients with Non-response to Previous Hepatitis B Vaccination.

Approximately 70% of kidney transplant recipients are non-responders to conventional hepatitis B virus (HBV) vaccines. We examined whether Fendrix™, an HBV vaccine containing 3-O-desacyl-4'-monophosphoryl lipid A (MPL) as adjuvant, could induce HBV immunity in these patients and compared their vaccination efficacy with healthy controls tested previously by the same assays. We selected 35 kidney transplant recipients who had been vaccinated at least thrice against HBV but had never displayed anti-HBs antibodies. We re-assessed their anti-HBs antibody titres and further determined cellular HBV immunity by proliferation assay and interferon (IFN)-γ ELISpot. Seventeen recipients did neither display humoral nor cellular immunity and could be tested prior to and at month 1 after vaccination. Of note, HLA antigens associated with non-response to HBV vaccination (HLA-DRB1*03 and HLA-DQB1*02) were over-represented in these 17 recipients. At month 1 after a single vaccination with Fendrix™, we observed a significant increase in anti-HBs antibodies (P = 0.02). In seven of 17 recipients, we detected anti-HBs antibodies ≥10 IU/l (10-264), in four HBV-specific lymphocyte proliferation (stimulation index of 2.6-8.7) and in one specific IFN-γ responses (12 spots increment). The vaccination response to Fendrix™ was significantly higher (P = 0.035) than the response to HBVaxPro™ in young healthy controls. In summary, the results show that a single vaccination with Fendrix™ could already induce HBV-specific humoral and/or cellular responses in ten of 17 kidney transplant patients. Thus, Fendrix™ appears as an efficient vaccine in this patient cohort.

Determination of unacceptable HLA antigen mismatches in kidney transplant recipients: recommendations of the German Society for Immunogenetics.

One of the major tasks of histocompatibility and immunogenetics laboratories is the pretransplant determination of unacceptable antigen mismatches (UAM) in kidney transplant recipients. In this procedure, human leucocyte antigen (HLA) specificities are defined against which the patient has circulating alloantibodies that are expected to harm the transplanted organ. Using the information on UAM and the potential donor's complete HLA typing, prediction of the crossmatch result, the so called 'virtual crossmatch', is possible. Currently, the laboratories are using different algorithms for the determination of UAM, and depending on the algorithm, more or fewer organ offers are excluded for patients with a similar antibody profile. In order to bring homogeneity into the allocation of organs to immunized patients in Germany, the German Society for Immunogenetics established, on the basis of current knowledge, recommendations for the determination of UAM. The UAM recommendations, which are thought to serve as a common tool for responsible physicians at different transplant centers, contain technical issues that need to be considered and are individualized for sensitized patients with a high or intermediate risk of antibody-mediated rejection. The present review contains these recommendations and puts them into perspective to current international practice.

16(th) IHIW: anti-HLA alloantibodies of the of IgA isotype in re-transplant candidates.

In this multicentre study, sera from 803 retransplant candidates, including 775 kidney transplant recipients, were analysed with regard to the presence and specificity of anti-HLA alloantibodies of the IgA isotype using a modified microsphere-based platform. Of the kidney recipients, nearly one-third (n = 237, 31%) had IgA alloantibodies. Mostly, these antibodies were found in sera that also harboured IgG alloantibodies that could be found in a total of 572 (74%) of patients. Interestingly, IgA anti-HLA antibodies were preferentially targeting HLA class I antigens in contrast to those of the IgG isotype, which targeted mostly both HLA class I and II antigens. Donor specificity of the IgA alloantibodies could be established for over half of the 237 patients with IgA alloantibodies (n = 124, 52%). A further 58 patients had specificities against HLA-C or HLA-DP, for which no information regarding donor typing was available. In summary, these data showed in a large cohort of retransplant candidates that IgA alloantibodies occur in about one-third of patients, about half of these antibodies being donor specific.

Inheritance of moyamoya disease in a Caucasian family.

BACKGROUND AND PURPOSE: Moyamoya disease is a very rare occlusive cerebrovascular disorder characterized by progressive stenosis or occlusion of the intracranial portion of the internal carotid artery and proximal cerebral arteries with an extensive network of fine collaterals. The aetiology and genetic susceptibility of moyamoya disease, especially in Caucasians, still remains unclear. METHODS AND RESULTS: We describe the cases of affected German father, daughter and son with juvenile stroke because of idiopathic moyamoya disease. The rare existing literature is reviewed and discussed. CONCLUSIONS: This is the first report on a father-to-child inheritance pattern in Caucasian patients with idiopathic Moyamoya disease (MMD). Our cases indicate possible genetic risk factors for the genesis of Caucasian Moyamoya disease.

Characterization of CD8+ T-cell response in acute and resolved hepatitis A virus infection.

BACKGROUND & AIMS: In contrast to the infection with other hepatotropic viruses, hepatitis A virus (HAV) always causes acute self-limited hepatitis, although the role for virus-specific CD8 T cells in viral containment is unclear. Herein, we analyzed the T cell response in patients with acute hepatitis by utilizing a set of overlapping peptides and predicted HLA-A2 binders from the polyprotein. METHODS: A set of 11 predicted peptides from the HAV polyprotein, identified as potential binders, were synthesized. Peripheral blood mononuclear cells (PBMCs) from patients were tested for IFNγ secretion after stimulation with these peptides and ex vivo with HLA-A2 tetramers. Phenotyping was carried out by staining with the activation marker CD38 and the memory marker CD127. RESULTS: Eight out of 11 predicted HLA-A2 binders showed a high binding affinity and five of them were recognized by CD8+ T cells from patients with hepatitis A. There were significant differences in the magnitude of the responses to these five peptides. One was reproducibly immunodominant and the only one detectable ex vivo by tetramer staining of CD8+ T cells. These cells have an activated phenotype (CD38hi CD127lo) during acute infection. Three additional epitopes were identified in HLA-A2 negative patients, most likely representing epitopes restricted by other HLA-class I-alleles (HLA-A11, B35, B40). CONCLUSIONS: Patients with acute hepatitis A have a strong multi-specific T cell response detected by ICS. With the tetramer carrying the dominant HLA-A2 epitope, HAV-specific and activated CD8+ T cells could be detected ex vivo. This first description of the HAV specific CTL-epitopes will allow future studies on strength, breadth, and kinetics of the T-cell response in hepatitis A.

Atrioventricular sequential pacing: comparison with ventricular pacing using systolic time intervals.

Nine patients with programmable atrioventricular sequential pacers were studied using systolic time intervals (QS2--the total electrical and mechanical systole, left ventricular ejection time, and pre-ejection period). These measurements were obtained by simultaneous recording of the electrocardiogram, phonocardiogram, and carotid pulse tracing. There was a dramatic fall of left ventricular ejection time (LVET) and an increase of the pre-ejection time (PEP) in all patients when the pacers were programmed from the atrioventricular to the ventricular mode at constant heart rate. This resulted in an increase of the ratio PEP/LVET from .428 to .574 suggesting loss of ventricular function. These measurements all reversed to baseline values when the pacers were re-programmed back to the atrioventricular mode. This study suggests systolic time intervals might be useful to select non-invasively pacer parameters such as mode, rate, and effective PR interval in order to provide the best hemodynamics in a given patient.

Clinical experience with permanent atrioventricular sequential pacing.

In a 23-moth period, we implanted 26 permanent atrioventricular (AV) sequential pacing units in 11 women and 15 men ranging from 37 to 85 years old (mean, 68 years). Indications for pacing were complete heart block n 12 patients and sick sinus syndrome in 14 patients. Cardiac index, using standard thermodilution techniques, was determined in 9 patients during ventricular pacing and AV sequential pacing at constant heart rate. Atrioventricular sequential pacing was superior in all patients, with a mean increase in cardiac index of 22% (p greater than 0.01). Complications of AV sequential pacing included the need to revise two pulse generator pockets due to the large size of the pulse generator. One transvenous atrial lead displacement occurred in a patient who had previously undergone right atrial appendage ligation at open-heart operation. No failures of pacing or sensing occurred during 279 patient-paced months. The theoretical hemodynamic advantage of AV sequential pacing has been confirmed in this clinical trial. Experience with electrode placement and improvements in pulse generator design should aid in eliminating complications with this pacing modality.