PID Comes Full Circle: Applications of V(D)J Recombination Excision Circles in Research, Diagnostics and Newborn Screening of Primary Immunodeficiency Disorders

The vast majority of patients suffering from a primary immunodeficiency (PID) have defects in their T- and/or B-cell compartments. Despite advances in molecular diagnostics, in many patients no underlying genetic defect has been identified. B- and T-lymphocytes are unique in their ability to create a receptor by genomic rearrangement of their antigen receptor genes via V(D)J recombination. During this process, stable circular excision products are formed that do not replicate when the cell proliferates. Excision circles can be reliably quantified using real-time quantitative (RQ-)PCR techniques. Frequently occurring δREC–ψJα T-cell receptor excision circles (TRECs) have been used to assess thymic output and intronRSS–Kde recombination excision circles (KREC) to quantify B-cell replication history. In this perspective, we describe how TRECs and KRECs are formed during precursor – T- and B-cell differentiation, respectively. Furthermore, we discuss new insights obtained with TRECs and KRECs and specifically how these excision circles can be applied to support therapy monitoring, patient classification and newborn screening of PID

"It Takes Two To Tango", A Research About The Risks And Control Measures For The Management Of A Performance Contract For Regular Maintenance Of Rail Infrastructure.

A research about the risks and the administrative measures during the management of a performance contract for the regular maintenance of rail infrastructure. In the sector of rail infrastructure output-contracts, in which the contractor is judged on achieved performances, are getting more in use. The assumption is that this will lead to a more efficient and innovative execution of the maintenance, because the parties involved in the contract have less contact and thus need to take more responsibilities for their proper tasks. Unknown however is how to manage such a contract: What are the risks a contracting partner is confronted with during the term of the contract and how could these risks be managed? This article will discuss a method that will provide answers to these questions. The method consists of a matrix of the possible risks and control measures that the management level of both the sourcing partner and the contractor should discuss. These are cooperation risks and not the safety and availability risks. Within HTM, the bus and tram company of The Hague, this method is used to give direction for a new maintenance contract. It was concluded that management based on performances not always means that contracting partner and contractor have less contact but that it resulted in another behavior and cooperation both for the contracting partner as the contracting party.Institute of Transport and Logistics Studies. Faculty of Economics and Business. The University of Sydne

Functional Antibody Responses Following Allogeneic Stem Cell Transplantation for TP53 Mutant pre-B-ALL in a Patient With X-Linked Agammaglobulinemia

Patients with X-linked agammaglobulinemia (XLA) have failure of B-cell development with lack of immunoglobulin (Ig) production. While immunoglobulin replacement therapy (IgRT) is beneficial, XLA patients remain at risk for infections, structural lung damage, and rarely, neoplasia. Allogeneic stem cell transplantation (alloSCT) may offer a potential cure, but is associated with significant life-threatening complications. Here, we present a 25-year old XLA patient who developed pre-B acute lymphocytic leukemia (ALL) with somatic TP53 mutation, and treatment for this high-risk malignancy involved full myeloablative conditioning and a HLA-matched sibling alloSCT. Full donor chimerism was achieved for CD3+ and CD3- cell fractions. The patient remains in morphological and flow cytometric remission 14 months post-transplant, with late-onset oral GvHD requiring low dose prednisolone and cyclosporin. Following IgRT discontinuation at 4 months post-transplantation, humoral immunity was established within 14 months as reflected by normal numbers of total B cells, memory B cells, serum IgG, IgM, and IgA, and production of specific IgG responses to Prevenar-13 vaccination. This is only the second reported case of an XLA patient with pre-B-ALL, and the most detailed report of engraftment following alloSCT in XLA. Together with the two previous XLA cases treated with alloSCT, our report provides evidence for the potential for successful humoral reconstitution with alloSCT in patients with B-cell intrinsic antibody deficiency. These observations may be relevant given IgRT, while beneficial, remains an imperfect solution to long-term infectious complications

EuroFlow-based flowcytometric diagnostic screening and classification of primary immunodeficiencies of the lymphoid system

Guidelines for screening for primary immunodeficiencies (PID) are well-defined and several consensus diagnostic strategies have been proposed. These consensus proposals have only partially been implemented due to lack of standardization in laboratory procedures, particularly in flow cytometry. The main objectives of the EuroFlow Consortium were to innovate and thoroughly standardize the flowcytometric techniques and strategies for reliable and reproducible diagnosis and classification of PID of the lymphoid system. The proposed EuroFlow antibody panels comprise one orientation tube and seven classification tubes and corresponding databases of normal and PID samples. The 8-color 12-antibody PID Orientation tube (PIDOT) aims at identification and enumeration of the main lymphocyte and leukocyte subsets; this includes naive pre-germinal center (GC) and antigen-experienced post-GC memory B-cells and plasmablasts. The seven additional 8(-12)-color tubes can be used according to the EuroFlow PID algorithm in parallel or subsequently to the PIDOT for more detailed analysis of B-cell and T-cell subsets to further classify PID of the lymphoid system. The Pre-GC, Post-GC, and immunoglobulin heavy chain (IgH)-isotype B-cell tubes aim at identification and enumeration of B-cell subsets for evaluation of B-cell maturation blocks and specific defects in IgH-subclass production. The severe combined immunodeficiency (SCID) tube and T-cell memory/effector subset tube aim at identification and enumeration of T-cell subsets for assessment of T-cell defects, such as SCID. In case of suspicion of antibody deficiency, PIDOT is preferably directly combined with the IgH isotype tube(s) and in case of SCID suspicion (e.g., in newborn screening programs) the PIDOT is preferably directly combined with the SCID T-cell tube. The proposed >= 8-color antibody panels and corresponding reference databases combined with the EuroFlow PID algorithm are designed to provide fast, sensitive and cost-effective flowcytometric diagnosis of PID of the lymphoid system, easily applicable in multicenter diagnostic settings world-wide

Long-Term Follow-Up of Patients with Scleritis After Rituximab Treatment Including B Cell Monitoring

Purpose: We report the long-term effect of rituximab (RTX) in scleritis and determine the value of B-cell monitoring for the prediction of relapses. Methods: We retrospectively studied 10 patients with scleritis, who were treated with RTX. Clinical characteristics were collected, and blood B-cell counts were measured before the start of RTX, and at various time points after treatment. Results:Clinical activity of scleritis decreased after RTX treatment in all patients within a median time of 8 weeks (range 3–13), and all reached remission. The median follow-up was 101 months (range 9–138). Relapses occurred in 6 out of 10 patients. All relapses, where B-cell counts were measured (11 out of 19), were heralded by returning B cells. However, B cells also returned in patients with long-term remissions.Conclusions: RTX is a promising therapeutic option for scleritis. Recurrence of B cells after initial depletion does not always predict relapse of scleritis.</p

The EuroFlow PID orientation tube for flow cytometric diagnostic screening of primary immunodeficiencies of the lymphoid system

Copyright © 2019 van der Burg, Kalina, Perez-Andres, Vlkova, Lopez-Granados, Blanco, Bonroy, Sousa, Kienzler, Wentink, Mejstríková, Šinkorova, Stuchly, van Zelm, Orfao and van Dongen. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.In the rapidly evolving field of primary immunodeficiencies (PID), the EuroFlow consortium decided to develop a PID orientation and screening tube that facilitates fast, standardized, and validated immunophenotypic diagnosis of lymphoid PID, and allows full exchange of data between centers. Our aim was to develop a tool that would be universal for all lymphoid PIDs and offer high sensitivity to identify a lymphoid PID (without a need for specificity to diagnose particular PID) and to guide and prioritize further diagnostic modalities and clinical management. The tube composition has been defined in a stepwise manner through several cycles of design-testing-evaluation-redesign in a multicenter setting. Equally important appeared to be the standardized pre-analytical procedures (sample preparation and instrument setup), analytical procedures (immunostaining and data acquisition), the software analysis (a multidimensional view based on a reference database in Infinicyt software), and data interpretation. This standardized EuroFlow concept has been tested on 250 healthy controls and 99 PID patients with defined genetic defects. In addition, an application of new EuroFlow software tools with multidimensional pattern recognition was designed with inclusion of maturation pathways in multidimensional patterns (APS plots). The major advantage of the EuroFlow approach is that data can be fully exchanged between different laboratories in any country of the world, which is especially of interest for the PID field, with generally low numbers of cases per center.The coordination and innovation processes of this study were supported by the EuroFlow Consortium (Chairmen: MvdB and AO). MvZ is supported by Senior Research Fellowship GNT1117687 from the Australian National Health and Medical Research Council. TK and EM were supported by projects 15-28541A from Ministry of Health, LO1604 from Ministry of Education, Youth and Sports and GBP302/12/G101 from Grant Agency of the Czech Republic. MP-A, EB, and AO were supported by a grant from the Junta de Castilla y León (Fondo Social Europeo, ORDEN EDU/346/2013, Valladolid, Spain) and the CB16/12/00400 grant (CIBER/ONC, Instituto de Salud Carlos III, Ministerio de Economía y Competitividad, - Madrid, Spain- and FONDOS FEDER), the FIS PI12/00905-FEDER grant (Fondo de Investigación Sanitaria of Instituto de Salud Carlos III, Madrid, Spain) and AP119882013 grant (Fundación Mutua Madrileña, Madrid, Spain). Publishing costs for this article were covered by the International Union of Immunological Societies (IUIS).info:eu-repo/semantics/publishedVersio

Decreased IL7Rα and TdT expression underlie the skewed immunoglobulin repertoire of human B-cell precursors from fetal origin

Newborns are unable to mount antibody responses towards certain antigens. This has been related to the restricted repertoire of immunoglobulin (Ig) genes of their B cells. The mechanisms underlying the restricted fetal Ig gene repertoire are currently unresolved. We here addressed this with detailed molecular and cellular analysis of human precursor-B cells from fetal liver, fetal bone marrow (BM), and pediatric BM. In the absence of selection processes, fetal B-cell progenitors more frequently used proximal V, D and J genes in complete IGH gene rearrangements, despite normal Ig locus contraction. Fewer N-nucleotides were added in IGH gene rearrangements in the context of low TdT and XRCC4 expression. Moreover, fetal progenitor-B cells expressed lower levels of IL7Rα than their pediatric counterparts. Analysis of progenitor-B cells from IL7Rα-deficient patients revealed that TdT expression and N-nucleotides additions in Dh-Jh junctions were dependent on functional IL7Rα. Thus, IL7Rα affects TdT expression, and decreased expression of this receptor underlies at least in part the skewed Ig repertoire formation in fetal B-cell precursors. These new insights provide a better understanding of the formation of adaptive immunity in the developing fetus

The identification of celiac disease in asymptomatic children: the Generation R Study

Background: The objective of our study was to assess whether TG2A levels in the healthy childhood population can be predictive of subclinical CD. Methods: A total of 4442 children (median age, 6.0 years) participating in a population-based prospective cohort study were screened on serum TG2A. Those with positive TG2A (≥7 U/ml; n = 60, 1.4%) were invited for clinical evaluation (median age, 9.0 years). Medical history, physical examination, serum TG2A, and IgA-endomysium (EMA) were assessed, as well as HLA DQ 2.2/2.5/8 typing. Patients with positive serologies and genetic risk types underwent duodenal biopsies. TG2A levels at the time of biopsy were compared with the degree of enteropathy. Results: Fifty-one TG2A-positive children were included in the follow-up: 31 (60.8%) children had CD, ten (19.6%) did not have CD, and ten (19.6%) were considered potential CD cases because of inconclusive serologies. Duodenal biopsies were performed in 26/31 children. CD with Marsh 3a/b enteropathy was observed in 75% (15/20) of children having TG2A levels ≥10ULN at 6 years of age, as well as in 75% (6/8) of children having a positive TG2A <10 ULN (OR 1.00; 95% CI 0.15–6.64). CD cases had a lower BMI SDS (mean −0.49, SD 0.92) than children without CD (mean 0.47, SD 1.37; p = 0.02). No differences were observed in gastrointestinal symptoms. Conclusions: Serum TG2A screening at 6 years of age in the healthy childhood population has a positive predictive value of 61% to detect subclinical CD. We did not find a positive correlation between serum TG2A levels and the degree of enteropathy