Kenichi Honma

Common variable immunodeficiency classification by quantifying T-cell receptor and immunoglobulin κ-deleting recombination excision circles

In the United States the regulation of nonstandardized AEs presented some similaritieswith our approach.AEswere classified into 4 categories according to scientific data supporting their use in diagnosis and treatment, and the extracts were regularly evaluated by the regulatory agencies. The last updatewas conducted between 2003 and 2011, and the process was recently reviewed by Slater et al. It was shown that for nearly half of nonstandardized AEs there were, in fact, little or no data to support their effectiveness. We had similar results: 66 of 84 AEs were validated for diagnosis, but only for 29 of 66 was there at least 1 published piece of data to support their effectiveness for immunotherapy (Table I). Among those 66 authorized AEs, approximately one third are standardized. There is no consensus about the standardization methods, and the European approaches present some differences compared with the US approach (see Table E1 in this article’s Online Repository at www.jacionline.org). Briefly, in-house reference preparation (IHRP) AEs are standardized in vivo and in vitro. Each manufacturer has its own IHRP, and there is no national standard. Batch-to-batch standardization is performed in vitro through a comparison of the AEs with the IHRP. In the future, the NPP list will be updated every 5 years, and requests for MAwill be made and processed for standardized AEs produced industrially and frequently used for immunotherapy. In conclusion, for the first time in Europe, this work guarantees that available AEs are clinically relevant and safe. Moreover, it guarantees that all AEs comply with recent European guidelines on APs, including rare allergens for which it is not possible to obtain large clinical studies requested for MA. The process involved all the representatives of allergists and manufacturers and is still ongoing. Fr ed eric de Blay, MD Virginie Doyen, MD Evelyne Bloch-Morot, MD Daniel Caillot, MD Jacques Gayraud, MD Aymar de Laval, MD Alain Thillay, MD for the APSI group*

RAG1 Deficiency May Present Clinically as Selective IgA Deficiency

BackgroundRecombination-activating gene (RAG) 1 and 2 deficiency is seen in patients with severe combined immunodeficiency (SCID) and Omenn syndrome. However, the spectrum of the disease has recently expanded to include a milder phenotype.ObjectiveWe analyzed a 4-year-old boy who was initially given the diagnosis of selective immunoglobulin A deficiency (SIgAD) based on immunoglobulin serum levels without any opportunistic infections, rashes, hepatosplenomegaly, autoimmunity or granulomas. The patient was found to be infected with varicella zoster; however, the clinical course was not serious. He produced antiviral antibodies.MethodsWe performed lymphocyte phenotyping, quantification of T cell receptor excision circles (TRECs) and kappa deleting recombination excision circles (KRECs), an analysis of target sequences of RAG1 and 2, a whole-genome SNP array, an in vitro V(D)J recombination assay, a spectratype analysis of the CDR3 region and a flow cytometric analysis of the bone marrow.ResultsLymphocyte phenotyping demonstrated that the ratio of CD4+ to CD8+ T cells was inverted and the majority of CD4+T cells expressed CD45RO antigens in addition to the almost complete lack of B cells. Furthermore, both TRECs and KRECs were absent. Targeted DNA sequencing and SNP array revealed that the patient carried a deletion of RAG1 and RAG2 genes on the paternally-derived chromosome 11, and two maternally-derived novel RAG1 missense mutations (E455K, R764H). In vitro analysis of recombination activity showed that both RAG1 mutant proteins had low, but residual function.ConclusionsThe current case further expands the phenotypic spectrum of mild presentations of RAG deficiency, and suggests that TRECs and KRECs are useful markers for detecting hidden severe, as well as mild, cases.

Common Variable Immunodeficiency Caused by FANC Mutations

Common variable immunodeficiency (CVID) is the most common adult-onset primary antibody deficiency disease due to various causative genes. Several genes, which are known to be the cause of different diseases, have recently been reported as the cause of CVID in patients by performing whole exome sequencing (WES) analysis. Here, we found FANC gene mutations as a cause of adult-onset CVID in two patients. B cells were absent and CD4+ T cells were skewed toward CD45RO+ memory T cells. T-cell receptor excision circles (TRECs) and signal joint kappa-deleting recombination excision circles (sjKRECs) were undetectable in both patients. Both patients had no anemia, neutropenia, or thrombocytopenia. Using WES, we identified compound heterozygous mutations of FANCE in one patient and homozygous mutation of FANCA in another patient. The impaired function of FANC protein complex was confirmed by a monoubiquitination assay and by chromosome fragility test. We then performed several immunological evaluations including quantitative lymphocyte analysis and TRECs/sjKRECs analysis for 32 individuals with Fanconi anemia (FA). In total, 22 FA patients (68.8%) were found to have immunological abnormalities, suggesting that such immunological findings may be common in FA patients. These data indicate that FANC mutations are involved in impaired lymphogenesis probably by the accumulation of DNA replication stress, leading to CVID. It is important to diagnose FA because it drastically changes clinical management. We propose that FANC mutations can cause isolated immunodeficiency in addition to bone marrow failure and malignancy.

Wiskott-Aldrich syndrome mutation in two Turkish siblings with X-linked thrombocytopenia.

Wiskott-Aldrich syndrome (WAS) is a clinical condition characterized by thrombocytopenia, eczema, and life-threatening infections. In some cases autoimmunity-related problems and even malignancy might be seen; however, some patients have milder clinical manifestations due to mutations in the same gene family, such as in X-linked thrombocytopenia (XLT), which is generally not associated with serious symptoms of disease, except for thrombocytopenia. Herein we report 2 siblings with chronic thrombocytopenia that were diagnosed with XLT based on a missense mutation in the WASP gene (223G>A, Val75Met). To the best of our knowledge this mutation has not been previously reported in a Turkish patient with XLT.

Hematopoietic stem cell transplantation for progressive combined immunodeficiency and lymphoproliferation in patients with activated phosphatidylinositol-3-OH kinase δ syndrome type 1

Background: Activated phosphatidylinositol‐3‐OH kinase &dgr; syndrome type 1 (APDS1) is a recently described primary immunodeficiency syndrome characterized by recurrent respiratory tract infections, lymphoid hyperplasia, and Herpesviridae infections caused by germline gain‐of‐function mutations of PIK3CD. Hematopoietic stem cell transplantation (HSCT) can be considered to ameliorate progressive immunodeficiency and associated malignancy, but appropriate indications, methods, and outcomes of HSCT for APDS1 remain undefined. Objective: Our objective was to analyze the clinical manifestations, laboratory findings, prognosis, and treatment of APDS1 and explore appropriate indications and methods of HSCT. Methods: We reviewed retrospectively the medical records of cohorts undergoing HSCT at collaborating facilities. Results: Thirty‐year overall survival was 86.1%, but event‐free survival was 39.6%. Life‐threatening events, such as severe infections or lymphoproliferation, were frequent in childhood and adolescence and were common indications for HSCT. Nine patients underwent HSCT with fludarabine‐based reduced‐intensity conditioning. Seven patients survived after frequent adverse complications and engraftment failure. Most symptoms improved after HSCT. Conclusion: Patients with APDS1 showed variable clinical manifestations. Life‐threatening progressive combined immunodeficiency and massive lymphoproliferation were common indications for HSCT. Fludarabine‐based reduced‐intensity conditioning–HSCT ameliorated clinical symptoms, but transplantation‐related complications were frequent, including graft failure. GRAPHICAL ABSTRACT Figure. No caption available.

A Severe Anaphylactic Reaction Associated with IgM-Class Anti-Human IgG Antibodies in a Hyper-IgM Syndrome Type 2 Patient

PurposeA 42-year-old man with hyper-IgM syndrome type 2 caused by activation-induced cytidine deaminase (AID) deficiency developed a severe anaphylactic reaction to intravenous immunoglobulin. The purpose of this study was to clarify the cause of the anaphylactic reaction of the patient.MethodsWe measured IgM-class anti-human IgG and anti-human IgA antibodies in his serum by sandwich enzyme-linked immunosorbent assay (ELISA).ResultsThe sandwich ELISA assay revealed that serum from the patient, but not the controls, reacted to three different IgG products and purified human IgA. This indicated that the patient had IgM-class anti-human IgG and IgA antibodies in his serum, which associated with the anaphylactic reactions after the administration of IgG products. The anti-IgG antibody was likely to be the main cause of the reactions because an IgA-depleted IgG product also induced a severe reaction in this case and showed high absorbance in the ELISA system, similar to other IgG products containing more IgA.ConclusionsThis is the first report of IgM-class anti-human IgG associated with an anaphylactic reaction to an IgG infusion. The anaphylactic reactions were very severe in this case, probably because IgM-class antibodies are potent activators of the complement pathway.

Clinical and Immunological Characterization of ICF Syndrome in Japan

ObjectiveImmunodeficiency, centromeric instability, and facial anomalies (ICF) syndrome is a rare autosomal recessive primary immunodeficiency. Hypogammaglobulinemia is a major manifestation of ICF syndrome, but immunoglobulin replacement therapy does not seem to be effective for some ICF patients. Therefore, we aimed to reassess the immunological characteristics of this syndrome.MethodsEleven Japanese patients with ICF syndrome were enrolled. We performed whole-exome sequencing in four cases and homozygosity mapping using SNP analysis in two. We evaluated their clinical manifestations and immunological status.ResultsWe newly diagnosed six ICF patients who had tentatively been diagnosed with common variable immunodeficiency. We identified two novel mutations in the DNMT3B gene and one novel mutation in the ZBTB24 gene. All patients showed low serum IgG and/or IgG2 levels and were treated by periodic immunoglobulin replacement therapy. Three of the six patients showed worse results of the mitogen-induced lymphocyte proliferation test. Analyses of lymphocyte subpopulations revealed that CD19+CD27+ memory B cells were low in seven of nine patients, CD3+ T cells were low in three patients, CD4/8 ratio was inverted in five patients, CD31+ recent thymic emigrant cells were low in two patients, and CD19+ B cells were low in four patients compared with those in the normal controls. ICF2 patients showed lower proportions of CD19+ B cells and CD16+56+ NK cells and significantly higher proportions of CD3+ T cells than ICF1 patients. T cell receptor excision circles were undetectable in two patients. Despite being treated by immunoglobulin replacement therapy, three patients died of influenza virus, fatal viral infection with persistent Epstein–Barr virus infection, or JC virus infection. One of three dead patients showed normal intelligence with mild facial anomaly. Two patients presented with autoimmune or inflammatory manifestations. Infectious episodes decreased in three patients who were started on trimethoprim–sulfamethoxazole and/or antifungal drugs in addition to immunoglobulin replacement therapy. These patients might have suffered from T cell immunodeficiency.ConclusionThese results indicate that patients with ICF syndrome have a phenotype of combined immunodeficiency. Thus, to achieve a better prognosis, these patients should be treated as having combined immunodeficiency in addition to receiving immunoglobulin replacement therapy.