HLA-A and -B Type and Haplotype Frequencies in IgG Subclass Deficiency Subgroups.

We sought to determine whether HLA-A and -B type and haplotype frequencies differ between subgroups of adults with IgG subclass deficiency (IgGSD). We retrospectively compared type and haplotype frequencies of three subgroups of 269 unrelated adult IgGSD patients (70 subnormal IgG1; 121 subnormal IgG3; 78 subnormal IgG1/IgG3) and controls (1,321 for types; 751 for haplotypes). We selected types and haplotypes because their uncorrected frequencies differed significantly from controls in a previous adult IgGSD/common variable immunodeficiency cohort: A*24; B*14; B*35; B*40; B*49; B*50; B*58; B*62; A*01,B*08; A*02,B*44; A*02,B*60; A*03,B*07; A*03,B*14; A*03,B*44; A*31,B*40; and A*32,B*14. We used χ2 analysis (2 × 4 tables) to identify frequency differences across three subgroups and controls. If the null hypothesis was rejected (p < 0.05), we computed 2 × 2 χ2 tables to compare six combinations of subgroup and control frequencies [Bonferroni p < 0.0083 (< 0.05/6)]. Mean age was 48 ± 13 years; 82.2% were women. B*35 and B*40 frequencies were higher in subnormal IgG1 than subnormal IgG3 patients (0.1000 vs. 0.0248 and 0.0571 vs. 0.0083, respectively; p ≤ 0.0061). B*62 frequencies were lower in three IgGSD subgroups than controls (p < 0.0001, respectively). A*02, B*44 frequency was higher in subnormal IgG1/IgG3 patients than controls (0.1282 vs. 0.0632, respectively; p = 0.0024). A*02, B*60 frequency was lower in subnormal IgG3 patients than controls (0.0 vs. 0.0233, respectively; p = 0.0051). HLA-B*35 and -B*40 frequencies differ significantly between some IgGSD subgroups. B*62, A*02, B*44, and A*02, B*60 frequencies differ significantly between some IgGSD subgroups and controls.

ALG12-CDG: novel glycophenotype insights endorse the molecular defect.

Congenital disorders of glycosylation (CDG) are genetic diseases characterized by deficient synthesis (CDG type I) and/or abnormal processing (CDG type II) of glycan moieties linked to protein and lipids. The impact of the molecular defects on protein glycosylation and in turn on the clinical phenotypes of patients with CDG is not yet understood. ALG12-CDG is due to deficiency of ALG12 α1,6-mannosyltransferase that adds the eighth mannose residue on the dolichol-PP-oligosaccharide precursor in the endoplasmic reticulum. ALG12-CDG is a severe multisystem disease associated with low to deficient serum immunoglobulins and recurrent infections. We thoroughly investigated the glycophenotype in a patient with novel ALG12 variants and immunodeficiency. We analyzed serum native transferrin, as first line test for CDG and we profiled serum IgG and total serum N-glycans by a combination of consolidated (N-glycan analysis by MALDI MS) and innovative mass spectrometry-based protocols, such as GlycoWorks RapiFluor N-glycan analysis coupled with LC-ESI MS. Intact serum transferrin showed, as expected for a CDG type I defect, underoccupancy of N-glycosylation sites. Surprisingly, total serum proteins and IgG N-glycans showed some specific changes, consisting in accumulating amounts of definite high-mannose and hybrid structures. As a whole, ALG12-CDG behaves as a dual CDG (CDG-I and II defects) and it is associated with distinct, abnormal glycosylation of total serum and IgG N-glycans. Glycan profiling of target glycoproteins may endorse the molecular defect unraveling the complex clinical phenotype of CDG patients.

Fcγ-receptor polymorphisms associated with clinical symptoms in patients with immunoglobulin G subclass deficiency.

BACKGROUND: Immunoglobulin G subclass deficiencies (IgGsd) are associated with recurrent respiratory tract infections. Immunoglobulin substitution therapy may be needed to prevent chronic lung tissue damage but tools for identifying the patients that will benefit from this treatment are still insufficient. Some FcγR polymorphisms seem to predispose for an increased risk for infections. In this study we wanted to evaluate if the FcγR-profile differs between individuals with IgGsd and a control population. METHODS: Single nucleotide polymorphisms (SNPs) of FcγRIIa, FcγRIIIa and FcγRIIc in 36 IgGsd patients and 192 controls with similar sex and geographical distribution were analyzed by TaqMan allelic discrimination assay or Sanger sequencing. RESULTS: In the IgGsd-group, homozygous frequency for FcγRIIa-R/R131 (low-binding capacity isoform) was higher (p = .03) as well as for non-classical FcγRIIc-ORF (p = .03) and classical FcγRIIc-ORF tended (p = .07) to be more common compared to the controls. There was no difference between the groups regarding FcγRIIIa. CONCLUSION: The gene for classical FcγRIIc-ORF tended to be more frequent in individuals with immunoglobulin G subclass deficiency and the genes for non-classical FcγRIIc-ORF as well as low-binding capacity receptor FcγRIIa-R/R131 were more frequent. Further studies on the FcγR polymorphisms may pave way for identifying individuals that will benefit from immunoglobulin substitution.

Altered marginal zone and innate-like B cells in aged senescence-accelerated SAMP8 mice with defective IgG1 responses.

Aging has a strong impact on the activity of the immune system, enhancing susceptibility to pathogens and provoking a predominant pre-inflammatory status, whereas dampening responses to vaccines in humans and mice. Here, we demonstrate a loss of marginal zone B lymphocytes (MZ, CD19+CD45R+CD21++CD23lo) and a decrease of naive B cells (CD19+IgD+), whereas there is an enhancement of a CD19+CD45Rlo innate-like B cell population (B1REL) and the so-called aged B cell compartment (ABC, CD45R+CD21loCD23loCD5-CD11b-) in aged senescence-accelerated (SAMP8) mice but not in aged senescence-resistant (SAMR1) mice. These changes in aged SAMP8 mice were associated with lower IgG isotype levels, displaying low variable gene usage repertoires of the immunoglobulin heavy chain (VH) diversity, with a diminution on IgG1-memory B cells (CD11b-Gr1-CD138-IgM-IgD-CD19+CD38+IgG1+), an increase in T follicular helper (TFH, CD4+CXCR5+PD1+) cell numbers, and an altered MOMA-1 (metallophilic macrophages) band in primary follicles. LPS-mediated IgG1 responses were impaired in the B1REL and ABC cell compartments, both in vitro and in vivo. These data demonstrate the prominent changes to different B cell populations and in structural follicle organization that occur upon aging in SAMP8 mice. These novel results raise new questions regarding the importance of the cellular distribution in the B cell layers, and their effector functions needed to mount a coordinated and effective humoral response.

Fibromyalgia in 300 adult index patients with primary immunodeficiency.

OBJECTIVES: We sought to determine the prevalence and clinical and laboratory associations of fibromyalgia in adults with primary immunodeficiency (immunoglobulin (Ig) G subclass deficiency (IgGSD) and common variable immunodeficiency (CVID). METHODS: We performed a retrospective analysis of these observations in 300 non-Hispanic white adult index patients with recurrent/severe respiratory tract infections and IgGSD or CVID: age; sex; IgGSD; fibromyalgia; chronic fatigue; autoimmune conditions (ACs); interstitial cystitis (IC); diabetes; body mass index; serum Ig isotypes; blood lymphocytes and subsets; and human leukocyte antigen (HLA)-A and -B types and haplotypes. We performed univariate comparisons, logistic multivariable regressions, and an analysis of covariance. RESULTS: Mean age was 49 ± 12 (standard deviation) y. There were 246 women (82.0%). IgGSD was diagnosed in 276 patients (92.0%). Fifty-six patients had fibromyalgia (18.7%; female:male 13:1). Other characteristics included: chronic fatigue, 63.0%; aggregate ACs, 35.3%; Sjögren's syndrome, 8.0%; IC, 3.0%; diabetes, 10.3%; and HLA-A*29, B*44 positivity, 9.7%. Prevalences of female sex; chronic fatigue; IC; and HLA-A*29, B*44 positivity were greater in patients with fibromyalgia. Logistic regression on fibromyalgia revealed three positive associations: chronic fatigue (p=0.0149; odds ratio 2.6 [95% confidence interval 1.2, 5.6]); Sjögren's syndrome (p=0.0004; 5.2 [2.1, 13.2]); and IC (p=0.0232; 5.7 [1.3, 25.7]). In an analysis of covariance, there were significant interactions of chronic fatigue, Sjögren's syndrome, and interstitial cystitis on fibromyalgia. CONCLUSIONS: Fibromyalgia is common in non-Hispanic white adult index patients with primary immunodeficiency, especially women. Chronic fatigue, Sjögren's syndrome, and IC are significantly associated with fibromyalgia after adjustment for other independent variables.

Primary immunodeficiency associated with chromosomal aberration - an ESID survey.

BACKGROUND: Patients with syndromic features frequently suffer from recurrent respiratory infections, but little is known about the spectrum of immunological abnormalities associated with their underlying chromosomal aberrations outside the well-known examples of Down and DiGeorge syndromes. Therefore, we performed this retrospective, observational survey study. METHODS: All members of the European Society for Immunodeficiencies (ESID) were invited to participate by reporting their patients with chromosomal aberration (excluding Down and DiGeorge syndromes) in combination with one or more identified immunological abnormalities potentially relating to primary immunodeficiency. An online questionnaire was used to collect the patient data. RESULTS: Forty-six patients were included from 16 centers (24 males, 22 females; median age 10.4 years [range 1.0-69.2 years]; 36 pediatric, 10 adult patients). A variety of chromosomal aberrations associated with immunological abnormalities potentially relating to primary immune deficiency was reported. The most important clinical presentation prompting the immunological evaluation was 'recurrent ear-nose-throat (ENT) and airway infections'. Immunoglobulin isotype and/or IgG-subclass deficiencies were the most prevalent immunological abnormalities reported. CONCLUSIONS: Our survey yielded a wide variety of chromosomal aberrations associated with immunological abnormalities potentially relating to primary immunodeficiency. Although respiratory tract infections can often also be ascribed to other causes (e.g. aspiration or structural abnormalities), we show that a significant proportion of patients also have an antibody deficiency requiring specific treatment (e.g. immunoglobulin replacement, antibiotic prophylaxis). Therefore, it is important to perform immunological investigations in patients with chromosomal aberrations and recurrent ENT or airway infections, to identify potential immunodeficiency that can be specifically treated.

Comparisons of CVID and IgGSD: referring physicians, autoimmune conditions, pneumovax reactivity, immunoglobulin levels, blood lymphocyte subsets, and HLA-A and -B typing in 432 adult index patients.

Common variable immunodeficiency (CVID) and immunoglobulin (Ig) G subclass deficiency (IgGSD) are heterogeneous disorders characterized by respiratory tract infections, selective Ig isotype deficiencies, and impaired antibody responses to polysaccharide antigens. Using univariable analyses, we compared observations in 34 CVID and 398 IgGSD adult index patients (81.9% women) referred to a hematology/oncology practice. Similarities included specialties of referring physicians, mean ages, proportions of women, reactivity to Pneumovax, median serum IgG3 and IgG4 levels, median blood CD56+/CD16+ lymphocyte levels, positivity for HLA-A and -B types, and frequencies of selected HLA-A, -B haplotypes. Dissimilarities included greater prevalence of autoimmune conditions, lower median IgG, IgA, and IgM, and lower median CD19+, CD3+/CD4+, and CD3+/CD8+ blood lymphocytes in CVID patients. Prevalence of Sjögren's syndrome and hypothyroidism was significantly greater in CVID patients. Combined subnormal IgG1/IgG3 occurred in 59% and 29% of CVID and IgGSD patients, respectively. Isolated subnormal IgG3 occurred in 121 IgGSD patients (88% women). Logistic regression on CVID (versus IgGSD) revealed a significant positive association with autoimmune conditions and significant negative associations with IgG1, IgG3, and IgA and CD56+/CD16+ lymphocyte levels, but the odds ratio was increased for autoimmune conditions alone (6.9 (95% CI 1.3, 35.5)).

High-affinity IgG antibodies develop naturally in Ig-knockout rats carrying germline human IgH/Igκ/Igλ loci bearing the rat CH region.

Mice transgenic for human Ig loci are an invaluable resource for the production of human Abs. However, such mice often do not yield human mAbs as effectively as conventional mice yield mouse mAbs. Suboptimal efficacy in delivery of human Abs might reflect imperfect interaction between the human membrane IgH chains and the mouse cellular signaling machinery. To obviate this problem, in this study we generated a humanized rat strain (OmniRat) carrying a chimeric human/rat IgH locus (comprising 22 human V(H)s, all human D and J(H) segments in natural configuration linked to the rat C(H) locus) together with fully human IgL loci (12 Vκs linked to Jκ-Cκ and 16 Vλs linked to Jλ-Cλ). The endogenous Ig loci were silenced using designer zinc finger nucleases. Breeding to homozygosity resulted in a novel transgenic rat line exclusively producing chimeric Abs with human idiotypes. B cell recovery was indistinguishable from wild-type animals, and human V(D)J transcripts were highly diverse. Following immunization, the OmniRat strain performed as efficiently as did normal rats in yielding high-affinity serum IgG. mAbs, comprising fully human variable regions with subnanomolar Ag affinity and carrying extensive somatic mutations, are readily obtainable, similarly to conventional mAbs from normal rats.

Safety, efficacy and pharmacokinetics of a new 10% liquid intravenous immunoglobulin (IVIG) in patients with primary immunodeficiency.

INTRODUCTION: An investigational 10% liquid intravenous immunoglobulin (IVIG) was studied in 63 patients with primary immunodeficiency (PID) at 15 study sites. METHODS: Patients were treated every 3 or 4 weeks with 254-1029 mg/kg/infusion of IVIG. RESULTS: Overall, Biotest-IVIG infusions were well tolerated. The proportion of infusions that were associated with adverse events during infusion, and up to 72 h after infusion, including those unrelated to study product, was 27.7% with an upper 95% confidence limit ≤30.6%. Two serious bacterial infections (SBIs) were observed resulting in a serious bacterial infection rate of 0.035 per person per year and an upper one-sided 99% confidence limit of ≤0.136 SBI/patient/year. The number of days of work or school missed due to infection were relatively low at 2.28 days/patient/year. Two patients were hospitalized for infection producing a rate of 0.21 hospitalization days/patient/year. The IgG half-life was approximately 30 days with variation among individuals. CONCLUSIONS: Pharmacokinetic parameters of specific antibody activities were essentially the same as those of total IgG. Biotest-IVIG is safe and effective in the treatment of PID.

Human MSH6 deficiency is associated with impaired antibody maturation.

Ig class-switch recombination (Ig-CSR) deficiencies are rare primary immunodeficiencies characterized by defective switched isotype (IgG/IgA/IgE) production. Depending on the molecular defect, defective Ig-CSR may also be associated with impaired somatic hypermutation (SHM) of the Ig V regions. Although the mechanisms underlying Ig-CSR and SHM in humans have been revealed (at least in part) by studying natural mutants, the role of mismatch repair in this process has not been fully elucidated. We studied in vivo and in vitro Ab maturation in eight MSH6-deficient patients. The skewed SHM pattern strongly suggests that MSH6 is involved in the human SHM process. Ig-CSR was found to be partially defective in vivo and markedly impaired in vitro. The resolution of γH2AX foci following irradiation of MSH6-deficient B cell lines was also found to be impaired. These data suggest that in human CSR, MSH6 is involved in both the induction and repair of DNA double-strand breaks in switch regions.

IgG deficiency and expansion of CTG repeats in myotonic dystrophy.

OBJECTIVES: Expansion of CTG repeats in myotonic dystrophy (DM1) alters the regulated expression of numerous genes. It is considered to explain the major clinical features of DM1. IgG deficiency is common in DM1 and is due to altered FcRn-related hypercatabolism. We hypothesized that the IgG catabolic rate is correlated with CTG repeat expansion. METHODS: Correlations between serum immunoglobulin levels, peripheral lymphocyte subset counts and CTG repeat numbers were performed in 52 DM1 patients. RESULTS: Serum IgG and IgG1 levels were below the normal limit respectively in 54% and 72% of patients. Increasing CTG repeat numbers were significantly correlated with decreasing serum IgG and IgG1 levels, and with decreasing CD3(+) T-cell and CD3(+)-CD8(+) cell counts. An abnormal immunoglobulin profile at protein electrophoresis was found in 4 patients. CONCLUSION: We conclude that the catabolic rate of IgG is linked to expanded CTG repeats, possibly involving an altered immune response.

[Assessment of immunoglobulins in a long-term non-interventional study (SIGNS Study). Rationale, design, and methods]. / Prospektive Versorgungsforschungsstudie zur Therapie mit Immunglobulinen (SIGNS): Rationale, Design und Methodik.

Non-modified human immunoglobulins (IgG) are standard of care for replacement therapy with primary (inherited) immunodeficiencies, and secondary immunodeficiencies due to multiple myeloma (MM) or chronic lymphocytic leukemia (CLL). Further, they have effectively been used as immunomodulation in neurological autoimmune diseases such as Guillain-Barré syndrome (GBS), chronic inflammatory demyelinating polyneuropathy (CIDP), and multifocal motor neuropathy (MMN). A variety of IgG preparations for intravenous and subcutaneous use are available. In view of the broad range of indications, data on the utilization of the IgG preparations in everyday clinical care are of high clinical interest. Furthermore, data on the outcomes of IgG therapy outside the setting of controlled clinical trials are needed. Therefore, the SIGNS study (Assessment of Immunoglobulins in a Long-Term Non-Interventional Study) was set up as a non-interventional prospective open-label cohort study and was approved by the ethics committee. Led by an interdisciplinary steering board, hospital- and office-based investigators in 30-40 centers throughout Germany (neurologists, pediatricians, oncologists, other) will document approximately 300 patients, and will follow them for at least 2 years. Patients of both genders and any age are eligible if they have received, or are scheduled for, IgG therapy for primary or severe secondary immunodeficiency or neurological autoimmune diseases, and have provided written informed consent. No exclusion criteria have been defined in order to minimize selection bias. Long-term outcome data will be collected on patient characteristics in the various indications, drug utilization (e.g., treatment and dosing patterns), effectiveness (i.e., number of infections), tolerability, health-related quality of life, and economic variables (number of hospitalizations, sick-leave days, etc.) with the possibility to estimate direct costs. For the neurological autoimmune diseases, detailed data will be gathered, among others, on neurological function, muscular function, physical function (grip strength, INCAT disability scale, etc.) and stabilization or progression of symptoms over time. Data collection in SIGNS is performed using a secure internet site and an MySQL database. A number of quality measures are routinely performed including automated plausibility checks at data entry, queries, and on-site monitoring with source data verification. It is expected that SIGNS will contribute to optimization of therapy in this diverse patient population.

Humoral immune deficiency and hemifacial microsomia seen in one family.

We present a patient with hemifacial microsomia and immune deficiency. The patient is a 5-year-old with grade III microtia and Pruzansky type I right mandibular hypoplasia. She developed 25 pulmonary infections in 3 years, required hospitalization every 6 weeks to receive antibiotics, and experienced recurrent herpes stomatitis and esophagitis, staphylococcal bacteremia, urinary tract, sinus, and ear infections. She had low total IgG, IgG1, IgG2, IgA, and anti-pneumococcal antibody levels. She was unable to maintain protective pneumococcal titers following vaccination. The patient's 7-year-old sister also suffered from recurrent infections, had a left facial skin tag, and a left arachnoid cyst. We conclude that immune deficiency can occur in association with hemifacial microsomia.

Efficacy of intravenous gammaglobulin for immunoglobulin G subclass and/or antibody deficiency in adults.

BACKGROUND: The clinical significance and efficacy of treating patients who have immunoglobulin (Ig) G subclass deficiency and/or antibody deficiency with Ig-replacement therapy has been debated. There are no clear guidelines to recommend intravenous gammaglobulin (IgIV) in these patients as there are few published studies documenting its efficacy. METHODS: We studied in an open-label protocol 10 adult patients with recurrent respiratory infections and IgG subclass and/or antibody deficiency. All patients received monthly IgIV for 12 months and then were observed for 3 months without IgIV infusions. We studied quality of life, incidence of infections, need for antibiotics, frequency of hospitalizations due to infections, IgG subclass and antibody (tetanus and pneumococcal) levels. Innate immunity was evaluated by studying the status of Toll-like receptors and polymorphisms, mannan-binding lectin levels and genotypes. Correction of the immune defects during IgIV therapy was evaluated. RESULTS: Monthly IgIV significantly improved quality of life, decreased the number of infections and the need for antibiotics, and improved IgG subclass and antibody serum levels. No consistent finding of innate immunity could be detected. CONCLUSIONS: IgIV could be beneficial in patients with IgG subclass or antibody deficiency.

Restricted immunoglobulin constant heavy G chain genes in primary immunodeficiencies.

Some primary immunodeficiencies (PIDs) express low serum levels of antibodies. The constant heavy G chain (IGHG) genes, also representing Fc domains of gamma 3, gamma 1 and gamma 2 on chromosome 14q32.3, genotyped by the alternative IgG subclass allotypes, found in four fixed IGHG haplotypes, designating four B cell variants, were identified by a competitive ELISA and double immunodiffusion. IGHG genes were hypothesized to contribute to the development of PIDs. From 235 Caucasian patients, the homozygous IGHG *bf-n/*bf-n diplotype (B*(bf-n)/B*(bf-n) cells) dominated significantly in 43 IgG2 deficiency (OR 6.0), 32 common variable immunodeficiency (OR 4.6) and 22 Ataxia telangiectasia (OR 3.0) and the IGHG*ga-n/*ga-n diplotype (B*(ga-n)/B*(ga-n) cells) dominated in 53 IgG3 deficiency (OR 10.6) and 21 Wiscott-Aldrich syndrome (OR 4.1). 62 IgA deficiency patients were dominated by both diplotypes (OR 2.3 and OR 2.8 respectively). Restricted IGHG genes, restricted IgG allotypes (Fc domains) and restricted B cells are significant in PIDs for diagnosis, treatment and pathogenetic mechanisms.

The role of Fas in the immune system biology of IL-2R alpha knockout mice: interplay among regulatory T cells, inflammation, hemopoiesis, and apoptosis.

Introducing lpr mutation prevents early mortality associated with IL-2Ralpha knockout (KO) mice, prompting us to determine the role of Fas in the immune system biology of IL-2Ralpha KO mice. Consistent with a defect in CD4+CD25+ regulatory T (Treg) cell expression, spontaneous lymphocyte activation in lymphoid organs was observed in 6-wk-old mice. In 16- to 22-wk-old mice, infiltration of leukocytes was observed in bone marrow, colon, lung, pancreas, lacrimal gland, and salivary gland, but not in heart, thyroid, liver, stomach, small intestine, ovary, and kidney. In the lymphocytes-infiltrated bone marrow, B cell lymphopoiesis was blocked at pro-B to pre-B/immature B stage, culminating in an age-dependent B cell loss in the periphery. These phenotypes were also observed in IL-2Ralpha KO mice bearing the lpr mutation (DM mice), indicating Treg cell function and the phenotypes attributed directly to Treg cell abnormality are largely Fas-independent. However, anemia and body weight loss were partially prevented, tissue cell apoptosis was inhibited, and lifespan was improved in the DM mice, demonstrating Fas-dependent elements in these processes. Our age-dependent, lifelong analysis of IL-2Ralpha KO and DM mice supports a CD4+CD25+ Treg cell-based mechanism for the abnormal immune system biology observed in IL-2Ralpha KO mice and provides a global view of the interplays among Treg cells, multiorgan inflammation, hemopoiesis, and apoptosis.