Clinical heterogeneity among pediatric patients with autoimmune type 1 diabetes stratified by immunoglobulin deficiency.

BACKGROUND: Type 1 diabetes (T1D) may coexist with primary immunodeficiencies, indicating a shared genetic background. OBJECTIVE: To evaluate the prevalence and clinical characteristics of immunoglobulin deficiency (IgD) among children with T1D. METHODS: Serum samples and medical history questionnaires were obtained during routine visits from T1D patients aged 4-18 years. IgG, IgA, IgM, and IgE were measured by nephelometry and enzyme-linked immunosorbent assay (ELISA). IgG and IgM deficiency (IgGD, IgMD) were defined as IgG/IgM >2 standard deviations (SD) below age-adjusted mean. IgE deficiency was defined as IgE <2 kIU/L. IgA deficiency (IgAD) was defined as IgA >2 SD below age-adjusted mean irrespective of other immunoglobulin classes (absolute if <0.07 g/L, partial otherwise) and as selective IgAD when IgA >2 SD below age-adjusted mean with normal IgG and IgM (absolute if <0.07 g/L, partial otherwise). RESULTS: Among 395 patients (53.4% boys) with the median age of 11.2 (8.4-13.7) and diabetes duration 3.6 (1.1-6.0) years, 90 (22.8%) were found to have hypogammaglobulinemia. The IgGD and IgAD were the most common each in 40/395 (10.1%). Complex IgD was found in seven patients. Increased odds of infection-related hospitalization (compared to children without any IgD) was related to having any kind of IgD and IgAD; OR (95%CI) = 2.1 (1.2-3.7) and 3.7 (1.8-7.5), respectively. Furthermore, IgAD was associated with having a first-degree relative with T1D OR (95%CI) = 3.3 (1.4-7.6) and suffering from non-autoimmune comorbidities 3.3 (1.4-7.6), especially neurological disorders 3.5 (1.2-10.5). CONCLUSIONS: IgDs frequently coexist with T1D and may be associated with several autoimmune and nonimmune related disorders suggesting their common genetic background.

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.

B cells do not have a major pathophysiologic role in acute ischemic stroke in mice.

BACKGROUND: Lymphocytes have been shown to play an important role in the pathophysiology of acute ischemic stroke, but the properties of B cells remain controversial. The aim of this study was to unravel the role of B cells during acute cerebral ischemia using pharmacologic B cell depletion, B cell transgenic mice, and adoptive B cell transfer experiments. METHODS: Transient middle cerebral artery occlusion (60 min) was induced in wild-type mice treated with an anti-CD20 antibody 24 h before stroke onset, JHD -/- mice and Rag1 -/- mice 24 h after adoptive B cell transfer. Stroke outcome was assessed at days 1 and 3. Infarct volumes were calculated from 2,3,5-triphenyltetrazolium chloride (TTC)-stained brain sections, and neurological scores were evaluated. The local inflammatory response was determined by real-time PCR and immunohistochemistry. Apoptosis was analyzed by TUNEL staining, and astrocyte activation was revealed using immunohistochemistry and Western blot. RESULTS: Pharmacologic depletion of B cells did not influence infarct volumes and functional outcome at day 1 after stroke. Additionally, lack of circulating B cells in JHD -/- mice also failed to influence stroke outcome at days 1 and 3. Furthermore, reconstitution of Rag1 -/- mice with B cells had no influence on infarct volumes. CONCLUSION: Targeting B cells in experimental stroke did not influence lesion volume and functional outcome during the acute phase. Our findings argue against a major pathophysiologic role of B cells during acute ischemic stroke.

Immunological and clinical profile of adult patients with selective immunoglobulin subclass deficiency: response to intravenous immunoglobulin therapy.

Selective immunoglobulin (Ig)G3 subclass deficiency in adults, especially its immunological profile, has not been described previously in detail. Therefore, a retrospective chart review was conducted to characterize the immune profile and clinical manifestations in adult patients with selective IgG3 deficiency. We reviewed the charts of 17 adult patients attending our subspeciality immunology clinic with a diagnosis of selective IgG3 deficiency. The following immunological test results were recorded: lymphocyte subsets, proliferative response to mitogens (phytohaemagglutinin, concanavalin A, pokeweed mitogen) and soluble antigens (mumps, Candida albicans, tetanus toxoid), specific antibody response to tetanus toxoid and pneumococcal antigens, neutrophil oxidative burst and natural killer cell cytotoxicity. In addition, we recorded information about the types of infections and other associated diseases, and response to intravenous immunoglobulin therapy (IVIG). In the majority of patients, lymphocyte subsets were normal. Proliferative responses to mitogens and antigens were decreased in 33% and 40% of patients, respectively. Specific antibody responses to tetanus were normal; however, responses to various pneumococcal serotypes were impaired in a subset of patients. Patients suffered from recurrent upper respiratory tract infections, which usually decreased in frequency and severity following treatment with IVIG. The majority of these patients also had concurrent atopic diseases in the form of allergic rhinitis or asthma. Selective IgG3 subclass deficiency should be considered in adults with recurrent upper respiratory tract infections with or without allergic rhinitis or asthma, who may have normal levels of total IgG. IVIG appears to be an effective therapy.

Characterization of adult patients with IgG subclass deficiency and subnormal IgG2.

BACKGROUND: Adults with IgG subclass deficiency (IgGSD) with subnormal IgG2 are inadequately characterized. METHODS: We retrospectively analyzed observations in unrelated adults with IgGSD evaluated in a single hematology clinic (1991-2019) and selected those with subnormal serum IgG2 (<117 mg/dL (<1.2 g/L)) without corticosteroid therapy to describe: age; prevalence of women; upper/lower respiratory infection; autoimmune condition(s); atopy; other allergy; frequent or severe respiratory tract infection in first-degree relatives; IgG, IgG subclasses, IgA, and IgM; blood lymphocyte subpopulations; human leukocyte antigen (HLA)-A and -B types and haplotypes; and 23-valent pneumococcal polysaccharide vaccination (PPSV23) responses. We determined the prevalence of subnormal IgG2 among unrelated adults with IgGSD without corticosteroid therapy and compared general characteristics of those with and without subnormal IgG2. RESULTS: There were 18 patients (94.4% women) with subnormal IgG2. Mean age was 52 ± 11 y. Upper/lower respiratory infection occurred in 94.4%/74.8%, respectively. Autoimmune condition(s), atopy, other allergy, and frequent or severe respiratory infection in first-degree relatives occurred in 44.4%, 44.4%, 61.1%, and 22.2%, respectively. Median IgG2 was 105 mg/dL (83, 116). Subnormal IgG, IgG1, IgG3, IgG4, IgA, and IgM was observed in 66.7%, 50.0%, 100.0%, 5.6%, 33.3%, and 0%, respectively. Lymphocyte subpopulations were normal in most patients. HLA frequencies were similar in patients and controls. Three of 4 patients had no protective S. pneumoniae serotype-specific IgG levels before or after PPSV23. These 18 patients represent 7.6% of 236 adults with IgGSD. Prevalence of subnormal IgG, subnormal IgG3, and subnormal IgA was significantly greater in 18 adults with subnormal IgG2 than 218 adults without subnormal IgG2. Prevalence of subnormal IgM was significantly lower in patients with subnormal IgG2. CONCLUSIONS: Characteristics of adults with IgGSD with subnormal IgG2 include female predominance, other immunologic abnormalities, subnormal IgG3 and/or IgG1, lack of HLA-A and -B association, and suboptimal PPSV23 response.

Clinical and Immunological Features of 78 Adult Patients with Primary Selective IgG Subclass Deficiencies.

The purpose of this study is to describe both clinical and immunological features in large cohort of adult patients with IgG subclass deficiency, and response to immunoglobulin therapy. This is a retrospective study of data obtained from electronic medical records and paper charts of 78 patients with IgG subclass deficiency seen and followed at our immunology clinics from 2010 to 2016. Both isolated selective IgG subclass deficiency as well as combined (two) subclass deficiencies were observed. IgG3 subclass deficiency, isolated and in combination with other IgG subclass deficiency, is the most frequent of IgG subclass deficiency. A majority of patients presented with upper and lower respiratory tract infections, especially chronic sinusitis. Both allergic and autoimmune manifestations are common; however, there is no subclass preference. The proportions and absolute numbers of CD3+ T cells, CD4+ T and CD8+ T cells, CD19+ B cells, and CD3-CD16+CD56+ NK cells were normal in the majority of patients in all IgG subclass deficiencies. Total serum IgG levels did not correlate with IgG subclass levels across all IgG subclass deficiencies. Anti-pneumococcal polysaccharide antibody responses were impaired in 56% of patients. IgG3 subclass deficiency is the most common IgG subclass deficiency, and anti-polysaccharide antibody responses are distributed among IgG subclasses with modest preference in IgG2 subclass. The majority of patients treated with immunoglobulin responded by reduction in frequency of infections and requirement of antibiotics.

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.

Selective IgG2 subclass deficiency--a marker for the syndrome of pre/postnatal growth retardation, developmental delay, hypotrophy of distal extremities, dental anomalies and eczema.

We report a third family with members displaying pre- and postnatal growth retardation, hypotonia, psychomotor retardation, small puffy hands and feet, dental anomalies and eczematous skin. The four affected members are all females born to unrelated parents consistent with the previously proposed autosomal recessive mode of inheritance. We report a further clinical feature of selective immunoglobulin IgG2 subclass deficiency which would explain some of the clinical findings and might provide an immunological marker for diagnostic confirmation of the syndrome.

Histopathological and immunohistological analyses in IgA deficient lymphoplasia (aly/aly) mouse.

The aly/aly mouse has a severe immunodeficiency, because it lacks peripheral lymph nodes as well as IgA and IgG immunoglobulin synthesis. In the present study, we performed histopathological and immunohistological examinations to clarify histological disorders of various immune organs in these mice. Carbon CH40 injections into the apex of the tongue confirmed the absence of submandibular lymph nodes in aly/aly mice. The thymus had a poorly constructed cortex and medulla, and the number of lymphoid follicles was clearly decreased in the spleen. No IgG- or IgA- producing cells were found in any immune organs, including the mucosal immune sites, though several IgM -producing cells were identified. Other characteristic findings included perivascular lymphocytes accumulation in the salivary glands, lungs, liver and pancreas, which caused tissues damage. These results demonstrated that the various lymphoid tissues disorders and organ-specific lymphocyte infiltration cause immuno-deficiency in the aly/aly mouse.

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.

Immune deficiency: office evaluation and treatment.

Congenital deficiencies of the immune system occur in children or adults and can cause severe or recurrent infections. The overall incidence of these immunodeficiency diseases is estimated at approximately 1 in 10,000, excluding selective immunoglobulin A deficiency, but this estimation is based on population studies, not hospital or clinic populations. The majority of immune defects involve antibody production; these immune deficiencies are found more often in adults than infants and children. In an allergy practice, recurrent infections are common, and determining if an immune defect is likely to be present can be problematic. Some guidelines concerning the clinical presentation and laboratory evaluation and treatment options can aid the practicing clinician.

Severe neutropenia associated with IgG2 subclass deficiency and bone marrow T-lymphocyte infiltration.

Patients with selective IgG2 subclass deficiency (IgG2 SD) usually suffer from recurrent respiratory infections. The occurrence of cytopenia is extremely rare in these patients. We report on two patients with isolated IgG2 SD who experienced unexplained severe neutropenia associated with T-lymphocyte proliferation. IgG2 SD clearly preceded the occurrence of neutropenia in one patient. In the other patient, the long-standing history of recurrent respiratory infections prior to diagnosis of agranulocytosis suggests that IgG2 SD also preceded the occurrence of neutropenia. Analysis of bone marrow biopsy in both patients and skin tissue lesions in one patient showed massive infiltration with CD4+ and CD8+ T-lymphocytes. The pathological feature did not suggest any malignant lymphoproliferative disorder. Neutropenia was refractory to i.v. Ig in both patients and to recombinant G-CSF, steroids, and cyclophosphamide in one patient. Severe cellulitis led to death in one patient. In summary, we reported herein a heretofore undescribed syndrome characterized by the association of IgG2 SD with severe neutropenia and tissue T-cell infiltration. It suggests that bone marrow analysis as well as determination of serum IgG subclasses need to be performed in patients with unexplained neutropenia.

[Juvenile Adamantiades-Behçet disease in decreased stimulation with anti-CD3 monoclonal antibody]. / Juveniler Morbus Adamantiades-Behçet bei erniedrigter Stimulation mit Anti-CD3-monoklonalen Antikörper.

A 12 year old boy developed the complete symptom complex of Adamantiades-Behçet's disease over a two-year period. He presented with the mucocutaneous variant with recurrent to persistent oral ulcers which extended into the pharynx, recurrent genital ulcers, perianal lesions, and a positive pathergy test. Ocular involvement and other symptoms associated with the disease were absent. However, the early onset of the disease and the male gender indicated a bad prognosis. The patients father deficiency of suffered from bronchial asthma with recurrent respiratory infections. An IgG-3 subclass was detected. Lymphocyte transformation tests showed markedly diminished response to stimulation with anti-CD3 monoclonal antibody in both patients, while response to PWM, CoA and PHA was normal. In addition, the concentration of serum soluble interleukin 6 receptor was reduced in both patients.

Lupus vulgaris in a patient with systemic lupus erythematosus and persistent IgG deficiency.

We present the case of a patient with juvenile onset systemic lupus erythematosus (SLE) who developed a persistent, acquired hypogammaglobulinaemia with IgG deficiency. The hypogammaglobulinaemia was probably a complication of high dose corticosteroid treatment. The serum IgG level remained subnormal despite intravenous immunoglobulin therapy. Lupus vulgaris, which developed on the nasal cartilage in this patient with SLE, is not an expected finding. This patient is probably the first reported case of SLE associated with lupus vulgaris.

IL-12 deficiency in MRL-Fas(lpr) mice delays nephritis and intrarenal IFN-gamma expression, and diminishes systemic pathology.

Autoimmune disease in MRL-Fas(lpr) mice is characterized by fatal nephritis, systemic pathology, and autoantibodies, mimicking human lupus. We previously reported that 1) intrarenal IL-12 elicits nephritis by fostering the accumulation of intrarenal IFN-gamma-secreting T cells, and 2) MRL-Fas(lpr) mice deficient in the IFN-gamma receptor were spared from nephritis. Therefore, we hypothesized that eliminating IL-12 in MRL-Fas(lpr) mice reduces IFN-gamma-secreting cells and thereby prevents systemic pathology. For this purpose, we constructed an IL-12p40-deficient MRL-Fas(lpr)(IL-12(-/-)) strain. We determined that glomerular and interstitial, but not perivascular, renal pathology were decreased in IL-12(-/-) mice vs the wild-type (WT) strain (5 mo of age). Similarly, systemic pathology (lung, lacrimal and salivary glands, skin, and lymphadenopathy) was diminished. The intrarenal accumulation of T cells (CD4(+), CD8(+), CD4(-)CD8(-)B220(+)) and macrophages was dramatically reduced in IL-12(-/-) MRL-Fas(lpr) kidneys. We determined that there were fewer IFN-gamma transcripts (>70%) in the IL-12(-/-) protected kidneys compared with the WT kidneys. Similarly, cells propagated from IL-12(-/-) MRL-Fas(lpr) kidneys generated substantially less IFN-gamma when stimulated with IL-12 and IL-18 compared with those from WT kidneys, and we detected fewer CD8 and B220 T cells producing IFN-gamma in these IL-12(-/-) MRL-Fas(lpr) kidneys. Of note, survival was modestly extended in the IL-12(-/-) MRL-Fas(lpr) mice. While lung and lacrimal and salivary gland pathology remained reduced in moribund IL-12(-/-) MRL-Fas(lpr) mice, renal pathology and IFN-gamma expression were equivalent to those in the WT strain. Thus, we suggest that IL-12 is a therapeutic target for multiple tissues in lupus; however blocking IL-12 alone is not sufficient to confer enduring protection from lupus nephritis.