Adiponectin Receptors and Pro-inflammatory Cytokines Are Modulated in Common Variable Immunodeficiency Patients: Correlation With Ig Replacement Therapy.

Adiponectin exerts beneficial pleiotropic effects through three receptors, AdipoR1, AdipoR2, and T-cadherin; it also exerts immunomodulatory effects. We previously demonstrated that adiponectin levels are altered in common variable immunodeficiency disease (CVID). The purpose of the present study was to investigate further the specific involvement of adiponectin in CVID by characterizing (i) the expression profile of adiponectin receptors on peripheral blood mononuclear cells; (ii) the levels of another relevant adipokine, namely leptin; (iii) the levels of five other cytokines (IL-2, IL-6, IL-10, TNFα, and IFNγ) in 24 patients on maintenance therapy, in 18 treatment-naïve patients (before and 24 h after the first Ig infusion) and in 28 healthy controls. We found that (i) adiponectin was down-expressed in patients on maintenance therapy and in treatment-naïve patients, and that it increased in treatment-naïve patients 24 h after the first Ig infusion; (ii) leptin expression did not differ between maintenance patients and controls either before or after the first Ig infusion; (iii) AdipoR1 expression was significantly higher on B lymphocytes, monocytes and NK cells of CVID patients than in controls; (iv) the expression of AdipoR1 and AdipoR2 on B lymphocytes, monocytes and NK cells was higher after the first Ig infusion than in treatment-naïve patients; (v) T-cadherin expression did not differ between treatment- naïve CVID patients and controls, and was not affected by Ig infusion; and (vi) IL-6, IL-8, IL-10, and TNFα levels were differently expressed in CVID patients on therapy maintenance and were not affected by the first Ig replacement therapy. This is the first study to demonstrate that the expression of AdipoRs in peripheral blood mononuclear cells from CVID patients differs from that of controls, and changes after the first Ig infusion. The specificity of adiponectin involvement in CVID is supported by the absence of changes in leptin levels and in the levels of the cytokines investigated. Taken together, these results suggest that the adiponectin system plays an important and specific role in CVID. A better understanding of adiponectin as a link in the cross-talk between the immune system and adipose tissue may provide additional benefits for the management of CVID patients.

Immunosuppressive therapy with rituximab in common variable immunodeficiency.

Common variable immunodeficiency (CVID) is the most frequent symptomatic primary antibody deficiency in adulthood and is characterized by the marked reduction of IgG and IgA serum levels. Thanks to the successful use of polyvalent immunoglobulin replacement therapy to treat and prevent recurrent infections, non-infectious complications, including autoimmunity, polyclonal lymphoproliferation and malignancies, have progressively become the major cause of morbidity and mortality in CVID patients. The management of these complications is particularly challenging, often requiring multiple lines of immunosuppressive treatments. Over the last 5-10 years, the anti-CD20 monoclonal antibody (i.e., rituximab) has been increasingly used for the treatment of both autoimmune and non-malignant lymphoproliferative manifestations associated with CVID. This review illustrates the evidence on the use of rituximab in CVID. For this purpose, first we discuss the mechanisms proposed for the rituximab mediated B-cell depletion; then, we analyze the literature data regarding the CVID-related complications for which rituximab has been used, focusing on autoimmune cytopenias, granulomatous lymphocytic interstitial lung disease (GLILD) and non-malignant lymphoproliferative syndromes. The cumulative data suggest that in the vast majority of the studies, rituximab has proven to be an effective and relatively safe therapeutic option. However, there are currently no data on the long-term efficacy and side effects of rituximab and other second-line therapeutic options. Further randomized controlled trials are needed to optimize the management strategies of non-infectious complications of CVID.

Superantigenic Activation of Human Cardiac Mast Cells.

B cell superantigens, also called immunoglobulin superantigens, bind to the variable regions of either the heavy or light chain of immunoglobulins mirroring the lymphocyte-activating properties of classical T cell superantigens. Protein A of Staphylococcus aureus, protein L of Peptostreptococcus magnus, and gp120 of HIV are typical immunoglobulin superantigens. Mast cells are immune cells expressing the high-affinity receptor for IgE (FcεRI) and are strategically located in the human heart, where they play a role in several cardiometabolic diseases. Here, we investigated whether immunoglobulin superantigens induced the activation of human heart mast cells (HHMCs). Protein A induced the de novo synthesis of cysteinyl leukotriene C4 (LTC4) from HHMCs through the interaction with IgE VH3+ bound to FcεRI. Protein L stimulated the production of prostaglandin D2 (PGD2) from HHMCs through the interaction with κ light chains of IgE. HIV glycoprotein gp120 induced the release of preformed (histamine) and de novo synthesized mediators, such as cysteinyl leukotriene C4 (LTC4), angiogenic (VEGF-A), and lymphangiogenic (VEGF-C) factors by interacting with the VH3 region of IgE. Collectively, our data indicate that bacterial and viral immunoglobulin superantigens can interact with different regions of IgE bound to FcεRI to induce the release of proinflammatory, angiogenic, and lymphangiogenic factors from human cardiac mast cells.

Gastroduodenal Disorders in Patients with CVID Undergoing Immunoglobulin Therapy.

BACKGROUND: Common variable immunodeficiency (CVID) encompasses a heterogeneous group of primary antibody deficiency disorders characterized by recurrent infections, autoimmunity and malignancies. Gastrointestinal manifestations are frequently associated with CVID. OBJECTIVE: In this cross-sectional study, we evaluated gastric and duodenal involvement in a cohort of adult patients with CVID. METHODS: Upper gastrointestinal endoscopy was performed in 58 patients (26 males, mean age 47.8±15.6 years), diagnosed with CVID according to 2014 ESID criteria. Random biopsies were collected from gastric antrum and descending duodenum for the all enrolled subjects. Intraepithelial lymphocytosis in descending duodenum was defined as the presence of 25 lymphocytes per 100 enterocytes. RESULTS: The major histopathological findings that we found were: a) chronic active gastritis (44.8%), Helicobacter pylori-associated (8.6%), b) chronic duodenitis (39.6%) with intraepithelial lymphocytosis (31%) and absence of plasma cells (18.9%) and c) autoimmune atrophic gastritis (5.2%). Three patients (5.2%) presented Intestinal Metaplasia (IM) of the gastric antrum. This finding was associated with H. pylori infection and persisted after the eradication in one patient. IM was associated with autoimmune atrophic gastritis in two cases. Giardia lamblia infection was observed in the duodenum samples from three patients (5.2%). A diagnosis of Gastric adenocarcinoma was made in a 58-year- old woman diagnosed with gastric dysplasia one year earlier. CONCLUSION: In our cohort of CVID patients, gastro-duodenal histopathological findings, including malignancies, are frequent and can affect long-term prognosis. A rigorous endoscopic follow-up is needed in CVID patients irrespective of the gastrointestinal symptoms.

Thymic Stromal Lymphopoietin Isoforms, Inflammatory Disorders, and Cancer.

Thymic stromal lymphopoietin (TSLP) is a pleiotropic cytokine originally isolated from a murine thymic stromal cell line. TSLP exerts its biological effects by binding to a high-affinity heteromeric complex composed of thymic stromal lymphopoietin receptor chain and IL-7Rα. TSLP is primarily expressed by activated lung and intestinal epithelial cells, keratinocytes, and fibroblasts. However, dendritic cells (DCs), mast cells, and presumably other immune cells can also produce TSLP. Different groups of investigators have demonstrated the existence of two variants for TSLP in human tissues: the main isoform expressed in steady state is the short form (sf TSLP), which plays a homeostatic role, whereas the long form (lfTSLP) is upregulated in inflammatory conditions. In addition, there is evidence that in pathological conditions, TSLP can be cleaved by several endogenous proteases. Several cellular targets for TSLP have been identified, including immune (DCs, ILC2, T and B cells, NKT and Treg cells, eosinophils, neutrophils, basophils, monocytes, mast cells, and macrophages) and non-immune cells (platelets and sensory neurons). TSLP has been originally implicated in a variety of allergic diseases (e.g., atopic dermatitis, bronchial asthma, eosinophilic esophagitis). Emerging evidence indicates that TSLP is also involved in chronic inflammatory (i.e., chronic obstructive pulmonary disease and celiac disease) and autoimmune (e.g., psoriasis, rheumatoid arthritis) disorders and several cancers. These emerging observations greatly widen the role of TSLP in different human diseases. Most of these studies have not used tools to analyze the expression of the two TSLP isoforms. The broad pathophysiologic profile of TSLP has motivated therapeutic targeting of this cytokine. Tezepelumab is a first-in-class human monoclonal antibody (1) that binds to TSLP inhibiting its interaction with TSLP receptor complex. Tezepelumab given as an add-on-therapy to patients with severe uncontrolled asthma has shown safety and efficacy. Several clinical trials are evaluating the safety and the efficacy of tezepelumab in different inflammatory disorders. Monoclonal antibodies used to neutralize TSLP should not interact or hamper the homeostatic effects of sf TSLP.

Chronic Diarrhea in Common Variable Immunodeficiency: a Case Series and Review of the Literature.

Common variable immunodeficiency (CVID) is a primary immunodeficiency characterized by reduced immunoglobulin serum levels and absent or impaired antibody production. Clinical manifestations, including infections, inflammatory and autoimmune diseases, and malignancies, also involve various segments of the gastrointestinal tract. Chronic diarrhea is one of the most common gastrointestinal symptoms and may cause a wide spectrum of potentially life-threatening conditions as malabsorption and protein-energy malnutrition. We describe three female CVID adult patients presenting with chronic diarrhea, weight loss, and protein-energy malnutrition due to different underlying conditions. Our review of the literature explores the various gastrointestinal involvements in CVID and points out several histopathological findings proper of the disease, thus highlighting the relevance of the endoscopic and histological assessment in CVID patients presenting with chronic diarrhea.

Immunoglobulin replacement therapy in primary and secondary antibody deficiency: The correct clinical approach.

Immunoglobulin therapy is the administration of human polyvalent IgG and represents the most effective treatment to prevent recurrent infections in antibody deficiency patients. Primary antibody deficiency represents the main indication of immunoglobulin replacement therapy and includes a wide range of disorders characterized by impaired antibody production in response to pathogens and recurrent infections. However, not all primary antibody deficiency patients require immunoglobulin replacement. Indeed, immunoglobulin preparations are expensive and, once prescribed, usually result in lifelong therapy. Moreover, many patients significantly benefit from a long-term antibiotic prophylaxis and a prompt begin of antibiotic therapy in case of infectious events. Even more controversial is the decision to initiate immunoglobulin replacement therapy in secondary antibody deficiency, a heterogeneous and expanding group including B-cell lymphoproliferative syndromes, protein losing states and therapeutic agents. This review seeks to define the indication to immunoglobulin replacement in primary and secondary antibody deficiency disorders, distinguishing those in which the beginning of immunoglobulin therapy is always indicated at the same time as the diagnosis has been made, from those lacking of defined indication to replacement therapy. In addition, we propose a clinical approach, mainly based on the evaluation of infectious history, vaccine response and bronchiectasis finding, to support the decision to initiate immunoglobulin therapy in an individual patient.

Delay in diagnosis affects the clinical outcome in a cohort of cvid patients with marked reduction of iga serum levels.

Common variable immunodeficiency disorders (CVID) represent a collection of diseases leading to an absent or strongly impaired antibody production. CVID presents a wide range of immunological abnormalities and clinical manifestations, including infections, inflammatory and autoimmune diseases, and malignancies. The aim of this observational study was to analyze the epidemiological and clinical features of a cohort of 75 Italian CVID patients, and evaluate the correlation with comorbidity and mortality. Clinical data were retrospectively collected: the cohort was followed-up for a maximum of 30years (mean time of 10.24years, median of 9years). An higher age at the diagnosis of CVID and an higher age at onset of symptoms were significantly associated with a reduction of patients survival if stratified per median of IgA (less than or >8.00mg/dl). Thus IgA levels at diagnosis are correlated with patients survival contributing to identify a subset with a worse prognostic outcome.

Heart failure not responsive to standard immunosuppressive therapy is successfully treated with high dose intravenous immunoglobulin therapy in a patient with Eosinophilic Granulomatosis with Polyangiitis (EGPA).

Glucocorticoids and immunosuppressive drugs represent the first-line treatment of eosinophilic granulomatosis with polyangiitis (EGPA, former Churg-Strauss syndrome), even though the combined therapy is not successful in achieving the disease remission in some patients with neurological or cardiac involvement. We describe a case of an EGPA male patient with impaired left ventricular function not responsive to glucocorticoid and immunosuppressive therapy. We observed that high-dose (2g/kg/4weeks) intravenous immunoglobulin (IVIG) therapy significantly improved cardiac function, which was deteriorated after reducing IVIG dose at 0.5g/kg/4weeks, and was restored increasing again IVIG dose to 2g/kg/4weeks. The finding highlights the relevance of IVIG as treatment of choice in EGPA patients with cardiac involvement not responsive to the standard glucocorticoid and immunosuppressive therapy. Moreover, at a follow-up of 24months, the continuance of high dose IVIG therapy was required to maintain a sustained remission of the heart failure.

Intravenous versus subcutaneous immunoglobulin replacement in secondary hypogammaglobulinemia.

In this study, we compared intravenous immunoglobulins (IVIG) and subcutaneous immunoglobulins (SCIG) in terms of serum IgG concentration and incidence of infections in patients with hypogammaglobulinemia secondary to chemo-immunotherapy regimens including the anti-CD20 monoclonal antibody rituximab. Fourteen patients with a B-cell lymphoproliferative disease treated for at least six months with a rituximab-including chemo-immunotherapy regimen were recruited. Mean serum levels of IgG were higher during replacement therapy than at the end of rituximab treatment (p<0.001). Moreover, serum IgG level was higher during replacement therapy with SCIG than with IVIG (p<0.001). No differences in the incidence of infections were observed. Although the non-randomized design and the small number of patients do not allow definitive conclusions to be drawn, study results suggest that higher mean serum IgG levels are reached when using the subcutaneous route after a switch from the intravenous regimen, and that IVIG and SCIG offer comparable protection against infections.

Omalizumab in patients with eosinophilic granulomatosis with polyangiitis: a 36-month follow-up study.

OBJECTIVE: Eosinophilic granulomatosis with polyangiitis (EGPA) is a systemic vasculitis characterized by asthma and blood eosinophilia, with the lung being the organ most frequently affected. Oral glucocorticoids and/or immunosuppressive drugs are the mainstay therapy of EGPA. Occasional reports suggest that EGPA patients can be treated with omalizumab in addition to conventional therapy to achieve asthma control. To investigate the long-term effects of omalizumab in patients with EGPA and asthma (2 females, 3 males, age 41-64 years), we carried out a 36-month follow-up observational study. At the time of enrollment, the patients were on maintenance therapy and had moderate to severe allergic asthma, eosinophilia and rhinosinusitis. Mononeuropathy/polyneuropathy and/or histological evidence of tissue eosinophilic infiltration were also present. METHODS: Patients were treated with omalizumab (300-600 mg s.c. every 2-4 weeks) as add-on therapy to prednisone, inhaled steroids and bronchodilators. During omalizumab treatment, spirometry, the asthma control test (ACT) score and eosinophilia were evaluated, and prednisone dosage was recorded. RESULTS: During the 36 months of omalizumab treatment asthma progressively improved as indicated by spirometry and the ACT score. Eosinophilia progressively decreased. The oral prednisone dose was reduced or withdrawn during treatment. No adverse events were recorded. CONCLUSIONS: In patients with EGPA and moderate to severe allergic asthma, omalizumab can be beneficial and safe. It enables corticosteroid tapering while decreasing eosinophilia and improving asthma symptoms over 36 months.

Angiogenesis and lymphangiogenesis in inflammatory skin disorders.

Angiogenesis, the growth of new blood vessels from pre-existing vessels, occurs physiologically in wound healing, during inflammatory diseases, and in tumor growth. Lymphangiogenesis can be activated in inflammation and tumor metastasis. The family of vascular endothelial growth factors (VEGFs) and angiopoietins are essential for angiogenesis and lymphangiogenesis. The angiogenic process is tightly regulated by VEGFs, angiopoietins, and endogenous inhibitors. VEGFs and angiopoietins exert their effects by activating specific receptors present on blood and lymphatic endothelial cells. There is now compelling evidence that cells of innate and adaptive immunity (macrophages, mast cells, neutrophils, eosinophils, lymphocytes) are a major source of angiogenic and lymphangiogenic factors. Chronic inflammatory skin diseases such as psoriasis and atopic dermatitis are characterized by altered angiogenesis, lymphangiogenesis, or both. Also such acute inflammatory skin disorders as urticaria, ultraviolet B-induced damage, and angioedema are associated with changes in angiogenic factors. In systemic sclerosis there is a switch from proangiogenic to antiangiogenic factors that play a role in the defective vascular process of this disorder. As yet, there are no clinical trials showing that canonical VEGF/VEGF receptor-targeted strategies can modulate inflammatory skin diseases. Novel strategies targeting other angiogenic/lymphangiogenic pathways should also be investigated.

Immunopharmacological modulation of mast cells.

Mast cells produce a wide spectrum of mediators and they have been implicated in several physiopathological conditions (e.g. allergic reactions and certain tumors). Pharmacologic agents that modulate the release of mediators from mast cells has helped to elucidate the biochemical mechanisms by which immunological and non-immunological stimuli activate these cells. Furthermore, the study of surface receptors and signaling pathways associated with mast cell activation revealed novel pharmacologic targets. Thus, the development of pharmacologic agents based on this new wave of knowledge holds promise for the treatment of several mast cell-mediated disorders.

Basophils: historical reflections and perspectives.

Basophils were discovered by Paul Ehrlich in 1879 and account for less than 1% of blood leukocytes, which suggests a tightly controlled regulation of basopoiesis. The conservation of basophils in a wide spectrum of the animal kingdom suggests a non-redundant role in innate and adaptive immunity. In the early 1990s, it was demonstrated that murine and human basophils synthesize interleukin (IL)-4 and IL-13, thereby suggesting that these cells are important for Th2 polarization and IgE synthesis. Human basophils also synthesize IL-3, VEGFs and other pro-angiogenic molecules. Recently, various groups have introduced the use of basophil-depleting antibodies or have developed transgenic mice that constitutively lack basophils by more than 90%. These models have highlighted previously unrecognized roles of basophils, distinct from those played by mast cells, in innate and adaptive immunity. Although the physiologic role of basophils remains unknown, there is now compelling evidence that basophils, despite their small numbers in peripheral blood and inflamed tissues, are critically involved in a wide spectrum of immunologic disorders (allergic, autoimmune and infectious diseases, immunodeficiencies and cancer). It is not inconceivable that basophils and/or their products could be promising therapeutic targets for such disorders.

Immune cells as a source and target of angiogenic and lymphangiogenic factors.

Angiogenesis and lymphangiogenesis are distinct and complex processes requiring a finely tuned balance between stimulatory and inhibitory signals. Immune and inflammatory cells can contribute to these processes by multiple mechanisms: directly by producing a broad array of angiogenic growth factors, and indirectly by secreting several cytokines, chemokines and other mediators able to coordinate the cell-cell interactions. Immune cells can stimulate or inhibit angiogenesis/lymphangiogenesis, depending on their activation status and subset specificity. We summarize recent findings reporting the expression and activity of angiogenic and lymphangiogenic factors and their receptors and coreceptors in immune cells. It is evident that modulation of angiogenesis and lymphangiogenesis by the innate and adaptive immune cells (mast cells, macrophages, dendritic cells, basophils, eosinophils, and some subsets of T cells) is a highly complex process not yet completely understood.

Human heart as a shock organ in anaphylaxis.

Anaphylaxis is a potentially fatal, immediate hypersensitivity reaction. Mast cells and basophils, by elaborating vasoactive mediators and cytokines, are the main primary effector cells of anaphylaxis. Mast cells have been identified in human heart between myocardial fibers, perivascularly, in the adventitia, and in the arterial intima. Mast cells isolated from human heart tissue (HHMC) of patients undergoing cardiac transplantation express high affinity immunglobulin E (IgE) receptors (FcεRI), C3a, C5a, and kit receptors (KIT). Anti-IgE, anti-FcεRI, and immunoglobulin superallergens induce in vitro secretion of preformed mediators (histamine, tryptase, chymase, and renin) and the de novo synthesis of cysteinyl leukotriene C4 (LTC4) and prostaglandin D2 (PGD2) from HHMC. Complement is activated and anaphylatoxin forms during anaphylaxis. C5a and C3a cause the in vitro release of histamine and tryptase from HHMC. Therapeutic (general anesthetics, protamine, etc.) and diagnostic agents (radio contrast media, etc.), which can cause anaphylactoid reactions, activate HHMC in vitro. Low concentrations of histamine and cysteinyl leukotrienes given to subjects undergoing diagnostic catheterisation caused significant systemic and coronary hemodynamic effects. These data indicate that human heart mast cells and their mediators play a role in severe anaphylactic reactions.

Proteomic analysis of sera from common variable immunodeficiency patients undergoing replacement intravenous immunoglobulin therapy.

Common variable immunodeficiency is the most common form of symptomatic primary antibody failure in adults and children. Replacement immunoglobulin is the standard treatment of these patients. By using a differential proteomic approach based on 2D-DIGE, we examined serum samples from normal donors and from matched, naive, and immunoglobulin-treated patients. The results highlighted regulated expression of serum proteins in naive patients. Among the identified proteins, clusterin/ApoJ serum levels were lower in naive patients, compared to normal subjects. This finding was validated in a wider collection of samples from newly enrolled patients. The establishment of a cellular system, based on a human hepatocyte cell line HuH7, allowed to ascertain a potential role in the regulation of CLU gene expression by immunoglobulins.

Human cardiac mast cells in anaphylaxis.

Human heart mast cells (HHMC), by elaborating vasoactive mediators, cytokines and chemokines, are the main primary effector cells of anaphylaxis. Mast cells have been identified perivascularly, close to myocytes and in the arterial intima in human heart tissue. Mast cells isolated from human heart tissue (HHMC) of patients undergoing cardiac transplantation express high-affinity receptors for IgE (FcepsilonRI) and C5a receptors. Activation of HHMC in vitro with anti-IgE or anti-FcepsilonRI induced the release of preformed mediators (histamine, tryptase, chymase, and renin) and the de novo synthesis of LTC(4) (approximately =18 ng/l0(6) cells) and PGD(2) (approximately =18 ng/l0(6) cells). Complement is activated and anaphylatoxin forms during anaphylaxis. C5a causes rapid release of histamine and tryptase from HHMC. These cells are activated in vitro by therapeutic (general anesthetics, protamine, etc.) and diagnostic agents (radiocontrast media, etc.) which can cause anaphylactoid reactions. Low concentrations of histamine and cysteinyl leukotrienes given to subjects undergoing diagnostic catheterization caused significant systemic and coronary hemodynamic effects. These results indicate that HHMC probably have a role in anaphylactic reactions.