In vivo modulation of the expressions of Fas and CD25 by intravenous immunoglobulin in common variable immunodeficiency

Responsiveness to i.v. immunoglobulin therapy in patients with toxic epidermal necrolysis: A novel pharmaco-immunogenetic concept

Toxic epidermal necrolysis (TEN) represents a rare drug-induced autoimmune reaction with delayed-type hypersensitivity that initiates the process of developing massive keratinocyte apoptosis, dominantly in the dermoepidermal junction. Although the etiopathophysiology has not yet been fully elucidated, the binding of Fas ligand (FasL, CD95L) to the Fas receptor (CD95) was shown to play a key role in the induction of apoptosis in this syndrome. The knowledge of the role of immunoglobulin G (IgG) in inhibition of Fas-mediated apoptosis contributed to the introduction of i.v. Ig (IVIg) in the therapy of TEN patients. Despite great enthusiasm for this therapy at the end of the 1990s, subsequent studies in various populations and meta-analyses could not unequivocally confirm the efficacy of the IVIg-based treatment concept. Today, therefore, we are faced with the dilemmas of how to adjust therapy of TEN patients most effectively, which patients could benefit from IVIg therapy and what dose of the preparation should be administrated. The ground-breaking question is: do the host genetic profiles influence the responsiveness and side-effects of IVIg therapy in TEN patients? Based on recent pharmacological, immunological and genetic findings, we suggest that the variability of IVIg therapy outcomes in TEN patients may be related to functional variants in Fas, FasL and Fc-γ receptor genes. This novel concept could lead to improved quality of care for patients with TEN, facilitating personalized therapy to reduce mortality.

Long-term efficacy, safety, and tolerability of recombinant human hyaluronidase-facilitated subcutaneous infusion of immunoglobulin (Ig) (fSCIG; HyQvia(®)) in immunodeficiency diseases: real-life data from a monocentric experience

Humoral immunodeficiency diseases represent a heterogeneous group of disorders that require long-term therapies. Thus, the treatment provided must not only be effective but also safe and well tolerated. In this paper, we report our data on the efficacy, safety, and tolerability of recombinant human hyaluronidase-facilitated subcutaneous infusion of immunoglobulin (Ig) (fSCIG; HyQvia(^®)) in immunodeficiency patients. We collected retrospective data from 30 patients with primary and secondary immunodeficiency diseases in therapy with fSCIG from September 2014 to December 2019. We evaluated the efficacy of the therapy, taking into account serum IgG values during follow-up and the number of annual infectious events and serious bacterial infections reported by patients. Safety was assessed on the basis of the number and intensity of adverse events (AEs) and local reactions reported. Our real-life data suggest that long-term repeated self-administration of recombinant human hyaluronidase-facilitated subcutaneous infusion of immunoglobulins results in a reduced rate of infectious events if compared to the pre-treatment rate. Both AEs and local reactions are mild to moderate and were never reasons for treatment discontinuation. Therapy with HyQvia shows prolonged efficacy and good tolerability; these aspects, together with the possibility of self-administration at home, minimize the impact the illness has on patients.

Intravenous immunoglobulin replacement treatment does not alter polymorphonuclear leukocytes function and surface receptors expression in patients with common variable immunodeficiency

The study of the expression of CD16, CD11b and Siglec 9 receptors and the oxidative burst provides insights on polymorphonuclear leukocytes (PMN) functionality in common variable immunodeficiency (CVID) and on the possible effects of intravenous immunoglobulin (IVIg) infusion. We evaluated in vivo before and soon after IVIg administration the CD16, CD11b and Siglec 9 expression on unstimulated and Escherichia coli-stimulated PMN and the oxidative burst induced by Escherichia coli and PMA. The E. coli stimulation up-regulated CD16 and Siglec 9 expression and it induced a strong CD11b up-regulation at baseline and soon after IVIg. The oxidative burst overlapped that observed in healthy donors when induced by Escherichia coli while it increased when induced by PMA. Soon after IVIg infusion, the oxidative burst decreased only when induced by PMA. Our results showed that the IVIg infusion in vivo had a minimal effect on CVID's PMN.

Application of whole genome and RNA sequencing to investigate the genomic landscape of common variable immunodeficiency disorders

Common Variable Immunodeficiency Disorders (CVIDs) are the most prevalent cause of primary antibody failure. CVIDs are highly variable and a genetic causes have been identified in <5% of patients. Here, we performed whole genome sequencing (WGS) of 34 CVID patients (94% sporadic) and combined them with transcriptomic profiling (RNA-sequencing of B cells) from three patients and three healthy controls. We identified variants in CVID disease genes TNFRSF13B, TNFRSF13C, LRBA and NLRP12 and enrichment of variants in known and novel disease pathways. The pathways identified include B-cell receptor signalling, non-homologous end-joining, regulation of apoptosis, T cell regulation and ICOS signalling. Our data confirm the polygenic nature of CVID and suggest individual-specific aetiologies in many cases. Together our data show that WGS in combination with RNA-sequencing allows for a better understanding of CVIDs and the identification of novel disease associated pathways.

Mechanisms of action of Ig preparations: immunomodulatory and anti-inflammatory effects

Primary immunodeficiency (PID) disorders that predispose patients to recurrent infections require immunoglobulin (Ig) replacement therapy. Ig replacement therapy has been stated as beneficial, although the optimal IgG trough level to be maintained over time in order to minimize infectious risk has not been established. The most common route of administration of Ig has been intravenously, although there are different options, one of them being the subcutaneous route. Ig replacement therapy has been a life-saving treatment for patients suffering from primary and secondary antibody immunodeficiency. The key role of regular Ig replacement in patients with antibody deficiencies is related to the ability to provide specific antibodies that could not be produced by these patients as demonstrated by the reduction of severe infections such as meningitis and pneumonia. The therapeutic benefits of Ig may also be due to an active role in various anti-inflammatory and immunomodulatory activities, which may complicate the clinical picture of PID. Anti-inflammatory activities are seen more generally when intravenous Ig is administered at high dose. The immunomodulatory and anti-inflammatory activities are important not only in the treatment of autoimmune diseases but also in patients suffering from immunodeficiency.

Impact of intravenous immunoglobulin on the dopaminergic system and immune response in the acute MPTP mouse model of Parkinson's disease

Intravenous immunoglobulin (IVIg) is a blood-derived product, used for the treatment of immunodeficiency and autoimmune diseases. Since a range of immunotherapies have recently been proposed as a therapeutic strategy for Parkinson’s disease (PD), we investigated the effects of an IVIg treatment in a neurotoxin-induced animal model of PD. Mice received four injections of MPTP (15 mg/kg) at 2-hour intervals followed by a 14-day IVIg treatment, which induced key immune-related changes such as increased regulatory T-cell population and decreased CD4⁺/CD8⁺ ratio. The MPTP treatment induced significant 80% and 84% decreases of striatal dopamine concentrations (P < 0.01), as well as 33% and 40% reductions in the number of nigral dopaminergic neurons (P < 0.001) in controls and IVIg-treated mice, respectively. Two-way analyses of variance further revealed lower striatal tyrosine hydroxylase protein levels, striatal homovanillic acid concentrations and nigral dopaminergic neurons (P < 0.05) in IVIg-treated animals. Collectively, our results fail to support a neurorestorative effect of IVIg on the nigrostriatal system in the MPTP-treated mice and even suggest a trend toward a detrimental effect of IVIg on the dopaminergic system. These preclinical data underscore the need to proceed with caution before initiating clinical trials of IVIg in PD patients.

Pediatric allergy and immunology in Turkey

Allergic diseases constitute a significant health problem in Turkey. According to a recent multicenter study, which used the ISAAC questionnaire, the mean prevalence of wheezing, rhinoconjunctivitis, and eczema in 10-yr-old school children during the past year was 15.8%, 23.5%, and 8.1%, respectively. A healthcare level system, regulated by Ministry of Health, is available in Turkey. Pediatric allergists and pediatric immunologists provide patient care at the tertiary level. Currently, 48 centers deliver care for allergic and immunologic diseases in children. There are 136 pediatric and 61 adult allergists/immunologists. Although the number of allergy/clinical immunology specialists is limited, these centers are capable of delivering many of the procedures required for the proper management and diagnosis of allergy/immunology. Pediatric allergy and/or immunology is a subspecialty lasting 3 yr and follows a 4-yr pediatric specialist training. Fellow training involves gaining knowledge in basic and clinical allergy and immunology as well as the performance and interpretation of laboratory procedures in the field of allergy and clinical immunology. The Turkish National Society of Allergy and Clinical Immunology (TNSACI) was officially established in 1989 and currently has 356 members. The society organizes a national congress annually and winter schools for fellowship training as well as training courses for patients and their relatives. TNSACI also has a strong representation in European Academy of Allergy and Clinical Immunology (EAACI) and European Society for Immunodeficiencies (ESID) through its participation in the executive committee, consensus reports, and initiatives in the diagnosis of allergic and immunologic diseases of children. The 30th Congress of the EAACI is also due to be held in Istanbul, Turkey, between June 11 and 15, 2011.

Intravenous immunoglobulins in immunodeficiencies: more than mere replacement therapy

Intravenous immunoglobulin (IVIG) is a therapeutic compound prepared from pools of plasma obtained from several thousand healthy blood donors. For more than 20 years, IVIG has been used in the treatment of a wide range of primary and secondary immunodeficiencies. IVIG now represents a standard therapeutic option for most antibody deficiencies. Routinely, IVIG is used in patients with X-linked agammaglobulinaemia (XLA), common variable immunodeficiency (CVID), X-linked hyper-IgM, severe combined immunodeficiency, Wiskott-Aldrich syndrome, and selective IgG class deficiency. In addition, IVIG is used extensively in the treatment of a wide variety of autoimmune disorders. IVIG is administered at distinct doses in the two clinical settings: whereas immunodeficient patients are treated with replacement levels of IVIG, patients with autoimmune and inflammatory diseases are administered with very high doses of IVIG. Several lines of experimental evidence gathered in the recent years suggest that the therapeutic beneficial effect of IVIG in immunodeficiencies reflects an active role for IVIG, rather than a mere passive transfer of antibodies.

Intravenous immunoglobulin induces proliferation and immunoglobulin synthesis from B cells of patients with common variable immunodeficiency: a mechanism underlying the beneficial effect of IVIg in primary immunodeficiencies

Common variable immunodeficiency (CVID) is associated with low serum immunoglobulin concentrations and an increased susceptibility to infections and autoimmune diseases. The treatment of choice for CVID patients is replacement intravenous immunoglobulin (IVIg) therapy. IVIg has been beneficial in preventing or alleviating the severity of infections and autoimmune and inflammatory process in majority of CVID patients. Although the mechanisms of action of IVIg given as 'therapeutic high dose' in patients with autoimmune diseases are well studied, the underlying mechanisms of beneficial effects of IVIg in primary immunodeficiencies are not completely understood. Therefore we investigated the effect of 'replacement dose' of IVIg by probing its action on B cells from CVID patients. We demonstrate that IVIg at low doses induces proliferation and immunoglobulin synthesis from B cells of CVID patients. Interestingly, B cell stimulation by IVIg is not associated with induction of B cell effector cytokine IFN-γ and of transcription factor T-bet. Together, our results indicate that in some CVID patients, IVIg rectifies the defective signaling of B cells normally provided by T cells and delivers T-independent signaling for B cells to proliferate. IVIg 'replacement therapy' in primary immunodeficiencies is therefore not a merepassive transfer of antibodies to prevent exclusively the recurrent infections; rather it has an active role in regulating autoimmune and inflammatory responses through modulating B cell functions and thus imposing dynamic equilibrium of the immune system.

Autoimmunity in common variable immunodeficiency: correlation with lymphocyte phenotype in the French DEFI study

Common variable immunodeficiency (CVID) is the most frequent clinically expressed primary immunodeficiency in adults and is characterized by primary defective immunoglobulin production. Besides recurrent infectious manifestations, up to 20% of CVID patients develop autoimmune complications. In this study, we took advantages of the French DEFI database to investigate possible correlations between peripheral lymphocyte subpopulations and autoimmune clinical expression in CVID adult patients. In order to analyse homogeneous populations of patients with precise clinical phenotypes, we first focused on patients with autoimmune cytopenia because they represent prototypic autoantibody mediated diseases. In a secondary analysis, we have tested our conclusions including all "autoimmune" CVID patients. We describe one of the largest European studies with 311 CVID patients, including 55 patients with autoimmune cytopenia and 61 patients with clinical or serologic autoimmune expression, excluding autoimmune cytopenia. We clarify previous reports and we confirm a very significant correlation between an increased proportion of CD21(low) B cells and CVID associated autoimmune cytopenia, but independently of the presence of other autoimmune disorders or of splenomegaly. Moreover, in CVID associated autoimmune cytopenia, T cells display an activated phenotype with an increase of HLA-DR and CD95 expression and a decrease in the naïve T cell numbers. Patients with other autoimmune manifestations do not harbour this "T and B cells phenotypic picture". In view of recent findings on CD21(low) B cells in CVID and RA, we suggest that both a restricted subset of B cells and a T cell help are required for a breakdown of B cell tolerance against membrane auto antigens in CVID.