Is dosing of therapeutic immunoglobulins optimal? A review of a three-decade long debate in europe

Shortage of plasma-derived medicinal products: what is next? narrative literature review on its causes and counteracting policies in Italy

Introduction: This paper describes the peculiarities of the plasma-derived medicinal product (PDMP) market and illustrates the results of a review of the literature on policies aimed at counteracting the shortage of PDMPs. Characteristics of PDMPs: Plasma is primarily used for the industrial production of blood products (80%). The demand for PDMPs, particularly immunoglobulins (IGs), is increasing. However, the production of PDMPs is complex, long (7-12 months), and expensive, accounting, according to US estimates, for 57% of the total costs of PDMPs compared to 14% for small molecules. PDMP market: Unexpected increases in clinical need cannot be addressed in the short term. Once the demand for some diseases is satisfied, the collection and fractionation of plasma will only be used to supply some specific patients. Hence, the full weight of the marginal costs, which remain constant, are borne by a few products. According to last liter economics, the industry stops producing when the marginal revenue equals the marginal cost, thereby reducing the convenience of producing the most commonly used PDMPs (albumin and IG). The imbalance between the demand and supply of PDMPs was exacerbated by the COVID-19 pandemic, which further increased the cost of plasma collection. Shortage issue and possible solutions: Policies to counteract this imbalance have also been discussed. If the demand is inappropriate, it should be reduced. If the demand is appropriate and supply cannot be increased, the demand should be prioritized for patients for whom PDMPs are the only available treatment. If the shortage depends on insufficient supply and technical and allocative efficiency, both production and supply should be improved, together with incentives for all stakeholders involved in the PDMP market to increase the sustainability of production/supply. The paper is focused on this second issue, that is supply-driven unbalance.

Intravenous immunoglobulin prophylaxis is associated with decreased rate of infection-related hospitalizations in multiple myeloma patients

This study explored the efficacy of intravenous immunoglobulin (IVIG) prophylaxis in reducing infection-related hospitalizations (IRHs) in MM patients. This was a retrospective study of MM patients who received IVIG at Taussig Cancer Center between July 2009 and July 2021. The primary endpoint was rate of IRHs per patient-year on-IVIG versus off-IVIG. 108 patients were included. There was a significant difference in the primary endpoint of rate of IRHs per patient-year on-IVIG versus off-IVIG in the overall study population (0.81 vs. 1.08; Mean Difference [MD], -0.27; 95% Confidence Interval [CI], -0.57 to 0.03; p value [P] = 0.04). The subgroup of patients with a 1-year period of continuous IVIG (49, 45.3%), the subgroup with standard-risk cytogenetics (54, 50.0%) and the subgroup with 2 or more IRHs (67, 62.0%) all showed a significant reduction in IRHs while on-IVIG versus off-IVIG (0.48 vs. 0.78; MD, -0.30; 95% CI, -0.59 to 0.002; p = 0.03) and (0.65 vs. 1.01; MD, -0.36; 95% CI, -0.71 to -0.01; p = 0.02) and (1.04 vs. 1.43; MD, -0.39; 95% CI, -0.82 to 0.05; p = 0.04) respectively. IVIG showed significant benefit in reducing IRHs in the overall population and in multiple subgroups.

Efficacy of intravenous immunoglobulin (IVIg) on COVID-19-related neurological disorders over the last 2 years: an up-to-date narrative review

Introduction

Among the clinical manifestations of SARS-CoV-2 infection, neurological features have been commonly reported and the state-of-the-art technique suggests several mechanisms of action providing a pathophysiological rationale for central and peripheral neurological system involvement. However, during the 1st months of the pandemic, clinicians were challenged to find the best therapeutic options to treat COVID-19-related neurological conditions.

Methods

We explored the indexed medical literature in order to answer the question of whether IVIg could be included as a valid weapon in the therapeutic arsenal against COVID-19-induced neurological disorders.

Results

Virtually, all reviewed studies were in agreement of detecting an acceptable to great efficacy upon IVIg employment in neurological diseases, with no or mild adverse effects. In the first part of this narrative review, the interaction of SARS-CoV-2 with the nervous system has been discussed and the IVIg mechanisms of action were reviewed. In the second part, we collected scientific literature data over the last 2 years to discuss the use of IVIg therapy in different neuro-COVID conditions, thus providing a summary of the treatment strategies and key findings.

Discussion

Intravenous immunoglobulin (IVIg) therapy is a versatile tool with multiple molecular targets and mechanisms of action that might respond to some of the suggested effects of infection through inflammatory and autoimmune responses. As such, IVIg therapy has been used in several COVID-19-related neurological diseases, including polyneuropathies, encephalitis, and status epilepticus, and results have often shown improvement of symptoms, thus suggesting IVIg treatment to be safe and effective.

Pharmacokinetics of antibodies during pregnancy: General pharmacokinetics and pregnancy related physiological changes (Part 1)

Pharmacokinetics (PK) studies are important to determine a safe and effective dose of both small and large molecule drugs. Intrinsic factors such as pregnancy can substantially alter the PK of a drug. Several PK studies have been published for small molecules administered during pregnancy, but such investigations are scarce for macromolecules including monoclonal and polyclonal antibodies. In this part 1 of 2 reviews, we first provide a general description of macromolecule drugs, the PK differences with small molecules, and current knowledge on their absorption, distribution, metabolism and elimination in non-pregnant subjects. We then review in detail the physiological changes during pregnancy. While some of the physiologic adaptions of pregnancy, for example increased plasma volume and cardiac output, are expected to impact PK of antibody therapeutics, the effects of others, such as increased GFR and altered immune responses are not fully understood. We conclude that further investigations are needed to fully elucidate how pregnancy can impact PK properties of macromolecules.

Relationship between Body Composition and Serum Immunoglobulin Concentrations after Administration of Intravenous Immune Globulin-Preclinical and Clinical Evidence

The purpose of this study was to investigate the effect of obesity on immunoglobulin G (IgG) pharmacokinetics in a rat model of obesity, and to collect clinical evidence for an association between the body composition and intravenous immune globulin (IVIG) pharmacokinetic parameters in humans. In a preclinical study, pharmacokinetics of human IgG was evaluated after intravenous (IV) and subcutaneous (SC) delivery to obese and lean rats (n = 6 in each group). Serial serum samples were analyzed using an ELISA. The animal body composition was assessed using computer tomography. Patients with primary immunodeficiency currently managed with IVIG, and at a steady state, were enrolled in the clinical study (n = 8). Serum immune globulin (Ig) concentrations were measured at baseline and immediately after the administration of two consecutive treatments, with an additional measurement at two weeks after the first administration. In addition to the patient demographic and clinical characteristics, body composition was measured using bioelectrical impedance analysis. The pharmacokinetics of human IgG was significantly different between the obese and lean rats after both the IV and SC administration of 0.5 g/kg. Furthermore, a significant difference in endogenous rat IgG was observed between the two strains. In the human study, total serum IgG and subtype (IgG1, IgG2, IgG3, IgG4) half-life negatively correlated with the body mass index and fat mass. The mean change in the total serum IgG concentration was significantly correlated to body mass index and fat mass. The results of the studies corroborated one another. In the animal study, most pharmacokinetic parameters of human IgG following IV and SC administration were significantly affected by obesity and changes in the body composition. In the clinical study, the mean serum IgG change after the IVIG administration strongly correlated to the BMI and body fat mass. Future studies are needed to establish the outcomes achieved with more frequent dosing in obese individuals with primary immunodeficiency.

Low rates of headache and migraine associated with intravenous immunoglobulin infusion using a 15-minute rate escalation protocol in 123 patients with primary immunodeficiency

Introduction

Headache and migraine adverse events are common concerns in the administration of intravenous immune globulins (IVIG). Trials of IVIG for primary immunodeficiency (PI) are typically small and have reported headache and migraine data inconsistently.

Methods

We analyzed headache and migraine in pooled data from three pivotal trials of Gammaplex® 5% and 10% in PI (NCT00278954 from January 18, 2006; NCT01289847 from January 27, 2011; NCT01963143 from September 13, 2013). The trials were pooled in a retrospective analysis that included two 12-month open-label non-comparative trials of the 5% IVIG product and one 6-month open-label crossover bioequivalence trial comparing the 5% IVIG and 10% IVIG products. The population included adult and pediatric patients, who received IVIG infusions of 300-800 mg/kg/infusion every 21 or 28 days using a 15-minute rate escalation protocol.

Results

In total, 1482 infusions were administered to 123 patients, with 94.6% of infusions achieving the maximum infusion rate. At least one product-related headache was reported in 6.1% (90/1482) of infusions. At least one product-related migraine was reported in 0.5% (7/1482) of infusions. Headache rates were higher for adults vs pediatric patients, females vs males, and 21-day vs 28-day dosing schedules, but were similar for the 5% and 10% IVIG products. Most headaches and migraines occurred during or within 72 hours of the infusion. Rates decreased after the first few infusions.

Discussion

Patients receiving this IVIG product on a 15-minute rate escalation protocol had low rates of headache and migraine for both the 5% and 10% formulations.

Using a scenario approach to assess for the current and future demand of immunoglobulins: An interview and literature study from The Netherlands

OBJECTIVES

To explore the current and future demand of immunoglobulins globally and specifically for the Netherlands by assessing: (I) which specialties contribute to current demand, (II) new areas of medical need, (III) which transformational factors may impact demand and to what effect, by using a scenario approach.

BACKGROUND

As immunoglobulin demand continues to increase globally, there is concern of increasing shortages and questions of whether and how future demand will continue based on medical need.

METHODS/MATERIALS

In line with scenario principles, a scoping review of Pubmed, Web of Science, Embase and Cochrane and grey literature was conducted. Semi-structured interviews with subject matter experts were held. The results of the review and interviews were analysed for major themes.

RESULTS

The scoping review resulted in 97 articles, 74 regarding clinical uses, and 23 regarding organisational and other themes. Fifteen clinical and non-clinical experts were interviewed. I) Neurology, immunology, and haematology were specialties that contribute most to current demand. II) Regarding potential new areas of medical need, the literature review resulted in more indications than the interviews, for example, post-renal transplants. III) Four groups of key transformational factors were found: factors that could increase immunoglobulin demand (e.g., EMA revisions), decrease demand (e.g., replacement products, Dutch Transfer Act 2021), factors that remain to be seen how it impacts demand (e.g., further evidence), and miscellaneous factors (e.g., supply-related).

CONCLUSION

Having identified the specialties and relevant transformational factors that affect immunoglobulin demand, more research is needed on what clinical or organisational strategies would be effective in controlling demand in general for the Netherlands and abroad. Other blood establishments may also use a scenario approach to increase preparedness for future (un)expected developments.

Population Pharmacokinetic Modelling of Intravenous Immunoglobulin Treatment in Patients with Guillain-Barré Syndrome

Background and Objective

Intravenous immunoglobulin (IVIg) at a standard dosage is the treatment of choice for Guillain–Barré syndrome. The pharmacokinetics, however, is highly variable between patients, and a rapid clearance of IVIg is associated with poor recovery. We aimed to develop a model to predict the pharmacokinetics of a standard 5-day IVIg course (0.4 g/kg/day) in patients with Guillain–Barré syndrome.

Methods

Non-linear mixed-effects modelling software (NONMEM^®) was used to construct a pharmacokinetic model based on a model-building cohort of 177 patients with Guillain–Barré syndrome, with a total of 589 sequential serum samples tested for total immunoglobulin G (IgG) levels, and evaluated on an independent validation cohort that consisted of 177 patients with Guillain–Barré syndrome with 689 sequential serum samples.

Results

The final two-compartment model accurately described the daily increment in serum IgG levels during a standard IVIg course; the initial rapid fall and then a gradual decline to steady-state levels thereafter. The covariates that increased IgG clearance were a more severe disease (as indicated by the Guillain–Barré syndrome disability score) and concomitant methylprednisolone treatment. When the current dosing regimen was simulated, the percentage of patients who reached a target ∆IgG > 7.3 g/L at 2 weeks decreased from 74% in mildly affected patients to only 33% in the most severely affected and mechanically ventilated patients (Guillain–Barré syndrome disability score of 5).

Conclusions

This is the first population-pharmacokinetic model for standard IVIg treatment in Guillain–Barré syndrome. The model provides a new tool to predict the pharmacokinetics of alternative regimens of IVIg in Guillain–Barré syndrome to design future trials and personalise treatment.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40262-022-01136-z.

Immunomodulation mediated by polyclonal IgG replacement in patients with CLL may be important in infection prevention

We read with interest the article by Idanna Innocenti and colleagues where a fixed dose of 10g hyaluronidase-free SCIg (subcutaneous immunoglobulin IgG) was administered every two weeks for one year to 10 patients with chronic lymphocytic leukaemia (CLL) and was highly effective in preventing infections [1]. It is generally accepted that frequency of infusions with hyaluronidase-free SCIg preparations are once weekly to maintain 'adequate' trough IgG [2], but this has been extrapolated from use in primary immunodeficient patients who typically have a complete antibody deficiency in contrast to the deficit observed in CLL This article is protected by copyright. All rights reserved.

Cost-minimization analysis of immunoglobulin treatment of primary immunodeficiency diseases in Spain

Primary immunodeficiency diseases (PID), which are comprised of over 400 genetic disorders, occur when a component of the immune system is diminished or dysfunctional. Patients with PID who require immunoglobulin (IG) replacement therapy receive intravenous IG (IVIG) or subcutaneous IG (SCIG), each of which provides equivalent efficacy. We developed a cost-minimization model to evaluate costs of IVIG versus SCIG from the Spanish National Healthcare System perspective. The base case modeled the annual cost per patient of IVIG and SCIG for the mean doses (per current expert clinical practice) over 1 year in terms of direct (drug and administration) and indirect (lost productivity for adults and parents/guardians of pediatric patients) costs. It was assumed that all IVIG infusions were administered in a day hospital, and 95% of SCIG infusions were administered at home. Drug costs were calculated from ex-factory prices obtained from local databases minus the mandatory deduction. Costs were valued on 2018 euros. The annual modeled costs were €4,266 lower for patients with PID who received SCIG (total €14,466) compared with those who received IVIG (total €18,732). The two largest contributors were differences in annual IG costs as a function of dosage (- €1,927) and hospital administration costs (- €2,688). However, SCIG incurred training costs for home administration (€695). Sensitivity analyses for two dose-rounding scenarios were consistent with the base case. Our model suggests that SCIG may be a cost-saving alternative to IVIG for patients with PID in Spain.

Replacement and Immunomodulatory Activities of 20% Subcutaneous Immunoglobulin Treatment: A Single-Center Retrospective Study in Autoimmune Myositis and CVID Patients

Background

Immunoglobulin (Ig) replacement therapy represents a life-saving treatment in primary antibody deficiencies. The introduction of subcutaneous Ig (SCIg) administration brings a major improvement in quality of life for patients, compared to the traditional intravenous administration. In recent years, an additional role has been proposed for Ig therapy for various inflammatory and immune-mediated diseases. Consequently, the use of SCIg has expanded from immunodeficiencies to immune-mediated diseases, such as polymyositis (PM) and dermatomyositis (DM). Given the rarity of these conditions, it is still difficult to evaluate the real impact of SCIg treatment on PM and DM, and additional data are constantly required on this topic, particularly for long-term treatments in real-life settings.

Aim

This study aimed to increase the knowledge about the anti-inflammatory and immunomodulatory effects of SCIg treatment for myositis. To this aim, a long-term evaluation of the effectiveness of 20% human SCIg treatment (20% SCIg, Hizentra^®, CSL Behring) was carried out in patients with PM/DM in care at our Center. In addition, an evaluation of the 20% SCIg therapy in CVID patients was provided. This analysis, beside adding knowledge about the use of SCIg therapy in this real-life setting, was intended as a term of comparison, regarding the safety profile.

Results

Results support the beneficial effect and tolerability of long-term 20% SCIg therapy in PM/DM patients, reporting a significant improvement in creatine kinase levels, muscle strength, skin conditions, dysphagia, disease activity (MITAX score) and disability (HAQ-DI score). None of the patients reported systemic reactions. The duration of the reported local reactions was a few hours in 80% of the patients, and all resolved spontaneously. CVID patients reported an improvement in all the considered effectiveness parameters at the end of 20% SCIg therapy. The frequency of the adverse events reported by PM/DM patients was not different from what reported in CVID patients, where the use of SCIg therapy is more consolidated

Conclusions

This study suggests that 20% SCIg treatment represents a viable and safe treatment for PM/DM patients and a valid therapeutic alternative to IVIg, with important advantages for patients’ quality of life.

Immunoglobulin shortage: Practice modifications and clinical outcomes in a reference centre

BACKGROUND

Growing numbers of indications for intravenous immunoglobulins (IVIg) in recent years has resulted in an increase in the consumption of these products. A lack of raw material has led to IVIg shortage. The objective of this work was to evaluate the impact of this situation on patient care in one French referral centre considering practice modifications and clinical impact.

METHODS

All patients treated with IVIg for chronic inflammatory demyelinating polyneuropathy, multifocal motor neuropathy and myasthenia gravis from October 2017 to October 2018 were included.

RESULTS

Out of 142 patients, 111 (78%) had a modification of their IVIg treatment. We noted that 75 (68%) patients had a delay in IVIg treatment, 41 (37%) patients had a decrease in IVIg doses and 31 (28%) experienced IVIg treatment interruption. Thirty percent of patients for whom IVIg treatment was discontinued were switched to other treatments mainly plasma exchange (16%) or corticosteroids (13%). Switches to plasma exchange or corticosteroids were carried out in order to save immunoglobulins for patients who had no other alternatives. Fifty-eight (52%) patients presented a deterioration of their clinical score after IVIg treatment changes including 31 (28%) patients who had a moderate or a clinically significant deterioration. Concerning practice modifications, we noted a substantial though not significant decrease in median IVIg dose for myasthenia gravis and a significant increase in the delay between IVIg courses for chronic inflammatory demyelinating polyneuropathy and multifocal motor neuropathy (P=0.011 and P=0.018 respectively).

CONCLUSION

Our study showed a rather important number of changes in IVIg treatment related to IVIg shortage during the period considered. These changes had a negative impact on the clinical status of some patients.

Stimulatory Effect of CMV Immunoglobulin on Innate Immunity and on the Immunogenicity of CMV Antigens

Background.

Cytomegalovirus (CMV) immunoglobulin (CMVIG) is used for the prophylaxis of CMV infection after transplantation. Beyond providing passive CMV-specific immunity, CMVIG exerts enhancing and suppressive immunomodulatory functions. Although the anti-inflammatory activities of CMVIG have been extensively documented, its immunostimulatory activities remain poorly characterized.

Methods.

This exploratory study analyzed the capacity of CMVIG to modulate cell-mediated innate and adaptive immunities in vitro on freshly isolated peripheral blood mononuclear cells (PBMCs) of CMV-seropositive and -seronegative healthy individuals, using interferon-γ (IFN-γ) enzyme-linked immunospot and intracellular cytokine staining assays.

Results.

We showed that CMVIG treatment increases the number of IFN-γ–secreting PBMCs of both CMV-seronegative and -seropositive individuals, indicating a global stimulatory effect on innate immune cells. Indeed, CMVIG significantly increased the frequency of natural killer cells producing the T helper cell 1–type cytokines tumor necrosis factor and IFN-γ. This was associated with the induction of interleukin-12–expressing monocytes and the activation of cluster of differentiation (CD) 4⁺ and CD8⁺ T cells, as measured by the expression of tumor necrosis factor and IFN-γ. Interestingly, stimulation of PBMCs from CMV-seropositive subjects with CMVIG-opsonized CMV antigens (phosphoprotein 65, CMV lysate) enhanced CD4⁺ and CD8⁺ T-cell activation, suggesting that CMVIG promotes the immunogenicity of CMV antigens.

Conclusions.

Our data demonstrate that CMVIG can stimulate effector cells of both innate and adaptive immunities and promote the immunogenicity of CMV antigens. These immunostimulatory properties might contribute to the protective effect against CMV infection mediated by CMVIG.

Estimation of the latent therapeutic demand for immunoglobulin therapies in autoimmune neuropathies in the United States

BACKGROUND AND OBJECTIVES

The use of immunoglobulin (IG) solutions as an immunomodulatory therapy in certain neurological conditions has become an established modality and represents a significant proportion of total IG use. The estimation of the evidence-based potential demand designated as the latent therapeutic demand (LTD) for IG in these diseases is required for adequate planning of the plasma supply required to manufacture the product.

MATERIALS AND METHODS

The diseases studied included chronic inflammatory demyelinating polyneuropathy (CIDP), Guillain-Barré syndrome (GBS) and multifocal motor neuropathy (MMN). The LTD for IG was assessed using a decision analysis model, using Microsoft Excel. The model analysed the epidemiological and clinical factors contributing to IG usage. One-way sensitivity analysis and probabilistic sensitivity analysis derived the LTD in grams per 1000 inhabitants. The key variables included the treatment schedule and the prevalence of the disease.

RESULTS

The model estimates that an average annual IG demand and standard deviation for CIDP, GBS and MMN in the United States is 83.05 ± 24.5, 6.1 ± 3.2 and 36.1 ± 25.5 g/1000 inhabitants, respectively.

CONCLUSION

Together with previous work on the LTD for IG in immunodeficiencies, these results indicate that current IG usage reflects the estimated LTD for the main indications for IG in the United States The wide range of LTD found in all these studies emphasizes the need for more precise assessment of the underlying variables, particularly disease prevalence and dosage. Further studies on other indications such as secondary immunodeficiencies will augment these results and will assist in guiding demand planning for IG use and plasma collection in the United States and inform blood policy in other countries.

A clinician survey for management of the secondary immunodeficiency caused by hematological malignancies in China

Unlike Western countries, there are still few clinical immunology specialists in China, and the optimal care for secondary immunodeficiency caused by hematological malignancies is unknown. Therefore, we initiated this clinician survey study to describe the current situation of the care for malignancy patients with hypogammaglobulinemia in China.We adapted a previously published online questionnaire of current clinical practices regarding the management of secondary immunodeficiency caused by hematological malignancies and then distributed the questionnaire to 52 hematologists in China via WeChat mobile software; the survey collected demographic details, starting dosage, target immunoglobulin (Ig) level, monitoring, criteria for stopping Ig replacement, vaccination use, and oral antibiotic prophylaxis for hypogammaglobulinemia patients.Forty-eight hematologists responded. 28(58.33%) respondents had more than 10 years of experience. Nevertheless, 40(83.33%) respondents reported that they did not use any specific criteria for prophylactic Ig replacement in hypogammaglobulinemia patients. However, 27(56.25%) respondents reported that they had used intravenous immunoglobulin (IVIG); however, the starting dose, frequency, and target Ig level were significantly varied. Additionally, the criteria for stopping Ig replacement were significantly varied. Only one respondent (2.08%) used subcutaneous immunoglobulin (SCIG). Moreover, 35(72.92%) respondents reported no vaccination prior to Ig replacement, and 47(97.92%) respondents reported that they had not used antibiotic prophylaxis in secondary hypogammaglobulinemia patients.Official guideline for the care for secondary immunodeficiency (SID) of the hematological malignancies patients should be issued in China, and significant attention of the hematologists should be paid to the use of prophylactic antibiotics and Ig replacement for the care of patients with hypogammaglobulinemia caused by hematological malignancies, as these agents could significantly reduce the infection rate in China.

Global immunoglobulin supply: steaming towards the iceberg?

PURPOSE OF REVIEW

This review describes how plasma is sourced for fractionation into plasma-derived medicinal products (PDMPs), such as immunoglobulin (Ig) together with differences between plasma from whole blood (recovered plasma) and from plasmapheresis (source plasma) in terms of global plasma supply. Specific areas of growth in immunoglobulin use are identified alongside novel therapies, which may reduce demand for some immunoglobulin indications.

RECENT FINDINGS

There has been a 6--8% annual growth in immunoglobulin use. Secondary immunodeficiency alongside improved recognition and diagnosis primary immunodeficiency disorders are drivers whereas the novel neonatal Fc receptor inhibitors (FcRni) may reduce demand for some immunomodulatory indications.

SUMMARY

There is a significant geographical imbalance in global supply of plasma with 65% collected in the United States. This results in a dependency of other countries on United States supply and argues for both more plasma supply and greater regionally balanced plasma collection. In addition, progress towards a transparent, regulated and well tolerated framework for the coexistence of unpaid and compensated plasma donations is needed as unpaid donation will not be sufficient. These discussions should be informed by the needs of patients for this life-saving therapy, the care of donors and the safety of plasma and PDMPs.

Implications of Fc Neonatal Receptor (FcRn) Manipulations for Transplant Immunotherapeutics

Alloimmune injury to allografts is mediated by pathogenic donor-specific alloantibodies, usually of the IgG isotype. Currently, strategies used to reduce donor-specific alloantibodies are collectively called desensitization. Despite successes, these treatments have limited efficacy and can be associated with adverse events, infectious complications, and high cost. Fc neonatal receptor (FcRn) was originally discovered as a transport mechanism for IgG from maternal circulation to fetus. FcRn receptors are now known to be widely distributed in virtually all tissues. IgG and albumin binding to FcRn is pH-dependent, which results in a significant prolongation their half-life. Structural analysis shows FcRn is a nonclassical major histocompatibility complex Class I receptor, which is emerging as a novel target to significantly reduce the half-life of pathogenic antibodies or extend the half-life of therapeutic monoclonals. Manipulation of IgG-Fc/FcRn interactions has implications for treatment of virtually all IgG-mediated diseases. The use of monoclonals directed at the FcRn can rapidly enhance the turnover of total IgG, including pathogenic IgG. In this review, we highlight the aspects of FcRn biology responsible for development of FcRn targeted therapeutics aimed at pathogenic autoantibodies and alloantibodies. We also explore the novel modifications of therapeutic monoclonals that exploit FcRn functions to enhance therapeutic efficacy.

Increased Respiratory Viral Detection and Symptom Burden Among Patients with Primary Antibody Deficiency: Results from the BIPAD Study

BACKGROUND

Patients with primary antibody deficiency (PAD) are at increased risk of respiratory tract infections, but our understanding of their nature and consequences remains limited.

OBJECTIVE

To define the symptomatic and microbial burden of upper airway infection in adults with PAD relative to age-matched controls.

METHODS

Prospective 12-month observational study consisting of a daily upper and lower airway symptom score alongside fortnightly nasal swab with molecular detection of 19 pathogen targets.

RESULTS

A total of 44 patients and 42 controls (including 34 household pairs) were recruited, providing more than 22,500 days of symptom scores and 1,496 nasal swabs. Swab and questionnaire compliance exceeded 70%. At enrollment, 64% of patients received prophylactic antibiotics, with a 34% prevalence of bronchiectasis. On average, patients with PAD experienced symptomatic respiratory exacerbations every 6 days compared with 6 weeks for controls, associated with significant impairment of respiratory-specific quality-of-life scores. Viral detections were associated with worsening of symptom scores from a participant's baseline. Patients with PAD had increased odds ratio (OR) for pathogen detection, particularly viral (OR, 2.73; 95% CI, 2.09-3.57), specifically human rhinovirus (OR, 3.60; 95% CI, 2.53-5.13) and parainfluenza (OR, 3.06; 95% CI, 1.25-7.50). Haemophilus influenzae and Streptococcus pneumoniae were also more frequent in PAD. Young child exposure, IgM deficiency, and presence of bronchiectasis were independent risk factors for viral detection. Prophylactic antibiotic use was associated with a lower risk of bacterial detection by PCR.

CONCLUSIONS

Patients with PAD have a significant respiratory symptom burden associated with increased viral infection frequency despite immunoglobulin replacement and prophylactic antibiotic use. This highlights a clear need for future therapeutic trials in the population with PAD, and informs future study design.

An update on X-Linked agammaglobulinaemia: clinical manifestations and management

PURPOSE OF REVIEW

X-linked agammaglobulinaemia (XLA) is a congenital defect of development of B lymphocytes leading to agammaglobulinaemia. It was one of the first primary immunodeficiencies described, but treatment has remained relatively unchanged over the last 60 years. This summary aims to outline the current outcomes, treatments and future research areas for XLA.

RECENT FINDINGS

Immunoglobulin therapy lacks IgA and IgM, placing patients at theoretical risk of experiencing recurrent respiratory tract infections and developing bronchiectasis despite best current therapy. Recent cohort studies from Italy and the USA conform that bronchiectasis remains a major burden for this group despite best current efforts. However, gene therapy offers a potential cure for these patients with proven proof of concept murine models.

SUMMARY

The potential limitations of current immunoglobulin therapy appear to be confirmed by recent cohort studies, and therefore further work in the development of gene therapy is warranted. Until this is available, clinicians should strive to reduce the diagnostic delay, regularly monitor for lung disease and individualize target immunoglobulin doses to reduce infection rates for their patients.

Intravenous Immune Globulin (IVIG) for Treatment of Autoimmune Heparin-Induced Thrombocytopenia: A Systematic Review

OBJECTIVE

To evaluate intravenous immune globulin (IVIG) for autoimmune heparin-induced thrombocytopenia (aHIT), including platelet recovery, IVIG dose, dosing weight, IVIG product used, and complications reported.

DATA SOURCES

PubMed and EMBASE were searched from inception through June 21, 2020. Search terms included heparin-induced thrombocytopenia, HIT, intravenous immune globulin, IVIG, autoimmune HIT, aHIT, and immune globulin.

STUDY SELECTION AND DATA EXTRACTION

Patients administered IVIG for HIT and diagnosed by immunoassay (optical density ≥2) or positive activation assay were included.

DATA SYNTHESIS

Twenty-four cases were reviewed; 92% had persistent aHIT. Time to IVIG administration post-nonheparin anticoagulant initiation was 9 days (median). Most common IVIG cumulative dose was 2 g/kg (dosed as 1 g/kg/d for 2 consecutive days); 75% had a favorable platelet increase (≥50 × 10⁹/L) within 5 days of initial IVIG dosing.

RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE

aHIT is characterized by critically low platelets, thrombosis, and a persistent delay in platelet recovery despite treatment with a nonheparin anticoagulant. An immunoassay and subsequent confirmatory activation assay (at low, high, and 0 IU/mL unfractionated heparin levels) is recommended to confirm diagnosis. Patients nonresponsive to nonheparin anticoagulants within 5 days of initiation should be evaluated for IVIG treatment (2 g/kg cumulative dose). More data are needed to clarify appropriate IVIG dosing weight, although based on current published literature, it is recommended to use actual body weight.

CONCLUSIONS

Data reported support use of IVIG as adjunctive therapy for patients with aHIT. Judicious IVIG use based on key clinical and laboratory findings is critical.

High-Dose Intravenous Immunoglobulins in the Treatment of Severe Acute Viral Pneumonia: The Known Mechanisms and Clinical Effects

The current outbreak of viral pneumonia, caused by novel coronavirus SARS-CoV-2, is the focus of worldwide attention. The WHO declared the COVID-19 outbreak a pandemic event on Mar 12, 2020, and the number of confirmed cases is still on the rise worldwide. While most infected individuals only experience mild symptoms or may even be asymptomatic, some patients rapidly progress to severe acute respiratory failure with substantial mortality, making it imperative to develop an efficient treatment for severe SARS-CoV-2 pneumonia alongside supportive care. So far, the optimal treatment strategy for severe COVID-19 remains unknown. Intravenous immunoglobulin (IVIg) is a blood product pooled from healthy donors with high concentrations of immunoglobulin G (IgG) and has been used in patients with autoimmune and inflammatory diseases for more than 30 years. In this review, we aim to highlight the known mechanisms of immunomodulatory effects of high-dose IVIg therapy, the immunopathological hypothesis of viral pneumonia, and the clinical evidence of IVIg therapy in viral pneumonia. We then make cautious therapeutic inferences about high-dose IVIg therapy in treating severe COVID-19. These inferences may provide relevant and useful insights in order to aid treatment for COVID-19.

Considerations for Optimizing Dosing of Immunoglobulins Based on Pharmacokinetic Evidence

Immunoglobulins (IGs) are widely used for the treatment of immunodeficiency syndromes and several autoimmune diseases. In neonates, IGs have been used for the treatment of alloimmune thrombocytopenia, in neonatal infections and in the rare cases of neonatal Kawasaki disease. This review aims to examine the various dosing regimens of IGs following intravenous (IV) and subcutaneous (SC) administration, pharmacokinetics (PK) of IGs, and the importance of trough values for the prevention of infections in patients with primary immune deficiency (PID). The review also focuses on the mechanism of catabolism of IGs and the impact on the half-life of IGs. Data and reviews were obtained from the literature and the FDA package inserts. The authors suggest that for dosing, the PK of IGs should be evaluated on the baseline-corrected concentrations since this approach provides an accurate estimate of half-life and clearance of IGs. We also suggest employing clearance as a primary PK parameter for dosing determination of IGs. We suggest that IV dosing would be more effective if given more frequently to adjust for the increased clearance at high doses and because the baseline-corrected half-life is much shorter than the baseline-uncorrected half-life. Regarding SC administration, the dose should be adjusted based on the absolute bioavailability (determined against IV dosing) of the product. Finally, we highlight clinical and PK data gaps for optimum and individualized dosing of IGs.

Romiplostim for management of refractory immune thrombocytopenic purpura in the immediate postpartum period

We present a case of a pregnant woman with chronic immune thrombocytopenic purpura and chronic hypertension who developed pre-eclampsia with severe features warranting delivery. Her overall clinical picture and liver enzymes improved in the immediate postpartum period, however, aggressively progressing thrombocytopenia posed a diagnostic dilemma to the interdisciplinary care team. After failing to respond to first-line therapies including high-dose corticosteroids and intravenous immunoglobulin, she was successfully managed with a trial of the thrombopoietin receptor agonist, Romiplostim.

The growing importance of achieving national self-sufficiency in immunoglobulin in Italy. The emergence of a national imperative

Since the inception of industrial plasma fractionation during the Second World War, a succession of protein therapies isolated from plasma have determined the volume of plasma requiring collection, and have also shaped the economics of the industry. These so-called plasma drivers have successively included albumin, coagulation Factor VIII (FVIII) and, for the past thirty years, intravenously (IV) and subcutaneously (SC) administered immunoglobulin (IG) solutions. The sale of IG underpins the profitability of the industry and has experienced continuous growth over the past decades, as the result of growing clinical demand. Modelling this demand using decision analysis indicates that supplying the evidence-based indications for IG therapies will generate a need for IG which exceeds the current plasma collection capacity of most countries. A notable exception to this situation is the United States (US) of America, whose population of compensated plasma donors generates two thirds of the global supply of plasma for fractionation. The US is also the leading consumer of IG, and its health care providers pay the highest price for the product globally. Shortages of IG occur whenever the demand for the product outstrips the supply. Current shortages, following other historical periods of shortage, threaten the well-being of patients dependant on these products and incur heavy costs on health systems. In Italy, the national blood system, which is based on voluntary unpaid donors, reflects a policy of national self-sufficiency in blood-derived therapies (a strategic objective of the national blood system itself), based on solidarity as an ethical principle. This system has increased the collection of plasma for fractionation by 3.8% per annum over 2008-2017, in accordance to a plan for plasma procurement targeting a collection rate of 14.1 L of plasma per thousand (10³) population by 2020. Over the same period, IG usage has increased by 8.5/per annum, to 89.2 g IG/10³ population. In this paper, we review the factors which, increasingly, are causing an imbalance between the global supply and demand for IG, and we assess Italy's capacity to ensure that increasing this level of independence is no longer simply an ethical, but also an economic imperative, with implications for the security of Italy's health system.

Efficacy and safety of a new intravenous immunoglobulin (Panzyga® ) in chronic immune thrombocytopenia

Objectives

To assess the efficacy and safety of intravenous immunoglobulin (IVIG) 10% (Panzyga^®), a novel human normal IVIG 10%, in patients with chronic immune thrombocytopenia (ITP).

Background

First‐line treatment options in ITP include IVIGs.

Methods

In this prospective, open‐label, non‐controlled, multicentre, phase III study, patients received a daily dose of IVIG 10% (1 g kg⁻¹ body weight) for two consecutive days. The primary end point was clinical response rate; secondary end points included alternate response definitions, time to response, response duration, platelet counts, regression of bleeding and safety.

Results

Forty patients were enrolled (57·5% male, mean age 36·7 years); the full analysis set comprised 36 patients. A clinical response was seen for 29 of 36 patients (80·6%). Median time to response and response duration was 2 days and 14 days, respectively. IVIG 10% was well tolerated at a maximum infusion rate of 8 mg (kg min)⁻¹ in all but one patient; adverse events were mainly mild to moderate in severity, and the most frequent was headache (42·5%).

Conclusion

IVIG 10% is well tolerated even at a high infusion speed and induces a rapid platelet count increase, thus decreasing the bleeding rate and the severity of bleeding events.

Trial registry: http://ClinicalTrials.gov record: NCT01349790.

Health-Related Quality of Life in Patients with CVID Under Different Schedules of Immunoglobulin Administration: Prospective Multicenter Study

Objective

We assessed the health-related quality of life (HRQoL) in CVID adults receiving different schedules of immunoglobulin replacement therapy (IgRT) by intravenous (IVIG), subcutaneous (SCIG), and facilitated (fSCIG) preparations. For these patients, IgRT schedule was chosen after a period focused on identifying the most suitable individual option.

Methods

Three hundred twenty-seven participants were enrolled in a prospective, observational, 18-month study. Participants received IgRT for at least 2 years. The first 6 months were devoted to the educational process during which the choices related to IgRT were regularly re-assessed, and the shift to alternative regimen was permitted. During the following 12 months, clinical data were prospectively collected, and only patients who did not further modify their IgRT schedule were included in the analysis of HRQoL measured by CVID_QoL, a specific instrument, and by GHQ-12, a tool to assess minor psychiatric nonpsychotic disorders.

Results

Three hundred four patients were included in the analysis. CVID_QoL global score and its dimensions (emotional functioning, relational functioning, gastrointestinal symptoms) were similar in IVIG, SCIG, and fSCIG recipients. Patients receiving IgRT by different routes of administration reported similar capacity to make long-term plans, discomfort due to therapy, and concern to run out of medications. Multivariate analysis revealed the GHQ-12 status, but not the IgRT mode of administration, as the major factor impacting on treatment-related QoL items, and a significant impact of age on discomfort related to IgRT.

Conclusions

IgRT schedules do not impact the HRQoL in CVID if the treatment is established after an extensive educational period focused on individualizing the best therapeutic regimen.

Electronic supplementary material

The online version of this article (10.1007/s10875-019-0592-5) contains supplementary material, which is available to authorized users.

Direct and Indirect Costs of Immunoglobulin Replacement Therapy in Patients with Common Variable Immunodeficiency (CVID) and X-Linked Agammaglobulinemia (XLA) in Italy

BACKGROUND

In Italy, there is scarce evidence on the epidemiological and economic burden induced by primary antibody deficiencies.

OBJECTIVE

The aim of this study was to elaborate the available epidemiological and cost data in order to estimate the annual expenditure induced by the management of patients affected by the common variable immunodeficiency (CVID) and X-linked agammaglobulinemia (XLA) requiring immunoglobulin (Ig) replacement therapy.

METHODS

A probabilistic cost-of-illness model was developed to estimate the number of patients with CVID and XLA, and the economic burden associated with their therapy in terms of direct or indirect costs. A systematic literature review was carried out to reveal both epidemiological and economic data. Furthermore, a probabilistic sensitivity analysis with 5000 Monte Carlo simulations was performed.

RESULTS

The epidemiological model allowed us to estimate the number of prevalent patients affected by XLA and CVID in Italy in 2017, corresponding to 1885 (95% confidence interval [CI] 944-3145) and 133 (95% CI 115-152) patients, respectively. The estimated total expenditure for the treatment and management of patients with CVID and XLA requiring Ig replacement therapy amounts to €42.68 million (95% CI €14.38-€86.1 million).

CONCLUSIONS

This information provides a comprehensive perspective of the economic issues, and facilitates better-informed public health decision making, in the management of CVID and XLA in Italy.

Long-Term Efficacy and Safety of Hizentra® in Patients with Primary Immunodeficiency in Japan, Europe, and the United States: a Review of 7 Phase 3 Trials

Many patients with primary immunodeficiency (PID) require immunoglobulin G (IgG) replacement therapy, delivered as intravenous IgG (IVIG) or subcutaneous IgG (SCIG). We aim to identify trends in efficacy and safety that would not be evident in individual studies of small patient numbers. Seven open-label, Phase 3, prospective, multicenter studies of the efficacy and safety of Hizentra® (a SCIG), conducted in Japan, Europe, and the US were summarized. Overall, 125 unique patients received 15,013 weekly infusions during a total observation period of 250.9 patient-years. Mean weekly doses of Hizentra® were 83.22–221.3 mg/kg body weight; infusion rates per patient (total body rate) were 25.2–49.3 mL/h across studies. The rates of infections and serious bacterial infections were 3.10 and 0.03 events per patient/year, respectively. Annualized rates of days hospitalized due to infection, out of work/school, and prophylactic antibiotic use were 0.95, 5.14, and 36.78 per patient, respectively. For the equivalent monthly dose, weekly Hizentra® SCIG administration resulted in expectedly-increased serum IgG trough levels in patients switching from IVIG, and maintained levels in patients switching from previous SCIG. Adverse events (AEs) totaled 5039 (events/infusion 0.094–0.773), almost all of which were mild/moderate. Three thousand one hundred ninety-seven were considered treatment-related, the most common of which were injection site reactions (2919 events; 0.001–0.592 AEs per infusion). Systemic AEs were very uncommon. The results from these seven studies indicate that Hizentra® therapy was both efficacious and well tolerated during long-term treatment. This is particularly important in patients with PID, who may require lifelong IgG replacement therapy.

Fatigue and the wear-off effect in adult patients with common variable immunodeficiency

Patients with common variable immunodeficiency (CVID) have increased fatigue compared with the general population. Fatigue is associated with lower quality of life (QoL), which is associated with higher mortality in CVID. This study aimed to determine the prevalence of self-reported fatigue for patients with CVID and to identify its possible drivers and burden on QoL. We analysed data from the 2013 Immune Deficiency Foundation (IDF) treatment survey. Answers were included from 873 CVID patients who responded (respondents). Of the 873 respondents included in the analysis, 671 (76·9%) reported fatigue, of whom 400 (83·7%) were receiving intravenous (i.v.) immunoglobulins (IVIG) and 271 (68·6%) were receiving subcutaneous (s.c.) immunoglobulins. This difference in fatigue between patients receiving IVIG and SCIG was statistically significant (P < 0·001). Dose and frequency of immunoglobulin replacement therapy (IgGRT) did not affect fatigue prevalence. Fatigued patients on IVIG reported greater infection rates and required more anti-microbials during the wear-off period. Fatigued patients reported worse health status than non-fatigued patients, and had lower rates of employment, education, household income and school attendance than their non-fatigued counterparts. Fatigue is increased in CVID, especially among patients receiving IVIG, compared to SCIG. Fatigue has a significant impact on QoL and productivity in patients with CVID. Further studies to identify the mechanisms of fatigue are warranted to help advance therapeutic measures to treat this disease and improve patients' QoL and wellbeing.

The FcRn inhibitor rozanolixizumab reduces human serum IgG concentration: A randomized phase 1 study

Pathogenic immunoglobulin G (IgG) autoantibodies characterize some human autoimmune diseases; their high concentration and long half-life are dependent on recycling by the neonatal Fc receptor (FcRn). Inhibition of FcRn is an attractive new treatment concept for IgG-mediated autoimmune diseases. Rozanolixizumab (UCB7665; CA170_01519.g57 IgG4P) is an anti-human FcRn monoclonal antibody. In cynomolgus monkeys, rozanolixizumab reduced IgG (maximum 75 to 90% by about day 10), was well tolerated, and did not increase risk of infection. We also report a first-in-human, randomized, double-blind, placebo-controlled, dose-escalating study of intravenous (IV) or subcutaneous (SC) rozanolixizumab in healthy subjects (NCT02220153). The primary objective was to evaluate safety and tolerability. Secondary objectives were assessment of rozanolixizumab pharmacokinetics and pharmacodynamics, including effects on circulating IgG concentrations. Forty-nine subjects were randomized to receive rozanolixizumab (n = 36) or placebo (n = 13) across six cohorts. The first three cohorts received IV doses, and the subsequent three cohorts received SC doses, of rozanolixizumab 1, 4, or 7 mg/kg (n = 6 for each cohort; plus n = 7 or 6 for placebo, respectively). The most frequent treatment-emergent adverse event [TEAE; headache, 14 of 36 (38.9%) subjects] was dose-dependent and more prominent after IV administration. Severe TEAEs occurred in four subjects, all in the highest-dose IV group [headache (n = 3) and back pain (n = 1)]. Rozanolixizumab pharmacokinetics demonstrated nonlinear increases with dose. There were sustained dose-dependent reductions in serum IgG concentrations (IV and SC rozanolixizumab). These data provide clinical evidence for the therapeutic potential of rozanolixizumab.

Intravenous immunoglobulin replacement treatment reduces in vivo elastase secretion in patients with common variable immune disorders

BACKGROUND

Intravenous immunoglobulin (IVIg) treatment partially replaces antibody defects and modulates innate and adaptive immune cells in patients with primary antibody deficiencies.

MATERIALS AND METHODS

This study was focused on the evaluation of the effects of in vivo IVIg administration on neutrophils from patients with common variable immune disorders (CVID). We examined polymorphonuclear neutrophil (PMN) phagocytosis, PMN oxidative burst, release of neutrophil elastase, serum level of interleukin-8 and PMN expression of CXCR1, CD11c and CD66b.

RESULTS

CVID patients on chronic IVIg treatment had reduced elastase release, but normal expression of CXCR1, CD66b and CD11c receptors on PMN, normal phagocytic ability and normal secretion of interleukin-8. We found that IVIg infusions rapidly reduced the serum level of interleukin-8, the expression of its receptor, CXCR1, and the release of neutrophil elastase, suggesting that IVIg exert a dampening effect on neutrophil activity. In contrast, IVIg infusions did not alter neutrophil phagocytosis or the expression of the other receptors analysed.

DISCUSSION

These findings add further information regarding the anti-inflammatory role of immunoglobulins and suggest additional benefits in keeping with recent attempts to use new therapies targeting neutrophil inflammation.

Latent therapeutic demand model for the immunoglobulin replacement therapy of primary immune deficiency disorders in the USA

BACKGROUND AND OBJECTIVES

Our research aim is to model latent therapeutic demand (LTD) for the immunoglobulin replacement therapy (IgGRT) of primary immune deficiency disorders (PIDDs) in the USA. Given the high level of variability of IgGRT use and major differences among American and European practices in the management of patients with PIDDs, we develop a USA-specific LTD model for common variable immune deficiency (CVID), hyper IGM syndrome, severe combined immune deficiency, Wiskott-Aldrich syndrome and X-linked agammaglobulinemia (XLA).

METHODS AND MATERIALS

We use decision analysis methods to model the underlying IgGRT demand for PIDDs by assessing USA-specific epidemiology and treatment. Data for the epidemiology and treatment variables were obtained from the medical literature, USIDNET and Immune Deficiency Foundation. The uncertainty surrounding the variables was modelled using probability distributions and evaluated using Monte Carlo simulation.

RESULTS

The mean treatment dose from USIDNET and European Society for Immunodeficiencies (ESID) was significantly different for treating CVID, and the number of annual infusions from USIDNET and ESID was significantly different for treating CVID and XLA. The mean and standard deviation of LTD for all PIDDs is 105·1 ± 88·5 g per 1000 population, with CVID contributing the most to LTD.

CONCLUSION

Estimating country-specific LTD is important to ensure an adequate supply of IgGRT and an optimal treatment for patients with PIDDs and for improving national healthcare policymaking and production planning.

II Brazilian Consensus on the use of human immunoglobulin in patients with primary immunodeficiencies

In the last few years, new primary immunodeficiencies and genetic defects have been described. Recently, immunoglobulin products with improved compositions and for subcutaneous use have become available in Brazil. In order to guide physicians on the use of human immunoglobulin to treat primary immunodeficiencies, based on a narrative literature review and their professional experience, the members of the Primary Immunodeficiency Group of the Brazilian Society of Allergy and Immunology prepared an updated document of the 1^st Brazilian Consensus, published in 2010. The document presents new knowledge about the indications and efficacy of immunoglobulin therapy in primary immunodeficiencies, relevant production-related aspects, mode of use (routes of administration, pharmacokinetics, doses and intervals), adverse events (major, prevention, treatment and reporting), patient monitoring, presentations available and how to have access to this therapeutic resource in Brazil.

Maintenance IV immunoglobulin treatment in chronic inflammatory demyelinating polyradiculoneuropathy

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) patients treated with intravenous immunoglobulin (IVIg) usually start with a standard dosage of 2 g/kg bodyweight. Only a minority of patients has a sustained improvement, and most require ongoing maintenance treatment. Preferred IVIg regimens, however, vary considerably between doctors and at present it is unknown which is optimal. As there are also large differences in IVIg dosage and interval requirements between patients, optimal IVIg maintenance treatment of CIDP is even more complex. The lack of evidence-based guidelines on how IVIg maintenance treatment should be administered may potentially lead to under- or overtreatment of this expensive therapy. We provide an overview of published practical IVIg maintenance treatment regimens, IVIg maintenance schedules used in randomized controlled trials and one based upon our own long-term experience on how this treatment could be given in CIDP.

Network inference from glycoproteomics data reveals new reactions in the IgG glycosylation pathway

Immunoglobulin G (IgG) is a major effector molecule of the human immune response, and aberrations in IgG glycosylation are linked to various diseases. However, the molecular mechanisms underlying protein glycosylation are still poorly understood. We present a data-driven approach to infer reactions in the IgG glycosylation pathway using large-scale mass-spectrometry measurements. Gaussian graphical models are used to construct association networks from four cohorts. We find that glycan pairs with high partial correlations represent enzymatic reactions in the known glycosylation pathway, and then predict new biochemical reactions using a rule-based approach. Validation is performed using data from a GWAS and results from three in vitro experiments. We show that one predicted reaction is enzymatically feasible and that one rejected reaction does not occur in vitro. Moreover, in contrast to previous knowledge, enzymes involved in our predictions colocalize in the Golgi of two cell lines, further confirming the in silico predictions.

A randomized multicenter study: safety and efficacy of mini-pool intravenous immunoglobulin versus standard immunoglobulin in children aged 1-18 years with immune thrombocytopenia

BACKGROUND

Because there is a global shortage of intravenous immunoglobulin, there is a need for new products to fill the gap.

STUDY DESIGN AND METHODS

This was a multicenter, open-label study investigating the safety and efficacy of a newly developed mini-pool intravenous immunoglobulin G for children with immune thrombocytopenia. Seventy-two patients ages 1 to 18 years with newly diagnosed (<1 month) immune thrombocytopenia who had platelet counts from 5 to 20 × 10⁹ /L with no serious bleeding were recruited from four centers in Egypt. Eligible patients were randomized into three groups 1:1:1. Group A (n = 24) received blood group-specific mini-pool intravenous immunoglobulin in a dose equivalent to immunoglobulin 1 g/kg over 6 to 8 hours, Group B (n = 24) received standard intravenous immunoglobulin (approximately 1g/kg) as a single dose, and Group C (n = 24) did not receive any platelet-enhancing therapy. Parents signed informed consent.

RESULTS

Of the patients who received mini-pool intravenous immunoglobulin, 14 achieved a complete response (CR) (58.8%), and four had a response (16.6%). Of the patients who received intravenous immunoglobulin G, 16 achieved a complete response (66.6%), and four had a response (16.6%). In Group C, eight patients achieved a complete response (33.3%), and four had a response (16.6%). The median time to response was 8, 9, and 21 days in Group A, B, and C, respectively, which was significantly higher in Group C than Groups A and B (p < 0.001). Patients in Groups A and B reported 16 adverse drug reactions.

CONCLUSION

Mini-pool intravenous immunoglobulin G was well tolerated, presented no safety issues, and was effective in the treatment of immune thrombocytopenia, with efficacy comparable to that of the standard intravenous immunoglobulin G group, and it was significantly more effective than no treatment.

Hemolysis related to intravenous immunoglobulins is dependent on the presence of anti-blood group A and B antibodies and individual susceptibility

BACKGROUND

Patients treated with intravenous immunoglobulins (IVIG) rarely experience symptomatic hemolysis. Although anti-A and anti-B isoagglutinins from the product are involved in most cases, the actual mechanisms triggering hemolysis are unclear.

STUDY DESIGN AND METHODS

A prospective, open-label, multicenter, single-arm clinical trial in 57 patients with immune thrombocytopenia treated with IVIG (Privigen, CSL Behring) was conducted.

RESULTS

Twenty-one patients received one infusion (1 g/kg) and 36 received two infusions (2 × 1 g/kg) of IVIG. After a study duration of more than 2 years, no cases of clinically significant hemolysis as defined in the protocol were identified. Data of patients with mild hematologic and biochemical changes were analyzed in more detail. Twelve cases (10/23 patients with blood group A1 and 2/11 patients with blood group B, all having received 2 g/kg IVIG) were adjudicated as mild hemolysis (median hemoglobin [Hb] decrease, -3.0 g/dL); Hb decreases were transient, with partial or full recovery achieved by last visit. Eighteen patients (31.6%), all with non-O blood group, of whom 16 (88.9%) received 2 g/kg IVIG, fulfilled post hoc criteria for hemolytic laboratory reactions. Red blood cell (RBC) eluates of all direct antiglobulin test-positive samples were negative for non-ABO blood group antibodies. Blood groups A and B antigen density on RBCs appeared to be a risk factor for hemolytic laboratory reactions. Platelet response to treatment was observed in 42 patients (74%); eight of 12 patients with complete response had blood group A1.

CONCLUSION

Isoagglutinins are involved in clinically nonsignificant hemolysis after treatment with IVIG, but individual susceptibility varies greatly.

Modulatory Effects of Antibody Replacement Therapy to Innate and Adaptive Immune Cells

Intravenous immunoglobulin administered at replacement dosages modulates innate and adaptive immune cells in primary antibody deficiencies (PAD) in a different manner to what observed when high dosages are used or when their effect is analyzed by in vitro experimental conditions. The effects seem to be beneficial on innate cells in that dendritic cells maturate, pro-inflammatory monocytes decrease, and neutrophil function is preserved. The effects are less clear on adaptive immune cells. IVIg induced a transient increase of Treg and a long-term increase of CD4 cells. More complex and less understood is the interplay of IVIg with defective B cells of PAD patients. The paucity of data underlies the need of more studies on patients with PAD before drawing conclusions on the in vivo mechanisms of action of IVIg based on in vitro investigations.

Considerations for dosing immunoglobulin in obese patients

Obesity is a very common condition; however, the effect of excess body weight on the appropriate dose of immunoglobulin has not been defined empirically. The proposed pharmacokinetic differences between lean and obese patients and the opportunity to reduce costs has led to the proposition that obese patients should receive proportionally lower doses of immunoglobulin once a certain threshold is reached. Here the theoretical factors which could affect dosing in obese patients are considered alongside the available empirical evidence. The available evidence indicates that obesity may affect the pharmacokinetics of immunoglobulin; however, the effect is likely to be too small to have a clinically important effect on dosing. Wide interpatient individuality and highly variable clinical need mean that obesity should not play a major factor in dosing considerations. However, patients who are obese are more likely to have multiple cardiovascular risk factors and their weight indicates a large dose. This puts these patients at a higher risk of adverse reactions, and therefore caution is advised.

[Therapeutic administration of immunoglobulins]

BACKGROUND

Intravenously administered immunoglobulins have multiple modes of action that are anti-inflammatory. They can therefore be beneficial in a number of autoimmune disorders.

OBJECTIVE

The aim of this article is to analyze and summarize studies on the administration of intravenous immunoglobulins in rheumatological diseases.

METHODS

A selective search and analysis of the literature was carried out related to the mode of action and efficacy of intravenous immunoglobulins in rheumatological diseases.

RESULTS AND CONCLUSION

Intravenous immunoglobulins have a broad mode of action and can therefore be beneficial in almost all autoimmune diseases. Conditions in which they are of special benefit include immunothrombopenia (ITP), Kawasaki disease and idiopathic inflammatory myopathies. In rare situations, they may also be indicated in systemic lupus erythematosus (SLE), Sjögren's syndrome and neuropathies, catastrophic antiphospholipid syndrome (APS), scleroderma, antineutrophil cytoplasmic antibody (ANCA) associated vasculitis, pyoderma gangrenosum and scleromyxedema. Severe adverse events are rare. In view of the high costs of the therapy, intravenous immunoglobulins are mostly applied in emergency situations, as salvage therapy when other standard therapies have failed or when severe infections are a contraindication to the administration of immunosuppressants.

The lack of BTK does not impair monocytes and polymorphonuclear cells functions in X-linked agammaglobulinemia under treatment with intravenous immunoglobulin replacement

The lack of BTK in X-linked agammaglobulinemia (XLA) patients does not affect monocytes and polymorphonuclear cells (PMN) phenotype and functions. In this study, we show that XLA patients had an increased frequency of the intermediate monocytes subset and that BTK-deficient monocytes and PMN had a normal expression of receptors involved in the activation and cellular responses. We demonstrate that BTK is not required for migration, phagocytosis and the production of reactive oxygen species (ROS) following engagement of FC gamma receptors (FcγR). XLA monocytes and PMN showed an efficient calcium (Ca2+)-independent activation of oxidative burst, suggesting that oxidative burst is less dependent by Ca2+ mobilization. The phagocytosis was functional and it remained unaltered also after Ca2+ chelation, confirming the independence of phagocytosis on Ca2+ mobilization. Intravenous immunoglobulin (IVIg) infusion exerted an anti-inflammatory effect by reducing the frequency of pro-inflammatory monocytes. In monocytes, the IVIg reduce the oxidative burst and phagocytosis even if these functions remained efficient.