Effect of intravenous immunoglobulin administration on erythrocyte and leucocyte parameters

Peripheral immune profiling highlights a dynamic role of low-density granulocytes in myasthenia gravis

BACKGROUND

Myasthenia gravis (MG) is an autoimmune neuromuscular disease marked by dysregulation of several immune cell populations. Here we explored peripheral immune landscape, particularly the role of low-density granulocytes (LDGs).

METHODS

Single-cell and bulk RNA sequencing analyzed peripheral immune cells from MG patients pre- (n = 4) and after treatment (n = 2), as well as healthy controls (n = 3). Flow cytometry was employed for validating LDG subsets, and various functional assays were conducted to assess their impact on T cell proliferation and differentiation, NET formation, and ROS production.

RESULTS

Single-cell analysis highlighted a shift towards inflammatory Th1/Th17/Tfh subsets, an intense interferon-mediated immune response, and an expansion of immature myeloid subsets in MG. Flow cytometry showed increased LDGs correlated with disease severity. Unlike myeloid-derived suppressor cells, MG LDGs do not restrict T cell proliferation but induce a pro-inflammatory Th1/Th17 response. They also display enhanced spontaneous neutrophil extracellular traps (NETs) formation and basal reactive oxygen species (ROS) production. LDGs decreased after intravenous immunoglobulin and increased after prolonged immunotherapy in minimal manifestation status (MM), with reduced pro-inflammatory activity. Bulk RNA sequencing revealed significant transcriptional differences in LDGs, especially in cell cycle and granule protein genes.

CONCLUSION

Peripheral immune profiling sheds light on the intricate role of LDGs in MG. These cells, as a distinct subtype of neutrophils with a proinflammatory phenotype, are notable increased in MG, exacerbating chronic inflammation. Furthermore, immunotherapy expanded LDGs but reduced their proinflammatory capacities. The complex interplay of LDGs in MG underscores their potential as biomarkers and therapeutic targets.

Intravenous Immunoglobulin for Autoimmune Bullous Diseases: A Case Series from a Central European Referral Center

Background and Objectives: Autoimmune bullous diseases (AIBDs) may be treated with intravenous immunoglobulin (IVIG) infusions. This study aimed to evaluate the benefits and safety profiles of high-dose IVIG therapy in AIBD patients, as determined by clinical remission, the glucocorticosteroid-sparing effect, and adverse events at 12 months follow-up in a Central European university dermatology department setting. Materials and Methods: Our case series included 10 patients: five patients with pemphigus vulgaris, one with pemphigus herpetiformis, one with pemphigus foliaceus, one with bullous pemphigoid, two with epidermolysis bullosa acquisita. They underwent 4-12 monthly cycles of IVIG therapy at a dose of 2 g/kg per cycle. Results: The prednisone dosage reduction after 2, 6, and 12 months following the final IVIG course was 65.45%, 70.91%, and 76.37%, respectively. During the 12-month observation period, disease relapse was observed in 20% of patients, while others achieved complete or partial remission without or with minimal therapy. Side effects were seen in 80% of patients; they were transient and did not necessitate discontinuation of IVIG. Conclusions: IVIG demonstrates effectiveness as a treatment with a favorable safety profile. Nevertheless, its high cost remains a significant drawback, particularly in low-income countries. IVIG should be considered, especially in patients opposed to standard therapies or with contraindications to their use.

Incidence and risk factors for intravenous immunoglobulin-related hemolysis: A systematic review of clinical trial and real-world populations

Background

Severe hemolysis rarely occurs in patients receiving intravenous immunoglobulin (IVIG) therapy. A systematic review was performed to assess the incidence of IVIG‐related hemolysis and the impact of patient and product risk factors.

Study Design and Methods

A systematic literature search for terms related to “IVIG products”, “hemolysis,” and “adverse events” was conducted in Embase for articles published between January 1, 2015, and May 31, 2021. Studies with no clinical datasets, no IVIG treatment, or where IVIG was used to treat hemolytic conditions were excluded. Of the 430 articles retrieved, 383 were excluded based on titles/abstracts and 14 were excluded after in‐depth review.

Results

In total, 33 articles were analyzed and separated into observational studies (n = 16), clinical trials (n = 8), and case reports (n = 9). The incidence proportion for IVIG‐related hemolysis ranged from 0% to 19% in observational studies and 0%–21% in clinical trials. A higher incidence of IVIG‐related hemolysis was consistently reported in patients with blood groups A and AB. Hemolysis occurred more frequently in patients treated with IVIG for some conditions such as Kawasaki disease; however, this may be confounded by the high dose of IVIG therapy. IVIG‐related hemolysis incidence was lower in studies using IVIG products citing manufacturing processes to reduce isoagglutinin levels than products that did not.

Conclusion

This analysis identified patient and product risk factors including blood group, IVIG dose, and IVIG manufacturing processes associated with elevated IVIG‐related hemolysis incidence.

Immunomodulator use in paediatric severe sepsis and septic shock

INTRODUCTION

The use of drugs that modulate the immune system during paediatric severe sepsis and septic shock may alter the course of disease and is poorly studied. This study aims to characterise these children who received immunomodulators and describe their clinical outcomes.

METHODS

This is a retrospective chart review of patients with severe sepsis and septic shock admitted into the paediatric intensive care unit (PICU). Clinical, haematological and outcome characteristics of patients with or without exposure to immune-modulating drugs were compared. Primary outcome was PICU mortality; secondary outcomes were 28-day ventilator-free days (VFD) and intensive care unit-free days (IFD). Univariate and multivariable analyses were performed for these outcomes.

RESULTS

A total of 109 patients with paediatric severe sepsis or septic shock were identified. Of this number, 47 (43.1%), 16 (14.7%) and 3 (2.8%) patients received systemic corticosteroids, intravenous immunoglobulins and granulocyte colony stimulating factor, respectively. Patients who received immune-modulating drugs were more likely to require invasive ventilation (38/54 [70.4%] versus 26/55 [47.3%], P=0.019) compared to those who did not. PICU mortality was indifferent between the 2 groups (20/54 [37.0%] vs 11/55 [20.0%], P=0.058) even after accounting for chronic complex conditions and admission organ dysfunction (PELOD score) (adjusted odds ratio 1.90, confidence interval [0.72-5.01], P=0.193). However, VFD (19.5 [0-28] vs 25 [12-28] days, P=0.038) and IFD (15 [0-24] vs 22 [9-26] days, P=0.024) were decreased in the immunomodulator group compared to the non-immunomodulator group.

CONCLUSION

Immune-modulating drugs were frequently used in paediatric severe sepsis and septic shock. Patients who received these drugs seemed to require more PICU support. Further studies are required to examine this association thoroughly.

A monocyte/dendritic cell molecular signature of SARS-CoV-2-related multisystem inflammatory syndrome in children with severe myocarditis

Background

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in children is generally milder than in adults, but a proportion of cases result in hyperinflammatory conditions often including myocarditis.

Methods

To better understand these cases, we applied a multiparametric approach to the study of blood cells of 56 children hospitalized with suspicion of SARS-CoV-2 infection. Plasma cytokine and chemokine levels and blood cellular composition were measured, alongside gene expression at the bulk and single-cell levels.

Findings

The most severe forms of multisystem inflammatory syndrome in children (MIS-C) related to SARS-CoV-2 that resulted in myocarditis were characterized by elevated levels of pro-angiogenesis cytokines and several chemokines. Single-cell transcriptomics analyses identified a unique monocyte/dendritic cell gene signature that correlated with the occurrence of severe myocarditis characterized by sustained nuclear factor κB (NF-κB) activity and tumor necrosis factor alpha (TNF-α) signaling and associated with decreased gene expression of NF-κB inhibitors. We also found a weak response to type I and type II interferons, hyperinflammation, and response to oxidative stress related to increased HIF-1α and Vascular endothelial growth factor (VEGF) signaling.

Conclusions

These results provide potential for a better understanding of disease pathophysiology.

Funding

Agence National de la Recherche (Institut Hospitalo-Universitaire Imagine, grant ANR-10-IAHU-01; Recherche Hospitalo-Universitaire, grant ANR-18-RHUS-0010; Laboratoire d’Excellence ‘‘Milieu Intérieur,” grant ANR-10-LABX-69-01; ANR-flash Covid19 “AIROCovid” and “CoVarImm”), Institut National de la Santé et de la Recherche Médicale (INSERM), and the “URGENCE COVID-19” fundraising campaign of Institut Pasteur.

Children with SARS-CoV-2 infection were initially thought to have only mild COVID-19 symptoms. However, several weeks into the first wave of SARS-CoV-2 infections, there was a surge of a postacute pathology called multisystem inflammatory syndrome in children (MIS-C). The authors recruited a cohort of children with suspicion of SARS-CoV-2 infection and uncovered hyperinflammation, hypoxic conditions, exacerbation of TNF-α signaling via NF-κB, and absence of responses to type I and type II IFN secretion in the most severe forms of MIS-C with severe myocarditis. This work led the authors to identify in monocytes and validate in peripheral blood mononuclear cells a molecular signature of 25 genes that allows discrimination of the most severe forms of MIS-C with myocarditis.

Intravenous Immunoglobulin-Associated Hemolytic Anemia

Intravenous immunoglobulin (IVIG) is an important therapeutic tool for the treatment of a variety of conditions, including immune thrombocytopenic purpura (ITP). Although IVIG has many approved indications and is typically well tolerated, a number of adverse effects have been reported. Hemolysis is a documented but under-recognized adverse effect associated with large individual or cumulative doses of IVIG. Hemolytic complications are typically mild and detected incidentally when screening tests, such as a complete blood count (CBC) showing decreased hemoglobin or a complete metabolic panel (CMP) resulting in elevated bilirubin, are performed for another reason. Herein, we report a case of significant hemolytic anemia in a 59 year old Caucasian woman, who required packed red blood cell transfusion after administration of IVIG for the treatment of ITP. Increased awareness of the potential for clinically significant hemolysis after the use of moderate cumulative doses of IVIG is needed, particularly in patients with risk factors for hemolysis.

Neutropenia resulting from high-dose intravenous immunoglobulin in dermatological patients

BACKGROUND AND OBJECTIVES

Current guidelines recommend high-dose intravenous immunoglobulin (IVIG) as a rescue therapy to treat severe cutaneous autoimmune disorders. Data on IVIG-induced hematological adverse events are limited in dermatological patients. We assessed the incidence and clinical implications of IVIG-induced neutropenia.

PATIENTS AND METHODS

Patients who received one or several cycles of IVIG between 2014 and 2019 were retrospectively evaluated. IVIG was given according to standardized infusion protocols. Daily differential blood counts were performed. Information on clinical baseline data, dermatological diagnosis, immunosuppressive pre-treatment, and IVIG-related adverse events was retrieved from patient files.

RESULTS

Seventeen patients received 106 IVIG treatment cycles. Neutrophil counts below 1,500/μL were documented during 36 (34.0 %) cycles, and neutrophils fell below 1,000/μL in 14 (13.2 %) cases. The average drop of neutrophils from day one (pre-dose) to days 2 and 3 of IVIG therapy was statistically significant (p = 0.006, and p = 0.002, respectively) despite correction for hemodilution, and so was a slight decrease of thrombocytes (p = 0.029, and p = 0.011, respectively). Four patients developed seven episodes of bacterial infections during or immediately after IVIG therapy.

CONCLUSIONS

IVIG-induced neutropenia is frequent in dermatological patients. A risk of secondary bacterial infections cannot be excluded.

Antibody-mediated immune suppression by antigen modulation is antigen-specific

Alloantibodies developing after exposure to red blood cell (RBC) alloantigens can complicate pregnancy and transfusion therapy. The only method currently available to actively inhibit RBC alloantibody formation is administration of antigen-specific antibodies, a phenomenon termed antibody-mediated immune suppression (AMIS). A well-known example of AMIS is RhD immune globulin prophylaxis to prevent anti-D formation in RhD- individuals. However, whether AMIS is specific or impacts alloimmunization to other antigens on the same RBC remains unclear. To evaluate the specificity of AMIS, we passively immunized antigen-negative recipients with anti-KEL or anti-hen egg lysozyme (HEL) antibodies, followed by transfusion of murine RBC expressing both the HEL-ovalbumin-Duffy (HOD) and human KEL antigens (HOD × KEL RBC). Significant immunoglobulin G deposition on transfused HOD × KEL RBC occurred in all passively immunized recipients. Complement deposition and antigen modulation of the KEL antigen occurred on transfused RBC only in anti-KEL-treated recipients, whereas HEL antigen levels decreased only in the presence of anti-HEL antibodies. Western blot analysis confirmed the specificity of antigen loss, which was not attributable to RBC endocytosis and appears distinct for the 2 antigens. Specifically, removal of KEL was attenuated by clodronate treatment, whereas loss of HEL was unaffected by clodronate in vivo but sensitive to protease treatment in vitro. Antigen-specific modulation correlated with antigen-specific AMIS, with anti-KEL treated recipients forming antibodies to the HOD antigen and anti-HEL-treated recipients developing antibodies to the KEL antigen. Together, these results demonstrate that passively administered antibodies can selectively inhibit the immune response to a specific antigen.