Effects of IGM-enriched solution on polymorphonuclear neutrophil function, bacterial clearance, and lung histology in endotoxemia

Comparative Molecular and Biological Characteristic of the Systemic Inflammatory Response in Adult and Old Male Wistar Rats with Different Resistance to Hypoxia

Morphological, molecular, and biological features of the systemic inflammatory response induced by LPS administration were assessed in adult and old male Wistar rats with high and low resistance to hypoxia. In 6 h after LPS administration, mRNA expression levels of Hif1a, Vegf, Nfkb, and level of IL-1β protein in old rats were higher than in adult rats regardless of hypoxia tolerance. The morphometric study showed that the number of neutrophils in the interalveolar septa of the lungs was significantly higher in low-resistant adult and old rats 6 h after LPS administration. Thus, in old male Wistar rats, systemic inflammatory response is more pronounced than in adult rats and depends on the initial tolerance to hypoxia, which should be considered when developing new approaches to the therapy of systemic inflammatory response in individuals of different ages.

Multifaceted Tissue-Protective Functions of Polyvalent Immunoglobulin Preparations in Severe Infections-Interactions with Neutrophils, Complement, and Coagulation Pathways

Severe infections induce immune defense mechanisms and initial tissue damage, which produce an inflammatory neutrophil response. Upon dysregulation of these responses, inflammation, further tissue damage, and systemic spread of the pathogen may occur. Subsequent vascular inflammation and activation of coagulation processes may cause microvascular obstruction at sites distal to the primary site of infection. Low immunoglobulin (Ig) M and IgG levels have been detected in patients with severe infections like sCAP and sepsis, associated with increased severity and mortality. Based on Ig's modes of action, supplementation with polyvalent intravenous Ig preparations (standard IVIg or IgM/IgA-enriched Ig preparations) has long been discussed as a treatment option for severe infections. A prerequisite seems to be the timely administration of Ig preparations before excessive tissue damage has occurred and coagulopathy has developed. This review focuses on nonclinical and clinical studies that evaluated tissue-protective activities resulting from interactions of Igs with neutrophils, complement, and the coagulation system. The data indicate that coagulopathy, organ failure, and even death of patients can possibly be prevented by the timely combined interactions of (natural) IgM, IgA, and IgG with neutrophils and complement.

Clinical efficacy of IgM-enriched immunoglobulin as adjunctive therapy in neonatal and pediatric sepsis: a systematic review and meta-analysis

Background

Sepsis is a major cause of mortality and morbidity globally, with around one-quarter of all sepsis-related deaths occurring in children under the age of 5. We conducted a meta-analysis and systematic review of the literature to evaluate the clinical effectiveness of an IgM-enriched immunoglobulin preparation in pediatrics patients and neonates with sepsis.

Methods

Systematic searches of PubMed, the Cochrane Library and Embase databases were performed in November 2022, with no date limitations, to identify studies in which IgM-enriched immunoglobulin was used as adjunctive therapy in neonatal and pediatric patients with sepsis.

Results

In total, 15 studies fulfilled the eligibility criteria, 13 neonatal studies and 2 pediatric studies. Pooled estimates from all studies indicated that mortality rates were significantly lower in patients who received treatment with the IgM-enriched immunoglobulin compared with controls (OR 0.41; 95% CI 0.32-0.55). Further analyses in neonatal studies, alone, showed a significant benefit with longer treatment durations (>3 days) vs. the recommended treatment duration (3 days) (OR 0.32; 95% CI 0.22-0.47) vs. (OR 0.61; 95% CI 0.41-0.92). Treatment with IgM-enriched immunoglobulin was associated with a lower mortality risk compared with controls in prospective studies vs. retrospective analyses (OR 0.37; 95% CI 0.27-0.51) vs. (OR 0.73; 95% CI 0.41-1.30).

Conclusions

This systematic review suggests that adjunctive treatment with IgM-enriched immunoglobulin may reduce the risk of mortality in neonatal and pediatric populations. However, large randomized controlled trials are required to further substantiate and evaluate these findings.

A new hope? Possibilities of therapeutic IgA antibodies in the treatment of inflammatory lung diseases

Inflammatory lung diseases represent a persistent burden for patients and the global healthcare system. The combination of high morbidity, (partially) high mortality and limited innovations in the last decades, have resulted in a great demand for new therapeutics. Are therapeutic IgA antibodies possibly a new hope in the treatment of inflammatory lung diseases? Current research increasingly unravels the elementary functions of IgA as protector against infections and as modulator of overwhelming inflammation. With a focus on IgA, this review describes the pathological alterations in mucosal immunity and how they contribute to chronic inflammation in the most common inflammatory lung diseases. The current knowledge of IgA functions in the circulation, and particularly in the respiratory mucosa, are summarized. The interplay between neutrophils and IgA seems to be key in control of inflammation. In addition, the hurdles and benefits of therapeutic IgA antibodies, as well as the currently known clinically used IgA preparations are described. The data highlighted here, together with upcoming research strategies aiming at circumventing the current pitfalls in IgA research may pave the way for this promising antibody class in the application of inflammatory lung diseases.

Best-practice IgM- and IgA-enriched immunoglobulin use in patients with sepsis

Background

Sepsis is a life-threatening organ dysfunction caused by a dysregulated host response to infection. Despite treatment being in line with current guidelines, mortality remains high in those with septic shock. Intravenous immunoglobulins represent a promising therapy to modulate both the pro- and anti-inflammatory processes and can contribute to the elimination of pathogens. In this context, there is evidence of the benefits of immunoglobulin M (IgM)- and immunoglobulin A (IgA)-enriched immunoglobulin therapy for sepsis. This manuscript aims to summarize current relevant data to provide expert opinions on best practice for the use of an IgM- and IgA-enriched immunoglobulin (Pentaglobin) in adult patients with sepsis.

Main text

Sepsis patients with hyperinflammation and patients with immunosuppression may benefit most from treatment with IgM- and IgA-enriched immunoglobulin (Pentaglobin). Patients with hyperinflammation present with phenotypes that manifest throughout the body, whilst the clinical characteristics of immunosuppression are less clear. Potential biomarkers for hyperinflammation include elevated procalcitonin, interleukin-6, endotoxin activity and C-reactive protein, although thresholds for these are not well-defined. Convenient biomarkers for identifying patients in a stage of immune-paralysis are still matter of debate, though human leukocyte antigen–antigen D related expression on monocytes, lymphocyte count and viral reactivation have been proposed. The timing of treatment is potentially more critical for treatment efficacy in patients with hyperinflammation compared with patients who are in an immunosuppressed stage. Due to the lack of evidence, definitive dosage recommendations for either population cannot be made, though we suggest that patients with hyperinflammation should receive an initial bolus at a rate of up to 0.6 mL (30 mg)/kg/h for 6 h followed by a continuous maintenance rate of 0.2 mL (10 mg)/kg/hour for ≥ 72 h (total dose ≥ 0.9 g/kg). For immunosuppressed patients, dosage is more conservative (0.2 mL [10 mg]/kg/h) for ≥ 72 h, without an initial bolus (total dose ≥ 0.72 g/kg).

Conclusions

Two distinct populations that may benefit most from Pentaglobin therapy are described in this review. However, further clinical evidence is required to strengthen support for the recommendations given here regarding timing, duration and dosage of treatment.

Use of Intravenous Immunoglobulins in Sepsis Therapy-A Clinical View

Sepsis is a life-threatening organ dysfunction, defined by a dysregulated host immune response to infection. During sepsis, the finely tuned system of immunity, inflammation and anti-inflammation is disturbed in a variety of ways. Both pro-inflammatory and anti-inflammatory pathways are upregulated, activation of the coagulation cascade and complement and sepsis-induced lymphopenia occur. Due to the manifold interactions in this network, the use of IgM-enriched intravenous immunoglobulins seems to be a promising therapeutic approach. Unfortunately, there is still a lack of evidence-based data to answer the important questions of appropriate patient populations, optimal timing and dosage of intravenous immunoglobulins. With this review, we aim to provide an overview of the role of immunoglobulins, with emphasis on IgM-enriched formulations, in the therapy of adult patients with sepsis and septic shock.

IgM-enriched immunoglobulins (Pentaglobin) may improve the microcirculation in sepsis: a pilot randomized trial

BACKGROUND

Polyclonal or IgM-enriched immunoglobulins may be beneficial during sepsis as an adjuvant immunomodulatory therapy. We aimed to test whether the infusion of IgM-enriched immunoglobulins improves microvascular perfusion during sepsis.

METHODS

Single-centre, randomized, double-blind, placebo-controlled phase II trial including adult patients with a diagnosis of sepsis or septic shock for less than 24 h. Patients received an intravenous infusion of 250 mg/kg (5 mL/kg) per day of IgM-enriched immunoglobulins (Pentaglobin, n = 10) for 72 h or placebo (NaCl 0.9%, n = 9). At baseline and after 24 and 72 h of infusion, the sublingual microcirculation was assessed with Incident Dark Field videomicroscopy. Thenar near-infrared spectroscopy (NIRS) was applied with a vascular occlusion test to assess tissue oxygenation and microvascular reactivity. Levels of interleukin (IL) 1-beta, IL-6, IL-8, IL-10 and tumour necrosis factor alpha were measured in the serum.

RESULTS

The perfused vessel density (PVD) for small vessels (diameter < 20 micron) increased in the Pentaglobin group (from 21.7 ± 4.7 to 25.5 ± 5.1 mm/mm²) and decreased in the placebo group (from 25 ± 5.8 to 20.7 ± 4.1 mm/mm², p for interaction < 0.001, two-way analysis of variance). The absolute between-group difference at 72 h was 4.77 (standard error 2.34), p = 0.140. The microvascular flow index for small vessels increased at 24 h in the Pentaglobin group (from 2.68 [2.38-2.78] to 2.93 [2.82-3], p < 0.01) and decreased at 72 h in the placebo group (from 2.83 [2.60-2.97] to 2.67 [2.48-2.73], p < 0.05). Changes in general parameters, cytokines and NIRS-derived parameters were similar between the two groups, except for IL-6 and IL-10 that significantly decreased at 72 h only in the Pentaglobin group.

CONCLUSIONS

A 72-h infusion of IgM-enriched immunoglobulins (Pentaglobin) in patients with sepsis or septic shock may be associated with an increase in sublingual microvascular perfusion. Further studies are needed to confirm our findings. Trial registration NCT02655133, www.ClinicalTrials.gov, date of registration 7th January 2016, https://www.clinicaltrials.gov/ct2/show/NCT02655133.

The novel polyclonal Ab preparation trimodulin attenuates ex vivo endotoxin-induced immune reactions in early hyperinflammation

Sepsis is a syndrome associated with excessive inflammation. Since mortality from sepsis remains high, more laboratory research is needed to provide insight into more effective ways to use novel, potentially more beneficial agents in sepsis. We investigated the ex vivo immunomodulatory effect of a novel polyclonal Ab preparation, trimodulin, containing IgM (∼23%), IgA (∼21%) and IgG (∼56%). Using whole blood and purified PBMCs from healthy volunteers and patients with sepsis, various ex vivo investigations upon endotoxin challenge and pre- and post-trimodulin treatment were performed. Endotoxin-induced TNF-α secretion was noticeably lower with than without trimodulin, implying attenuation of the hyper-responsive state. Trimodulin also lowered TLR2, TLR4, CD11b and CD64 detection on LPS/lipoteichoic acid-stimulated monocytes. These responses were observed in cells from healthy volunteers only shortly after ex vivo endotoxin stimulation and in whole blood from patients with early-stage sepsis. Furthermore, trimodulin markedly reduced lymphocyte proliferation and release of pro- and anti-inflammatory cytokines, but did not affect phagocytosis or oxidative-burst activities of endoxin-stimulated cells. Thus, trimodulin mitigated monocyte and lymphocyte hyperinflammatory responses early after endotoxin exposure. Determining whether early in vivo administration of trimodulin will elicit similar positive immunomodulatory effects and offer a clinical benefit warrants investigation.

Dependence of the severity of the systemic inflammatory response on resistance to hypoxia in male Wistar rats

Purpose

The aim of the study was to characterize the severity of the systemic inflammatory response induced by lipopolysaccharide (LPS) in animals with different resistance levels to hypoxia.

Materials and methods

Two to three months old male Wistar rats (220–240 g) were divided according to hypoxia tolerance in a hypobaric chamber. After a month, they were injected intraperitoneally with Escherichia coli LPS at a dose of 1.5 mg/kg. After 3, 6 and 24 hours of LPS injection, we studied the levels of IL-1β, C-reactive protein (CRP) and TGF-β in the serum, the expression of Hif-1α and Nf-kb in the liver, morphological disorders in the lung and ex vivo production of IL-10 by splenic cells activated by ConA.

Results

In the early periods after the injection of LPS, increase in Nf-kb expression in the liver was observed only in the rats susceptible to hypoxia. After 6 hours of LPS injection, the number of neutrophils in the interalveolar septa of the lungs of rats susceptible to hypoxia was higher than in tolerant rats. This points to the development of more pronounced LPS-induced inflammation in the rats susceptible to hypoxia and is accompanied by increased expression of Hif-1α in the liver after 6 hours of LPS administration, serum IL-1β level after 3 hours and CRP level after 24 hours. The production of the anti-inflammatory cytokine IL-10 by the spleen was significantly decreased after 6 hours of LPS injection only in the animals tolerant to hypoxia. After 24 hours of LPS injection, a significant decrease in serum TGF-β level occurred in the rats tolerant to hypoxia in comparison with the control group, which improved the survival rates of the animals.

Conclusion

We have demonstrated the differences in the severity of the LPS-induced inflammatory response in male Wistar rats with different resistance levels to hypoxia. Rats susceptible to hypoxia are characterized by a more pronounced inflammatory response induced by LPS.

IgM Natural Autoantibodies in Physiology and the Treatment of Disease

Antibodies are vital components of the adaptive immune system for the recognition and response to foreign antigens. However, some antibodies recognize self-antigens in healthy individuals. These autoreactive antibodies may modulate innate immune functions. IgM natural autoantibodies (IgM-NAAs) are a class of primarily polyreactive immunoglobulins encoded by germline V-gene segments which exhibit low affinity but broad specificity to both foreign and self-antigens. Historically, these autoantibodies were closely associated with autoimmune disease. Nevertheless, not all human autoantibodies are pathogenic and compelling evidence indicates that IgM-NAAs may exert a spectrum of effects from injurious to protective depending upon cellular and molecular context. In this chapter, we review the current state of knowledge regarding the potential physiological and therapeutic roles of IgM-NAAs in different disease conditions such as atherosclerosis, cancer, and autoimmune disease. We also describe the discovery of two reparative IgM-NAAs by our laboratory and delineate their proposed mechanisms of action in central nervous system (CNS) disease.

Effects of the timing of administration of IgM- and IgA-enriched intravenous polyclonal immunoglobulins on the outcome of septic shock patients

BACKGROUND

The administration of endovenous immunoglobulins in patients with septic shock could be beneficial and preparations enriched with IgA and IgM (ivIgGAM) seem to be more effective than those containing only IgG. In a previous study Berlot et al. demonstrated that early administration of ivIgGAM was associated with lower mortality rate. We studied a larger population of similar patients aiming either to confirm or not this finding considering also the subgroup of patients with septic shock by multidrug-resistant (MDR) pathogens.

METHODS

Adult patients with septic shock in intensive care unit (ICU) treated with ivIgGAM from August 1999 to December 2016 were retrospectively examined. Collected data included the demographic characteristics of the patients, the diagnosis at admission, SOFA, SAPS II and Murray Lung Injury Score (LIS), characteristics of the primary infection, the adequacy of antimicrobial therapy, the delay of administration of ivIgGAM from the ICU admission and the outcome at the ICU discharge. Parametric and nonparametric tests and logistic regression were used for statistic analysis.

RESULTS

During the study period 107 (30%) of the 355 patients died in ICU. Survivors received the ivIgGAM earlier than nonsurvivors (median delay 12 vs 14 h), had significantly lower SAPS II, SOFA and LIS at admission and a lower rate of MDR- and fungal-related septic shock. The appropriateness of the administration of antibiotics was similar in survivors and nonsurvivors (84 vs 79%, respectively, p: n.s). The delay in the administration of ivIgGAM from the admission was associated with in-ICU mortality (odds ratio per 1-h increase = 1.0055, 95% CI 1.003-1.009, p < 0.001), independently of SAPS II, LIS, cultures positive for MDR pathogens or fungi and onset of septic shock. Only 46 patients (14%) had septic shock due to MDR pathogens; 21 of them (46%) died in ICU. Survivors had significantly lower SAPS II, SOFA at admission and delay in administration of ivIgGAM than nonsurvivors (median delay 18 vs 66 h). Even in this subgroup the delay in the administration of ivIgGAM from the admission was associated with an increased risk of in-ICU mortality (odds ratio 1.007, 95% CI 1.0006-1.014, p = 0.048), independently of SAPS II.

CONCLUSIONS

Earlier administration of ivIgGAM was associated with decreased risk of in-ICU mortality both in patients with septic shock caused by any pathogens and in patients with MDR-related septic shock.

IgM and IgA enriched polyclonal immunoglobulins reduce short term mortality in extremely low birth weight infants with sepsis: a retrospective cohort study

BACKGROUND

Immunoglobulin supplementation is a debated strategy in fighting sepsis. We evaluated a polyclonal IgM and IgA enriched immunoglobulin (IgMeIVIG) preparation in reducing the short-term mortality in extremely low birth weight neonates (ELBW) with proven infection.

METHODS

ELBW infants born from January 2008 to December 2014 were eligible for this retrospective case-control analysis if they were symptomatic and had a positive blood culture after 72 hours of life. Patients received antibiotic treatment with or without IgMeIVIG (intravenously, 250 mg/kg/day for 3 days) within the 24 hours from clinical suspicion as per indication of the attending physician. Short-term (7 and 21 days) mortality was the study primary outcome while secondary outcomes were: mortality at discharge, intraventricular hemorrhage, necrotizing enterocolitis, bronchopulmonary dysplasia, periventricular leukomalacia, and retinopathy of prematurity.

RESULTS

Each group was composed by thirty-nine infants. Both groups were similar for antenatal steroids, mode of delivery, birth weight, gestational age and SNAPII score as indicator of disease severity. Infants receiving IgMeIVIG had a significantly lower short-term mortality compared with neonates receiving antibiotics alone: 6/39 (15%) vs. 14/39 (36%); P=0.038. No differences in other outcomes were found.

CONCLUSIONS

This study shows that IgMeIVIG may have a role as adjuvant therapy in ELBW infants with proven sepsis. We warrant future prospective, blinded RCT studies where IgMeIVIG can be consistently used if needed throughout the NICU admission in ELBW septic neonates to appropriately evaluate its effect on mortality at discharge.

A double blind randomized experimental study on the use of IgM-enriched polyclonal immunoglobulins in an animal model of pneumonia developing shock

BACKGROUND

Patients with severe pneumonia often develop septic shock. IgM-enriched immunoglobulins have been proposed as a potential adjuvant therapy for septic shock. While in vitro data are available on the possible mechanisms of action of IgM-enriched immunoglobulins, the results of the in vivo experimental studies are non-univocal and, overall, unconvincing. We designed this double blinded randomized controlled study to test whether IgM-enriched immunoglobulins administered as rescue treatment in a pneumonia model developing shock, could either limit lung damage and/or contain systemic inflammatory response.

METHODS

Thirty-eight Sprague Dawley rats were ventilated with injurious ventilation for 30min to prime the lung. The rats were subsequently randomized to received intratracheal instillation of either lipopolysaccharide (LPS) (12mg/kg) or placebo followed by 3.5h of protective mechanical ventilation. IgM-enriched immunoglobulins at 25mg/h (0.5mL/h) or saline were intravenously administered in the last hour of mechanical ventilation. During the experiment, gas exchange and hemodynamic measurements were recorded. Thereafter, the animals were sacrificed, and blood and organs were stored for cytokines measurements.

RESULTS

Despite similar lung and hemodynamic findings, the administration of IgM-enriched immunoglobulins compared to placebo significantly modulates the inflammatory response by increasing IL-10 levels in the bloodstream and by decreasing TNF-α in bronchoalveolar lavage (BAL) fluid. Furthermore, in vitro data suggest that IgM-enriched immunoglobulins induce monocytes production of IL-10 after LPS stimulation.

CONCLUSIONS

In an in vivo model of pneumonia developing shock, IgM-enriched immunoglobulins administered as rescue treatment enhance the anti-inflammatory response by increasing blood levels of IL-10 and reducing TNF-α in BAL fluid.

Site-Specific N-Glycosylation of Recombinant Pentameric and Hexameric Human IgM

Glycosylation is known to play an important role in IgG antibody structure and function. Polymeric IgM, the largest known antibody in humans, displays five potential N-glycosylation sites on each heavy chain monomer. IgM can exist as a pentamer with a connecting singly N-glycosylated J-chain (with a total of 51 glycosylation sites) or as a hexamer (60 glycosylation sites). In this study, the N-glycosylation of recombinant pentameric and hexameric IgM produced by the same human cell type and culture conditions was site-specifically profiled by RP-LC-CID/ETD-MS/MS using HILIC-enriched tryptic and GluC glycopeptides. The occupancy of all putative N-glycosylation sites on the pentameric and hexameric IgM were able to be determined. Distinct glycosylation differences were observed between each of the five N-linked sites on the IgM heavy chains. While Asn171, Asn332, and Asn395 all had predominantly complex type glycans, differences in glycan branching and sialylation were observed between the sites. Asn563, a high mannose-rich glycosylation site that locates in the center of the IgM polymer, was only approximately 60% occupied in both the pentameric and hexameric IgM forms, with a difference in relative abundance of the glycan structures between the pentamer and hexamer. This study highlights the information obtained by characterization of the site-heterogeneity of a highly glycosylated protein of high molecular mass with quaternary structure, revealing differences that would not be seen by global glycan or deglycosylated peptide profiling. Graphical Abstract ᅟ.

IgM-enriched solution BT086 improves host defense capacity and energy store preservation in a rabbit model of endotoxemia

Introduction

The therapeutic value of intravenous immunoglobulin (IVIG) as an adjuvant therapy in sepsis remains debatable. We hypothesized that intravenous administration of BT086, a predominantly IgM IVIG solution, would improve host defense in an established rabbit model of endotoxemia and systemic sepsis.

Methods

New Zealand white rabbits were randomized into the following four groups: (1) the negative control group without lipopolysaccharide (LPS, control), (2) the positive control group with LPS infusion (LPS group), (3) the albumin‐treated LPS group (ALB+LPS group), and (4) the BT086‐treated LPS group (BT086 + LPS group). A standardized amount of E. coli was intravenously injected into all of the animals. The vital parameters, the concentration of E. coli in the blood and other organs, the residual granulocyte phagocytosis activity, and the levels of the inflammatory mediators were measured. Histological changes in the lung and liver tissue were examined following autopsy.

Results

The elimination of E. coli from the bloodstream was expedited in the BT086‐treated group compared with the LPS‐ and albumin‐treated groups. The BT086 + LPS group exhibited higher phagocytic activity of polymorphonuclear neutrophils (PMNs) than the control and ALB+LPS groups. The liver energy stores were higher in the BT086 + LPS group than in the other groups.

Conclusion

Our data suggest that the IgM‐enriched IVIG has the potential to improve host defense in a rabbit model of endotoxemia. Studies using different animal models and dosages are necessary to further explore the potential benefits of IgM‐enriched IVIG solutions.

Effects of intravenous immunoglobulin therapy on behavior deficits and functions in sepsis model

Background

We aim to demonstrate behavioral alterations in a sepsis model using intravenous (IV) immunoglobulin G (IgG) and immunoglobulins enriched with IgA and IgM (IgGAM).

Methods

We divided 48 Wistar albino rats into five groups: control group, sham-operated group (only antibiotic treatment), cecal ligation and puncture (CLP) group (CLP plus antibiotic treatment), IgG group (250 mg/kg IV IgG) and IgGAM group (250 mg/kg IV IgGAM). Intravenous immunoglobulins were given 5 min after the CLP procedure. Experimental animals put into three behavioral tasks 10, 30 and 60 days after the surgery; to evaluate the locomotor activity, an open field test was performed, elevated plus maze test was used to measure anxiety levels, and depressive state was assessed by forced swimming test. The effects of therapy which were acquired from the results of these tests were used to estimate the behavioral changes after CLP.

Results

The mortality rate of 50% in the septic rats decreased to 30 and 20% with the administration of IgG and IgGAM, respectively. Significant changes on locomotor activity and depressive-like behavior were reported in the sepsis group; on the other hand, the treatment with immunoglobulins reduced the symptoms. Treatment with immunoglobulins attenuated the sepsis-related anxiogenic-like responses. Behavioral alterations returned to normal on day 60 in all groups.

Conclusions

Sepsis caused deterioration on behavioral parameters. Immunoglobulin treatments alleviated the symptoms of functional disturbances and caused early reversal of behavioral deficits in septic animals.

The protective effects of IgM-enriched immunoglobulin and erythropoietin on the lung and small intestine tissues of rats with induced sepsis: biochemical and histopathological evaluation

CONTEXT

Sepsis continues to be a significant problem for critical care patients.

OBJECTIVE

To evaluate the protective effects of IgM-enriched immunoglobulin and erythropoietin on pulmonary and small intestine tissues in a rat model of intra-abdominal sepsis induced via the cecal ligation and puncture (CLP) method.

MATERIALS AND METHODS

Male Sprague-Dawley rats were used. Control group (n = 6): surgical procedure was not performed. Laparotomy was only performed in the sham group (n = 6) and CLP was only performed in the sepsis (CLP) group (n = 30). After erythropoietin (2000 U/kg, intraperitoneal) was given in the sepsis + erythropoietin (CLP + EPO) group (n = 30), IgM-enriched immunoglobulin (600 mg/kg, intraperitoneal) was given in the sepsis + pentaglobin (CLP + PEN) group (n = 30), CLP was created. Intracardiac blood samples were collected for biochemical analysis; lung and small intestine tissue samples were removed for histopathological evaluation.

RESULTS

Plasma TNF-α levels (pg/ml) were similar among CLP, CLP + EPO, and CLP + PEN groups (204.0 ± 52.4, 198.5 ± 17.3, and 214.6 ± 93.6, respectively). The CLP group had higher plasma IL-1β levels (pg/ml) compared with CLP + EPO and CLP + PEN groups (325.1 ± 134.1, 164.3 ± 25.6, and 186.3 ± 26.0, respectively) (p < 0.05). Rats in CLP + EPO and CLP + PEN groups had abolished histopathologic appearance of lung and small intestine tissues compared with rats in the CLP group.

DISCUSSION AND CONCLUSION

Our findings support the use of EPO and IgM-enriched immunoglobulin in the prevention of lung and small intestine injuries associated with sepsis.

Early therapy with IgM-enriched polyclonal immunoglobulin in patients with septic shock

PURPOSE

To determine whether there was an association between adjunctive therapy with IgM-enriched immunoglobulin (IgM) and the 30-day mortality rate in patients with septic shock.

METHODS

In 2008 we introduced IgM as a possible adjunctive therapy to be provided within 24 h after shock onset in the management protocol for patients with septic shock. In this retrospective study we included the adult patients suitable for IgM therapy admitted to our ICU from January 2008 to December 2011. An unadjusted comparison between patients who did or did not receive IgM therapy, a multivariate logistic model adjusted for confounders and propensity score-based matching were used to evaluate the association between early IgM treatment and mortality.

RESULTS

One hundred and sixty-eight patients were included in the study. Of these, 92 (54.8%) received IgM therapy. Patients who did or did not receive IgM were similar with regards to infection characteristics, severity scores and sepsis treatment bundle compliance. Patients who received IgM were more likely to have blood cultures before antibiotics and to attain a plateau inspiratory pressure less than 30 cmH2O (p < 0.05). The 30-day mortality rate was reduced by 21.1% (p < 0.05) in the group that received IgM compared to the group that did not. The multivariate adjusted regression model (OR 0.17; CI 95% 0.06-0.49; p = 0.001) and the propensity score-based analysis (OR 0.35; CI 95% 0.14-0.85; p = 0.021) confirmed that IgM therapy was associated with reduced mortality at 30 days after the onset of septic shock.

CONCLUSIONS

Our experience indicates that early adjunctive treatment with IgM may be associated with a survival benefit in patients with septic shock. However, additional studies are needed to better evaluate the role of IgM therapy in the early phases of septic shock.

Reconstituted human polyclonal plasma-derived secretory-like IgM and IgA maintain the barrier function of epithelial cells infected with an enteropathogen

Intravenous administration of polyclonal and monoclonal antibodies has proven to be a clinically valid approach in the treatment, or at least relief, of many acute and chronic pathologies, such as infection, immunodeficiency, and a broad range of autoimmune conditions. Plasma-derived IgG or recombinant IgG are most frequently used for intravenous or subcutaneous administration, whereas a few IgM-based products are available as well. We have established recently that secretory-like IgA and IgM can be produced upon association of plasma-derived polymeric IgA and IgM with a recombinant secretory component. As a next step toward potential future mucosal administration, we sought to unravel the mechanisms by which these secretory Igs protect epithelial cells located at the interface between the environment and the inside of the body. By using polarized epithelial Caco-2 cell monolayers and Shigella flexneri as a model enteropathogen, we found that polyspecific plasma-derived SIgA and SIgM fulfill many protective functions, including dose-dependent recognition of the antigen via formation of aggregated immune complexes, reduction of bacterial infectivity, maintenance of epithelial cell integrity, and inhibition of proinflammatory cytokine/chemokine production by epithelial cells. In this in vitro model devoid of other cellular or molecular interfering partners, IgM and secretory IgM showed stronger bacterial neutralization than secretory IgA. Together, these data suggest that mucosally delivered antibody preparations may be most effective when combining both secretory-like IgA and IgM, which, together, play a crucial role in preserving several levels of epithelial cell integrity.

Polyclonal and monoclonal antibodies in clinic

Immunoglobulins (Ig) or antibodies are heavy plasma proteins, with sugar chains added to amino-acid residues by N-linked glycosylation and occasionally by O-linked glycosylation. The versatility of antibodies is demonstrated by the various functions that they mediate such as neutralization, agglutination, fixation with activation of complement and activation of effector cells. Naturally occurring antibodies protect the organism against harmful pathogens, viruses and infections. In addition, almost any organic chemical induces antibody production of antibodies that would bind specifically to the chemical. These antibodies are often produced from multiple B cell clones and referred to as polyclonal antibodies. In recent years, scientists have exploited the highly evolved machinery of the immune system to produce structurally and functionally complex molecules such as antibodies from a single B clone, heralding the era of monoclonal antibodies. Most of the antibodies currently in the clinic, target components of the immune system, are not curative and seek to alleviate symptoms rather than cure disease. Our group used a novel strategy to identify reparative human monoclonal antibodies distinct from conventional antibodies. In this chapter, we discuss the therapeutic relevance of both polyclonal and monoclonal antibodies in clinic.

Are IgM-enriched immunoglobulins an effective adjuvant in septic VLBW infants?

Aim

To investigate the effectiveness of IgM-enriched immunoglobulins (IgM-eIVIG) in reducing short-term mortality of neonates with proven late-onset sepsis.

Methods

All VLBW infants from January 2008 to December 2012 with positive blood culture beyond 72 hours of life were enrolled in a retrospective cohort study. Newborns born after June 2010 were treated with IgM-eIVIG, 250 mg/kg/day iv for three days in addition to standard antibiotic regimen and compared to an historical cohort born before June 2010, receiving antimicrobial regimen alone. Short-term mortality (i.e. death within 7 and 21 days from treatment) was the primary outcome. Secondary outcomes were: total mortality, intraventricular hemorrhage, necrotizing enterocolitis, periventricular leukomalacia, bronchopulmonary dysplasia at discharge.

Results

79 neonates (40 cases) were enrolled. No difference in birth weight, gestational age or SNAP II score (disease severity score) were found. Significantly reduced short-term mortality was found in treated infants (22% vs 46%; p = 0.005) considering all microbial aetiologies and the subgroup affected by Candida spp. Secondary outcomes were not different between groups.

Conclusion

This hypothesis-generator study shows that IgM-eIVIG is an effective adjuvant therapy in VLBW infants with proven sepsis. Randomized controlled trials are warranted to confirm this pilot observation.

Polyvalent immunoglobulin significantly attenuated the formation of IL-1β in Escherichia coli-induced sepsis in pigs

Evidence suggests that adjunctive treatment with intravenous immunoglobulin preparations enriched with IgA and IgM reduce mortality in sepsis. The mode of action of polyvalent immunoglobulin is complex, including neutralization of toxins and modulation of complement activation and cytokine formation toward an anti-inflammatory profile. In this study we explored the effect of Pentaglobin, containing IgG, IgA and IgM, on the initial inflammatory reaction as well as on hemodynamics, using a well characterized and standardized porcine model of sepsis. Anesthetized and mechanically ventilated pigs, mean weight 14.9 kg, were allocated into two groups of 8 animals, receiving either Pentaglobin or saline, before sepsis was induced by intravenous Escherichia coli infusion. Five negative controls received saline only. All animals were observed for 4 h under extensive invasive monitoring. Pentaglobin significantly (p < 0.05) attenuated IL-1β formation by 38% at the end of the experiment, and markedly increased (p < 0.05) the formation of IL-10 at 60 min. TNF-α, IL-6, IL-8 and expression of the cell surface marker wCD11R3 were lower in the Pentaglobin group, but the differences were not significant. The serum concentration of LPS was three times higher in the Pentaglobin group (p < 0.005), indicating binding of LPS to Pentaglobin. Complementary in vitro experiments showed a higher binding affinity for IgM and IgA to LPS than for IgG. LPS-induced formation of IL-6 was significantly (p < 0.05) attenuated by Pentaglobin in an in vitro whole blood model. In conclusion, Pentaglobin decreased the key inflammasome IL-1β molecule in an E. coli-model of pigs sepsis.

Natural IgM in immune equilibrium and harnessing their therapeutic potential

Natural IgM Abs are the constitutively secreted products of B1 cells (CD5(+) in mice and CD20(+)CD27(+)CD43(+)CD70(-) in humans) that have important and diverse roles in health and disease. Whereas the role of natural IgM as the first line of defense for protection against invading microbes has been extensively investigated, more recent reports have highlighted their potential roles in the maintenance of tissue homeostasis via clearance of apoptotic and altered cells through complement-dependent mechanisms, inhibition of inflammation, removal of misfolded proteins, and regulation of pathogenic autoreactive IgG Abs and autoantibody-producing B cells. These observations have provided the theoretical underpinnings for efforts that currently seek to harness the untapped therapeutic potential of natural IgM either by boosting in vivo natural IgM production or via therapeutic infusions of monoclonal and polyclonal IgM preparations.

Role of active nitrogen molecules in progression of septic shock

INTRODUCTION

Active nitrogen molecules are formed as a result of cell metabolism. They are essential for cell metabolism, but when produced in excess, they contribute to the pathogenesis of several disease processes. These nitrogen molecules play an important role in vascular instability of septic shock. This study was planned to detect the role of active nitrogen molecules in the progression of septic shock.

MATERIALS AND METHODS

Blood samples were collected from 118 critically ill patients admitted in ICU and from 95 healthy relatives accompanying the patients. Patients were categorized into three groups: systemic inflammatory response syndrome (n = 54), sepsis (n = 35) and septic shock (n = 29). Plasma total nitrite (nitrites and nitrates), cytokines like tumour necrosis factor-α (TNF-α) and plasma lactate were measured to assess inflammatory activity and severity of septic shock.

RESULTS

High plasma levels of nitrite and nitrate (No₂-/No₃-) were observed in critically ill patients (mean level 78.92 μmol/l in sepsis and 97.20 μmol/l in septic shock). Mean plasma TNF-α level in sepsis was 213.50 pg/ml and septic shock was 227.38 pg/ml.

CONCLUSION

Plasma No₂-/No₃- and TNF-α levels were high in patients with sepsis and septic shock, which increased with severity of sepsis.

The importance of natural IgM: scavenger, protector and regulator

The existence of IgM has been known for more than a century, but its importance in immunity and autoimmunity continues to emerge. Studies of mice deficient in secreted IgM have provided unexpected insights into its role in several diverse processes, from B cell survival to atherosclerosis, as well as in autoimmunity and protection against infection. Among the various distinct properties that underlie the functions of IgM, two stand out: its polyreactivity and its ability to facilitate the removal of apoptotic cells. In addition, new B cell-targeted therapies for the treatment of autoimmunity have been shown to cause a reduction in serum IgM, potentially disrupting the functions of this immunoregulatory molecule and increasing susceptibility to infection.

Molecular biology of inflammation and sepsis: a primer

BACKGROUND

Remarkable progress has been made during the last decade in defining the molecular mechanisms that underlie septic shock. This rapidly expanding field is leading to new therapeutic opportunities in the management of severe sepsis.

AIM

To provide the clinician with a timely summary of the molecular biology of sepsis and to better understand recent advances in sepsis research.

DATA SELECTION

Medline search of relevant publications in basic mechanisms of sepsis/severe sepsis/septic shock, and selected literature review of other manuscripts about the signalosome, inflammasome, apoptosis, or mechanisms of shock. DATA SYNTHESIS AND FINDINGS: The identification of the toll-like receptors and the associated concept of innate immunity based upon pathogen- or damage-associated molecular pattern molecules allowed significant advances in our understanding of the pathophysiology of sepsis. The essential elements of the inflammasome and signal transduction networks responsible for activation of the host response have now been characterized. Apoptosis, mitochondrial dysfunction, sepsis-related immunosuppression, late mediators of systemic inflammation, control mechanisms for coagulation, and reprogramming of immune response genes all have critical roles in the development of sepsis.

CONCLUSIONS

Many of these basic discoveries have direct implications for the clinical management of sepsis. The translation of these "bench-to-bedside" findings into new therapeutic strategies is already underway. This brief review provides the clinician with a primer into the basic mechanisms responsible for the molecular biology of sepsis, severe sepsis, and septic shock.