IgM levels in plasma predict outcome in severe pandemic influenza

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.

The immunomodulating activity of trimodulin (polyvalent IgM, IgA, IgG solution): a post hoc analysis of the phase II CIGMA trial

BACKGROUND

The phase II CIGMA trial performed in 160 patients with severe community-acquired pneumonia (sCAP) found treatment with trimodulin (human polyvalent immunoglobulin [Ig]: ~ 23% IgM, ~ 21% IgA, ~ 56% IgG) was associated with a lower mortality in those patients with elevated baseline serum levels of C-reactive protein (CRP) and/or subnormal IgM.

METHODS

In this post hoc analysis, the pharmacodynamic effects of trimodulin treatment (182.6 mg/kg/day for 5 days) were investigated on Ig replenishment, cellular markers of inflammation (absolute neutrophil [ANC] and lymphocyte [ALC] count, neutrophil-to-lymphocyte ratio [NLR]), and soluble markers of inflammation (procalcitonin [PCT] and CRP). The impact of these pharmacodynamic effects on mortality was also evaluated.

RESULTS

Compared with healthy subjects, baseline serum levels of IgM, IgG, and ALC were significantly lower, and ANC, NLR, PCT and CRP significantly higher in sCAP patients (p < 0.0001). Low Ig concentrations increased with trimodulin. Normalization of ANC (analysis of variance [ANOVA] p = 0.016) and PCT (ANOVA p = 0.027) was more rapid with trimodulin compared with placebo. These and other effects were more evident in patients with low baseline IgM levels. Normalization of PCT and CRP levels was both steadier and faster with trimodulin treatment. In patients with low baseline ALC, trimodulin was associated with a lower 28-day all-cause mortality rate (14.5% vs 32.1% in placebo, p = 0.043) and more ventilator-free days ([VFD]; median VFD: 3.5 vs 11 in placebo, p = 0.043). These numerical differences were greater if baseline IgM was also low (low ALC, low IgM: 8.1% mortality vs 34.1% placebo, p = 0.006; 3 VFD vs 15 VFD, p = 0.009, respectively). Results were consistent in patients with high baseline CRP (low ALC, high CRP: 10.9% mortality vs 34.1% placebo, p = 0.011).

CONCLUSIONS

This post hoc pharmacodynamic analysis of a blinded phase II trial suggests that trimodulin compensates for, and more rapidly modifies, the dysregulated inflammatory response seen in sCAP patients. Trimodulin was associated with significantly lower mortality and more VFD in subgroups with high CRP and low ALC. This effect was particularly marked in patients who also had low baseline IgM values. These findings require confirmation in prospective trials.

Exploring the active ingredients and pharmacological mechanisms of the oral intake formula Huoxiang Suling Shuanghua Decoction on influenza virus type A based on network pharmacology and experimental exploration

Objective

To investigate the active ingredients, underlying anti-influenza virus effects, and mechanisms of Huoxiang Suling Shuanghua Decoction (HSSD).

Materials and methods

The therapeutic effect of HSSD were confirmed through the survival rate experiment of H1N1-infected mice. Then, the HSSD solution and the ingredients absorbed into the blood after treatment with HSSD in rats were identified by UPLC/Q-TOF MS, while the main contents of ingredients were detected by high performance liquid chromatography (HPLC). Next, a systems pharmacology approach incorporating target prediction, gene ontology (GO) enrichment, kyoto encyclopedia of genes and genomes (KEGG) pathway analysis, and molecular docking were performed to screen out the active compounds and critical pathways of HSSD in treating influenza. According to prediction results, real-time quantitative polymerase chain reaction (RT-qPCR) and immunohistochemistry assay were used to detect the mRNA and protein expression levels of critical targets in H1N1-infected mice lungs.

Results

Huoxiang Suling Shuanghua Decoction improved the survival rate of H1N1-infected mice and prolonged the mice’s lifespan. Besides, HSSD exerts an antivirus effect by decreasing the levels of hemagglutinin (HA) and nucleoprotein (NP) to inhibit the replication and proliferation of H1N1, reducing the lung pathological state, inhibiting the cell apoptosis in the lung, and regulating the abnormal responses of peripheral blood, including GRA, LYM, white blood cell (WBC), PLT, and hemoglobin (HGB). Then, 87 compounds in the HSSD solution and 20 ingredients absorbed into the blood after treatment with HSSD were identified. Based on this, combined with the network analysis and previous research on antivirus, 16 compounds were screened out as the active components. Moreover, 16 potential targets were predicted by network pharmacology analysis. Next, molecular docking results showed stable binding modes between compounds and targets. Furthermore, experimental validation results indicated that HSSD regulates the contents of Immunoglobulin A (IgA), Immunoglobulin M (IgM), and Immunoglobulin G (IgG) in serum, modulating the levels of IFN-γ, IL-6, IL-10, MCP-1, MIP-1α, and IP-10 in the lung tissue, and significantly decreasing the mRNA and protein expressions of TLR4, CD14, MyD88, NF-κB p65, HIF1 α, VEGF, IL17A, and IL6 in the lung tissue.

Conclusion

Huoxiang Suling Shuanghua Decoction exerts an anti-influenza effect by affecting the expressions of mRNA and protein including TLR4, CD14, MyD88, NF-kB p65, HIF-1α, VEGF, IL17A, IL6, and inhibiting the accumulation of inflammation. Our study provided experimental pieces of evidence about the practical application of HSSD in treating influenza.

Early predictors of lung necrosis severity in children with community-acquired necrotizing pneumonia

OBJECTIVE

To analyze baseline clinical and laboratory characteristics and explore the possible predictors of lung necrosis severity in children with community-acquired necrotizing pneumonia (NP).

METHODOLOGY

This retrospective observational study was performed in a tertiary referral center. A total of 104 patients aged <15 years with community-acquired pneumonia and radiologically confirmed NP by computed tomography (CT) were included. Patients were classified into the mild, moderate, or massive necrosis groups.

RESULTS

Among them, 29, 41, and 34 patients had mild, moderate, and massive necrosis, respectively. Moreover, 34.6% of the patients were admitted to pediatric intensive care unit. Massive necrosis was more likely to occur during winter (p < 0.05) and was associated with more severe clinical outcomes, such as longer duration of fever, longer hospitalization, increased mortality, and a higher risk of subsequent surgical intervention (p < 0.05). Multivariate analysis demonstrated that the following were independent risk factors for massive necrosis in this study: C-reactive protein (CRP) (p = 0.036), serum albumin (p = 0.009), and immunoglobulin M (IgM) (p = 0.022). Receiver operating characteristic analysis showed that when the cut-off value for CRP, serum albumin, and IgM were set at 122 mg/L, 30.8 g/L, and 95.7 mg/dl, respectively, they showed good diagnostic performance for differentiating patients with massive necrosis from all patients with NP.

CONCLUSION

NP is a potentially severe complication of pediatric community-acquired pneumonia. Different severities of lung necrosis can lead to different clinical outcomes. CRP, serum albumin, and IgM levels are independent predictors of the degree of lung necrosis.

Low SARS-CoV-2 antibody titers may be associated with poor clinical outcomes for patients with severe COVID-19

Recently, immune response to coronavirus disease (COVID-19) has attracted attention where an association between higher antibody titer and worsening disease severity has been reported. However, our experiences with severe COVID-19 patients with low antibody titers led to hypothesizing that suppressed humoral immune response may be associated with poorer prognosis in severe COVID19. In this study, antibody titers in severe COVID19 patients were measured at 7, 10, 12, and 14 days after onset. Patients were divided into survivors and non-survivors. SARS-CoV-2 IgM in survivors and non-survivors were 0.06 AU and 0.02 AU (P = 0.048) at 10 days, 0.1 AU and 0.03 AU (P = 0.02) at 12 days, and 0.17 AU and 0.06 AU (P = 0.02) at 14 days. IgG in survivors and non-survivors were 0.01 AU and 0.01 AU (P = 0.04) at 7 days, 0.42 AU and 0.01 AU (P = 0.04) at 12 days, and 0.42 AU and 0.01 AU (P = 0.02) at 14 days. Multivariate analysis showed better survival among patients with IgM positivity at 12 days (P = 0.04), IgG positivity at 12 days (P = 0.04), IgM positivity at 14 days (P = 0.008), and IgG positivity at 14 days (P = 0.005). In severe COVID-19, low antibody titers on days 12 and 14 after onset were associated with poorer prognosis.

Therapeutic antibodies for COVID-19: is a new age of IgM, IgA and bispecific antibodies coming?

Early humoral immune responses to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are dominated by IgM and IgA antibodies, which greatly contribute to virus neutralization at mucosal sites. Given the essential roles of IgM and IgA in the control and elimination of SARS-CoV-2 infection, the mucosal immunity could be exploited for therapeutic and prophylactic purposes. However, almost all neutralizing antibodies that are authorized for emergency use and under clinical development are IgG antibodies, and no vaccine has been developed to boost mucosal immunity for SARS-CoV-2 infection. In addition to IgM and IgA, bispecific antibodies (bsAbs) combine specificities of two antibodies in one molecule, representing an important alternative to monoclonal antibody cocktails. Here, we summarize the latest advances in studies on IgM, IgA and bsAbs against SARS-CoV-2. The current challenges and future directions in vaccine design and antibody-based therapeutics are also discussed.

Management of pneumonia in critically ill patients

Severe pneumonia is associated with high mortality (short and long term), as well as pulmonary and extrapulmonary complications. Appropriate diagnosis and early initiation of adequate antimicrobial treatment for severe pneumonia are crucial in improving survival among critically ill patients. Identifying the underlying causative pathogen is also critical for antimicrobial stewardship. However, establishing an etiological diagnosis is challenging in most patients, especially in those with chronic underlying disease; those who received previous antibiotic treatment; and those treated with mechanical ventilation. Furthermore, as antimicrobial therapy must be empiric, national and international guidelines recommend initial antimicrobial treatment according to the location's epidemiology; for patients admitted to the intensive care unit, specific recommendations on disease management are available. Adherence to pneumonia guidelines is associated with better outcomes in severe pneumonia. Yet, the continuing and necessary research on severe pneumonia is expansive, inviting different perspectives on host immunological responses, assessment of illness severity, microbial causes, risk factors for multidrug resistant pathogens, diagnostic tests, and therapeutic options.

A literature review of severity scores for adults with influenza or community-acquired pneumonia - implications for influenza vaccines and therapeutics

Influenza vaccination and antiviral therapeutics may attenuate disease, decreasing severity of illness in vaccinated and treated persons. Standardized assessment tools, definitions of disease severity, and clinical endpoints would support characterizing the attenuating effects of influenza vaccines and antivirals. We review potential clinical parameters and endpoints that may be useful for ordinal scales evaluating attenuating effects of influenza vaccines and antivirals in hospital-based studies. In studies of influenza and community-acquired pneumonia, common physiologic parameters that predicted outcomes such as mortality, ICU admission, complications, and duration of stay included vital signs (hypotension, tachypnea, fever, hypoxia), laboratory results (blood urea nitrogen, platelets, serum sodium), and radiographic findings of infiltrates or effusions. Ordinal scales based on these parameters may be useful endpoints for evaluating attenuating effects of influenza vaccines and therapeutics. Factors such as clinical and policy relevance, reproducibility, and specificity of measurements should be considered when creating a standardized ordinal scale for assessment.

Differentiating severe and non-severe lower respiratory tract illness in patients hospitalized with influenza: Development of the Influenza Disease Evaluation and Assessment of Severity (IDEAS) scale

BACKGROUND

Experimental studies have shown that vaccination can reduce viral replication to attenuate progression of influenza-associated lower respiratory tract illness (LRTI). However, clinical studies are conflicting, possibly due to use of non-specific outcomes reflecting a mix of large and small airway LRTI lacking specificity for acute lung or organ injury.

METHODS

We developed a global ordinal scale to differentiate large and small airway LRTI in hospitalized adults with influenza using physiologic features and interventions (PFIs): vital signs, laboratory and radiographic findings, and clinical interventions. We reviewed the literature to identify common PFIs across 9 existing scales of pneumonia and sepsis severity. To characterize patients using this scale, we applied the scale to an antiviral clinical trial dataset where these PFIs were measured through routine clinical care in adults hospitalized with influenza-associated LRTI during the 2010-2013 seasons.

RESULTS

We evaluated 12 clinical parameters among 1020 adults; 210 (21%) had laboratory-confirmed influenza, with a median severity score of 4.5 (interquartile range, 2-8). Among influenza cases, median age was 63 years, 20% were hospitalized in the prior 90 days, 50% had chronic obstructive pulmonary disease, and 22% had congestive heart failure. Primary influencers of higher score included pulmonary infiltrates on imaging (48.1%), heart rate ≥110 beats/minute (41.4%), oxygen saturation <93% (47.6%) and respiratory rate >24 breaths/minute (21.0%). Key PFIs distinguishing patients with severity < or ≥8 (upper quartile) included infiltrates (27.1% vs 90.0%), temperature ≥ 39.1°C or <36.0°C (7.1% vs 27.1%), respiratory rate >24 breaths/minute (7.9% vs 47.1%), heart rate ≥110 beats/minute (29.3% vs 65.7%), oxygen saturation <90% (14.3% vs 31.4%), white blood cell count >15,000 (5.0% vs 27.2%), and need for invasive or non-invasive mechanical ventilation (2.1% vs 15.7%).

CONCLUSION

We developed a scale in adults hospitalized with influenza-associated LRTI demonstrating a broad distribution of physiologic severity which may be useful for future studies evaluating the disease attenuating effects of influenza vaccination or other therapeutics.

The Dual Role of a Polyvalent IgM/IgA-Enriched Immunoglobulin Preparation in Activating and Inhibiting the Complement System

Activation of the complement system is important for efficient clearance of a wide variety of pathogens via opsonophagocytosis, or by direct lysis via complement-dependent cytotoxicity (CDC). However, in severe infections dysregulation of the complement system contributes to hyperinflammation. The influence of the novel IgM/IgA-enriched immunoglobulin preparation trimodulin on the complement pathway was investigated in in vitro opsonophagocytosis, binding and CDC assays. Immunoglobulin levels before and after trimodulin treatment were placed in relation to complement assessments in humans. In vitro, trimodulin activates complement and induces opsonophagocytosis, but also interacts with opsonins C3b, C4b and anaphylatoxin C5a in a concentration-dependent manner. This was not observed for standard intravenous IgG preparation (IVIg). Accordingly, trimodulin, but not IVIg, inhibited the downstream CDC pathway and target cell lysis. If applied at a similar concentration range in healthy subjects, trimodulin treatment resulted in C3 and C4 consumption in a concentration-dependent manner, which was extended in patients with severe community-acquired pneumonia. Complement consumption is found to be dependent on underlying immunoglobulin levels, particularly IgM, pinpointing their regulative function in humans. IgM/IgA provide a balancing effect on the complement system. Trimodulin may enhance phagocytosis and opsonophagocytosis in patients with severe infections and prevent excessive pathogen lysis and release of harmful anaphylatoxins.

Effects of α-glyceryl monolaurate on growth, immune function, volatile fatty acids, and gut microbiota in broiler chickens

This study was conducted to determine the effects of dietary addition of α-glyceryl monolaurate (α-GML) on growth performance, immune function, volatile fatty acids production and cecal microbiota in broiler chickens. A total of 480 1-day-old yellow-feathered broilers were randomly assigned in equal numbers to 4 dietary treatments: basal diet (NCO) or supplementations with 30 mg/kg bacitracin (ANT), 500 mg/kg α-GML, or 1,000 mg/kg α-GML (GML2). And, each treatment contained 8 replicates with 15 chickens per replicate. After supplementation with α-GML, the total BW gain and average daily weight gain of broilers increased significantly (P < 0.05) compared with the broilers on the NCO diet. Moreover, compared with the NCO group, higher levels of immune globulin M and immune globulin Y were observed in both GML groups and the ANT group. Concentrations of acetate, propionate, butyrate, valerate, and isovalerate in GML2 were significantly higher (P < 0.05) than those in the NCO group on day 28. However, acetate, propionate, valerate, and isovalerate concentrations were reduced to significantly (P < 0.05) lower than those in the NCO group on day 56. The abundance and diversity of microbiota were found to be improved in broilers that were supplemented with GML, using operational taxonomic unit and diversity analyses. Furthermore, the GML treatments increased favorable microbiota, particularly acid-producing bacteria, on day 28 and, also, reduced opportunistic pathogens, such as Alistipes tidjanibacter and Bacteroides dorei by day 56. These results suggest that α-GML supplementation modulates cecal microbiota and broiler immunity and improves volatile fatty acid levels during the early growth stages of broilers.

Immunoglobulins concentration and B cell counts as severity markers in adult community-acquired pneumonia: Cross sectional study

Community-acquired pneumonia (CAP) is a worldwide cause of morbidity and mortality. Immunoglobulins (Igs) and B cells quantification studies in CAP are few and show discrepancies. Serum IgA acts as a powerful natural anti-inflammatory factor, but its role in the CAP has not yet been defined. The highly sensitive xMAP Luminex technique allows better immunoglobulins quantification. The aim of this study was to analyze the relation between clinical severity and circulating Igs and B cells in adults with CAP.Igs (M, A, G1, G2, G3, and G4) and B cells were quantified in peripheral blood of 190 Chilean patients ≥18 years old hospitalized for CAP and in 21 adults without respiratory disease, using xMAP Luminex and flow cytometry, respectively. Clinical history was recorded and PSI and CURB-65 scores were calculated for evaluation of clinical severity.The total IgM, IgG2 and total IgG levels were lower in CAP than in asymptomatic adults (P < .05). No significant differences of Igs levels were found between patients classified as severe and mild by PSI and CURB-65 scores. Fatal cases had higher levels of IgA (P < .05). No differences in CD19 B cells frequency was found between CAP and asymptomatic adults (P = .40). In PSI severe cases, CD19 B cells were significantly lower than in mild cases (P = .008). No differences were found in CURB-65 severe and mild groups (P = .11). In fatal cases (11/82) group, CD19 B cells frequency was lower than in 71 survivors (P = .2). No differences in memory B lymphocytes were detected between asymptomatic and CAP adults, severe and mild patients, survivors and fatal cases (P > .05).Serum IgA levels were significantly higher in fatal CAP cases, raising it as a potential biomarker for severe disease considering its relatively universal availability. In PSI severe patients, B cells showed lower levels and could have a role on its physiopathology. Finding new markers rooted in physiopathology could improve the possibility of scoring severe CAP cases. Luminex technology showed promising quantification serum Igs.

Elevated Interleukin-6 Levels within 72 Hours Post Admission Are Associated with Disease Progression in Nonseptic Critically Ill Children

It has been established that the innate and adaptive immune suppression was heterogeneous in septic and nonseptic critically ill patients, while the value of immune function in pediatric patients with nonseptic critical illness is limited. We conducted a single-center retrospective study to explore this issue. A total of 65 children with nonseptic illnesses were studied for lymphocyte subpopulations, immunoglobulin concentrations, complement concentrations, and cytokines in peripheral blood in the next 72 hours after admission to our Pediatric Intensive Care Unit (PICU). When compared to clinically recovered patients, patients with disease progression had a numerically lower but not significantly different median pediatric critical illness score and longer PICU median stays. The analysis of serum immunoglobulin (IgG, IgM, and IgA), serum complement (C3, C4) concentrations, and lymphocyte subpopulations showed no significantly difference between patients with and without relieved clinical symptoms by day 4. For the cytokine analysis, the level of IL-6 was significantly higher in patients with disease progression than that in patients who clinically recovered (p = 0.046). In the univariate Cox regression analysis, plasma IL-6 levels were associated with outcome. Multivariate analysis evidenced that the level of plasma IL-6 was one of the factors determining the length of hospital stays. In conclusions, our results demonstrate that increased IL-6 levels in the initial 72 hours post admission are associated with prolonged stays and disease progression in nonseptic critically ill children in the PICU.

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.

Screening for Humoral Immunodeficiency in Patients with Community-Acquired Pneumonia

BACKGROUND

Immunodeficiency is an underrecognized risk factor for infections, such as community-acquired pneumonia (CAP).

OBJECTIVE

We evaluated patients admitted with CAP for humoral immunodeficiency.

DESIGN

Prospective Cohort Study.

SETTING

Inpatients.

PATIENTS, INTERVENTION, AND MEASUREMENTS

We enrolled 100 consecutive patients admitted with a diagnosis of CAP from February 2017 to April 2017. Serum IgG, IgM, IgA, and IgE levels were obtained within the first 24 hours of admission. CURB-65 score and length of hospital stay were calculated. The Wilcoxon rank-sum test, Kruskal-Wallis test, and simple linear regression analysis were used in data analysis.

RESULTS

The prevalence of hypogammaglobinemia in patients with CAP was 38% (95% confidence interval: 28.47% to 48.25%). Twenty-seven of 100 patients had IgG hypogammaglobinemia (median: 598 mg/dL, IQ range: 459-654), 23 of 100 had IgM hypogammaglobinemia (median: 38 mg/dL, IQ range: 25-43), and 6 of 100 had IgA hypogammaglobinemia (median: 36 mg/dL, IQ range: 18-50). The median hospital length of stay for patients with IgG hypogammaglobinemia was significantly higher when compared to patients with normal IgG levels (five days, IQ range [3-10] vs three days, IQ range [2-5], P = .0085). Fourteen patients underwent further immune evaluation, resulting in one diagnosis of multiple myeloma, three patients diagnosed with specific antibody deficiency, and one patient diagnosed with selective IgA deficiency.

CONCLUSION

There is a high prevalence of hypogammaglobinemia in patients hospitalized with CAP, with IgG and IgM being the most commonly affected classes. IgG hypogammaglobinemia was associated with an increased length of hospitalization. Screening immunoglobulin levels in CAP patients may also uncover underlying humoral immunodeficiency or immunoproliferative disorders.

Human IgM monoclonal antibodies block HIV-transmission to immune cells in cervico-vaginal tissues and across polarized epithelial cells in vitro

The importance of natural IgM antibodies in protection against infections is still emerging and these antibodies have a potential role in the maintenance of homeostasis through clearance of apoptotic bodies, complement-dependent mechanisms, inflammation and exclusion of misfolded proteins. Natural IgM act as a first line of defence against unknown hazardous factors and are present in most vertebrates. We investigated the functional capacity of anti-HIV-1 IgM monoclonal antibodies, from a combinatorial Fab library derived from healthy individuals, and evaluated their protective role in inhibiting HIV-1 in vitro when passing across the human mucosal epithelial barrier. Primary HIV-1 isolates were efficiently transmitted over the tight polarized epithelial cells when added to their apical surface. Efficient inhibition of HIV-1 transmission was achieved when anti-HIV-1 IgM monoclonal antibodies were added to the basolateral side of the cells. Two of these human IgM MoAbs had the ability to neutralize HIV and reduced infection of dendritic cells in primary cervico-vaginal tissue biopsies in vitro. This indicates a potential role of natural IgM antibodies in the reduction of HIV-1 transmission in mucosal tissues and improve our understanding of how natural IgM antibodies against a neutralizing epitope could interfere with viral transmission.

Efficacy and safety of trimodulin, a novel polyclonal antibody preparation, in patients with severe community-acquired pneumonia: a randomized, placebo-controlled, double-blind, multicenter, phase II trial (CIGMA study)

Purpose

The CIGMA study investigated a novel human polyclonal antibody preparation (trimodulin) containing ~ 23% immunoglobulin (Ig) M, ~ 21% IgA, and ~ 56% IgG as add-on therapy for patients with severe community-acquired pneumonia (sCAP).

Methods

In this double-blind, phase II study (NCT01420744), 160 patients with sCAP requiring invasive mechanical ventilation were randomized (1:1) to trimodulin (42 mg IgM/kg/day) or placebo for five consecutive days. Primary endpoint was ventilator-free days (VFDs). Secondary endpoints included 28-day all-cause and pneumonia-related mortality. Safety and tolerability were monitored. Exploratory post hoc analyses were performed in subsets stratified by baseline C-reactive protein (CRP; ≥ 70 mg/L) and/or IgM (≤ 0.8 g/L).

Results

Overall, there was no statistically significant difference in VFDs between trimodulin (mean 11.0, median 11 [n = 81]) and placebo (mean 9.6; median 8 [n = 79]; p = 0.173). Twenty-eight-day all-cause mortality was 22.2% vs. 27.8%, respectively (p = 0.465). Time to discharge from intensive care unit and mean duration of hospitalization were comparable between groups. Adverse-event incidences were comparable. Post hoc subset analyses, which included the majority of patients (58–78%), showed significant reductions in all-cause mortality (trimodulin vs. placebo) in patients with high CRP, low IgM, and high CRP/low IgM at baseline.

Conclusions

No significant differences were found in VFDs and mortality between trimodulin and placebo groups. Post hoc analyses supported improved outcome regarding mortality with trimodulin in subsets of patients with elevated CRP, reduced IgM, or both. These findings warrant further investigation.

Trial registration: NCT01420744.

Electronic supplementary material

The online version of this article (10.1007/s00134-018-5143-7) contains supplementary material, which is available to authorized users.

Serum levels of immunoglobulins and severity of community-acquired pneumonia

Instruction

There is evidence of a relationship between severity of infection and inflammatory response of the immune system. The objective is to assess serum levels of immunoglobulins and to establish its relationship with severity of community-acquired pneumonia (CAP) and clinical outcome.

Methods

This was an observational and cross-sectional study in which 3 groups of patients diagnosed with CAP were compared: patients treated in the outpatient setting (n=54), patients requiring in-patient care (hospital ward) (n=173), and patients requiring admission to the intensive care unit (ICU) (n=191).

Results

Serum total IgG (and IgG subclasses IgG1, IgG2, IgG3, IgG4), IgA and IgM were measured at the first clinical visit. Normal cutpoints were defined as the lowest value obtained in controls (≤680, ≤323, ≤154, ≤10, ≤5, ≤30 and ≤50 mg/dL for total IgG, IgG1, IgG2, IgG3, IgG4, IgM and IgA, respectively). Serum immunoglobulin levels decreased in relation to severity of CAP. Low serum levels of total IgG, IgG1 and IgG2 showed a relationship with ICU admission. Low serum level of total IgG was independently associated with ICU admission (OR=2.45, 95% CI 1.4 to 4.2, p=0.002), adjusted by the CURB-65 severity score and comorbidities (chronic respiratory and heart diseases). Low levels of total IgG, IgG1 and IgG2 were significantly associated with 30-day mortality.

Conclusions

Patients with severe CAP admitted to the ICU showed lower levels of immunoglobulins than non-ICU patients and this increased mortality.

Relevant Cytokines in the Management of Community-Acquired Pneumonia

Community-acquired pneumonia (CAP) is the leading cause of infectious death in the world. Immune dysregulation during acute lung infection plays a role in lung injury and the systemic inflammatory response. Cytokines seem to be major players in severe lung infection cases. Here, we present a review of published papers in the last 3 years regarding this topic. The cytokine response during pneumonia is different in bacterial vs viral infections; some of these cytokines correlate with clinical severity scales such as CURB65 or SOFA. Treatment focused in the cytokine environment is an interesting area that could impact the prognosis of CAP. Some of the agents that have been studied as co-adjuvant therapy are corticosteroids, macrolides, and linezolid, but anyone of those have shown a clear or proven efficacy or have been recommended as a part of the standard of care for CAP. More studies designed to define the role of immunomodulatory agents, such as co-adjuvant therapy in pneumonia, are needed.

Endogenous immunoglobulins and sepsis: New perspectives for guiding replacement therapies

The recently emerging concept of immunosuppression developing in the field of severe sepsis generated the need to measure circulating immunoglobulins as part of the necessary tests to evaluate immunocompetence status in patients suffering from this condition. Serum concentrations can be used as a surrogate marker of the final outcome and as a biomarker to explore the need for supplementation of the host with intravenous immunoglobulin preparations. Available evidence from recent clinical studies pinpoints the main observations. The first is that circulating IgM is a phenomenon associated with progression from severe sepsis to septic shock. Deficient kinetics of circulating IgM during the first 7 days following the start of vasopressors is linked with unfavourable outcome. The second is the development of immunoscores using low levels of IgM, IgG1 and IgA. These immunoscores can predict 28-day mortality with an odds ratio ranging between 3 and 5. Novel techniques for evaluating patient's immune status are shedding new light on the development of modern therapeutics where immunoglobulin replacement may be part of a personalised therapeutic approach.

Community-acquired pneumonia

PURPOSE OF REVIEW

This review examines the epidemiology, diagnosis, prognosis, treatment and prevention of community-acquired pneumonia (CAP) in adults.

RECENT FINDINGS

CAP is a significant cause of morbidity and mortality. Streptococcus pneumoniae is the most common CAP pathogen; however, microbial cause varies by geographic location and host factors. Identification of a microbial cause in CAP remains challenging - 30-65% of cases do not have a pathogen isolated. The use of molecular techniques in addition to culture, serology and urinary antigen testing has improved diagnostic yield. Scoring systems are useful for CAP prognostication and site of care decisions. Studies evaluating novel biomarkers including pro-B-type natriuretic peptide and procalcitonin suggest potential adjunctive roles in CAP prognosis. Guideline-based treatment for CAP has changed little in recent years. Effective and timely antimicrobial therapy is crucial in optimizing outcomes and should be based on local antimicrobial susceptibility patterns. Macrolides may have additional anti-inflammatory properties and a mortality benefit in severe CAP. Preventive strategies include immunization and modification of specific patient risk factors.

SUMMARY

CAP is common and causes considerable morbidity and mortality. A comprehensive approach including advanced diagnostic testing, effective and timely antimicrobial therapy and prevention is required to optimize CAP outcomes.