Relationship between serum IgA levels and low percentage forced expiratory volume in the first second in asthma

Objective: Immunoglobulin A (IgA) is suggested to have pathogenic effects in respiratory inflammatory diseases, including asthma. We aimed to analyze the relationship between serum IgA, and clinical indicators and biomarkers of asthma.Methods: This study was a post hoc analysis of the NHOM Asthma Study. In this study, serum IgA was measured using serum samples stored. We determined an association between the serum IgA level and clinical variables and biomarkers using multivariate linear regression and analyzed the differences in clinical indices between IgA high- and IgA low-asthma.Results: In this study, 572 patients with asthma were included in the final analysis. Lower percentage forced expiratory volume in the first second (%FEV1), higher serum eotaxin levels, lower serum ST2 levels, and higher serum MIP-1β levels, were independently and significantly associated with higher serum IgA levels among asthma patients by multivariate linear regression analysis (%FEV1, 95% confidence interval [CI], -8.18- -0.613, p < 0.05; eotaxin, 95% CI, 8.95-46.69, p < 0.001; ST2, 95% CI, -73.71- -7.37, p < 0.05; and MIP-1β, 95% CI, 1.47-18.71, p < 0.05). Furthermore, IgA high-asthma (serum IgA ≥ 238 mg/dL, n = 270) and IgA low-asthma (serum IgA < 238 mg/dL, n = 302) were compared separately. %FEV1 was significantly lower, the percentage of atopy was higher, and serum MIP-1β level was higher in IgA high-asthma.Conclusions: This study suggests that serum IgA may be involved in the worsening of asthma outcomes, as assessed by %FEV1 and enhanced inflammation via elevated serum MIP-1β.

Mendelian randomization study on the causal effect of serum IgA levels on H7N9 avian influenza A virus susceptibility

Avian influenza A viruses (IAVs) that cross the species barrier to infect humans have the potential to initiate a new pandemic. However, the host factors influencing avian IAV infection remain poorly understood. To address this knowledge gap, we conducted a two-sample Mendelian randomization (MR) analysis by integrating our in-house genome-wide association study (GWAS) of avian IAV H7N9 susceptibility (with 217 cases and 116 controls) with the largest GWAS of serum IgA levels to date (sample size 41 263). Using the inverse-variance weighted (IVW) method, we discovered that genetically decreased serum IgA levels were associated with an increased risk of H7N9 infection (β = -2.528, 95% confidence interval [CI]: -4.572 to -0.484; p = 0.015). Consistent results were obtained from three other MR methods, including robust IVW estimation (β = -2.506, 95% CI: -4.109 to -0.902; p = 0.002), generalized summary-data-based MR (GSMR) (β = -2.238, 95% CI: -4.106 to -0.602; p = 0.019), and MR-pleiotropy residual sum and outlier (MR-PRESSO) (β = -2.528, 95% CI: -4.396 to -0.892; p = 0.026). In conclusion, our analysis provided compelling evidence support a causal relationship between genetically predicted serum IgA levels and avian IAV H7N9 susceptibility.

A study to estimate the serum IgA and salivary IgA levels in patients with oral leukoplakia and oral squamous cell carcinoma

Context

The increasing death rate because of oral cancer is mainly due to its late diagnosis. Tumour markers are often detected in abnormal amounts in blood, urine or saliva of patients with certain types of cancer. Diagnosing cancer through human saliva has advantages such as low invasiveness, minimum cost and easy sample collection. We have used serum immunoglobulin A (IgA) and salivary IgA for our present study.

Aims

The aim of present study was to estimate serum and salivary IgA levels in oral leukoplakia and oral squamous cell carcinoma (OSCC) patients.

Settings and Design

The study included 40 patients; 10 in the control group, 15 cases with oral leukoplakia and 15 cases with OSCC.

Methods and Material

The blood samples and saliva were taken from clinically diagnosed oral leukoplakia and OSCC patients and were tested for IgA levels.

Statistical analysis used

The data were analysed using SPSS 16.0. The mean values were compared between the groups by using analysis of variance (ANOVA) followed by post-hoc test for group-wise comparison. P value ≤ 0.05 was considered significant.

Results

It was observed that the comparison of levels of serum IgA in control and leukoplakia group; control and OSCC group; leukoplakia and OSCC group were found to be statistically significant. Also, comparison between the levels of salivary IgA in control and OSCC group was found to be statistically significant.

Conclusion

It is suggested that the serum and salivary IgA levels could be a better adjuvant diagnostic marker along with routine markers in patients with premalignant and malignant lesions.

Can anti-PGL-I antibody isotypes differentiate leprosy contacts and leprosy patients?

BACKGROUND

Serological tests for antibody measurement in leprosy have a series of limitations in discriminating contacts and patients. The present paper intends to evaluate if association of more than one antibody isotype in serum samples may be a useful tool in leprosy diagnosis.

METHODS

This study evaluated 395 leprosy contacts and 71 leprosy index cases living in endemic municipalities in Northeastern Brazil. The participants were evaluated according to their anti-phenolic glycolipid antigen-I isotype (PGL-I) profile. Serum anti-PGL-I IgM, IgG, and IgA were measured by indirect ELISA.

RESULTS

A strong association was found for antibody positivity in MB leprosy index cases. The odds ratios were 6.11 (95% CI 3.08 - 12.16) for IgM, 3.31 (1.66 - 6.61) for IgG, and 16.97 (8.39 - 34.2) for IgA. For IgM associated with one or more isotypes, the OR was 21.0 (95% CI 10.11 - 43.64), and for IgG + IgA, the OR was 17.58 (6.23 - 49.54). The highest diagnostic sensitivity of 76.0% (95% CI 61.8 - 86.9) was observed for IgM, and the lowest value was 24.1% (13.0 - 38.2), which was observed for IgG + IgA isotypes. Regarding presumptive positive predictive values, the lowest value was obtained for IgM at 24.7% (95% CI 18.1 - 32.3), and the highest values were observed for IgM+ one or more isotypes and for IgG + IgA isotype at 60.0% (44.3 - 74.3) and 66.7% (41.0 - 86.7), respectively.

CONCLUSIONS

The present work demonstrated that by associating two or more positive antibody isotypes, the risk of facing a real case of leprosy may increase.

Selectivity of polyclonal repertoire of anti-microbial IgA and its subclasses in saliva and serum in humans

Increased interest in microbiota calls for the thorough analysis of antibody reactivity to different microorganisms. As salivary IgA represents the first line of defence against microorganisms contacting mucosal surfaces, we explored the binding and specificity of salivary IgA by testing the binding of purified, FITC-labelled salivary IgA to different microorganisms in flow cytometry and conclude that this kind of analysis enables the differentiation between species/strains with high IgA binding capacity, which should be corroborated on a larger sample size. Further we compare, with in-house ELISA, the binding of polyclonal salivary IgA with the binding of polyclonal serum IgA from the same individuals to whole microbial cells and to purified microbial components. High correlations were obtained in total salivary IgA binding to L. rhamnosus and E. coli, very distant bacterial species, as well as to isolated bacterial components (r=0.70-0.97). The binding of total salivary IgA resembled the binding of both salivary IgA1 and IgA2, with IgA2 predominating. For serum polyclonal IgA repertoire, substantially higher specificity was obtained. Serum IgA binding to E. coli correlated best with serum IgA binding to lipopolysaccharide (r=0.86), and serum IgA against L. rhamnosus correlated best with the anti-peptidoglycan IgA levels (r=0.88). We have also detected that total serum IgA response is governed by either IgA1 or IgA2 response, depending on the nature of the antigen/s. We conclude that steady state salivary IgA repertoire, unlike serum IgA repertoire, consists of polyreactive antibodies with innate specificity, questioning its capacity to select resident microbiota.

Characterization of the Humoral Immune Response to Porcine Epidemic Diarrhea Virus Infection under Experimental and Field Conditions Using an AlphaLISA Platform

Coronavirus infections are a continuous threat raised time and again. With the recent emergence of novel virulent strains, these viruses can have a large impact on human and animal health. Porcine epidemic diarrhea (PED) is considered to be a reemerging pig disease caused by the enteropathogenic alphacoronavirus PED virus (PEDV). In the absence of effective vaccines, infection prevention and control through diagnostic testing and quarantine are critical. Early detection and differential diagnosis of PEDV infections increase the chance of successful control of the disease. Therefore, there is a continuous need for development of reduced assay-step protocols, no-wash, high-throughput immunoassays. This study described the characterization of the humoral immune response against PEDV under experimental and field conditions using a rapid, sensitive, luminescent proximity homogenous assay (AlphaLISA). PEDV IgG and IgA antibodies were developed toward the beginning of the second week of infection. PEDV IgG antibodies were detected for at least 16 weeks post-exposure. Remarkably, the serum IgA levels remained high and relatively stable throughout the study, lasting longer than the serum IgG response. Overall, AlphaLISA allows the detection and characterization of pathogen-specific antibodies with new speed, sensitivity, and simplicity of use. Particularly, the bridge assay constitutes a rapid diagnostic that substantially improves upon the "time to result" metric of currently available immunoassays.

Elevated baseline serum IgA may predict earlier proteinuria remission in IgA nephropathy patients

The goals of this work were to investigate the correlations of elevated serum IgA with renal pathology and outcome of proteinuria in IgA nephropathy patients. Retrospective cohort analysis enrolled 90 IgA nephropathy patients (proteinuria ≥0.5 g/24 hr, estimated glomerular filtration rate (eGFR) ≥30 ml/min/1.73 m²) who were admitted to The Sixth Affiliated Hospital of Sun Yat-sen University from 2013.01 to 2017.04. The elevated serum IgA level was found in 20 (22.2%) patients. In clinical characteristics, serum IgG, ratio of IgA/C3 and recurrent mucosal infection rate were increased obviously in high serum IgA group compared with normal serum IgA group (serum IgG, 14.90±3.50 g/L vs. 10.27±3.49 g/L, P<0.001, IgA/C3, 4.45±1.21 vs. 2.77±0.75, P<0.001, recurrent mucosae infection rate, 40.0% vs. 14.3%, P=0.027). In kidney biopsy, mesangial proliferation was significantly more common in normal serum IgA group (81% vs. 50% in high serum IgA group, P=0.028). The proportion of crescent less than 25% more often occurred in elevated IgA group (81.3% vs. 63.8% in normal IgA group). The Kaplan-Meier curves showed that proteinuria remission rate for patients with high serum IgA was 80%, 85%, 90%, 95% and 95% after 3, 6, 9, 12 and 15 months compared with patients with normal serum IgA (proteinuria remission rate, 45%, 64%, 75%, 86% and 93%, P=0.020). Cox proportional hazard regression model indicated that elevated serum IgA (RR=1.984, P=0.040) and steroids therapy (RR=2.192, P=0.030) were independent predictors for proteinuria remission in IgA nephropathy patients. In view of our data, more active treatments may improve outcome of IgA nephropathy patients with elevated serum IgA. We conclude that elevated serum IgA may indicate a higher proteinuria remission rate within a shorter period of time in IgA nephropathy patients.

Effect of supplements: Probiotics and probiotic plus honey on blood cell counts and serum IgA in patients receiving pelvic radiotherapy

Background:

Radiotherapy is frequently used in treatment approaches of pelvic malignancies. Nevertheless, it has some known systemic effects on blood cells and the immune system that possibly results in their susceptibility to infection. Probiotics are live microbial food ingredients that provide a health advantage to the consumer. Honey has prebiotic properties. The aim of this clinical trial was to investigate probable effects of probiotic or probiotics plus honey on blood cell counts and serum IgA levels in patients receiving pelvic radiotherapy.

Materials and Methods:

Sixty-seven adult patients with pelvic cancer were enrolled. Patients were randomized to receive either: (1) Probiotic capsules (including: Lactobacillus casei, Lactobacillus acidophilus, Lactobacillus rhamnosus, Lactobacillus bulgaricus, Bifidobacterium breve, Bifidobacterium longum, and Streptococcus thermophiles) (n = 22), (2) probiotic capsules plus honey (n = 21) or (3) placebo capsules (n = 24) all for 6 weeks. Blood and serum samples were collected for one week before radiotherapy and 24-72 h after the end of radiotherapy.

Results:

White blood cells (WBC), red blood cells (RBC), platelet counts, and serum IgA level were not significantly changed in patients taking probiotic (alone or plus honey) during pelvic radiotherapy. The mean decrease in RBC count was 0.52, 0.18, and 0.23 × 10⁶ cells/μL, WBC count was 2.3, 1.21, and 1.34 × 10³ cells/μL and platelet count was, 57.6, 53.3, and 66.35 × 10³ cells/μL for the probiotic, probiotic plus honey, and placebo groups, respectively. The mean decrease of serum IgA was 22.53, 29.94, and 40.73 mg/dL for the probiotic, probiotic plus honey, and placebo groups, respectively.

Conclusion:

The observed nonsignificant effect of probiotics may be in favor of local effects of this product in the gut rather than systemic effects, however, as a trend toward a benefit was indicated, further studies are necessary in order to extract effects of probiotics or probiotic plus honey on hematologic and immunologic parameters in patients receiving pelvic radiotherapy.

Dietary lactosucrose suppresses influenza A (H1N1) virus infection in mice

This study examined the effects of lactosucrose (4^G-β-D-galactosylsucrose) on influenza A virus infections in mice. First, the effects of lactosucrose on fermentation in the cecum and on immune function were investigated. In female BALB/c mice, lactosucrose supplementation for 6 weeks promoted cecal fermentation and increased both secretory IgA (SIgA) levels in feces and total IgA and IgG2a concentrations in serum. Both the percentage of CD4⁺ T cells in Peyer’s patches and the cytotoxic activity of splenic natural killer (NK) cells increased significantly in response to lactosucrose. Next, we examined the effects of lactosucrose on low-dose influenza A virus infection in mice. After 2 weeks of dietary supplementation with lactosucrose, the mice were infected with low-dose influenza A virus. At 7 days post infection, a comparison with control mice showed that weight loss was suppressed, as were viral titers in the lungs. In the spleens of lactosucrose-fed mice, there was an increase in the percentage of NK cells. Lastly, mice fed lactosucrose were challenged with a lethal dose of influenza A virus. The survival rate of these mice was significantly higher than that of mice fed a control diet. These results suggested that lactosucrose supplementation suppresses influenza A virus infection by augmenting innate immune responses and enhancing cellular and mucosal immunity.