Distinct Serum Immunoglobulins Pattern in Egyptian Patients with Chronic HCV Infection Analyzed by Nephelometry

Analysis of the IgG subclass profile and IgG sum-total discrepancy in COVID-19 convalescent plasma donors: A single-centre prospective cohort study

INTRODUCTION

Although IgG1 and IgG3 have been shown to be the dominant subclasses in the acute phase of SARS-CoV-2 infection, little is known about the distribution of IgG subclasses during the recovery phase of COVID-19. The aim of the study was to analyze the profile of IgG subclasses in COVID-19 convalescent plasma donors.

METHODS

A total of 36 convalescent plasma donors were included in the analysis. IgG and IgG subclass levels were measured using a nephelometric assay in plasma samples obtained directly from the plasma container.

RESULTS

Although there was no significant difference in the concentration of IgG subclasses between the study and control groups, the contribution of IgG1 to the total IgG pool between the study and control groups was statistically significant (p = 0.0478). In addition, there was a discrepancy between the total IgG and IgG sum values in the study group, exceeding 15 % in 19,4 % of samples (n = 7), while in the control group no samples with a sum/ total IgG difference > 15 % were observed.

CONCLUSIONS

The selective affinity of the IgG1 subclass for the polyclonal anti-IgG reagent may interfere with the determination of total IgG and should be considered when interpreting the results of enzyme immunoassays DATA AVAILABILITY: The data that support the findings of this study are available on request from the corresponding author.

A quantitative enzyme-linked immunosorbent assay for quantification of secretory immunoglobulin A in serum

Secretory immunoglobulin A (SIgA) in serum is possibly the best index of SIgA presence in mucosal secretions in digestive tract and the mirror of its immunologic barrier against many pathogenic aggressions. The measurement of salivary SigA alone may be affected by total salivary secretion and its final concentration in the gland lumen is probably not useful as an appropriate index of mucosal secretions in the digestive tract. The usefulness of the determination of SigA against various epitopes in serum from patients with various autoimmune disease has been demonstrated. The aetiology of many digestive related disorders could be triggered by an alteration of mucose SIgA barrier. The determination of Igs is important for different liver diseases and specifically the SIgA in autoimmune diseases such as rheumatoid arthritis. We developed an easy and efficient immunologic assay to quantify SIgA in serum samples.