Immunoglobulin A promotes IL-6 and IL-8 production, proliferation, and migration by the human bronchial smooth muscle cells

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.

Immunoglobulins in COVID-19 pneumonia: from the acute phase to the recovery phase

BACKGROUND

COVID-19 pneumonia causes hyperinflammatory response that culminates in acute respiratory syndrome (ARDS) related to increased multiorgan dysfunction and mortality risk. Antiviral-neutralizing immunoglobulins production reflect the host humoral status and illness severity, and thus, immunoglobulin (Ig) circulating levels could be evidence of COVID-19 prognosis.

METHODS

The relationship among circulating immunoglobulins (IgA, IgG, IgM) and COVID-19 pneumonia was evaluated using clinical information and blood samples in a COVID-19 cohort composed by 320 individuals recruited during the acute phase and followed up to 4 to 8 weeks (n = 252) from the Spanish first to fourth waves.

RESULTS

COVID-19 pneumonia development depended on baseline Ig concentrations. Circulating IgA levels together with clinical features at acute phase was highly associated with COVID-19 pneumonia development. IgM was positively correlated with obesity (ρb = 0.156, P = 0.020), dyslipemia (ρb = 0.140, P = 0.029), COPD (ρb = 0.133, P = 0.037), cancer (ρb = 0.173, P = 0.007) and hypertension (ρb = 0.148, P = 0.020). Ig concentrations at recovery phase were related to COVID-19 treatments.

CONCLUSIONS

Our results provide valuable information on the dynamics of immunoglobulins upon SARS-CoV-2 infection or other similar viruses.

Serum IgA augments adhesiveness of cultured lung microvascular endothelial cells and suppresses angiogenesis

Immunoglobulin A (IgA) is important in local immunity and is also abundant in the blood. This study aimed to evaluate the effects of serum IgA on cultured lung microvascular endothelial cells (HMVEC-Ls), which are involved in the pathogenesis of inflammatory lung diseases. Serum IgA induced adhesion molecules and inflammatory cytokine production from HMVEC-Ls, and enhanced adhesion of peripheral blood mononuclear cells to HMVEC-Ls. In contrast, migration, proliferation, and tube formation of HMVEC-Ls were significantly suppressed by serum IgA. Experiments with siRNAs and western blotting revealed that two known IgA receptors, β1,4-galactosyltransferase 1 (b4GALT1) and asialoglycoprotein receptor 1 (ASGR1), and mitogen-activated protein kinase and nuclear factor-kappa B pathways were partly involved in serum IgA-induced cytokine production by HMVEC-Ls. Collectively, serum IgA enhanced cytokine production and adhesiveness of HMVEC-L, with b4GALT1 and ASGR1 partially being involved, and suppressed angiogenesis. Thus, serum IgA may be targeted to treat inflammatory lung diseases.