Selective IgA deficiency and COVID-19

Impaired mucosal IgA response in patients with severe COVID-19

Several studies have investigated the antibody response to SARS-CoV-2, focusing particularly on the systemic humoral immune response and the production of immunoglobulin G (IgG) antibodies. IgA antibodies play a crucial role in protecting against respiratory viral infections but have also been associated with the pathophysiology of COVID-19. We performed a prospective study of 169 COVID-19 patients - 50 with critical/severe (ICU), 47 with moderate (Non-ICU), and 72 with asymptomatic COVID-19 - to explore the humoral immune response to SARS-CoV-2 infection. We found that the early systemic IgA response strongly induced in patients with severe disease did not block IgG neutralization functions and activated FcRs more effectively than IgG. However, even if SIgA levels were high, mucosal IgA antibodies could not control the infection effectively in patients with severe disease. Our findings highlight the complexity of the immune response to SARS-CoV-2 exhibiting high systemic levels of IgA with strong neutralizing capacity in severe cases, together with higher levels of IgA-FcR activation than in asymptomatic patients. They also suggest the need for further research to fully understand the role of IgA and its structural alterations in mucosal tissues in cases of severe disease and the impact of these antibodies on disease progression.

A Possible Protective Effect of IgA Against Severe Acute Respiratory Syndrome Corona Virus 2 (SARS-CoV-2) in Bronchoalveolar Lavage in COVID-19 Patients Admitted to Intensive Care Unit

SARS-CoV-2 infection induces a humoral immune response, producing virus-specific antibodies such as IgM, IgG, and IgA. IgA antibodies are present at mucosal sites, protecting against respiratory and other mucosal infections, including SARS-CoV-2, by neutralizing viruses or impeding attachment to epithelial cells. Since SARS-CoV-2 spreads through the nasopharynx, the specific IgAs of SARS-CoV-2 are produced quickly after infection, effectively contributing to virus neutralization. Dimeric IgA has been reported to be 10 to 15 times more potent than its equivalent IgG, suggesting that this isotype may be particularly interesting in developing new monoclonal antibodies and/or new vaccines efficiently neutralizing the virus at the mucosal sites. It is still unclear whether IgA antibodies in BAL might play a role in the disease course and if their presence may have a prognostic significance. However, a harmful effect on diseases with high IgA titers has been reported. This study evaluated mucosal-specific IgA and IgG profiles in BAL of patients with COVID-19 acute respiratory failure admitted to the ICU. We included 57 patients (41 males and 16 females), admitted to the ICU of the University of Foggia. We used a commercially available ELISA assay to evaluate the presence of SARS-CoV-2 IgG and IgA antibodies in plasma and BAL of the 57 hospitalized patients with severe COVID-19 respiratory failure. However, 40/57 BAL and plasma from infected patients were available for the ELISA test; the remaining specimens were unsuitable. IgG and IgA antibodies against SARS-CoV-2 were detectable in 37 (92.5%) and 40 (100%) plasma specimens, respectively. IgG antibodies were found in a single sample, while IgAs were detected in 19 of 40 BAL samples analyzed. Correlations between these parameters and patient outcomes reveal a signature associated with survival. Interestingly, a statistically significant inverse correlation was found between the mortality rate and the presence of IgA to SARS-CoV-2 in BAL specimens. None of the 19 patients with a positive IgA died, compared to 7 out of 12 patients with a negative IgA-BAL (p: <0.0004). Despite being limited in size, this study suggests a significant protective effect of mucosal immunity in COVID-19 patients, even in advanced disease stages, and a role of IgA in the defense against the virus, as well as the possible use of effective vaccines and therapeutic strategies based on IgA antibodies.

Clinical Characteristics, Outcomes, and Risk Factors for Mortality in Pregnant/Puerperal Women with COVID-19 Admitted to ICU in Turkey: A Multicenter, Retrospective Study from a Middle-Income Country

BACKGROUND

Coronaviruses have been the cause of 3 major outbreaks during the last 2 decades. Information on coronavirus diseases in pregnant women is limited, and even less is known about seriously ill pregnant women. Data are also lacking regarding the real burden of coronavirus disease 2019 (COVID-19) infection in pregnant women from low/middle-income countries. The aim of this study was to determine the characteristics and clinical course of COVID-19 in pregnant/puerperal women admitted to ICUs in Turkey.

METHODS

This was a national, multicenter, retrospective study. The study population comprised all SARS-CoV-2-infected pregnant/puerperal women admitted to participating ICUs between 1 March 2020 and 1 January 2022. Data regarding demographics, comorbidities, illness severity, therapies, extrapulmonary organ injuries, non-COVID-19 infections, and maternal and fetal/neonatal outcomes were recorded. LASSO logistic regression and multiple logistic regression analyses were used to identify predictive variables in terms of ICU mortality.

RESULTS

A total of 597 patients (341 pregnant women, 255 puerperal women) from 59 ICUs in 44 hospitals were included and of these patients, 87.1% were unvaccinated. The primary reason for ICU admission was acute hypoxemic respiratory failure in 522 (87.4%), acute hypoxemic respiratory failure plus shock in 14 (2.3%), ischemic cerebrovascular accident (CVA) in 5 (0.8%), preeclampsia/eclampsia/HELLP syndrome in 6 (1.0%), and post-caesarean follow-up in 36 (6.0%). Nonsurvivors were sicker than survivors upon ICU admission, with higher APACHE II (p < 0.001) and SOFA scores (p < 0.001). A total of 181 (30.3%) women died and 280 (46.6%) had received invasive mechanical ventilation (IMV). Myocardial injury, the highest SOFA score during ICU stay, LDH levels on admission, the highest levels of AST during ICU stay, average daily dose of corticosteroids, IMV, prophylactic dose anticoagulation (compared with therapeutic dose anticoagulation), PaO2/FiO2 ratio <100, pulmonary embolism, and shock were identified as predictors of mortality. Rates of premature birth (46.4%), cesarean section (53.7%), fetal distress (15.3%), stillbirth (6.5%), and low birth weight (19.4%) were high. Rates of neonatal death (8%) and respiratory distress syndrome (21%) were also high among live-born infants.

CONCLUSIONS

Severe/critical COVID-19 infection during the pregnancy/puerperal period was associated with high maternal mortality and fetal/neonatal complication rates in Turkey.