The putative mechanism of lymphopenia in COVID-19 patients

Pulmonary Function and Survival 1 Year After Dupilumab Treatment of Acute Moderate to Severe Coronavirus Disease 2019: A Follow-up Study From a Phase 2a Trial

Background

We previously conducted a phase 2a randomized placebo-controlled trial of 40 subjects to assess the efficacy and safety of dupilumab use in people hospitalized with coronavirus disease 2019 (COVID-19) (NCT04920916). Based on our preclinical data suggesting that downstream pulmonary dysfunction with COVID-19 induced type 2 inflammation, we contacted patients from our phase 2a study at 1 year for assessment of post-COVID-19 conditions.

Methods

Subjects at 1 year after treatment underwent pulmonary function tests, high-resolution computed tomographic imaging, symptom questionnaires, neurocognitive assessments, and serum immune biomarker analysis, with subject survival also monitored. The primary outcome was the proportion of abnormal diffusion capacity for carbon monoxide (DLCO) or 6-minute walk test (6MWT) at the 1-year visit.

Results

Of those survivors who consented to 1-year visits (n = 16), subjects who had originally received dupilumab were less likely than those who received placebo to have an abnormal DLCO or 6MWT (Fisher exact P = .011; adjusted P = .058). As a secondary endpoint, we saw that 16% of subjects in the dupilumab group died by 1 year compared to 38% in the placebo group, though this was not statistically significant (log-rank P = .12). We did not find significant differences in neurocognitive testing, symptoms, or chest computed tomography between treatment groups but observed a larger reduction in eotaxin levels in those who received dupilumab.

Conclusions

In this observational study, subjects who received dupilumab during acute COVID-19 hospitalization were less likely to have a reduced DLCO or 6MWT, with a nonsignificant trend toward reduced mortality at 1 year compared to placebo.

Tonsils are major sites of persistence of SARS-CoV-2 in children

In the present study, we show that SARS-CoV-2 can infect palatine tonsils, adenoids, and secretions in children without symptoms of COVID-19, with no history of recent upper airway infection. We studied 48 children undergoing tonsillectomy due to snoring/OSA or recurrent tonsillitis between October 2020 and September 2021. Nasal cytobrushes, nasal washes, and tonsillar tissue fragments obtained at surgery were tested by RT-qPCR, immunohistochemistry (IHC), flow cytometry, and neutralization assay. We detected the presence of SARS-CoV-2 in at least one specimen tested in 27% of patients. IHC revealed the presence of the viral nucleoprotein in epithelial surface and in lymphoid cells in both extrafollicular and follicular regions, in adenoids and palatine tonsils. Also, IHC for the SARS-CoV-2 non-structural protein NSP-16 indicated the presence of viral replication in 53.8% of the SARS-CoV-2-infected tissues. Flow cytometry showed that CD20+ B lymphocytes were the most infected phenotypes, followed by CD4+ lymphocytes and CD123 dendritic cells, CD8+ T lymphocytes, and CD14+ macrophages. Additionally, IF indicated that infected tonsillar tissues had increased expression of ACE2 and TMPRSS2. NGS sequencing demonstrated the presence of different SARS-CoV-2 variants in tonsils from different tissues. SARS-CoV-2 antigen detection was not restricted to tonsils but was also detected in nasal cells from the olfactory region. Palatine tonsils and adenoids are sites of prolonged RNA presence by SARS-CoV-2 in children, even without COVID-19 symptoms. IMPORTANCE This study shows that SRS-CoV-2 of different lineages can infect tonsils and adenoids in one quarter of children undergoing tonsillectomy. These findings bring advancement to the area of SARS-CoV-2 pathogenesis, by showing that tonsils may be sites of prolonged infection, even without evidence of recent COVID-19 symptoms. SARS-CoV-2 infection of B and T lymphocytes, macrophages, and dendritic cells may interfere with the mounting of immune responses in these secondary lymphoid organs. Moreover, the shedding of SARS-CoV-2 RNA in respiratory secretions from silently infected children raises concern about possible diagnostic confusion in the presence of symptoms of acute respiratory infections caused by other etiologies.

Transcriptomic and proteomic assessment of tocilizumab response in a randomized controlled trial of patients hospitalized with COVID-19

High interleukin (IL)-6 levels are associated with greater COVID-19 severity. IL-6 receptor blockade by tocilizumab (anti-IL6R; Actemra) is used globally for the treatment of severe COVID-19, yet a molecular understanding of the therapeutic benefit remains unclear. We characterized the immune profile and identified cellular and molecular pathways modified by tocilizumab in peripheral blood samples from patients enrolled in the COVACTA study, a phase 3, randomized, double-blind, placebo-controlled trial of the efficacy and safety of tocilizumab in hospitalized patients with severe COVID-19. We identified markers of inflammation, lymphopenia, myeloid dysregulation, and organ injury that predict disease severity and clinical outcomes. Proteomic analysis confirmed a pharmacodynamic effect for tocilizumab and identified novel pharmacodynamic biomarkers. Transcriptomic analysis revealed that tocilizumab treatment leads to faster resolution of lymphopenia and myeloid dysregulation associated with severe COVID-19, indicating greater anti-inflammatory activity relative to placebo and potentially leading to faster recovery in patients hospitalized with COVID-19.

Pulmonary function and survival one year after dupilumab treatment of acute moderate to severe COVID-19: A follow up study from a Phase IIa trial

Background

We previously conducted a Phase IIa randomized placebo-controlled trial of 40 subjects to assess the efficacy and safety of dupilumab use in those hospitalized with COVID-19 (NCT04920916). Based on our pre-clinical data suggesting downstream pulmonary dysfunction with COVID-19 induced type 2 inflammation, we contacted patients from our Phase IIa study at 1 year for assessment of Post Covid-19 Conditions (PCC).

Methods

Subjects at 1 year after treatment underwent pulmonary function testing (PFTs), high resolution computed tomography (HRCT) imaging, symptom questionnaires, neurocognitive assessments, and serum immune biomarker analysis, with subject survival also monitored. The primary outcome was the proportion of abnormal PFTs, defined as an abnormal diffusion capacity for carbon monoxide (DLCO) or 6-minute walk testing (6MWT) at the 1-year visit.

Results

Sixteen of the 29 one-year survivors consented to the follow up visit. We found that subjects who had originally received dupilumab were less likely to have abnormal PFTs compared to those who received placebo (Fisher's exact p=0.011, adjusted p=0.058). We additionally found that 3 out of 19 subjects (16%) in the dupilumab group died by 1 year compared to 8 out of 21 subjects (38%) in the placebo group (log rank p=0.12). We did not find significant differences in neurocognitive testing, symptoms or CT chest imaging between treatment groups but observed evidence of reduced type 2 inflammation in those who received dupilumab.

Conclusions

We observed evidence of reduced long-term morbidity and mortality from COVID-19 with dupilumab treatment during acute hospitalization when added to standard of care regimens.