Pharmacotherapy in COVID 19: Potential Impact of Targeting the Complement System

Association of Serum Complement C3 Levels with Severity and Mortality in COVID 19

The severe acute respiratory distress syndrome-associated coronavirus-2 infection can activate innate and adaptive immune responses which may lead to harmful tissue damage, both locally and systemically. C3, a member of complement system of serum proteins, is a major component of innate immune and inflammatory responses. This study is aimed to assess serum C3 as a marker of COVID-19 severity and a predictor of disease progression. A total of 150 COVID-19 patients, confirmed by RT-PCR, and 50 healthy controls were recruited. Serum C3 levels were determined by using direct colorimetric method. Median levels of serum C3 in total cases and controls were 157.8 and 165.7 mg/dL respectively. Serum C3 although not significantly decreased, they were lower in cases when compared to controls. Similarly, significant differences were found between the groups, with severe group (140.6 mg/dL) having low levels of serum C3 protein when compared to mild (161.0 mg/dL) and moderate group (167.1 mg/dL). Interestingly, during hospitalization, significant difference between baseline (admission) and follow-up (discharge) was observed only in patients with moderate disease. Based on our results, lower levels of C3, with an increase in IL-6 and d-dimer levels, are associated with higher odds of mortality. Therefore, we would like to emphasize that measuring serum C3 levels along with other inflammatory markers might give an added advantage in early identification of patients who are prone to having a severe disease course and can help in a more effective follow-up of disease progression.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12291-023-01148-x.

Immune responses and safety of COVID-19 vaccination in atypical hemolytic uremic syndrome patients in Taiwan

Atypical hemolytic uremic syndrome is a rare, life-threatening disorder which can be triggered by COVID 19 infection and COVID 19 vaccination then induce multiple organ failure. Our study is the first to evaluate immune responses to COVID-19 vaccination and safety in a cohort of patients in a local single-center study in Taiwan.. Results indicate that vaccines effectively shield aHUS patients from severe COVID-19 complications without significant safety concerns. A double booster dose for the third vaccine is essential for optimal efficacy. Anti-complement therapy did not influence vaccination effectiveness. Transplant aHUS patients had the lowest immune response titers, indicating a need for additional vaccine doses. Compared to healthcare workers, aHUS patients had poor T-cell responses. We noted a superior trend with mixed-type COVID-19 vaccinations in aHUS patients, while fixed-type mRNA demonstrated better results in healthcare workers. Our findings endorse COVID-19 vaccination as a potent strategy to safeguard aHUS patients from severe complications, emphasizing the importance of vigilant monitoring pre- and post-vaccination.

Pediatric adenovirus pneumonia: clinical practice and current treatment

Adenovirus pneumonia is common in pediatric upper respiratory tract infection, which is comparatively easy to develop into severe cases and has a high mortality rate with many influential sequelae. As for pathogenesis, adenoviruses can directly damage target cells and activate the immune response to varying degrees. Early clinical recognition depends on patients' symptoms and laboratory tests, including those under 2 years old, dyspnea with systemic toxic symptoms, atelectasis or emphysema in CT image, decreased leukocytes, and significantly increased C-reaction protein (CRP) and procalcitonin (PCT), indicating the possibility of severe cases. Until now, there is no specific drug for adenovirus pneumonia, so in clinical practice, current treatment comprises antiviral drugs, respiratory support and bronchoscopy, immunomodulatory therapy, and blood purification. Additionally, post-infectious bronchiolitis obliterans (PIBO), hemophagocytic syndrome, and death should be carefully noted. Independent risk factors associated with the development of PIBO are invasive mechanical ventilation, intravenous steroid use, duration of fever, and male gender. Meanwhile, hypoxemia, hypercapnia, invasive mechanical ventilation, and low serum albumin levels are related to death. Among these, viral load and serological identification are not only "gold standard" for adenovirus pneumonia, but are also related to the severity and prognosis. Here, we discuss the progress of pathogenesis, early recognition, therapy, and risk factors for poor outcomes regarding severe pediatric adenovirus pneumonia.

Eculizumab in patients with severe coronavirus disease 2019 (COVID-19) requiring continuous positive airway pressure ventilator support: Retrospective cohort study

Background

Complement activation contributes to lung dysfunction in coronavirus disease 2019 (COVID-19). We assessed whether C5 blockade with eculizumab could improve disease outcome.

Methods

In this single-centre, academic, unblinded study two 900 mg eculizumab doses were added-on standard therapy in ten COVID-19 patients admitted from February 2020 to April 2020 and receiving Continuous-Positive-Airway-Pressure (CPAP) ventilator support from ≤24 hours. We compared their outcomes with those of 65 contemporary similar controls. Primary outcome was respiratory rate at one week of ventilator support. Secondary outcomes included the combined endpoint of mortality and discharge with chronic complications.

Results

Baseline characteristics of eculizumab-treated patients and controls were similar. At baseline, sC5b-9 levels, ex vivo C5b-9 and thrombi deposition were increased. Ex vivo tests normalised in eculizumab-treated patients, but not in controls. In eculizumab-treated patients respiratory rate decreased from 26.8±7.3 breaths/min at baseline to 20.3±3.8 and 18.0±4.8 breaths/min at one and two weeks, respectively (p<0.05 for both), but did not change in controls. Between-group changes differed significantly at both time-points (p<0.01). Changes in respiratory rate correlated with concomitant changes in ex vivo C5b-9 deposits at one (rs = 0.706, p = 0.010) and two (rs = 0.751, p = 0.032) weeks. Over a median (IQR) period of 47.0 (14.0–121.0) days, four eculizumab-treated patients died or had chronic complications versus 52 controls [HR_Crude (95% CI): 0.26 (0.09–0.72), p = 0.010]. Between-group difference was significant even after adjustment for age, sex and baseline serum creatinine [HR_Adjusted (95% CI): 0.30 (0.10–0.84), p = 0.023]. Six patients and 13 controls were discharged without complications [HR_Crude (95% CI): 2.88 (1.08–7.70), p = 0.035]. Eculizumab was tolerated well. The main study limitations were the relatively small sample size and the non-randomised design.

Conclusions

In patients with severe COVID-19, eculizumab safely improved respiratory dysfunction and decreased the combined endpoint of mortality and discharge with chronic complications. Findings need confirmation in randomised controlled trials.

Elucidation of Teicoplanin Interactions with Drug Targets Related to COVID-19

Teicoplanin is a glycopeptide antibiotic effective against several bacterial infections, has exhibited promising therapeutic efficiency against COVID-19 in vitro, and the rationale for its use in COVID-19 is yet to be recognized. Hence, in this study a number of molecular modeling techniques were employed to decrypt the mechanistic insight of teicoplanin interaction with several COVID-19 drug targets. Initially, molecular docking was employed to study the teicoplanin interaction with twenty-five SARS-CoV-2 structural and non-structural proteins which was followed by molecular mechanics/generalized Born surface area (MM/GBSA) computation for binding energy predictions of top ten models from each target. Amongst all macromolecular targets, the N-terminal domain of the nucleocapsid protein displayed the strongest affinity with teicoplanin showing binding energies of −7.4 and −102.13 kcal/mol, in docking and Prime MM/GBSA, respectively. Thermodynamic stability of the teicoplanin-nucleocapsid protein was further probed by molecular dynamics simulations of protein–ligand complex as well as unbounded protein in 100 ns trajectories. Post-simulation MM-GBSA computation of 50 frames extracted from simulated trajectories estimated an average binding energy of −62.52 ± 12.22 kcal/mol. In addition, conformational state of protein in complex with docked teicoplanin displayed stable root-mean-square deviation/fluctuation. In conclusion, computational investigation of the potential targets of COVID-19 and their interaction mechanism with teicoplanin can guide the design of novel therapeutic armamentarium for the treatment of SARS-CoV-2 infection. However, additional studies are warranted to establish the clinical use or relapses, if any, of teicoplanin in the therapeutic management of COVID-19 patients.