G6PD deficiency and severity of COVID19 pneumonia and acute respiratory distress syndrome: tip of the iceberg?

The severe pneumonia caused by the human coronavirus (hCoV)-SARS-CoV-2 has inflicted heavy casualties, especially among the elderly and those with co-morbid illnesses irrespective of their age. The high mortality in African-Americans and males, in general, raises the concern for a possible X-linked mediated process that could affect the viral pathogenesis and the immune system. We hypothesized that G6PD, the most common X-linked enzyme deficiency, associated with redox status, may have a role in severity of pneumonia. Retrospective chart review was performed in hospitalized patients with COVID19 pneumonia needing supplemental oxygen. A total of 17 patients were evaluated: six with G6PD deficiency (G6PDd) and 11 with normal levels. The two groups (normal and G6PDd) were comparable in terms of age, sex, co-morbidities, and laboratory parameters-LDH, IL-6, CRP, and ferritin, respectively. Thirteen patients needed ventilatory support ; 8 in the normal group and 5 in the G6PDd group (72% vs.83%). The main differences indicating increasing severity in normal vs. G6PDd groups included G6PD levels (12.2 vs. 5.6, P = 0.0002), PaO2/FiO2 ratio (159 vs. 108, P = 0.05), days on mechanical ventilation (10.25 vs. 21 days P = 0.04), hemoglobin level (10 vs. 8.1 P = 0.03), and hematocrit (32 vs. 26 P = 0.015). Only one patient with G6PDd died; 16 were discharged home. Our clinical series ascribes a possible biological role for G6PDd in SARS-CoV2 viral proliferation. It is imperative that further studies are performed to understand the interplay between the viral and host factors in G6PDd that may lead to disparity in outcomes. KEY POINTS: • COVID19 studies show higher mortality in men, due to severe pneumonia and ARDS, indicating possible X-linked mediated differences • G6PD, the most common X-linked enzymopathy, highly prevalent in African Americans and Italians, maintains redox homeostasis. • Preclinical studies using G6PD deficient (G6PDd) cells infected with human coronavirus (hCoV), show impaired cellular responses, viral proliferation and worsening oxidative damage. • Retrospective chart review in hospitalized patients with COVID19 pneumonia needing supplemental oxygen shows differences between the two groups (Normal and G6PDd) in hematological indices; the G6PDdgroup demonstrated prolonged PaO2/FiO2 ratio, and longer days on mechanical ventilation indicating the severity of the pneumonia.

Clinical Outcomes Following Tocilizumab Administration in Mechanically Ventilated Coronavirus Disease 2019 Patients.

Effective treatments for the critically ill patient with novel coronavirus disease 2019 are desperately needed. Given the role of cytokine release syndrome in the pathogenesis of coronavirus disease 2019-associated respiratory distress, therapies aimed at mitigating cytokine release, such as the interleukin-6 receptor-inhibiting monoclonal antibody tocilizumab, represent potential treatment strategies. Therefore, we examined the outcomes of critically ill coronavirus disease 2019 patients treated with tocilizumab and factors associated with clinical improvement. DESIGN: A retrospective cohort analysis of 21-day outcomes for consecutive mechanically ventilated patients treated with tocilizumab from March 24, 2020, to May 4, 2020. SETTING: Nine ICUs at six hospitals within a hospital system in Houston, Texas, United States. PATIENTS: The first 62 coronavirus disease 2019 patients on invasive mechanical ventilation who were treated with tocilizumab, which was considered for all patients with severe disease. INTERVENTIONS: Tocilizumab was administered either at a weight-based dose of 4-8 mg/kg or at a flat dose of 400 mg, with repeat administration in some patients at the physician's discretion. MEASUREMENTS AND MAIN RESULTS: The primary outcomes were mortality and clinical improvement, defined as extubation. By day 21 post-tocilizumab, clinical improvement occurred in 36 patients (58%) and 13 patients (21%) died. In both univariable and multivariable analyses, age less than 60 years was associated with clinical improvement. Transient transaminitis was the most common adverse reaction, occurring in 25 patients (40%). CONCLUSIONS: Based on clinical outcomes and mortality rates seen in previous reports of mechanically ventilated patients, tocilizumab, as part of the management strategy for severe coronavirus disease 2019, represents a promising option. These findings support the need for evaluation of tocilizumab in a randomized controlled trial.