Abstract:
Background: We have shown that acute COVID-19 pathophysiology is profoundly altered by infection of lung megakaryocytes (MKs) and platelets by SARS‑CoV‑2 (Zhu et al, 2022). A significant proportion of COVID-19 patients have symptoms persisting for > 3 months after initial infection with SARS-CoV-2, referred to as Long COVID or Post-acute Sequelae of SARS-CoV-2 (PASC) patients. Persistent or re-emerging symptoms are varied, with a predominance of asthenia, neuro-cognitive impairment and cardio-vascular symptoms. The pathophysiology underlying long-onset COVID remains poorly understood.
Methods: Blood was collected from patients with Long COVID with symptoms duration > 3 months (LC) (n=30), previously infected by SARS-CoV-2 but without persistent symptoms (resolved COVID-19 (CR), n=10), or healthy donor (n=20). MK frequency in blood was quantified by flow cytometry. Platelets and blood MKs were analysed for microclots, the presence of Spike protein and SARS-CoV-2 RNA by in situ hybridization and immunodetection visualized by confocal microscopy. Spike and serotonin were quantified in plasma.
Results: The frequency of CD41+ MKs in peripheral blood mononucleated cells (PBMCs) was significantly higher than healthy donors (0.28±0.05 versus 0.03±0.02) as a sign of MK infection, as we previously shown in acutely infected individuals with SARS-CoV-2 in platelets. Accordingly, in all samples analyzed, circulating MK in Long COVID sheltered both Spike and SARS-CoV-2 ssRNA, but also dsRNA suggestive of viral replication. These infected MKs produced blood platelets that contain also P Spike and SARS-CoV-2 ssRNA. Platelets microclots were detected in all tested Long COVID patients. Spike protein was detected at the pg level in 30 % of analyzed plasma from Long COVID but not CR individuals. The level of serotonin in platelet and of tryptophan hydroxylase-1 (TPH-1), the enzyme that regulates serotonin synthesis decreased significantly (p<0.0001) in blood of Long COVID patients compared to CR individuals.
Conclusions: In patients developing Long COVID, SARS-CoV-2 persists and replicates in MKs producing virus-containing platelets. The presence of spike in plasma might be an additional sign of viral persistence that could be used as a Long COVID biomarker. The presence of the virus could lead to abnormal platelet activation and the formation of microclots, which would contribute to the various symptoms and to deregulation of serotonin uptake, contributing to the neurocognitive symptoms observed in long-onset COVID.
Source: Feifan He, Boxin Huang, Andrea Cottignies-Calamarte, Wiem Bouchneb, Agathe Goubard, Faroudy Boufassa, Jacques Callebert, Dominique Salmon, Morgane Bomsel. Persistence of SARS-CoV-2 in Platelets and Megakaryocytes in Long COVID. The Conference on Retroviruses and Opportunistic Infections (CROI), March 3-6, 2024 | Denver, Colorado. https://www.croiconference.org/abstract/persistence-of-sars-cov-2-in-platelets-and-megakaryocytes-in-long-covid/