Background We sought to determine the immunologic abnormalities in patients following SARS-CoV-2 vaccines who experience post-acute sequelae of COVID-19 (PASC)-like symptoms > 4 weeks post vaccination. In addition, we investigated whether the potential etiology was similar to PASC. Design: We enrolled 50 post-vaccination individuals who experience PASC-like symptoms, 10 healthy individuals, and 35 individuals post-vaccination without symptoms. We performed multiplex cytokine/chemokine profiling with machine learning as well as SARS-CoV-2 S1 protein detection on monocyte subsets using flow cytometry and mass spectrometry. Results We determined that post-vaccination individuals with PASC-like symptoms had similar symptoms to PASC patients. When analyzing their immune profile, post-vaccination individuals had statistically significant elevations of sCD40L, CCL5, IL-6, and IL-8. SARS-CoV-2 S1 and S2 protein were detected in CD16 + monocytes using flow cytometry and mass spectrometry on sorted cells. Conclusions Post-vaccination individuals with PASC-like symptoms exhibit markers of platelet activation and pro-inflammatory cytokine production which may be driven by the persistence of SARS-CoV-2 S1 protein persistence in intermediate and non-classical monocytes.

Post-acute sequelae of COVID (PASC), or long COVID, is a multisystem complication of SARS-CoV-2 infection that continues to debilitate millions worldwide thus highlighting the public health importance of identifying effective therapeutics to alleviate this illness. One explanation behind PASC may be attributed to the recent discovery of persistent S1 protein subunit of SARS-CoV-2 in CD16+ monocytes up to 15 months after infection. CD16+ monocytes, which express both CCR5 and fractalkine receptors (CX3CR1), play a role in vascular homeostasis and endothelial immune surveillance. We propose targeting these receptors using the CCR5 antagonist, maraviroc, along with pravastatin, a fractalkine inhibitor, could disrupt the monocytic-endothelial-platelet axis that may be central to the etiology of PASC. Using five validated clinical scales (NYHA, MRC Dyspnea, COMPASS-31, modified Rankin, and Fatigue Severity Score) to measure 18 participants’ response to treatment, we observed significant clinical improvement in 6 to 12 weeks on a combination of maraviroc 300 mg per oral twice a day and pravastatin 10 mg per oral daily. Subjective neurological, autonomic, respiratory, cardiac and fatigue symptoms scores all decreased which correlated with statistically significant decreases in vascular markers sCD40L and VEGF. These findings suggest that by interrupting the monocytic-endothelial-platelet axis, maraviroc and pravastatin may restore the immune dysregulation observed in PASC and could be potential therapeutic options. This sets the framework for a future double-blinded, placebo-controlled randomized trial to further investigate the drug efficacy of maraviroc and pravastatin in treating PASC.

Post-acute sequelae of COVID (PASC), or long COVID, is a multisystem complication of SARS-CoV-2 infection that continues to debilitate millions worldwide thus highlighting the public health importance of identifying effective therapeutics to alleviate this illness. The pathophysiology behind PASC may be attributed to the recent discovery of persistent S1 protein subunit of SARS-CoV-2 in CD16+ monocytes up to 15 months after infection. CD16+ monocytes, which express both CCR5 and fractalkine receptors (CX3CR1), play a role in vascular homeostasis and endothelial immune surveillance. We believe targeting these receptors using the CCR5 antagonist, maraviroc, along with pravastatin, could disrupt the monocytic-endothelial-platelet axis that may be central to the etiology of PASC. Using five validated clinical scales (NYHA, MRC Dyspnea, COMPASS-31, modified Rankin, and Fatigue Severity Score) to measure 18 participants’ response to treatment, we observed significant clinical improvement in six to twelve weeks on a combination of maraviroc 300mg PO BID and pravastatin 10 mg PO daily. Subjective neurological (p=0.002), autonomic (p<0.0001), respiratory (p=0.0153), cardiac (p=0.002) and fatigue (p<0.0001) symptoms scores all decreased which correlated with statistically significant decreases in vascular markers sCD40L and VEGF. These findings suggest that by interrupting the monocytic-endothelial-platelet axis, maraviroc and pravastatin may restore the immune dysregulation observed in PASC and could be potential therapeutic options. This sets the framework for a future double-blinded, placebo-controlled randomized trial to further investigate the drug efficacy of maraviroc and pravastatin in treating PASC.

Lateral plate mesoderm is native to the developing limb while other cells such as neurons extend migratory axonal processes from the neural tube. Questions regarding how axons migrate to their proper location in the developing limb remain unanswered. Extracellular matrix molecules expressed in developing limb cartilages, such as the versican proteoglycan, may function as inhibitory cues to nerve migration, thus facilitating its proper patterning. In the present study, a method is described for co-culture of neural tissue with high density micromass preparations of mouse limb mesenchyme in order to investigate neurite patterning during limb chondrogenesis in vitro. Comparison of hdf (heart defect) mouse limb mesenchyme, which bears an insertional mutation in the versican proteoglycan core protein, with wild type demonstrated that the described technique provides a useful method for transgenic analysis in studies of chondrogenic regulation of neurite patterning. Differentiating wild type limb mesenchyme expressed cartilage characteristic Type II collagen and versican at 1 day and exhibited numerous well defined cartilage foci by 3 days. Wild type neurites extended into central regions of host cultures between 3 and 6 days and consistently avoided versican positive chondrogenic aggregates. Wild type neural tubes cultured with hdf limb mesenchyme, which does not undergo cartilage differentiation in a wild type pattern, showed that axons exhibited no avoidance characteristics within the host culture. Results suggest that differentiating limb cartilages may limit migration of axons thus aiding in the ultimate patterning of peripheral nerve in the developing limb.