An open resource for T cell phenotype changes in COVID-19 identifies IL-10-producing regulatory T cells as characteristic of severe cases

The pandemic spread of the novel coronavirus SARS-CoV-2 is due, in part, to the immunological properties of the host-viral interaction. The clinical presentation varies greatly from individual to individual, with asymptomatic carriers, mild to moderate-presenting patients and severely affected patients. Variation in immune response to SARS-CoV-2 may underlie this clinical variation. Using a high dimensional systems immunology platform, we have analyzed the peripheral blood compartment of 6 healthy individuals, 23 mild-to-moderate COVID-19 patients and 20 severe COVID-19 patients. We identify distinct immunological signatures in the peripheral blood of the mild-to-moderate and severe COVID-19 patients, including T cell lymphopenia, more consistent with peripheral hypo-than hyper-immune activation. Unique to the severe COVID-19 cases was a large increase in the proportion of IL-10-secreting regulatory T cells, a lineage known to possess anti-inflammatory properties in the lung. Annotated data is openly available (https://flowrepository.ors/experiments/2713) with clinical correlates, as a systems immunology resource for the COVID-19 research community.

Stage 3 pyomyositis of the gluteus minimus; Staphylococcus aureus sepsis, autoanticoagulation, proximal femoral osteomyelitis and the role of surgical intervention.

Primary pyomyositis is a rare bacterial infection of the skeletal muscle. Traditionally a tropical disease, it is increasingly described in westernised urban populations. The aetiology is due to transient bacteraemia in the presence of risk factors such as traumatised muscle, or immunocompromise. The condition presents in one of three stages, representing progression of disease severity. Intravenous antibiotic therapy is often sufficient for this disease at its early stage, but surgical drainage is necessary for advanced presentations. We report a severe case of stage 3 pyomyositis of the gluteus minimus, which led to Staphylococcus aureus sepsis, deranged liver function, acute kidney injury, autoanticoagulation and proximal femoral osteomyelitis in a healthy 64-year-old Caucasian man. This illustrates the potential severity of the disease, the life-threatening sequelae when diagnosis is delayed and the role of surgical drainage in averting the progression of systemic sepsis to end-organ dysfunction, disseminated intravascular coagulation and potentially death.

An unusual cause of Grey Turner's sign.

A woman in her late 70s presented to the acute general surgical take with a 3-day history of worsening right leg pain and swelling. She had undergone right revision total hip arthroplasty 20 months previously and reported chronic postoperative right thigh pain attributed to a femoral deep venous thrombosis for which she had been warfarinised. On examination, Grey Turner's sign (bruising of the flanks indicating retroperitoneal haemorrhage) was present, as well as a large tender mass in the right iliac fossa and pitting oedema throughout the right lower limb. Urgent CT scan with intravenous contrast revealed a right retroperitoneal haematoma secondary to a right acetabular screw protruding into the right external iliac vein. The patient was successfully managed with warfarin reversal and surgical removal of the relevant acetabular screw. At 2-month follow-up, the patient's symptoms continue to resolve.