Frequency, kinetics and determinants of viable SARS-CoV-2 in bioaerosols from ambulatory COVID-19 patients infected with the Beta, Delta or Omicron variants

Airborne transmission of SARS-CoV-2 aerosol remains contentious. Importantly, whether cough or breath-generated bioaerosols can harbor viable and replicating virus remains largely unclarified. We performed size-fractionated aerosol sampling (Andersen cascade impactor) and evaluated viral culturability in human cell lines (infectiousness), viral genetics, and host immunity in ambulatory participants with COVID-19. Sixty-one percent (27/44) and 50% (22/44) of participants emitted variant-specific culture-positive aerosols <10μm and <5μm, respectively, for up to 9 days after symptom onset. Aerosol culturability is significantly associated with lower neutralizing antibody titers, and suppression of transcriptomic pathways related to innate immunity and the humoral response. A nasopharyngeal Ct <17 rules-in ~40% of aerosol culture-positives and identifies those who are probably highly infectious. A parsimonious three transcript blood-based biosignature is highly predictive of infectious aerosol generation (PPV > 95%). There is considerable heterogeneity in potential infectiousness i.e., only 29% of participants were probably highly infectious (produced culture-positive aerosols <5μm at ~6 days after symptom onset). These data, which comprehensively confirm variant-specific culturable SARS-CoV-2 in aerosol, inform the targeting of transmission-related interventions and public health containment strategies emphasizing improved ventilation.

Coeliac Disease High-Risk Human Leukocyte Antigen Alleles in a South African Type One Diabetic Population

BACKGROUND

Coeliac disease (CD) is an autoimmune disorder strongly associated with Human Leukocyte Antigen (HLA) genes DQ2 and DQ8. These alleles are also associated with other autoimmune diseases including type 1 dia-betes (T1D) and these patients are consequently at a higher risk of developing CD. We examined the frequency of high-risk HLA alleles in a cohort of South African T1D pediatric patients.

METHODS

A total of 22 pediatric participants were recruited at an endocrinology clinic in a public sector hospital in Johannesburg, South Africa. Clinical details were collected, and all patients were HLA typed at the DQ loci.

RESULTS

Of our T1D patients, 63.6% had at least 1 high-risk HLA type alleles associated with CD. Of the patients with high-risk alleles, DQ2 was found in the majority which is consistent with CD literature.

CONCLUSIONS

This study provides preliminary insight into the frequency of the HLA-DQ types associated with CD in a South African population. The high prevalence of high-risk alleles in our T1D population motivates continual monitoring and further investigations into CD in South Africa.

Plasmablastic lymphoma in Johannesburg, South Africa, in the era of widescale antiretroviral therapy use

OBJECTIVES

Plasmablastic lymphoma (PBL) is a clinically aggressive lymphoma which has a predilection for extranodal sites and is frequently HIV-associated. The incidence of non-Hodgkin lymphoma is thought to be reduced by widescale antiretroviral therapy (ART) coverage, but the literature is sparse as regards the impact of ART on the incidence of PBL and its outcomes in South Africa (SA). This study aimed to compare factors of interest in cases of PBL diagnosed before and after the widespread availability of ART in Johannesburg, SA.

METHODS

All cases of PBL diagnosed in the state sector hospitals of Johannesburg in 2007 and 2017 (before and after the widespread availability of ART, respectively) were extracted from the laboratory information system, and factors of interest compared.

RESULTS

The majority (> 95%) of cases of PBL were seen among people with HIV infection (PWH) at both time-points, and the proportion of patients on ART and with virological suppression (VS) increased significantly in 2017. However, the number of cases of PBL did not differ significantly between the two years assessed, comprising 46/397 (11.6%) and 53/582 (9.6%) of all lymphomas in 2007 and 2017, respectively (P = 0.23). Ongoing risk for PBL among PWH with virological control and immunological recovery was evident in 2017, as 18.9% of the patients had both VS and CD4 counts > 200 cells/μL at diagnosis. Inferior survival times were associated with elevated lactate dehydrogenase (LDH) levels and Epstein Barr virus (EBV) negativity, but were not influenced by the presence of AIDS, ART or VS. EBV negativity was significantly associated with VS, and appeared to flag a particularly aggressive form of the disease.

CONCLUSIONS

Widescale ART coverage has not reduced the incidence of PBL in Johannesburg, and an ongoing risk for this disease among PWH with adequate virological control and immunological recovery persists.

Measuring hip muscle strength in patients with femoroacetabular impingement and other hip pathologies: A systematic review

Objectives

The aim of this study was to systematically review the literature on measurement of muscle strength in patients with femoroacetabular impingement (FAI) and other pathologies and to suggest guidelines to standardise protocols for future research in the field.

Methods

The Cochrane and PubMed libraries were searched for any publications using the terms ‘hip’, ‘muscle’, ‘strength’, and ‘measurement’ in the ‘Title, Abstract, Keywords’ field. A further search was performed using the terms ‘femoroacetabular’ or ‘impingement’. The search was limited to recent literature only.

Results

A total of 29 articles were reviewed to obtain information on a number of variables. These comprised the type of device used for measurement, rater standardisation, the type of movements tested, body positioning and comparative studies of muscle strength in FAI versus normal controls. The studies found that hip muscle strength is lower in patients with FAI; this is also true for the asymptomatic hip in patients with FAI.

Conclusions

Current literature on this subject is limited and examines multiple variables. Our recommendations for achieving reproducible results include stabilising the patient, measuring isometric movements and maximising standardisation by using a single tester and familiarising the participants with the protocol. Further work must be done to demonstrate the reliability of any new testing method.

Cite this article: E. Mayne, A. Memarzadeh, P. Raut, A. Arora, V. Khanduja. Measuring hip muscle strength in patients with femoroacetabular impingement and other hip pathologies: A systematic review. Bone Joint Res 2017;6:66–72. DOI: 10.1302/2046-3758.61.BJR-2016-0081.

The utility of thrombo-elastography in the monitoring of aspirin therapy

To assess the utility of the thrombo-elastogram in monitoring of aspirin therapy 25 healthy volunteers were selected and given low-dose aspirin therapy. Thrombo-elastography and platelet aggregometry were conducted at baseline and 1 week later. After 1 week of aspirin therapy, thrombo-elastogram data failed to demonstrate a significant change in the clotting profile. Platelet aggregometry identified significant changes in the clotting profile in response to stimulation with arachidonic acid, adrenaline and ADP. We conclude that thrombo-elastography may not have utility in monitoring of response to aspirin.

Octreotide in the treatment of gastrointestinal bleeding caused by angiodysplasia in two patients with von Willebrand's disease

Two cases of von Willebrand's disease and angiodysplasia with intractable gastrointestinal bleeding are presented. Replacement therapy with cryoprecipitate and variable purity von Willebrand factor (VWF) was ineffective, as were other treatments including steroids, immunoglobulin and hormonal replacement. Both patients required massive blood transfusion and product support. The efficacy of somatostatin and an analogue is described. In one patient, we observed a rise in von Willebrand factor activity after octreotide infusion.

Orthotopic liver transplantation for hepatitis C infection: the best Christmas present?

We report the case of a 60-year-old man with mild Christmas disease, Factor IX 10% of normal, who developed chronic hepatitis C infection after receiving coagulation factor concentrates. Subsequently he developed encephalopathy and liver failure and was referred for liver transplantation. Following transplantation, Factor IX levels rapidly normalised and have remained so, representing a phenotypic cure of his Christmas disease.

Malignant lymphoma in congenital dyserythropoietic anaemia type III

A 60 year old woman with congenital dyserythropoietic anaemia (CDA) type III developed a malignant T cell lymphoma with cutaneous and widespread nodal involvement. Bone marrow aspirates showed erythroid hyperplasia and dyserythropoiesis with multinucleate erythroblasts and gigantoblasts, in keeping with CDA type III. Electron microscopy showed multinucleate erythroblasts with notably irregular nuclear outlines and intranuclear clefts. The development of malignant lymphoma in this patient, together with a documented high prevalence of monoclonal gammopathy and multiple myeloma and a single case of Hodgkin's disease, may indicate an increased incidence of lymphoproliferative disease in CDA type III.