Background Convalescent plasma has been widely used to treat COVID-19 and is under investigation in numerous randomized clinical trials, but results are publicly available only for a small number of trials. The objective of this study was to assess the benefits of convalescent plasma treatment compared to placebo or no treatment and all-cause mortality in patients with COVID-19, using data from all available randomized clinical trials, including unpublished and ongoing trials (Open Science Framework, https://doi.org/10.17605/OSF.IO/GEHFX). Methods In this collaborative systematic review and meta-analysis, clinical trial registries (ClinicalTrials.gov, WHO International Clinical Trials Registry Platform), the Cochrane COVID-19 register, the LOVE database, and PubMed were searched until April 8, 2021. Investigators of trials registered by March 1, 2021, without published results were contacted via email. Eligible were ongoing, discontinued and completed randomized clinical trials that compared convalescent plasma with placebo or no treatment in COVID-19 patients, regardless of setting or treatment schedule. Aggregated mortality data were extracted from publications or provided by investigators of unpublished trials and combined using the Hartung–Knapp–Sidik–Jonkman random effects model. We investigated the contribution of unpublished trials to the overall evidence. Results A total of 16,477 patients were included in 33 trials (20 unpublished with 3190 patients, 13 published with 13,287 patients). 32 trials enrolled only hospitalized patients (including 3 with only intensive care unit patients). Risk of bias was low for 29/33 trials. Of 8495 patients who received convalescent plasma, 1997 died (23%), and of 7982 control patients, 1952 died (24%). The combined risk ratio for all-cause mortality was 0.97 (95% confidence interval: 0.92; 1.02) with between-study heterogeneity not beyond chance (I2 = 0%). The RECOVERY trial had 69.8% and the unpublished evidence 25.3% of the weight in the meta-analysis. Conclusions Convalescent plasma treatment of patients with COVID-19 did not reduce all-cause mortality. These results provide strong evidence that convalescent plasma treatment for patients with COVID-19 should not be used outside of randomized trials. Evidence synthesis from collaborations among trial investigators can inform both evidence generation and evidence application in patient care.

A 6-year-old girl presented with disseminated polymorphous skin lesions of several months' duration, joint pains, recurrent fever, anemia, and inguinal adenopathy. Subsequent evaluation of skin, lymph node, and bone marrow morphology showed infiltration of atypical lymphocytic cells. Immunohistochemical and flow cytometric analysis showed findings consistent with the rare but highly malignant blastic Natural killer cell lymphoma/leukemia also termed CD4/CD56 hematodermic neoplasm.

Eight cases of primary thyroid lymphoma were reported in a tertiary government hospital from January 2005 to August 2011. All patients presented with a diffuse enlargement of both thyroid lobes with associated obstructive symptoms. Five of these cases were extranodal marginal zone lymphoma and three were diffuse large B-cell lymphoma. Clinical features that would favor a thyroid lymphoma include tumor size of greater that 7cm, obstructive symptoms, clinical hypothyroidism or history of Hashimoto thyroiditis. Thus, these features must be considered in evaluating thyroid nodules during fine-needle aspiration biopsy. Histologically, extranodal marginal zone B-cell lymphoma shows vaguely nodular to diffuse infiltrates of small to intermediate size atypical lymphoid cells infiltrating the thyroid follicles, while diffuse large B-cell lymphoma shows sheets of large atypical lymphoid cells infiltrating the thyroid follicular epithelium. Keywords: Primary Thyroid Lymphoma, Extranodal Marginal Zone B-cell Lymphoma, Diffuse Large B-cell Lymphoma.