Pulse Therapy With Corticosteroids and Intravenous Immunoglobulin in the Management of Severe Tocilizumab-Resistant COVID-19: A Report of Three Clinical Cases.

We present the cases of three patients with severe, life-threatening coronavirus disease 2019 (COVID-19) who had failed to achieve substantial improvement on intial treatment. They subsequently received pulse therapy with methylprednisolone [1,000 mg/day intravenously (IV) for three consecutive days] and IV immunoglobulin (20 g/day). This treatment regimen was associated with a prompt resolution of respiratory failure, elimination of clinical manifestations of the cytokine release syndrome (CRS), and reversal of pulmonary CT changes. The treatment was generally safe and well-tolerated. There was no evidence of protracted persistence of the virus in the patients. Further randomized controlled trials are required to better understand the efficacy and safety of high-dose methylprednisolone and IV immunoglobulin, separately or in combination with each other, in the treatment of severe, life-threatening COVID-19.

Clonal chromosomal and genomic instability during human multipotent mesenchymal stromal cells long-term culture.

BACKGROUND AIMS: Spontaneous mutagenesis often leads to appearance of genetic changes in cells. Although human multipotent mesenchymal stromal cells (hMSC) are considered as genetically stable, there is a risk of genomic and structural chromosome instability and, therefore, side effects of cell therapy associated with long-term effects. In this study, the karyotype, genetic variability and clone formation analyses have been carried out in the long-term culture MSC from human gingival mucosa. METHODS: The immunophenotype of MSC has been examined using flow cytofluorometry and short tandem repeat (STR) analysis has been carried out for authentication. The karyotype has been examined using GTG staining and mFISH, while the assessment of the aneuploidy 8 frequency has been performed using centromere specific chromosome FISH probes in interphase cells. RESULTS: The immunophenotype and STR loci combination did not change during the process of cultivation. From passage 23 the proliferative activity of cultured MSCs was significantly reduced. From passage 12 of cultivation, clones of cells with stable chromosome aberrations have been identified and the biggest of these (12%) are tetrasomy of chromosome 8. The random genetic and structural chromosomal aberrations and the spontaneous level of chromosomal aberrations in the hMSC long-term cultures were also described. CONCLUSIONS: The spectrum of spontaneous chromosomal aberrations in MSC long-term cultivation has been described. Clonal chromosomal aberrations have been identified. A clone of cells with tetrasomy 8 has been detected in passage 12 and has reached the maximum size by passage 18 before and decreased along with the reduction of proliferative activity of cell line by passage 26. At later passages, the MSC line exhibited a set of cells with structural variants of the karyotype with a preponderance of normal diploid cells. The results of our study strongly suggest a need for rigorous genetic analyses of the clone formation in cultured MSCs before use in medicine.