Incidence and characteristics of COVID-19 in French professional football players during the 2020-2021 season.

OBJECTIVES: To describe the epidemiology of COVID-19 in French professional football players, and to compare the infection incidence with the general population across the first three waves. METHODS: During the 2020-2021 season, all professional football players (n = 1217) in the two primary French leagues underwent weekly testing for SARS-CoV-2 infection by nasopharyngeal PCR, in combination with rigorous infection control measures. RESULTS: Among all players, 572 (47%) tested positive at least once, with no COVID-19-related death or hospital admission. Monthly incidence estimates in players ranged from 1486 to 6731 per 100,000 individuals, i.e. 2-17 times higher than incidence estimates in the general population in France during the study period. CONCLUSION: Almost 50% of professional football players developed SARS-CoV-2 infection during the 2020-2021 season in France, with no severe complication.

Wound stimulation by growth-arrested human keratinocytes and fibroblasts: HP802-247, a new-generation allogeneic tissue engineering product.

BACKGROUND: HP802-247 is a new-generation, allogeneic tissue engineering product consisting of growth-arrested, human keratinocytes (K) and fibroblasts (F) delivered in a fibrin matrix by a spray device. OBJECTIVE: To identify the preferred dose of HP802-247 based on cell concentration and K/F ratio. METHODS: A multicenter, randomized, double-blind, placebo-controlled, explorative phase II study of 6 different doses of HP802-247 administered once per week for 12 consecutive weeks in chronic venous leg ulcers. RESULTS: HP802-247 was safe and well tolerated and showed increasing efficacy dependent on cell concentration and K/F ratio, in line with in vitro growth factor release data. The mean complete closure rate at week 12 for all patients treated with HP802-247 was 40%, and for placebo it was 33%. In contrast to placebo, all HP802-247 dose groups improved from week 12 to 24. CONCLUSION: As an integral part of a rational tissue engineering product development, this explorative trial identified the preferred dose of HP802-247 for further clinical studies.

Combined use of a collagen-based dermal substitute and a fibrin-based cultured epithelium: a step toward a total skin replacement for acute wounds.

Integra, a dermal replacement, is used as an immediate and temporary coverage for acute wounds, after which, autograft is used to reconstitute permanently the epidermal coverage. The fibrin sheet-cultured epithelium autograft (FS-CEA) could provide an effective alternative to the surgical procedure. To evaluate this hypothesis, we compared the association of Integra/FS-CE to Integra/control-cultured epithelium (control-CE). Their respective abilities: (1) to produce dermal-epidermal construct in vitro; (2) to generate skin replacement when grafted onto athymic mice were studied. We have shown that: (1) 83% of the FS-CE attached to the artificial dermis in vitro compared to only 33% for control-CE; (2) retraction of the grafted area was significantly lower 2 weeks after grafted with FS-CE than with the control-CE (P < 0.05); (3) 83% of the mice grafted with FS-CE showed the presence of a differentiated human epidermis 21 days after grafting, while such an epidermis was absent in all the animals of the control-CE group. We found that the use of FS-CE greatly improved adhesion, development of the epithelium and graft take onto the artificial dermis. We believe this technology should significantly improve the performance of dermal-epidermal skin replacement for acute wounds.

Allogeneic beta-islet cells correct diabetes and resist immune rejection.

Allogeneic MHC-incompatible organ or cell grafts are usually promptly rejected by immunocompetent hosts. Here we tested allogeneic beta-islet cell graft acceptance by immune or naive C57BL/6 mice rendered diabetic with streptozotocin (STZ). Fully MHC-mismatched insulin-producing growth-regulated beta-islet cells were transplanted under the kidney capsule or s.c. Although previously or simultaneously primed mice rejected grafts, STZ-treated diabetic mice accepted islet cell grafts, and hyperglycemia was corrected within 2-4 weeks in absence of conventional immunosuppression. Allogeneic grafts that controlled hyperglycemia expressed MHC antigens, were not rejected for >100 days, and resisted a challenge by allogeneic skin grafts or multiple injections of allogeneic cells. Importantly, the skin grafts were rejected in a primary fashion by the grafted and corrected host, indicating neither tolerization nor priming. Such strictly extralymphatic cell grafts that are immunologically largely ignored should be applicable clinically.