A comprehensive assessment of long-term SARS-CoV-2-specific adaptive immune memory in convalescent COVID-19 Solid Organ Transplant recipients.

Long-term adaptive immune memory has been reported among immunocompetent individuals up to eight months following SARS-CoV-2 infection. However, limited data is available in convalescent patients with a solid organ transplant. To investigate this, we performed a thorough evaluation of adaptive immune memory at different compartments (serological, memory B cells and cytokine [IFN-γ, IL-2, IFN-γ/IL12 and IL-21] producing T cells) specific to SARS-CoV-2 by ELISA and FluoroSpot-based assays in 102 convalescent patients (53 with a solid organ transplants (38 kidney, 5 liver, 5 lung and 5 heart transplant) and 49 immunocompetent controls) with different clinical COVID-19 severity (severe, mild and asymptomatic) beyond six months after infection. While similar detectable memory responses at different immune compartments were detected between those with a solid organ transplant and immunocompetent individuals, these responses were predominantly driven by distinct COVID-19 clinical severities (97.6%, 80.5% and 42.1%, all significantly different, were seropositive; 84% vs 75% vs 35.7%, all significantly different, showed IgG-producing memory B cells and 82.5%, 86.9% and 31.6%, displayed IFN-γ producing T cells; in severe, mild and asymptomatic convalescent patients, respectively). Notably, patients with a solid organ transplant with longer time after transplantation did more likely show detectable long-lasting immune memory, regardless of COVID-19 severity. Thus, our study shows that patients with a solid organ transplant are capable of maintaining long-lasting peripheral immune memory after COVID-19 infection; mainly determined by the degree of infection severity.

[How to implement a complete apheresis program within a hemodialysis unit]. / Comment mettre en place un plateau technique d'aphérèses.

Many apheresis techniques can be performed in a blood-bank facility or a hemodialysis (HD) facility. However, it makes sense to perform apheresis in a hemodialysis facility as apheresis involves extra-corporeal circuits and because HD can be performed at the same time as apheresis (tandem procedure). Apheresis techniques comprise therapeutic plasma exchange, double-filtration plasmapheresis, and its derivative (rheopheresis and LDL-apheresis), and immunoadsorption (specific and semi-specific). We have setup an apheresis platform in our hospital that fulfills health recommendations. This process has involved financial investment and significant human resources, and has enabled us to network with different specialties (neurology, hematology, vascular medicine). We have setup protocols according to the type of pathology to be treated by apheresis, and to monitor clinical and biological data for each apheresis session. The main side effects of apheresis are a fall in blood pressure when a session is initiated, an increase in fluid overload, hypocalcemia, and the loss of some essential plasmatic factors. However, these side-effects are easily identified and can be properly managed in real time. Within two-years, we have performed 1845 apheresis sessions (134 patients). Of these, 66 received apheresis before and/or after kidney transplantation for ABO and/or HLA incompatibility (desensitization), for humoral rejection, or in the setting of relapsing focal-segmental glomerulosclerosis. Our patients' outcomes have been similar to those reported in the literature. The other 68 patients had various conditions. Because our program is now well-established, we are currently forming a specialist center to train physicians and nurses in the various apheresis techniques/procedures.