[COVID-19 recurrence due to reinfection with SARS-CoV-2 in a hemodialysis patient: there and back again].

The COVID-19 pandemic has caused millions of infections and deaths so far. After recovery, the possibility of reinfection has been reported. Patients on hemodialysis are at high risk of contracting SARS-CoV-2 and developing serious complications. Furthermore, they are a relatively hypo-anergic population, in which the development and duration of the immune and antibody response is still partially unknown. This may play a role in the possible susceptibility to reinfection. To date, only 3 cases of SARS-CoV-2 reinfection from strains prior to the Omicron variant in patients on chronic hemodialysis have been reported in literature. In all of them, the first infection was detected by screening in the absence of symptoms, potentially indicating a poor immune response, and there are no data about the antibody titre developed. We report a case of recurrence of COVID-19 in 2020 - first infection likely from Wuhan strain; reinfection likely from English variant (Alpha) after 7 months - in a hemodialysis patient with clinical symptoms and pulmonary ultrasound abnormalities. Swabs were negative in the interval between episodes (therefore excluding any persistence of positivity) and the lack of antibody protection after the first infection was documented by the serological test. The role of the potential lack - or rapid loss - of immune protection following exposure to SARS-CoV-2 in hemodialysis patients needs to be better defined, also in consideration of the anti-COVID vaccination campaign and the arrival of the Omicron variant, which appears to elude the immunity induced by vaccines and by previous variants. For this purpose, prospective multicenter studies are in progress in several European countries. This case also highlights the need for a careful screening with nasopharyngeal swabs in dialysis rooms, even after patients overcome infection and/or are vaccinated.

Preferential allocation of marginal kidney allografts to elderly recipients combined with modified immunosuppression gives good results.

BACKGROUND: There is an increasing tendency to allocate kidneys from marginal donors in older recipients. This combination optimizes the uses of an expanded donor pool but demands attention for the higher nephrotoxic sensitivity of the kidney and the increased immunosuppression vulnerability of the elderly recipients. We aimed to reduce these hazards by means of a calcineurin-free induction therapy followed by a maintenance regimen targeted to minimize/withdraw steroid. METHODS: Eighty-eight single (43%) or double (57%) transplant recipients (58.4+/-5.7 years) from 88 marginal donors (67+/-8.3 years) received monoclonal anti-IL-2 receptor antibodies, mycophenolate mofetil (MMF), and steroid. When serum creatinine was less than 2.6 mg/dL, tacrolimus was started and MMF was withdrawn when the tacrolimus trough level was above 15 ng/ml. Steroid was tapered to 5 mg at day 45 and then progressively reduced. RESULTS: Overall patient and graft survival at the first and fourth year were respectively 100 and 96%, and 98 and 79%. Acute rejection rate was 13.6% (12/88), creatinine clearance remained stable (48.2 ml/min at the sixth month, 50.9 ml/min at 48th month). At the first, second, third, and fourth years, 23, 69, 80, and 100% of recipients were off steroids. For those on steroids, mean dose was respectively 2.6 mg/day from month 12. No recipient re-assumed steroids CONCLUSIONS: In the "old-for-old" allocation, the calcineurin-inhibitor avoidance at induction and the steroid withdrawal/minimization during the tacrolimus-based maintenance regimen allow a low acute rejection rate, a stable renal function, and favorable recipient and graft outcomes.