Background
There is increasing concern that persistent infection of SARS-CoV-2 within immunocompromised hosts could serve as a reservoir for mutation accumulation and subsequent emergence of novel strains with the potential to evade immune responses.
Methods
We describe three patients with acute lymphoblastic leukemia who were persistently positive for SARS-CoV-2 by real-time polymerase chain reaction. Viral viability from longitudinally-collected specimens was assessed. Whole-genome sequencing and serological studies were performed to measure viral evolution and evidence of immune escape.
Findings
We found compelling evidence of ongoing replication and infectivity for up to 162 days from initial positive by subgenomic RNA, single-stranded RNA, and viral culture analysis. Our results reveal a broad spectrum of infectivity, host immune responses, and accumulation of mutations, some with the potential for immune escape.
Interpretation
Our results highlight the need to reassess infection control precautions in the management and care of immunocompromised patients. Routine surveillance of mutations and evaluation of their potential impact on viral transmission and immune escape should be considered.
8 male patients undergoing maintenance hemodialysis were studied to determine the effect of administering supplements of pyridoxine hydrochloride, 50 mg/day for 3–5 weeks, on tests of immune function. In the 3 patients who initially had abnormal nitroblue tetrazolium reduction tests, the values returned to normal with therapy (p < 0.05). The generation of chemotactic factors from plasma was defective in all evaluated patients and improved after pyridoxine therapy in 4 of 5 patients (p < 0.01). The lymphocyte subpopulations changed with a rise in the populations of null cells after supplementation with pyridoxine. In addition, lymphocyte transformation in response to mitogens improved in the 3 patients who initially showed low values in these assays. The improvements occurred with pyridoxine therapy even though some patients who responded had no evidence for vitamin B6 deficiency before therapy, as indicated by a normal erythrocyte glumatic-pyruvic transaminase index. We conclude that several parameters of immune function are improved with pyridoxine supplementation. Studies are necessary to establish the minimum daily intake of pyridoxine which will maintain improved values of these tests of immune function in hemodialysis patients.
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