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American Journal of Kidney Diseases

In Reply to ‘Is SARS-CoV-2 Serology Relevant for Hemodialysis Patients With COVID-19?’

      In a small group of hemodialysis patients with confirmed SARS-CoV-2 infection, we reported that the presence of anti–SARS-CoV-2 IgG overlaps by several weeks with detectable viral RNA in the upper airways.
      • De Vriese A.S.
      • Reynders M.
      IgG antibody response to SARS-CoV-2 infection and viral RNA persistence in patients on maintenance hemodialysis.
      The core message of our communication is that this antibody response, although proof of recent exposure to SARS-CoV-2, should not be interpreted as prima facie evidence of immunity to the virus. Viral load was highest during the first week of illness, suggesting that patients are most infectious during this period. It remains unclear whether the lower viral loads during the following weeks associate with a clinically relevant transmissibility of SARS-CoV-2 requiring further quarantining. As also advocated by Dudreuilh et al
      • Dudreuilh C.
      • Kumar N.
      • Moxham V.
      • Hemsley C.
      • Goldenberg S.
      • Moutzouris D.A.
      De-isolation of COVID-19-positive hemodialysis patients in the outpatient setting: a single-center experience.
      and pending further evidence, we submit that the prudent approach is to await negative reverse transcriptase–polymerase chain reaction test results.
      We measured anti–SARS-CoV-2 IgG with an N protein–based enzyme-linked immunosorbent assay (NovaLisa; NovaTec). Dudreuilh et al suggest that the combination with an S protein–based assay may provide additional information.
      • Dudreuilh C.
      • Moutzouris D.-A.
      Is SARS-CoV-2 serology relevant for hemodialysis patients with COVID-19? Am J Kidney Dis.
      We have repeated our analyses with a combined S1 (spike protein subunit 1)– and N-protein–based assay (Vircell).
      • Kohmer N.
      • Westhaus S.
      • Rühl C.
      • Ciesek S.
      • Rabenau H.F.
      Clinical performance of different SARS-CoV-2 IgG antibody tests. J Med Virol.
      Although there was a slight variation in the individual immune responses, as clearly described in the literature, the overall conclusion (100% seroconversion within the first few weeks of symptom onset) remains unaltered.
      Dudreuilh et al rightly point out that the clinical relevance of the anti–SARS-CoV-2 antibody response is currently unclear. Further studies in larger populations of both survivors and nonsurvivors with prolonged sequential sampling starting from the onset of infection are required to determine the longevity of the antibody response and potential correlation with severity of disease in hemodialysis patients. However, more importantly, research should be directed at identifying biomarkers of immunity that can be used to ascertain natural or vaccine-induced resistance to the virus in both the general and hemodialysis populations.

      Article Information

      Financial Disclosure

      The authors declare that they have no relevant financial interests.

      Peer Review

      Received June 20, 2020. Accepted June 24, 2020, after editorial review by an Associate Editor and a Deputy Editor.

      References

        • De Vriese A.S.
        • Reynders M.
        IgG antibody response to SARS-CoV-2 infection and viral RNA persistence in patients on maintenance hemodialysis.
        Am J Kidney Dis. 2020; 76: 440-441
        • Dudreuilh C.
        • Kumar N.
        • Moxham V.
        • Hemsley C.
        • Goldenberg S.
        • Moutzouris D.A.
        De-isolation of COVID-19-positive hemodialysis patients in the outpatient setting: a single-center experience.
        Kidney Int. 2020; 98: 236-237
        • Dudreuilh C.
        • Moutzouris D.-A.
        Is SARS-CoV-2 serology relevant for hemodialysis patients with COVID-19? Am J Kidney Dis.
        Am J Kidney Dis. 2020; 76: 598
        • Kohmer N.
        • Westhaus S.
        • Rühl C.
        • Ciesek S.
        • Rabenau H.F.
        Clinical performance of different SARS-CoV-2 IgG antibody tests. J Med Virol.

      Linked Article

      • Is SARS-CoV-2 Serology Relevant for Hemodialysis Patients With COVID-19?
        American Journal of Kidney DiseasesVol. 76Issue 4
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          Although dialysis patients are known to have impaired antibody responses to pathogens and fluctuation of antibody levels,1 the response to coronavirus disease 2019 (COVID-19) in this population remains to be determined. De Vriese and Reynders2 present the first evaluation of potential antibody responses in a dialysis population. We agree that 2 sequential negative COVID-19 swabs before de-isolating dialysis patients is a reasonable approach, as we recently demonstrated.3 De Vriese and Reynders studied the presence of immunoglobulin G (IgG) against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) nucleocapsid (N) protein in 7 patients and concluded that patients develop an antibody response within 15 days.
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