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Patients undergoing renal dialysis show promising antibody levels 6 months after SARS-CoV-2 infection and then slowly decline. This suggests a good immune response to COVID-19 in these patients at high risk of serious outcomes.
“Our study is the largest to explain the longitudinal humoral response in a population that reflects the group most affected by SARS-CoV-2 infection,” said Dr. Shuchi Anand of Stanford University, California. A colleague writes. Research Published on May 18th Annual report of internal medicine..
“Almost all serum-affected patients in our study had evidence of an assay-detectable receptor-binding domain (RBD) immunoglobulin (Ig) G response through a 6-month follow-up,” they said. Is reporting. “Most met our assay criteria for high levels of response.”
“Median antibody levels declined slowly and continuously over time, but there was no indication that the humoral response of the weakened subgroup was short-lived.”
Age, comorbidities, and race did not diminish adaptive response
The study enrolled 2215 patients from a national sample representing 1200 dialysis centers across the United States. All patients showed evidence of SARS-CoV-2 infection prior to July 2020. The authors analyzed monthly levels of RBD IgG levels for up to 6 months using plasma samples from regular monthly lab work.
They found that 93% of patients (n = 2063) achieved or maintained an assay-detectable antibody response with an IgG index value of 1 or greater.
Immune response was classified as high (IgG ≥ 10) in 60% of patients, and 76% of participants in the group showed a persistent response that remained high.
After that, the median index antibody level declined slowly from July to December 2020 (P <.001); However, there was no significant difference in the pattern of level changes due to factors such as age, gender, race / ethnicity, and diabetic status.
“Although the distribution of these responses was widespread, the trajectory of the response may have been expected to weaken the adaptive immune response, either demographic (eg, elderly) or clinically (eg, diabetes). It did not change from layer to layer. ”The author reports.
However, there were some differences among the 137 patients who did not show a detectable response in the assay. Patients were likely to be Caucasian and were in either the younger (18-44 years) or older (80+) age group. It also reduces the chances of developing diabetes or hypoalbuminemia.
Inconsistent immune response patterns
Data on antibody response after COVID-19 in the general population are limited, and previous studies have shown conflicting patterns, with some reporting stable or flat antibody levels, and rapidly. Some are declining.
New discoveries suggest something among patients on dialysis.
“Our analysis confirms antibody persistence in the majority (> 90%) of people over 6 months, but there is no strong evidence of a plateau of RBD IgG responses,” the author writes. I have. “Rather, the response seems to indicate an overall slow and continuous decline in median.”
Previous studies involving people on dialysis influenza And Hepatitis B The vaccine suggests that humoral immunity is impaired compared to the general population. However, new findings suggest a more promising response after COVID-19 infection.
“In characterization of their response to natural SARS-CoV-2 infection … no evidence of a short-lived humoral immune response compared to the general population was found,” the author writes.
“There was no difference in response persistence between men and women, and among other clinically important groups,” they write.
Survivorship bias?
Dialysis patients hospitalized with COVID-19 are known to have a high mortality rate. Therefore, the people who formed the basis of this study, those who survived the infection and continued dialysis for monthly evaluation, may represent a subset of healthier patients, the authors said. I am.
Patients over the age of 80 are likely to have low or no antibodies, but the authors point out that overall, most patients over the age of 80 (204 of the 227 patients) had a detectable response. doing.
But importantly, the authors state that the role of antibody response level and duration in providing protection from SARS-CoV-2 reinfection remains unclear.
“Antibody titers are the only marker of immunity, and even people with low levels or undetectable antibody responses can initiate a subsequent protective response against reinfection that nullifies symptomatological disease.” They conclude.
This study was funded by Ascend Clinical Laboratories.
Intern Med. Published online on May 18, 2021. Full text
