Interpreting CD57
One of the researchers who participated in the study was Luis Martínez-Juárez, MD, MPH, DrPH. He is on the operative solutions team at the Carlos Slim Foundation. Dr. Martínez-Juárez pointed out that one of the contributions of this study was that it specifically examined the Mexican population. He noted that “according to the findings, obesity is not only a comorbidity associated with more severe progressions during acute COVID-19 disease, but also, through inflammation parameters, such as interleukin-6, interferon gamma-induced protein 10, and macrophage inflammatory protein-1 alpha, it’s involved in the development of clinical aspects related to postacute sequelae of COVID-19.”
Dr. Gómez-Martín added that finding proinflammatory and obesity parameters in the patients could potentially support the hypothesis of the persistence of virus fragments in adipose tissue as possibly involved in clinical aspects associated with PASC, as some groups have reported in the medical literature.
Angélica Cuapio, MD, DrMed, an immunologist and senior investigator at the Karolinska Institute, Stockholm, who did not participate in the study, said in an interview that the authors’ findings on the sustained increase of the CD57 marker in CD8+ lymphocytes are of notable interest. They may be associated with senescence states or cellular aging or with a stage of chronic viral infections. Therefore, Dr. Cuapio argued, it would have been valuable to include cellular markers of the innate system, such as natural killer cells, since in various infections, an increase in CD57 in lymphocytes is accompanied by an almost proportional increase of this marker in natural killer cells.
“This information would help to determine more accurately if we are talking about a cellular senescence or more about a chronic infection in persistent COVID-19.” The finding is important, but future research is needed in this developing field.
Dr. Cuapio pointed out that the authors found an interesting elevation in interleukin-1 alpha in patients with clinical aspects associated with PASC in a clinically well-characterized population in Mexico. “It is possible that this is a specific marker either of a specific population or location, or this could be an association with a humoral response. Despite the fact that this finding is new and unclear, it is worth investigating. This study is of great value for the scientific community because it’s one more piece in the complex puzzle of clinical aspects associated with postacute sequelae of COVID-19.”
Dr. Gómez-Martín noted that the main limitations of the study consist of its single-center design and the small patient sample. Dr. Martínez-Juárez added that the study did not consider reinfections. In future studies, it would be ideal to integrate other molecular assessments associated with various hypotheses of the physiopathology of clinical aspects associated with PASC, such as microbiota alteration, coagulation anomalies, endothelial damage, and dysfunctional neurologic signaling.
The study was supported and funded by the Carlos Slim Foundation. Dr. Gómez-Martín, Dr. Martínez-Juárez, and Dr. Cuapio have disclosed no relevant financial relationships.
A version of this article originally appeared on Medscape.com.