Day: April 25, 2022

Long COVID May be Due to Suppressed Immune System

Man wearing mask with headache
Source: Usman Yousaf on Unsplash

Scientists studying the effect of the monoclonal antibody Leronlimab on long COVID may have found a surprising clue to the baffling syndrome, one that contradicts their initial hypothesis. The cause may be down to an abnormally suppressed immune system, and not a persistently hyperactive one as they initially suspected.

The study was published in Clinical Infectious Diseases.

“While this was a small pilot study, it does suggest that some people with long COVID may actually have under-active immune systems after recovering from COVID, which means that boosting immunity in those individuals could be a treatment,” said senior author Professor Otto Yang.

COVID is known to be caused by hyperactive immune responses against SARS-CoV-2 resulting in damage to lungs and other organs, and sometimes a cytokine storm that overwhelms the individual, which could lead to severe illness and death.

For some who recover from COVID, various symptoms can persist for months, such as fatigue, mental haziness, and shortness of breath. Classified as long COVID, a limited understanding of the causes makes it difficult to develop treatments.

One suggested possibility is that persistence of immune hyperactivity after COVID is a major contributor. The researchers therefore ran a small exploratory trial of Leronlimab, an antibody that attaches to an immune receptor called CCR5 that is involved in inflammation, on 55 people with the syndrome. Leronlimab was originally being developed as an HIV treatment.

Participants were randomised to receiving either weekly injections of the antibody or a saline placebo for eight weeks, and changes in 24 symptoms associated with long COVID were tracked, including loss of smell and taste, muscle and joint pain, and brain fog.

Originally, the researchers believed that blocking CCR5 would calm an overactive immune system after COVID infection. Indeed, preliminary results from an earlier trial appeared to show an improvement with Leronlimab.

“But we found just the opposite,” Prof Yang said. “Patients who improved were those who started with low CCR5 on their T cells, suggesting their immune system was less active than normal, and levels of CCR5 actually increased in people who improved. This leads to the new hypothesis that long COVID in some persons is related to the immune system being suppressed and not hyperactive, and that while blocking its activity, the antibody can stabilize CCR5 expression on the cell surface leading to upregulation of other immune receptors or functions.”

The findings, the researchers wrote, “suggests a complex role for CCR5 in balancing inflammatory and anti-inflammatory effects, eg through T regulatory cells,” although the results need to be confirmed in a larger, more definitive study.

Source: University of California – Los Angeles Health Sciences

Dentures Could Worsen Nutritional Intake

Dentist checking teeth
Image by Caroline LM on Unsplash

Dentures could potentially worsen a person’s nutritional intake, according to new research in the Journal of Prosthodontics. The research team examined electronic dental and health records to gain a better understanding of how oral health treatments affect individuals’ overall health over time.

This is first known study to link lab values of nutritional biomarkers to dental records.

Thankam Thyvalikakath, DMD, MDS, PhD, senior author, explained the impact of dentures. “Dentures are a significant change for a person. They do not provide the same chewing efficiency, which may alter eating habits. Dentists need to be aware of this and provide advice or a referral for nutrition counselling. These patients need support during the transition and possible continued monitoring.”

The researchers matched the dental records of more than 10 000 patients which included lab test data, including malnutrition markers. The data included complete blood count, basic metabolic profile and lipid and thyroid panel tests. Comparing the lab results from two years before a patient received dentures to the two years after, the researchers found that people with dentures had a significant decline in certain nutrition markers over those two years.

People who did not wear dentures did not experience this decline. While marker levels were still within normal range, but the levels could potentially fall as more time passes, and the researchers urged dentists to be aware of this possibility.

Future research will look at other factors that may influence nutrition, including insurance status and dental clinic characteristics.

Source: Regenstrief Institute