Immune system’s T cells play bigger role in reducing COVID-19 severity: Study

Agencies
September 17, 2020

Vaccine candidates for COVID-19 should elicit a broad immune response that includes antibodies, and the body's helper and killer T cells, according to a study which says weak or uncoordinated immunity may lead to a poor disease outcome.

The research, published in the journal Cell, confirms that a multi-layered, virus-specific immune response is important for controlling the novel coronavirus during the acute phase of the infection and reducing COVID-19 disease severity.

"Our observations could also explain why older COVID-19 patients are much more vulnerable to the disease," said study senior author Shane Crotty from the La Jolla Institute for Immunology in the US.

"With increasing age, the reservoir of T cells that can be activated against a specific virus declines and the body's immune response becomes less coordinated, which looks to be one factor making older people drastically more susceptible to severe or fatal COVID-19," Crotty said.

In the research, the scientists collected blood samples from 50 COVID-19 patients, and analysed multiple branches of their immune system -- novel coronavirus specific antibodies, helper and killer T cells.

"It was particularly important to us to capture the whole range of disease manifestation from mild to critically ill so we could identify differentiating immunological factors," said study co-author and infectious disease specialist Sydney Ramirez.

The researchers found that all fully recovered individuals had measurable antibody, helper and killer T cell responses against the novel coronavirus SARS-CoV-2.

However, they said the response varied widely in acute COVID-19 patients, with some lacking neutralising antibodies, others helper or killer T cells or any combination thereof.

"When we looked at a combination of all of our data across all 111 measured parameters we found that in general, people who mounted a broader and well-coordinated adaptive response tended to do better," said Carolyn Moderbacher, another co-author of the study from La Jolla Institute for Immunology.

"A strong SARS-CoV-2 specific T cell response, in particular, was predictive of milder disease. Individuals whose immune response was less coordinated tended to have poorer outcomes," Moderbacher said.

The scientists found that the effect was magnified when they broke down the dataset by age.

"People over the age of 65 were much more likely to have poor T cell responses, and a poorly coordinated immune response, and thus have much more severe or fatal COVID-19," Crotty said.

The scientists explained that as people age, the immune system's supply of deployable immature T cells dwindles, with fewer cells available to be activated to respond to a new virus.

"This could either lead to a delayed adaptive immune response that is unable to control a virus until it is too late to limit disease severity or the magnitude of the response is insufficient," Moderbacher said.

The scientists believe T cells, and helper T cells in particular, are associated with better protective immune responses.

"This was perplexing to many people, but controlling a primary infection is not the same as vaccine-induced immunity, where the adaptive immune system is ready to pounce at time zero," Crotty said.

"Thus, these findings indicate it is plausible T cells are more important in natural SARS-CoV-2 infection, and antibodies more important in a COVID-19 vaccine," he said.

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News Network
October 26,2020

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Houston: Indian and Pakistani women are diagnosed with breast cancer, including more aggressive forms, at a younger age, according to a study that provides an insight into understanding the risk factors influencing the disease.

The study, published in the International Journal of Cancer, examined the characteristics of breast cancer among Indian and Pakistani-American and non-Hispanic white women in the US using data from the National Cancer Institute's Surveillance, Epidemiology and End Results Program.

Both, Indian and Pakistani women are diagnosed with more aggressive forms of the disease, at a younger age, according to the researchers.

The researchers, who are part of the Rutgers School of Public Health and Rutgers Cancer Institute of New Jersey, reviewed incidence data among Indian and Pakistani women between 1990 and 2014.

"Our results provide an insight into breast cancer in Indian and Pakistani women, suggesting several hypotheses to guide future scientific studies to better understand the risk factors influencing disease etiology and prognosis," said Jaya M Satagopan, lead author and director of the Center for South Asian Quantitative Health and Education at the Rutgers School of Public Health.

South Asians are the fastest-growing major ethnic group in the United States with breast cancer rates increasing within the population, but little is known about the disease in this socio-culturally unique population, according to the study.

The researchers also reviewed the disease characteristics, treatment and survival data between 2000 and 2016 for 4,900 Indian and Pakistani women and 482,250 non-Hispanic white women with breast cancer.

They found that the occurrence of breast cancer in Indian and Pakistani women was lower than in non-Hispanic white women, however, the number of Indian and Pakistani women diagnosed with breast cancer increased over the years.

Indian and Pakistani women with breast cancer were more likely to be diagnosed at a younger age and at more advanced stages of the disease. In addition, they received more subcutaneous or total mastectomies than non-Hispanic white women, it said.

While the researchers found that Indian and Pakistani women were less likely to die of breast cancer than their non-Hispanic white counterparts, their health was tracked for a shorter time.

Prior cancer research has shown that fewer Indian and Pakistani women participate in scientific studies and that several sociocultural factors may delay their seeking health care.

Research also has shown poor mammogram screening rates in Indian and Pakistani women, which is linked to a lack of family support, lack of transportation, modesty, fear, beliefs that cancer is divine punishment for past deeds, having lived in the United States for less than 10 years, low English proficiency and a lack of faith in the health system.

"Our study indicated that there are important differences in this population that justify further studies to better understand biological, sociocultural, and system level factors such as interactions with the health system, affecting breast cancer screening patterns, diagnosis, risk and survival among South Asian women, given the paucity of literature on this topic,” said the study's senior author Elisa V Bandera, co-leader of the Cancer Prevention and Control Research Program at Rutgers Cancer Institute of New Jersey and professor at Rutgers Robert Wood Johnson Medical School.

The study recommends identifying strategies to better engage Indian and Pakistani women in breast cancer studies and to improve interactions between health care providers and Indian and Pakistani women to identify sociocultural factors associated with screening decisions and health care use in this population.

"As the South Asian population in the United States — and especially in New Jersey — grows, it is imperative that we work to promote health equity in cancer prevention, screening, early diagnosis and treatment through community engagement and a team science approach," said Anita Kinney, director of the Center for Cancer Health Equity at Rutgers School of Public Health and Rutgers Cancer Institute of New Jersey and professor at the Rutgers School of Public Health, who is also one of the study's authors.

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Agencies
October 28,2020

An analysis of more than 80 studies reporting complications experienced by COVID-19 patients has revealed that about one-third of them have abnormalities in the frontal lobe of the brain, findings which shed light on the neurological symptoms of the disease.

The review of studies, published in Seizure: European Journal of Epilepsy, focused on abnormalities detected using electroencephalogram (EEG) scans, which are used to evaluate the electrical activity in the brain.

"We found more than 600 patients that were affected in this way. Before, when we saw this in small groups we weren't sure if this was just a coincidence, but now we can confidently say there is a connection," said Zulfi Haneef, assistant professor of neurology at Baylor College of Medicine in the US.

The scientists explained that patients are recommended an EEG test when they have a slowed reaction to stimuli, followed by seizure-like events, speech issues, confusion, or an inability to wake up after sedation.

From the review of studies, the researchers said the most common findings from the EEG were slowing or abnormal electrical discharge, mostly in the frontal lobe of the patients.

They said some of the EEG alterations found in COVID-19 patients may indicate damage to the brain that might not be repaired after recovering from the disease.

Since the brain cannot regenerate, Haneef cautioned that any damage to the organ will more than likely be permanent.

"We know that the most likely entry point for the virus is the nose, so there seems to be a connection between the part of the brain that is located directly next to that entry point," he said.

"Another interesting observation was that the average age of those affected was 61, one-third were female and two-thirds were males. This suggests that brain involvement in COVID-19 could be more common in older males," Haneef added.

However, the scientists believe more studies are needed to validate the conclusions drawn in the review research.

According to Haneef, the virus may not be directly causing the abnormal EEG readings in the brain.

He said alterations in oxygen intake, heart problems related to COVID-19, or other side effects may also be involved.

"These findings tell us that we need to try EEG on a wider range of patients, as well as other types of brain imaging, such as MRI or CT scans, that will give us a closer look at the frontal lobe," Haneef said.

"A lot of people think they will get the illness, get well and everything will go back to normal, but these findings tell us that there might be long-term issues, which is something we have suspected and now we are finding more evidence to back that up," he added.

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Agencies
October 24,2020

Washington, Oct 24: The initial phase of the COVID-19 lockdown, which was imposed through March and April in several countries, may have dramatically altered people's personal eating and sleeping habits, according to a new study based on a first-of-its-kind global survey.

The study, published in the journal Obesity, evaluated the inadvertent changes in health behaviours that took place under the pandemic's widespread restrictions.

According to the survey, conducted by the researchers, including those from Louisiana State University (LSU) in the US, the lockdown's effects were magnified among people with obesity.

"The stay-at-home orders did result in one major health positive. Overall, healthy eating increased because we ate out less frequently. However, we snacked more. We got less exercise. We went to bed later and slept more poorly. Our anxiety levels doubled," said study co-author Leanne Redman from Louisiana State University.

"Overall, people with obesity improved their diets the most. But they also experienced the sharpest declines in mental health and the highest incidence of weight gain," Redman said.

The survey ran during the month of April and included responses from 7,754 people and the majority of the respondents were in the US with residents of Australia, Canada, the UK, and more than 50 other countries also participating.

It revealed that about one-third of surveyed people with obesity gained weight during the lockdown, compared to 20.5 percent of people with normal weight or overweight.

"This study is the first to survey thousands of people across the globe on lifestyle behaviour changes in response to stay-at-home orders. The study demonstrates that chronic diseases like obesity affect our health beyond the physical," said John Kirwan, another co-author of the study.

The scientists believe physicians and scientists should modify the way they manage patients with obesity in two ways.

One of these methods is by increasing the number of mental health screenings during and after the pandemic, said Emily Flanagan, lead author of the study from LSU.

Flanagan said physicians should also monitor patients by remaining connected to the study participants through remote visits and telehealth to prevent irreversible health effects from the pandemic.

The scientists believe virtual visits via telehealth checkups can assuage patients' concerns about the safety of in-person visits.

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