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Delta’s trick to evade the body's immune response

The SARS‐CoV‐2 Delta variant may use a novel invasion method to evade the body’s immune response, causing more damage to the brain, intestine and kidneys than the original Wuhan strain, according to a Griffith University study published in mBio. Led by Menzies Health Institute Queensland’s Dr Xiang Liu, the researchers compared the original Wuhan strain with Delta in mice models and found distinct immune response patterns between the ancestral and Delta variant. “In our study, we found that Delta‐infection induced the similar levels of disease symptoms as the ancestral SARS‐CoV‐2 but with significant dissemination and tissue damage to multiple organs including tissue lesions in the brain and intestinal wall thinning,” Dr Liu said. “Surprisingly, the numbers of leukocytes recruited to the lung tissue during Delta infection were significantly lower. These observations suggest the Delta variant may have yet unknown immune evasion mechanisms which increases infection. We hope to discover how this biological process happens with future research.” Dr Adam Taylor, who co‐led the study, said as SARS‐CoV‐2 variants were continually emerging it was critical to study disease progress to understand and manage clinical threats. “These results will help shed light on the changing disease profile of COVID‐19 and may guide therapeutic interventions for emerging SARS‐CoV‐2 variants,” he said. The Delta variant first emerged from India in 2020 and was found to be highly contagious compared to the Wuhan strain. Pfizer and AstraZeneca COVID‐19 vaccines were shown to have reduced effectiveness against Delta.

Link found between arthritis, liver disease and haemochromatosis

Research from Edith Cowan University, published in Mayo Clinic Proceedings, has identified a crucial link between arthritis and the risk of serious liver disease in people with Australia’s most common genetic condition, haemochromatosis. An estimated 100000 Australians carry the high risk genotype for haemochromatosis, a condition affecting people of northern European descent which sees the body accumulate too much iron. It can lead to advanced hepatic fibrosis, which can cause cirrhosis and liver cancer. Early detection of advanced hepatic fibrosis can assist clinicians in identifying those most at risk and reducing the impact or occurrence of future complications. The study analysed data from 112 people with haemochromatosis. Of the 19 subjects with advanced stage 3–4 liver fibrosis, 84% also had arthritis. However, of the 65 subjects without arthritis, only 5% had advanced hepatic fibrosis. “Since hepatic fibrosis improves with treatment, it is important to accurately determine the presence or absence of advanced hepatic fibrosis when patients are evaluated,” said senior author Professor John Olynyk. “We recommend people with haemochromatosis who present with arthritis be properly evaluated for the presence of advanced hepatic fibrosis.” Professor Olynyk said the link with arthritis could help diagnose more people with haemochromatosis, which can often be difficult due to many symptoms being relatively non‐specific and common in the general population. “People of the correct background presenting with arthritis or liver disease should always be evaluated for potential haemochromatosis,” he said.

https://www.mayoclinicproceedings.org/article/S0025‐6196(22)00121‐5/fulltext