NEJM: RNA identification of PRIME cells can be used to predict rheumatoid arthritis flares.

The Team of Dana E. Orange of Rockefeller University in the United States, in cooperation with Robert B. Darnell, conducted RNA identification of PRIME cells (pre-inflammatory plaques) that predict rheumatoid arthritis flares.
the New England Journal of Medicine on July 6, 2020.
like many inflammatory diseases, rheumatoid arthritis is characterized by a period of rest and deterioration (flares), and the molecular mechanisms that cause flares remain unknown.
The newly discovered PRIME cells not only provide new insights that can better predict when severe pain and swelling will occur, but also provide new insights into the underlying causes of rheumatoid arthritis and may provide new ways to treat or even prevent flares from occurring.
this will reduce the destructiveness of flares and make them easier to manage.
the study, published in the New England Journal of Medicine, was entitled "RNA Finding of PRIME Cells Predicting Rheumatoid Arthritis Flares."
rheumatoid arthritis is an immune system disease that causes inflammation of joints, especially around the hands and feet.
it can be debilitating, often in people in their 30s or 40s.
symptoms are wavy and the stabilization period is often interrupted by unpredictable outbreaks of the disease.
current treatments (mainly steroids) can treat these symptoms, but there is no cure.
the severity of rheumatoid arthritis symptoms may vary, it is not clear what causes them to worsen and disappear.
that blood studies have found few genes significantly associated with rheumatoid arthritis activity.
study RNA and its links to diseases such as cancer and neurological diseases.
study of rheumatoid arthritis, the researchers did not look directly at the affected joints, but examined changes in the blood that led to flares.
they used longitudinal RNA sequencing techniques, which can analyze gene expression for long periods of time, to observe any changes during the state of the disease.
when a patient's arthritis symptoms come and go, the technique can pinpoint molecular changes.
a lot of data to use this method for immune events that cause rheumatoid arthritis attacks.
rheumatoid arthritis usually go to the hospital for a monthly blood test, but scientists want to know how blood gene expression patterns change each week.
, instead of letting patients come every week, they developed a finger-piercing kit for collecting samples at home.
this optimization method allows patients to obtain their own fingertip blood samples for RNA-sequencing (RNA-seq) to facilitate weekly blood samples from several months to several years.
team established a clinical technical program for patients with rheumatoid arthritis for multiple blood harvests after returning home for longitudinal RNA sequencing (RNA-seq).
364 point-in-time samples were taken over a four-year period during eight flares, and 3 patients took 235 point-in-time samples.
team identified transcripts of differential expressions before flares and compared them with single-cell RNA sequence data from sliding membranes.
other patients were validated using flow cytometers and classified blood cell RNA sequences.
changes were observed in the blood transcript 1-2 weeks before the onset of rheumatoid arthritis.
B cells were active, the circulating CD45-CD31-PDPN and pre-inflammatory pre-inflammatory charged cells (PRIME) in rheumatoid arthritis patients expanded.
these cells are characterized by inflammatory membrane fibroblasts.
all four patients had decreased levels of circulating PRIME cells during flares, and fluid cytometers and classified cell RNA-seq confirmed the presence of PRIME cells in 19 other patients with rheumatoid arthritis.
four years, patients mailed blood samples to the lab, reported symptoms, and pointed out the timing of the outbreak.
analyzed blood collected in the weeks before symptoms worsened.
Samples taken from portraits can search for transcriptional characteristics prior to clinical symptoms and compare these blood RNA scores with data from single-cell RNA-seq (scRNA-seq) to determine whether biologically coherent transcripts are identifiable.
they draw blood before symptoms begin and when the patient begins to show symptoms.
's initial observations were not entirely surprising.
samples collected two weeks before the outbreak, the researchers found an increase in immune system B cells.
this is not unforeseen, as researchers already know that these cells attack the joints of rheumatoid arthritis patients.
rheumatoid arthritis causes joint pain and inflammation.
B cells (shown here) play a role in the disease.
these cells activate prime cells, newly discovered cells that appear in the blood before symptoms begin.
samples collected a few days before the outbreak, the scientists noted that the increase in RNA did not match the genetic characteristics of any known type of blood or immune cell.
think this is the key point of the event.
these cells don't look like they would normally be found in the blood.
, RNA characteristics are similar to those of bones, cartilage, or muscle cells.
the authors found that genes expressed before flares broke out were usually active in bones, muscles, and extracellular substrings, a strange pathway found in blood cells, which also piqued the authors' interest.
these new cells, called PRIME cells, are usually present in the blood only at low levels, but then peak the week before the outbreak, which almost disappears when the outbreak period comes. Longitudinal genomic analysis of
rheumatoid arthritis flares reveals PRIME cells in the blood prior to the flare outbreak and suggests a model in which these cells are activated by B cells in the weeks leading up to the flare outbreak and then migrate from the blood to the membrane.
function of the PRIME cells has yet to be determined, but scientists already have some clues.
RNA expression spectrum, they found that cells look very similar to membrane fibroblasts, which are present in the tissue inner layers of joints.
the authors suggest that PRIME cells may be preludes to these fibroblasts, which are known to play a role in causing rheumatoid arthritis symptoms.
, for example, in mouse experiments, scientists transplanted fibroblasts from inflamed joints into healthy joints, which later became arthritis.
, the results present a model in which the sequential activation of B cells activates prime cells before an outbreak.
, these cells are clearly shown to be inflammatory fibroblasts during inflammation of the membrane.
are now trying to learn as much as possible about PRIME cells and how to detect them quickly.
if doctors can easily detect the presence of PRIME cells in the blood, they can warn patients about the possibility of flares.
, if PRIME cells are found to play a role in causing flares, the finding could open the door to the development of treatments that reduce inflammation.
team's strategy could also be used to study the ups and downs of other inflammatory diseases.
This changing clinical process is characterized by many autoimmune diseases, including multiple sclerosis, systemic lupus erythematosus and inflammatory bowel disease, and emphasizes the need to develop a way to understand the factors that trigger the transition from a stationary state to autoimmune flares.
the team's next step is to assess whether the presence of these PRIME cells can reproduce the prediction of flares in more patients.
are still recruiting patients for the study.
, the team's blood-picking system is only available for research.
also hope to study the molecular characteristics of PRIME cells.
published a commentary along with the publication.
the team identified gene expression traits associated with myelin cells, neophilic granulocytes, and plate plate plates prior to the outbreak, as well as another trait associated with childish B cells in samples taken two weeks before the outbreak.
interestingly, gene expression was strongly expressed in samples taken one week before the flare attack, reminiscent of interstate cells.
"We compared this interstuming marker with the single-cell RNA sequencing data collected previously by accelerated medical cooperation and found that the gene marker overlapped with the gene marker of fibroblasts under the slip membrane, suggesting that cells similar to the membrane fibroblasts may be in the blood.
," Orange said.
researchers took the theory one step further, looking for fibroblasts in blood samples from 19 other RA patients.
the cells they detected were CD31-CD45-PDPN plus, which is more common in RA patients than in healthy individuals.
sequenced the RNA of the selected blood CD31-CD45-PDPN plus cells and found gene affluation expressed in the genes and membrane fibroblasts that had been raised in the first week of the outbreak, allowing the researchers to name the cells as pre-inflammatory interstumuration (PRIME) cells.
"It is particularly interesting to find PRIME cells in the blood prior to ra attacks, as other studies have shown that RA membrane fibroblasts can spread arthritis and act as key gaterunns for glioblastitis immersion in animal models," Orange asserts.
since only four patients were involved in the long-term monitoring of the study, further research is needed to determine whether PRIME cells are in all RA patients and in all RA patients before the onset of the disease.
and colleagues also hope to study the possible mechanisms by which B cells activate or collect PRIME cells that occur two weeks before the outbreak.
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