A wristwatch-like device measures the cytokine level in passive sweat. Photo credit: Kai-Chun Lin

At the onset of the COVID-19 pandemic, doctors realized that patients who developed a “cytokine storm” – an increase in inflammatory immune proteins – were often the sickest and most at risk of death. A cytokine storm can also occur with other diseases such as influenza. Today, scientists report preliminary results from a sweat sensor that acts as an early warning system for an impending cytokine storm and could help doctors treat patients more effectively.

The researchers will present their results today at the American Chemical Society (ACS) spring meeting.

“Right now in the context of COVID-19, you could treat patients early if you can monitor pro-inflammatory cytokines and see that they are trending up even before they develop symptoms,” says Shalini Prasad, Ph.D., the investigator project lead who will present the work at the meeting.

Early detection is important because the excessive inflammation after a cytokine storm is triggered can damage organs and cause serious illness and death. In contrast, if doctors could administer steroid or other therapies once cytokine levels begin to rise, hospital stays and deaths could be reduced.

Although blood tests can measure cytokines, they are difficult to do at home and cannot continuously monitor protein levels. Cytokines are excreted to a lesser extent in sweat than in the blood. To collect enough sweat for testing, scientists have asked patients to exercise or applied a small electrical current to the patient’s skin. However, these procedures can change cytokine levels by themselves, notes Prasad. “When it comes to cytokines, we’ve found that you have to measure them in passive sweat. The big challenge, however, is that we don’t sweat a lot, especially in air-conditioned environments,” she says. Prasad, who works at the University of Texas at Dallas, estimates that most people produce only about 5 microliters, or a tenth of a drop of passive sweat, on a 0.5-inch square of skin in 10 minutes.

Therefore, the researchers wanted to develop an extremely sensitive method for measuring cytokine levels in tiny amounts of passive sweat. They drew on their previous work on a wearable sweat sensor to monitor markers for inflammatory bowel disease (IBD). The wristwatch-like device, launched by EnLiSense LLC (a company co-founded by Prasad), measures the levels of two proteins that rise during the flare-up of IBD. When the device is worn on the arm, passive sweat diffuses onto a disposable sensor strip attached to an electronic reader. The sensor strip, which contains two electrodes, is coated with antibodies that bind to the two proteins. The binding of the proteins to their antibodies changes the electrical current flowing through the e-reader. The reader then wirelessly transmits this data to a smartphone app, which converts electrical measurements into protein concentrations. After a few minutes, the old sweat diffuses out and newly excreted sweat reaches the strip for analysis.

For their new cytokine sensor (SWEATSENSER Dx), the researchers produced sensor strips with antibodies against seven pro-inflammatory proteins: interleukin-6 (IL-6), IL-8, tumor necrosis factor-α (TNF-α), TNF-related apoptosis-inducing Ligand, IL-10, interferon-γ-induced protein-10 and C-reactive protein. They put the strips in their device and tested them in a small observational study on six healthy people and five people with influenza. Two of the patients showed elevated cytokine levels, and in all participants the cytokines in passive sweat correlated with the levels of the same proteins in the serum.

The SWEATSENSER Dx was even sensitive enough to measure cytokines in patients taking anti-inflammatory drugs that secrete cytokines in the low picograms per milliliter range. The device tracked cytokine levels for up to 168 hours before the sensor strip had to be replaced.

EnLiSense is now planning, in collaboration with the researchers, clinical studies with the cytokine sensor in people with respiratory infections. “Accessing COVID-19 patients has been challenging because healthcare workers are overwhelmed and don’t have time to test exam equipment,” says Prasad. “But we will continue to test it for all respiratory infections because the cause of the disease itself doesn’t matter – it’s what happens to the cytokines that we want to monitor.”

Does the COVID-19 cytokine storm exist?

More information:
Abstract Title: SWEATSENSER DX is a technology that enables cytokines to be profiled on passively expressed eccrine sweat if required

Provided by the American Chemical Society

Quote: The sweat sensor could alert doctors and patients to an impending COVID cytokine storm (2021, April 16) that will occur on April 16, 2021 from https://medicalxpress.com/news/2021-04-sensor-doctors-patients- looming-covid.html was obtained

This document is subject to copyright. Except for fair trade for the purpose of private study or research, no part may be reproduced without written permission. The content is provided for informational purposes only.