Using immune system biomarker to diagnose TB

4 months ago 34
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BENGALURU: A team of

researchers

led by Prof

Vijaya

S from the IISc’s microbiology and cell biology department has found a new, faster and more efficient way to use a person’s immune response to certain proteins unique to

Tuberculosis

(TB) bacilli to detect whether they have active TB.
“TB, particularly in forms that affect body parts other than the lungs, can be tricky to diagnose. And, existing methods for diagnosis of even pulmonary TB have a lot of challenges. Our method rids the process of these challenges and can be easily rolled out,” Vijaya told TOI.
Pointing out that the existing methods of diagnosis depend on actually having to see the bacteria under a microscope,

Vijay

said that even then, they cannot say if it is a live bacteria without further tests which are time consuming.
“...Also, most cases of extrapulmonary TB go undiagnosed because clinicians don’t look for TB given that the symptoms are missing. Our method, by taking just 1ml of blood, can give an accurate diagnosis in 24 hours for all types of TB, even tell if it’s a live bacteria or if the treatment has worked,” Vijaya explained.
In addition to the funds from various government agencies, the team received Rs 1 crore from Beckman Coulter India for its research, to conduct which it partnered with ESI Hospital and Research Institute,

Rajajinagar

.
How it works
Immune cells in blood have different sets of

molecules

on their surface – proteins, sugars, small compounds – depending on whether they are inactive as in healthy people, fighting a current infection, or remembering a past infection.
Presence or absence of a certain unique combination of such molecules (called a biomarker) makes it possible to detect current disease in the body. Biomarkers are used by organs and the immune system to check and react to foreign particles, allergens and most importantly, harmful microorganisms.
Vijaya’s team has discovered that active TB can be diagnosed if blood samples have immune cells with specific signature having certain biochemicals but lacking some other, while releasing a messenger molecule called Tumor Necrotic Factor.
“If the patient has TB then the ‘T cells’ — a type of white blood cell that is of key importance to the immune system — display markers that show they are actively fighting the pathogen, if the patient doesn’t have it these signs are not there. Also, if a patient had TB and has been cured since, the T cells show markers that say that they are in the memory compartment and aren’ t actively fighting the bacteria,” Vijaya said.

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