Hyderabad, Telangana, 06/09/2024: Chief scientist and director of the CSIR-SCA Mission, Giriraj Ratan Chandak, with his colleagues during an interview with The Hindu in Hyderabad on Friday, September 6, 2024. Photo: RAMAKRISHNA G/The Hindu
| Photo Credit: G. Ramakrishna
A team of scientists at the CSIR-Centre for Cellular & Molecular Biology (CSIR-CCMB) has developed an accurate, rapid, and affordable molecular test for screening sickle cell anaemia (SCA). This test uses indigenously developed reagents and is designed to better detect the prevalence of this genetic disease, which affects a significant portion of both the tribal and mainland populations in the country.
Chief scientist and director of the CSIR-SCA Mission, Giriraj Ratan Chandak, announced that their polymerase chain reaction (PCR)-based test has been validated by the Indian Council of Medical Research (ICMR) with “100% sensitivity and 100% specificity.”
This test can screen individuals using just a drop of blood, identifying their status as normal, carriers, or patients in one go, at a cost of ₹100 or less. Besides being half the cost of current confirmatory tests, it eliminates the need for intravenous blood collection, storage, transport, and additional confirmatory tests.
Another advantage of this molecular test is that it allows for immediate prenatal diagnosis and genetic counseling, unlike current tests such as HPLC or Rapid Cart tests. Gene sequencing of about 16,000 samples demonstrated over 99.6% accuracy when validated against HPLC-based screening of pregnant women and newborns in Chhattisgarh, Maharashtra, and Rajasthan, added Chandak.
“We have got the patent for the test to make it available to the larger community in 17 States likely afflicted by SCA. We are also helping medical college and hospitals including AIIMS in Chhattisgarh, Madhya Pradesh and Maharashtra to set up such PCR centres by providing equipment and training personnel,” he said, in an exclusive interaction.
Mr. Chandak and his team launched the mission under the Council of Scientific and Industrial Research (CSIR) in 2018 with the goal of screening for the prevalence of SCA, which is predominantly found among the tribal population.
The disease is caused by a mutated gene that alters red blood cells (RBCs), making them sickle-shaped, which leads to their increased destruction, chronic anaemia, and associated complications such as pain. The team began screening tribal and non-tribal populations in Chhattisgarh, later expanding to Maharashtra, Madhya Pradesh, and Rajasthan, testing up to 30 lakh people for SCA over time.
“SCA-affected children display pronounced stunted growth. We have found the disease to have percolated to all strata of the society due to a specific genetic mutation and marriages. About 10% of people are carriers or patients — 9% are carriers and 1% are patients, as per our experience and published literature,” he explained.
The major issue was lack of awareness, screening, treatment and counselling which was the target of the project. After random population screenings, the team ensured treatment by making ‘Hydroxyurea’ available in more user-friendly forms, such as 200 mg tablets or syrup, after securing approval for its use in SCA from the Drug Controller General of India (DCGI).
“The medicine was available in a 500 mg capsule only and could not be properly administered to children, leading to poor compliance and poor consequences,” he said.
The SCA Mission now plans to rapidly expand the use of ‘Whole Blood/Dried Blood Spot (WB/DBS) PCR’-based molecular testing by establishing new PCR centres, upgrading those set up during COVID-19, and training personnel.
His team has mooted the idea of collection of blood samples on a dried blood card from villages and transport them to the primary health centre where a trained person can test up to 300 samples a day. “An accurate and early diagnosis is the key to preventive and treatment strategies. The more prevalent model of solubility testing has too many false negatives, is cumbersome and costly. The recently developed rapid card tests too has been giving poor results,” said Mr. Chandak.
The SCA Mission has tied up with Chhattisgarh Institute of Medical Sciences (CIMS, Bilaspur) and AIIMS-Nagpur to implement WB/DBS-PCR based molecular testing and screening facilities. Discussions are also under way with Jharkhand, Rajasthan and Madhya Pradesh. In Telangana, the plan is to collaborate with the Tata Trust, while Andhra Pradesh is not yet included.
Strangely, the CSIR-SCA Mission is not part of the National Mission for Elimination of SCA, launched in July 2023, which aims to screen 70 million people aged 0-40 years. This initiative estimates that around 6.3 million will be carriers and 7 lakh will be patients (9%).
“We do not want to run a parallel system. We have submitted our data and are discussing with various ministries on how our research and field experience can help them leap-frog into new age molecular testing, prenatal diagnostics and counselling. There is a need to invest in those simultaneously,” asserted the senior scientist.
Published – September 07, 2024 09:42 am IST
