Vacuolated lymphocytes help diagnose Batten in 7-year-old

Blood tests to look for a specific type of abnormal immune cell called vacuolated lymphocytes may help diagnose juvenile Batten disease, a report showed.

The study, “Vacuolated lymphocytes: a diagnostic biomarker for CLN3-related Batten disease,” was published in the Canadian Journal of Ophthalmology. 

Juvenile Batten disease is caused by mutations in the CLN3 gene. For most patients, the first sign of the disease, also called CLN3 disease, is vision loss.

That was the case for the 7-year-old boy at the center of the report. The boy, who had been experiencing increasingly worse vision loss for more than a year, was referred to a specialty clinic in Canada for detailed eye evaluations.

The eye examinations found many features indicative of juvenile Batten disease, including abnormalities in the retina (the area at the back of the eyes that houses cells responsible for detecting light). For example, he was found to have bull’s eye maculopathy, a characteristic change in the center of the retina that is commonly seen in people with the disease. Electroretinogram, a measure of the electrical activity in the retina, showed abnormally low electrical activity, which is also a common feature of juvenile Batten disease.

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Blood analysis reveals vacuolated lymphocytes

Based on these results, clinicians suspected that the boy might have juvenile Batten. They collected a sample of the boy’s blood for analysis under a microscope. This revealed that the boy had many vacuolated lymphocytes, immune cells filled with abnormal cavities that under microscopic observation look like bubbles inside of the cell. Vacuolated lymphocytes have previously been reported as a potential diagnostic marker of juvenile Batten disease.

With eye and blood tests all pointing towards juvenile Batten disease, genetic testing was conducted to definitively confirm the diagnosis. Tests revealed mutations in the CLN3 gene.

The researchers said their report highlights how testing for vacuolated lymphocytes, which can be done quickly and cheaply, can help diagnose juvenile Batten disease in patients who show characteristic signs of the disorder on eye exam.

“The average time from first presentation to diagnosis of [juvenile Batten disease] … is between 1.3 to 4 years,” the researchers wrote. “Early diagnosis of Batten disease is crucial in arranging multispecialty care for patients, improving their quality of life, and providing timely counselling to their families. Assessing for vacuolated lymphocytes by ophthalmologists in patients with ophthalmic features suspicious of [juvenile Batten disease] can facilitate this process.”