Many blood donors from the Middle East and Africa are missing the protein CD36, and DNA tests alone may not always identify this, according to a study recently published in Transfusion.
Those who lack this protein and become pregnant are at a higher risk of fetal and neonatal alloimmune thrombocytopenia (FNAITFetal and neonatal alloimmune thrombocytopenia A rare condition in which a mother’s immune system attacks fetal platelets, leading to dangerously low platelet levels before and/or after birth.). In FNAIT, early diagnosis and treatment are key to preventing severe symptoms.
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FNAIT happens when a mother’s body attacks her baby’s platelets—tiny blood cells that help stop bleeding. If a mother is born without CD36 but her baby has it, her body may make antibodies that attack anything the body sees as foreign. These antibodies can destroy the baby’s platelets.
In the study, researchers in Germany tested 1,250 blood donors. Many were born in the Middle East or North Africa. They found that 27 donors, or about two out of every 100, were missing CD36. Most of them were born in Syria (62.9%) or Egypt (11.2%).
Next, the researchers looked at the CD36 gene in these donors. They found 18 different changes, three of which had never been seen before.One donor who was missing CD36 surprised the researchers. Her DNA had no changes in the CD36 gene, but when they looked at the RNA copy her cells made from that gene, two pieces were missing. This means something went wrong when her cells were making the copy.
Read more about FNAIT testing and diagnosis
“Genomic sequencing alone may be insufficient,” the researchers wrote. This means DNA tests by themselves can miss some people who lack CD36. Doctors may need to run RNA tests too.
This matters for patients who have anti-CD36 antibodies, which can include babies with FNAIT. These patients need platelets from donors who also lack CD36. These donors are hard to find, and normal blood-type tests can’t spot them. Finding more of them could help blood banks build lists of rare donors. That way, these patients can get the safe blood they need.
