Testing for EBV IgA antibodies has become one of the steps to screen for and diagnose nasopharyngeal cancer. However, many people have a one-sided understanding of EBV testing, resulting in stories like the one below.
“Doctor, I ……” a young beauty in front of the consultation table had red eyes and choked up. The boyfriend next to her comforted her while saying, “The medical report came back yesterday afternoon and said that my girlfriend was ‘EBV positive’. We heard that it was related to nasopharyngeal cancer, and we were scared all night.”
The report did show “positive for EBV VCA-IgA”. After reading it, I asked the patient some questions and then carefully examined her nasopharynx with an indirect nasopharyngoscope.
At this point, I had a number in mind and said with a smile, “Based on your current condition, we can basically rule out nasopharyngeal cancer. Don’t worry.”
But her boyfriend still had doubts: “Doctor, if it is really nasopharyngeal cancer, just tell us, so that we can get early treatment. My uncle also had nasopharyngeal cancer 4 years ago, but he was cured.”
I had to explain patiently, “First of all, you have to understand that the detection of EBV-specific antibodies by serological methods is indeed an important tool for early detection of nasopharyngeal cancer. When the titer of EBV VCA-IgA is higher than 1:10, it is positive, but positive does not mean it is nasopharyngeal cancer; there are also some healthy people in the general population who are positive, which may be related to viral infections such as colds.
“If the test shows that the titer of VCA-IgA is greater than 1:40, or if the titer is found to be gradually increasing after multiple re-examinations, the possibility of nasopharyngeal cancer should be taken seriously and further nasal endoscopy, biopsy and/or CT examination of nasopharynx should be performed.”
“In fact, the occurrence of nasopharyngeal cancer is related to many factors such as genetics, EBV infection, environmental cancer-promoting carcinogens and autoimmunity; a positive screening test for nasopharyngeal cancer indicates that one has been infected with EBV, but having EBV is only one of the predisposing factors of the disease and does not mean that it will definitely occur.” Again, I emphasize this point to the patient.
“If you are still unsure, you can take another blood test for EA-IgA antibodies, which will be more accurate when combined with EBV VCA-IgA.”
For peace of mind, they decided to check it.
Three days later, the two came over with a new report that read: VCA-IgA 1:10 (+); EA-IgA (-).
“As far as the results are concerned, I can tell you again with certainty that it is not nasopharyngeal carcinoma.” I smiled, “However, for a positive result in the test, you are advised to review it regularly (every 3 to 12 months). If the titer is elevated, the interval between retests should be shortened again.”
EB negative, not all is well “So my boyfriend tested negative for EBV VCA-IgA, is that a complete relief?” The beautiful woman also began to care about her boyfriend. After all, her boyfriend’s uncle had nasopharyngeal cancer.
“That’s not the right way to think.” I answered her, “Because some patients with nasopharyngeal cancer can be negative for VCA-IgA. Since your boyfriend has a family history of nasopharyngeal cancer and is from Guangdong, it is still important to have regular nasopharyngeal examinations at an otolaryngology specialist, as well as blood tests for EBV VCA-IgA and EA-IgA; if nasopharyngeal cancer is highly suspected, further tests will be performed.”
“Also, your uncle had nasopharyngeal cancer four years ago, so you may want to test for EBV-specific DNAase (EBV-DNase) antibodies and EBV DNA,” I said in passing, introducing some of the latest advances. In hospitals where available, testing for EBV-DNase antibodies and EBV-DNA can help assess the course and prognosis of nasopharyngeal carcinoma in patients who have been diagnosed with the disease.
Reiterated: Those with one of the following conditions in serum test can be considered as high-risk subjects for nasopharyngeal cancer and should be alerted – ① VCA-lgA titers are very high, such as greater than 1:40; ② Those with positive antibodies to both VCA-IgA and EA-IgA; ③ Either of the two indicators, VCA-IgA and EA-IgA persistently elevated.