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HSV 2 Western Blot "atypical results"
Dear Dr. Hook,
I had protected sex one time with a partner who later (1week) had a positive blood test for HSV 2 as part of a general STD workup, despite never noticing any symptoms. I never noticed any symptoms that I recognized as herpes, but decided to get tested to be sure. Approximately 12 weeks later I asked my doctor for the HerpesSelect blood test, which came back positive HSV2 IGG 1.77. I do not know any more information about my partner's blood test (what kind, what number of positive).
This was over 18 months ago, and I have had only one partner since, very recently and always with protection. Based on reading posts in this forum, I decided to get the Western Blot Assay since it seemed that my previous test result was a low positive. In the meantime I began taking Valtrex (1g/daily) as a preventative measure to protect my new partner (plus condoms). I just received the results of my Western Blot, which are negative for HSV1, but report "atypical results" for HSV2. The actual phrasing was: "Atypical reactivity was noted against proteins on the HSV-2 Western Blot. This reactivity may or may not be due to HSV-specific antibody."
My NP recommends that I retake the test in 12-14 weeks because I was taking Valtrex at the time the blood was drawn. Would this actually affect the ambivalence of the WB test, and is that probably the reason for the vague result? I do plan to retake the test and stop the Valtrex now so that it may not interfere with the results. Because my new partner could be unprotected, I am wondering whether, in your experience, the indeterminate WB result while I was on Valtrex probably means that I am positive for HSV2 but the antibodies were suppressed by the antiviral medication?
If it may also be relevant to determine my risk factor, prior to my exposure 18 months ago I have had 5 partners, and always used protection. I also had Chicken Pox as a child.
Thank you for your help and any advice you think appropriate.
I had protected sex one time with a partner who later (1week) had a positive blood test for HSV 2 as part of a general STD workup, despite never noticing any symptoms. I never noticed any symptoms that I recognized as herpes, but decided to get tested to be sure. Approximately 12 weeks later I asked my doctor for the HerpesSelect blood test, which came back positive HSV2 IGG 1.77. I do not know any more information about my partner's blood test (what kind, what number of positive).
This was over 18 months ago, and I have had only one partner since, very recently and always with protection. Based on reading posts in this forum, I decided to get the Western Blot Assay since it seemed that my previous test result was a low positive. In the meantime I began taking Valtrex (1g/daily) as a preventative measure to protect my new partner (plus condoms). I just received the results of my Western Blot, which are negative for HSV1, but report "atypical results" for HSV2. The actual phrasing was: "Atypical reactivity was noted against proteins on the HSV-2 Western Blot. This reactivity may or may not be due to HSV-specific antibody."
My NP recommends that I retake the test in 12-14 weeks because I was taking Valtrex at the time the blood was drawn. Would this actually affect the ambivalence of the WB test, and is that probably the reason for the vague result? I do plan to retake the test and stop the Valtrex now so that it may not interfere with the results. Because my new partner could be unprotected, I am wondering whether, in your experience, the indeterminate WB result while I was on Valtrex probably means that I am positive for HSV2 but the antibodies were suppressed by the antiviral medication?
If it may also be relevant to determine my risk factor, prior to my exposure 18 months ago I have had 5 partners, and always used protection. I also had Chicken Pox as a child.
Thank you for your help and any advice you think appropriate.
MEDICAL PROFESSIONAL
Welcome to the Forum. As you already know, your risk for having HSV-2 is low. You have not had a suggestive outbreak, you had an exposure to a partner who may have HSV-2 but most exposures do not lead to infection, and you have a HerpeSelect "low positive" value in a range where less than half of tests turn out to be true positive. You now have an indeterminate Western blot, something that is not uncommon with low positive HerpeSelect tests.
As I suspect you know, many people with low positive HerpeSelect results have indeterminate Western blot test results in which there is some reactivity but not enough to say definitively that the person has antibodies to HSV. This limited reactivity may be due to prior chicken pox, prior HSV-1, prior infection with other non-HSV viruses or just a coincidental cross reactivity of their antibodies with the Western blot test. In a few people an indeterminate Western blot may also signal developing antibodies to HSV and when re-testing occurs after passage of a month or two, the Western blot is more typically positive.
To my knowledge the virus that causes most colds does not impact the Western blot test.
There is some information to suggest that when persons start taking antiviral therapy early (within days) following infection, antibody development may be delayed. In these situations, stopping the antiviral therapy seems to promote development of a more normal antibody test result. From what I understand from your post, this is not your situation. Further, this far out, I doubt that the delaying effect would still contribute to abnormal test results.
My advice. My sense is that it remains unlikely that you have genital herpes. I would certainly suggest you stop taking the valacyclovir. Should you have appearance of lesions or a genital rash, I would suggest you get a culture or PCR test taken from the area as quickly as possible (you do not need to have blisters or open sores to have the test taken). While I presume you do not have HSV at this time, if you want to be even more sure, repeat the Western blot after a month or two off of valacyclovir. If the test remains indeterminate, you can be confident that this is a feature of the indeterminate test and not an indication that you have herpes. Hope this comment helps. EWH
As I suspect you know, many people with low positive HerpeSelect results have indeterminate Western blot test results in which there is some reactivity but not enough to say definitively that the person has antibodies to HSV. This limited reactivity may be due to prior chicken pox, prior HSV-1, prior infection with other non-HSV viruses or just a coincidental cross reactivity of their antibodies with the Western blot test. In a few people an indeterminate Western blot may also signal developing antibodies to HSV and when re-testing occurs after passage of a month or two, the Western blot is more typically positive.
To my knowledge the virus that causes most colds does not impact the Western blot test.
There is some information to suggest that when persons start taking antiviral therapy early (within days) following infection, antibody development may be delayed. In these situations, stopping the antiviral therapy seems to promote development of a more normal antibody test result. From what I understand from your post, this is not your situation. Further, this far out, I doubt that the delaying effect would still contribute to abnormal test results.
My advice. My sense is that it remains unlikely that you have genital herpes. I would certainly suggest you stop taking the valacyclovir. Should you have appearance of lesions or a genital rash, I would suggest you get a culture or PCR test taken from the area as quickly as possible (you do not need to have blisters or open sores to have the test taken). While I presume you do not have HSV at this time, if you want to be even more sure, repeat the Western blot after a month or two off of valacyclovir. If the test remains indeterminate, you can be confident that this is a feature of the indeterminate test and not an indication that you have herpes. Hope this comment helps. EWH
MEDICAL PROFESSIONAL
Glad to help. Take care. EWH
Dear Dr. Hook,
Thank you very much for this information and the quick response. I did not know that low HSV results can correspond with the abnormal Western Blot. This is all very useful information and advice. I think I will be retested, but in the meantime I'll discuss all of this with my partner.
Also, this entire forum has been extremely useful for understanding both herpes and the testing processes. Thank you very much for your clear and detailed responses!
Thank you very much for this information and the quick response. I did not know that low HSV results can correspond with the abnormal Western Blot. This is all very useful information and advice. I think I will be retested, but in the meantime I'll discuss all of this with my partner.
Also, this entire forum has been extremely useful for understanding both herpes and the testing processes. Thank you very much for your clear and detailed responses!
As an additional piece of information, I also had a severe cold at the time the blood was drawn. Another NP told me that the presence of the cold virus can interact with the HerpesSelect test. Is the same true of the Western Blot?
Thank you again for your help.
Thank you again for your help.
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