Kickas.org Forums Ankylosing Spondylitis General Discussion #1 AS Web Support Group HLA-B27 negative

Is HLA-B27 negative a separate human leukocyte antigen, like HLA-B27 positive, or is HLA-B27 negative everything else except HLA-B27 positive?


Thanks,

Mike

Hi, Mike:

I would not choose either wording, but although there are more than 20 sub-types of the HLA B27 antigen, none of these are called 'negative.' If you are negative for B27, you still do not have information about the several other AS-genic antigens. Nor do you have a figure of merit, like in DNA sampling. If you actually have AS, but tested B27 negative (which should mean that you do not have any type of B27), there is almost an even possibility that the test result is incorrect.

Hope that You are doing well,
John

John:

I appreciate your input. I am in fact HLA-B27 positive and I know that I have A.S.

I asked this question, because my seventeen year old son who is not HLA-B27 positive, based on two separate blood tests, was told he has JRA. I think the diagonisis of JRA is bogus. The diagnosis of JRA is a diagnosis by exception. We don't think you have Lupus, Crohns, etc. We will just call it JRA. I think my son was misdiagnosed. He appears to have some type of Ulcerative Colitis based on a recent colonoscopy. I just wondered if there was an association between Crohns or Ulcerative Colitis and some HLA entity other than HLA-B27 positive.

Thanks,

Mike

Hi, Mike:

I THOUGHT you were positive.

People with Crohn's have a far lower chance of being B27 positive, but this is your son, and if he has cUC/AS symptoms he MUST have AS and, statistically speaking, he is certainly is B27 positive. Were both tests done at the same lab?

Yes there are genetic associations in Crohn's, but most of these have not been universally identified and cannot be detected in the testing currently available to us; it is more than the simple Osp B27 test can indicate. The MHCs are not the entire genetic profile, only a general approximation for tissue transplant purposes.

I would try for a retest at a different lab using a different method (DNA instead of serum...I think).

Best to You, and your son,
John

John:

I believe both tests were done at the same lab. I think a retest is in order. I have heard that some of the HLA-B27 tests are not accurate. I will ask for the DNA instead of serum. I did not know there was a different HLA-B27 test. (DNA vs. serum)

I hope you are doing better after your operation.


Thanks,

Mike

"People with Crohn's have a far lower chance of being B27 positive, but this is your son, and if he has cUC/AS symptoms he MUST have AS and, statistically speaking, he is certainly is B27 positive. Were both tests done at the same lab?"

John, I'm curious, are you saying that because Mike has AS and is HLA B27+ and that his son is exhibiting symptoms of ulcerative colitis that his son MUST BE HLA-B27+ and that HE MUST ALSO HAVE AS??? are you saying this with an absolute certainty?

Does this mean those of us who are HLA-B27+ with children, that our children are doomed to get our AS?

Puzzled,
Rita

Hi, Rita:

Quote:

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Does this mean those of us who are HLA-B27+ with children, that our children are doomed to get our AS?

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Not exactly, ...but now that you mention it, the observation has been made that people who are B27 positive in the general population could have a 14% chance of developing severe AS, but people in families where severe AS has already emerged, have a much higher incidence than the general population--closer to 35%. This has been explained by 'cultural inheritance;' we inherit our diets, also (albeit this might not be a--or thee--factor in Mike's specific case).

There are equal chances that any specific offspring will not have the antigen and, if they do, there is yet a better than even chance that they will never develop clinically identifiable severe AS.

Mike's son does not only have symptoms of cUC, but also arthritic symptoms associated with digestive issues. He is quite right that the diagnosis of JRA is almost certainly incorrect; the mathematical probabilities are thousands of times more in favor of JAS, and it is much more likely that the B27 test was a false negative, because there are many more cases like this than an AS-symptomatic scion actually B27- from an AS+ B27+ parent. The statistics are too strongly exclusionary--almost "absolute certainty."

Best Regards,
John

I think your information might be a little incorrect. According to multiple sources you can be HLA-B27 negative and still have AS. One source http://www.medicinenet.com/ankylosing_spondylitis/article.htm. The following excerpt "The tendency to develop ankylosing spondylitis is believed to be genetically inherited, and the majority (nearly 90%) of patients with ankylosing spondylitis are born with the HLA-B27 gene."

From what I read from this is you have also a 10% chance of having AS and testing HLA-B27 negative. Also, I have been tested 3 times now and have AS and tested HLA-B27 negative. Yes there is a small chance of getting a bad test result. From other sources people that have AS and are HLA-B27 negative have different AS symptoms than those that are HLA-B27 positive. One instance is that the disease affects their peripheral joints more that HLA-B27 positive patients which match my own symptoms.

Tim

Hi, Tim:

Quote:

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I think your information might be a little incorrect. According to multiple sources you can be HLA-B27 negative and still have AS.

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You should not allow yourself this level of confusion. Everyone in the club is aware that a person can be B27- and AS+, but this isolated fact simply does not support the fantastical leap required in finding the UNICORN (a non-B27 AS in a family with existing B27+ AS). It is NOT totally ruled out, but it is statistically unlikely--bordering upon impossible. WOW, I thought I made that clear enough...

Don't believe me?
Calculate the potentials for AS, both antigen- versus antigen+ within the unfiltered conjugate population. The chances against a B27+AS+ parent producing a B27-AS+ offspring are many millions to one. This is really simple arithmetic (you need not have even heard of Mendel).

What are YOU bettng on?
Potential for false negative B27 result: >5% (SWAG)
Potential for B27-AS+ scion of B27+AS+ parent: <0.0001% (I wanted to add all the zeroes, but it just LOOKED bad...)

REGARDS,
John

PS: Please stay away from Vegas; they don't really need the gratuitous roadkill...

Not to get into an argument on this issue but looking at MikeinSA's posts. He is concerned about his son having JRA if he is HLA-B27+ and his son is HLA-B27-. He did not say what his wife tested. So let’s assume he got lucky and his son won the lottery and he is HLA-B27-. This does not prevent his son from getting JRA since there is a suspicion in the medical community that other genes could cause JRA or AS. So I think MikeinSA's major concern is could his son have JRA. That's still possible since the genetic link has not been proven 100%. If they understood everything there would be a cure already.

Anyway just a question for ya.
Which parent has the greatest potential to pass on genetic traits, the male or female? Does it depend on the gene?

Tim