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Validity of Elispot LTT Lymes Test

Discussion in 'Lyme Disease and Co-Infections' started by yabeeb, Feb 17, 2015.

  1. yabeeb

    yabeeb

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    Hi All

    I has a positive Elispot LTT test recently and there were other biomarkers which suggested Lymes including low NK cells and very low CD57 and lymphctyes. So i am due to go to Belgium for 12 weeks IV abx in March.

    However a specialist in the UK refutes the diagnosis of chronic lymes as he says:
    'The Elispot LTT test has not been properly clinically validated; and that it has poor specificity . If 1 in 100 people have the disease and the test has 80% specificity, there will be one true result for every 20 false positives.'

    This has confused me and made me doubtful around the diagnosis of lymes. Can anyone give me some reassurance please? I don't really understand the tecnicalities of specificity well enough myself.

    Thanks
     
  2. Jonathan Edwards

    Jonathan Edwards "Gibberish"

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    I think your UK specialist is right to be sceptical. Tests like this require validation not just on acute infection cases but in the context of chronic disease. And that is extremely tricky if there is no reliable gold standard of culturing the organism. Tests of this sort took at least ten years to be reliably validated for TB. As far as I know the LTT Elispot is still at the early research stage. In simple terms, if a test like this is not confirmed by cross-laboratory blinded quality control exercises, it would not be considered by most physicians as reliable enough to use in clinical practice.

    This may not give you 'reassurance' but what I think you want is an honest answer and my answer would be that I doubt that this test is well enough validated to use for treating people.
     
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  3. barbc56

    barbc56 Senior Member

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    @Jonathan Edwards

    Im curious. Can a definitive diagnoses be made by looking at spinal fluid?

    Thanks.
    Barb
     
  4. yabeeb

    yabeeb

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    Thanks @Jonathan Edwards. In your opinion, does the combination of the Elispot test plus very low CD57+ and NK cells, increased IL-8 and MCP1 cytokines and a positive test for a co-infection (tularemia) make a chronic lymes diagnosis more plausible?
     
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  5. msf

    msf Senior Member

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    I also have a question for Prof. Edwards. The Infectolab website says that the LTT-ELISPOT for Mycoplasma Pneumoniae has the approved by the FDA. The implication seems to be that the testing procedure, which seems to be the same for all the LTT-ELISPOT tests, is valid. Is this a reasonable assumption, in your opinion, and if not, what kind of factors would affect the validity of individual tests?
     
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  6. msf

    msf Senior Member

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    Oh, and I take your point about the lack of a gold standard in chronic Lyme, but then that is also the case for the ELISA and the Western Blot. Most doctors therefore would seem to be more comfortable with a test that finds fewer positives in this situation (i.e. the ELISA). Is there any statistical reason for favouring such tests, or is it merely a case of 'first do no harm?'
     
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  7. msf

    msf Senior Member

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    Oops, got the organism wrong, here is the quote from the website: 'The Elispot-LTT method has been approved by the FDA in May 2011 for M. tuberculosis'
     
  8. nandixon

    nandixon Senior Member

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    The big study on the LTT for Lyme was this 2012 one here, which seemed to appear very good:
    The lymphocyte transformation test for borrelia detects active lyme borreliosis and verifies effective antibiotic treatment

    However, a commentary which was signed onto by a large number of peers then appeared in early 2014 heavily criticizing that study/procedure on a number of grounds, including conflict of interest (if I remember correctly - I don't have the full text anymore):
    The lymphocyte transformation test for the diagnosis of Lyme borreliosis has currently not been shown to be clinically useful

    Based on that commentary, which agreed with Professor @Jonathan Edwards, I decided not to have the test done myself.

    However, I see now that the authors of the 2012 study did make a rebuttal reply to that critical commentary just late last year here:
    The lymphocyte transformation test for the diagnosis of Lyme borreliosis could fill a gap in the difficult diagnostics of borreliosis

    I don't think I have access to the full text of that rebuttal, so I'm not sure whether they might have been able to refute the criticisms levied.

    Can someone provide copies/links for the full text of both of the last two citations I gave?
     
  9. Grace101980

    Grace101980

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  10. Valentijn

    Valentijn Senior Member

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    That's a bit odd, because the specificity is 98.7%, according to published research, and that's nearly identical to the older tests. Has this "specialist" conducted research which suggests 80% instead?

    The paper is at http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3474945/
     
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  11. yabeeb

    yabeeb

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    Hi @Valentijn. I think its cos i sent him the following paper which states sensitivity of 84%:
    iSpot Lyme™: A New Generation of Lyme Disease Testing
    I think sensitivity and specificity are two different things. My Public Health colleagues tried to explain it but went over my head! :)
     
  12. Valentijn

    Valentijn Senior Member

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    That's different from the Elispot-LTT.

    Sensitivity describes the ability to give accurate positive results. So if it gives negative results for people who are actually infected, those are "false negatives" and show a problem with sensitivity.

    Specificity describes the ability to accurately identify Lyme versus not-Lyme. If there is low specificity, too many "false positives" are being generated for patients who are actually not infected.
     
  13. Jonathan Edwards

    Jonathan Edwards "Gibberish"

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    That I do not know.
     
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  14. yabeeb

    yabeeb

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    Ha ha. Oh well i'm stupid then....
     
  15. Jonathan Edwards

    Jonathan Edwards "Gibberish"

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    I don't think it would make any difference to be honest. None of the other tests are actually diagnostic for Lyme infection as far as I know and the cytokine tests are also ones that seem to give strange results in the lab reports people post on PR.
     
  16. Jonathan Edwards

    Jonathan Edwards "Gibberish"

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    Yes, that is rather what I would have expected. Validity of a test like this in one disease gives no indication of validity for another disease. TB is a very strange organism that sends T cells berserk. Finding a reliable link between a T cell test and active TB is unsurprising, but even so my impression is that it took 10-20 years to get something to work reliably even in TB. The chances of getting a T cell test to give a reliable indication of chronic low grade infection with other organisms seems to me much less likely.

    The problem with tests like this is that they are not 'positive' or 'negative'. The tests is a bit like developing a photographic print in the old days with silver emulsion paper. If you put the print in the developer for about twenty seconds you get a clear picture with black grey and white bits. But if you leave it in longer the whole thing goes black. So if you leave any ELISPOT long enough it will come up 'positive'. The validity is all in the establishment of a reference range of colour development for people without the disease and people proven to have the disease. But of course the problem is that there is no other way of proving people have the disease or that the test does not come up positive in other conditions. As far as I know we simply do not have the relevant information for this particular test for Lyme.
     
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  17. msf

    msf Senior Member

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    Hi Prof. Edwards, a couple more questions, if you have time. if other organisms cause a weaker T-Cell response, does that mean that the cut-off for the ELISPOT would have to be lowered? And would this automatically result in a decrease in specificity? Sorry, I'm really not good at statistics and I haven't slept much this week, so I don't think I can work this out for myself.


    Oh, and how do the colours relate to the numbers that are given, such as SI > 2?
     
  18. Jonathan Edwards

    Jonathan Edwards "Gibberish"

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    There is probably no way that either you or I can work this out for ourselves because it is very complicated and full of pitfalls. Every ELISPOT test has its own calibration so there is no comparison of one with another. The T cell reaction with TB is not just a vigorous one, it is an aberrant one. TB survives by confusing T cells and macrophages, just as HIV does, but in a completely different way. The immune responses you get are more to do with the manipulation by the organism than the immune system itself.

    I don't know what SI means but in general an ELISA or ELISPOT test is read by putting the test plate under a spectrometer and measuring the amount of colour in the plate due to fixation of a dye. Sometimes that is called an OD or optical density. Very often the OD is converted to some sort of standard unit using a calibration curve.
     
  19. valentinelynx

    valentinelynx Senior Member

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    Tucson
    I found the text for the critical publication on "rel-risk.blogspot.com":

    Failing the LL Test for Chronic LD

    Dessau RB, et al. The lymphocyte transformation test for the diagnosis of Lyme borreliosis has currently not been shown to be clinically useful. Clin Micro Inf, 2014;20:O786–O787.


    This letter is a comment on a study using the lymphocyte transformation test (LTT) for the diagnosis of active Lyme borreliosis caused by Borrelia burgdorferi sensu lato*. The study has several major shortcomings. Concerning inclusion criteria, it was not clearly specified how the 94 patients with clinical Lyme borreliosis were defined.

    …and it remains unclear how it was determined that the 34 patients with migratory arthromyalgias were suffering from Lyme borreliosis. The 160 controls for the LTT were preselected as being seronegative for Borrelia-specific antibodies, and this could introduce a selection bias, because serology and LTT results tend to correlate.

    Concerning the selection criteria for the large group of 1480 patients, it is not clear what is meant by ‘clinical diagnosis of suspected Lyme borreliosis’, among what appears to be a mixture of protean disorders. The clinical spectrum of these patients was not described.

    Forty per cent of the 1480 patients suspected of having Lyme borreliosis were LTT-positive, and 63% were serology-positive. This is a high percentage of positive results as compared with a series of consecutive patients suspected of having Lyme borreliosis in Denmark, where 9.2% were found to be IgM-positive and 3.3% IgG-positive.

    …owing to the study design, evidence of active infection is lacking. Clinical features, including follow-up and/or detection of the organism by culture or PCR, are absent. Also, the conclusion that the Borrelia LTT may be used for follow-up monitoring of disseminated B. burgdorferi sensu lato infections and provide indications for antibiotic treatment is not supported by the study design, as this would require a prospective trial with a control group.

    An ethics statement is missing, and the authors declare no conflict of interest, but are associated with a commercial laboratory recommending this test (http://www.imd-berlin.de/leistungsschwerpunkte/borreliose/ltt-borrelien.html). This website indicates that a positive LTT result may indicate a persisting infection. However, both neurological and
    microbiological European guidelines discourage the use of LTTs, owing to insufficiently rigorous validation and a low reported specificity.

    …‘chronic Lyme borreliosis’ is a problematic concept, as discussed elsewhere. As an example, it is stated that ‘over 250 peer-reviewed scientific articles demonstrate the causal association between Lyme/tick-borne disease and mental illness’. This is contradicted by the conclusion based on a substantial review of the literature (Final Report of the Lyme Disease Review Panel of the Infectious Diseases Society of America; www.idsociety.org). In the Infectious Diseases Society of America review, it was determined that the large number of scientific articles concerning ‘chronic Lyme borreliosis’ were uncontrolled case observations, which do not give convincing evidence of the persistence of viable organisms or the effects of prolonged antibiotic treatment.



    *von Baehr V, Doebis C, Volk HD, von Baehr R. The lymphocyte transformation test for borrelia detects active Lyme borreliosis and verifies effective antibiotic treatment. Open Neurol J 2012; 6: 104–112.
     
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  20. nandixon

    nandixon Senior Member

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    @valentinelynx, thank you, now we just need to see the full text of the rebuttal commentary to that.
     

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