LTT=test de transformation lymphocytaire.
Le test est utilise en Allemagne par des specialistes de la borreliose (comme les medecins membres de la Societe Allemande de la Borreliose:Deutsche Borreliose Gesellschaft) pour diagnostiquer une borreliose .
Il teste la reaction des lymphocytes T contre les borrelies.
Ses avantages par rapport aux tests serologiques:
1) en cas de borreliose precoce il est
positif a partir du 10 eme jour apres la piqure de tique,tandis que les tests ELISA et WB ne sont positifs qu´au bout de 4 a 8 semaines.Il permet donc en cas d´absence d´EM d´avoir un diagnostique et donc un traitement plus precoce,ce qui augmente les chances de guerison.Le Dr Berghoff disait en effet pendant la conference de presse sur la borreliose en aout 2008 (organisateurs:Deutsche Borreliose Gesellschaft+Deutscher Borreliose Bund) que 80% des infectes,qui n´ont pas recu de traitement antibiotique efficace pendant les 4 premieres semaines apres une piqure de tique ,developpent une borreliose chronique!Ce chiffre souligne donc l´importance de soigner la borreliose le plus tot possible apres une piqure.Pour eviter de perdre du temps precieux,le Dr Hopf-Seidel recommande donc de faire le LTT des le 10 eme jour apres la piqure et de prendre l´antibiotique le jour meme du LTT (apres la prise de sang).Le laboratoire a besoin d´environ 2 semaines pour avoir un resultat.
2)Il indique si il y a une reponse cellulaire (lymphocytes T) aux borrelies,donc s´il y a une
activite actuelle du systeme immunitaire contre des borrelies,alors que les tests serologiques ELISA et WESTERNBLOT n´indiquent que la reponse humorale (anticorps),n´indiquent donc pas si le systeme immunitaire est actif contre les borrelies au moment du test (les anticorps IgM et surtout IgG peuvent persister tres longtemps apres le debut de l´infection,meme si celle-ci a ete eradiquee par le systeme immunitaire ou au contraire disparaitre completement,meme si des borrelies sont encore presentes dans l´organisme).
3) Il indique en cas de
borreliose seronegative (il y a des patients qui ne developpent jamais d´anticorps contre les borrelies) si le systeme immunitaire est actif contre les borrelies.
4)Le resultat indique s´il y a une reponse immunitaire cellulaire contre les
3 souches de borrelies:Borrelia burdgdorferi,Borrelia garinii,Borrelia afzelii.
Remarques:
1)le LTT peut etre faussement negatif pendant une antibiose.
Pour cette raison il ne peut etre fait que 6 semaines au plus tot apres la fin d´une antibiose.
2)en cas de borreliose chronique avec immunosuppression (CD 57 bas) le LTT peut etre negatif.Le systeme immunitaire cellulaire est alors trop faible pour repondre de maniere suffisante a l´infection.(Dr.Hopf-Seidel,Vortrag Berlin 2007)
Adresses de laboratoires ou le LTT (Lymphozytentransformationstest) peut -etre fait (recommandations du Dr Hopf-Seidel,neurologue allemande specialiste de la borreliose,membre de la Societe Allemande de la Borreliose):
Institut für Medizinische Diagnostik
Nicolaistr. 22
12247 Berlin
Tel:
030/77001-220
(le laboratoire fait aussi un Yersinien LTT)
http://www.imd-berlin.de/
Laborzentrum Ettlingen-Karlsruhe
Otto-Hahn-Str. 18
76275 Ettlingen
Tel:
07243/51601
http://www.laborzentrum.org/
(Borrelien+Ehrlichien LTT:ca. 93 € en tout)
Labor Laser
An der Wachsfabrik 25
50996 Köln
Tel:
02336/3911-0
http://www.labor-koeln.de/
Labor Sandkamp
Friedrich-Karls-Str 22
28205 Bremen
Tel:
0421/43070
http://www.ladr.de/labor/lvo/bremen/kontakt.php
Remarque:il faut demander un set de tubes au laboratoire avant la prise de sang.Un courrier vient chercher le set a domicile ou au cabinet medical le jour meme,car le sang doit etre analyse dans les 24 h apres la prise de sang pour etre valable.
Etudes en anglais:
Evaluation of the diagnostic significance of the lymphocyte proliferation test in patients with Lyme borreliosis
Borrelia-specific antibodies are not detectable until several weeks after infection and their presence alone is not proof of an active infection.
The sensitivity of culture methods and PCR for the confirmation or exclusion of Lyme borreliosis is too low.
Therefore, a method is required that detects an active Borrelia infection as early as possible.
For this purpose, a lymphocyte proliferation test (LPT) using three endogenous Borrelia antigens (Borrelia burgdorferi sensu stricto, Borrelia afzelii, and Borrelia garinii) and recombinant OspC was developed and validated by investigating seronegative (n=100) and seropositive (n=36) healthy individuals, as well as seropositive (n=44) patients with clinically overt borreliosis.
The sensitivity of the Borrelia LPT in clinical borreliosis before the administration of antibiotic treatment was 91%, while the specificity was 94%.
In 820 patients with clinical suspicion of borreliosis, positive and negative results by serology and LPT were in agreement in 77.3% of cases.
Some 165 patients (20.1%) were serologically positive and negative by LPT. These were mainly patients with borreliosis after antibiotic therapy.
Furthermore, 21 patients (2.6%) had negative serology and a positive LPT result, seven of whom had erythema migrans.
Following antibiotic treatment, the LPT becomes negative or borderline in patients with early manifestations of borreliosis, whereas in patients with late symptoms it demonstrates a regression while remaining positive.
Follow-up investigations over a period of 1 year yielded one reactivation among six patients with early manifestations, in contrast to eight out of ten patients with late symptomatology that exhibited frequent episodes of reactivation and/or persistently positive LPT reactions.
Therefore, we propose follow-up monitoring of disseminated Borrelia infections as the main indication for the Borrelia LPT.
http://www.reference-global.com/doi/abs ... M.2007.023
Seronegative Lyme disease Dissociation of specific T-and B- lymphocyte responses to Borrelia burgdorferi
RJ Dattwyler, DJ Volkman, BJ Luft, JJ Halperin, J Thomas, and MG Golightly
The diagnosis of Lyme disease often depends on the measurement of serum antibodies to Borrelia burgdorferi, the spirochete that causes this disorder.
Although prompt treatment with antibiotics may abrogate the antibody response to the infection, symptoms persist in some patients.
We studied 17 patients who had presented with acute Lyme disease and received prompt treatment with oral antibiotics, but in whom chronic Lyme disease subsequently developed.
Although these patients had clinically active disease, none had diagnostic levels of antibodies to B. burgdorferi on either a standard enzyme-linked immunosorbent assay or immunofluorescence assay.
On Western blot analysis, the level of immunoglobulin reactivity against B. burgdorferi in serum from these patients was no greater than that in serum from normal controls.
The patients had a vigorous T-cell proliferative response to whole B. burgdorferi, with a mean ( +/- SEM) stimulation index of 17.8 +/- 3.3, similar to that (15.8 +/- 3.2) in 18 patients with chronic Lyme disease who had detectable antibodies.
The T-cell response of both groups was greater than that of a control group of healthy subjects (3.1 +/- 0.5; P less than 0.001).
We conclude that the presence of chronic Lyme disease cannot be excluded by the absence of antibodies against B. burgdorferi and that a specific T-cell blastogenic response to B. burgdorferi is evidence of infection in seronegative patients with clinical indications of chronic Lyme disease.
Volume 319:1441-1446 December 1, 1988 Number 22
The Nex England Journal of Medicine
http://content.nejm.org/cgi/content/short/319/22/1441
->Je ne suis pas medecin.Les informations ci-dessus sont issues de mes recherches personelles sur Internet,sans garantie de fiabilitite.Je n´assume pas de responsabilite pour les consequences issues de la lecture de ces informations.