Treatment in inflammatory bowel disease affects IGRA performance

Résumé fourni par la source

Introduction: The detection LTBI in patients with inflammatory bowel disease (IBD) before treatment with anti-tumor necrosis factor α must be made with chest radiograph and TST. In immunocompromised patients the limitations of this strategy are well known, therefore it is advisable to use new diagnostic methods based on the release of interferon-γ (IGRA). Material and Methods: 204 IBD patients underwent screening for detection of LTBI where T-SPOT.TB (T.SPOT) and QuantiFERON-TB Gold In Tube (QTF) determinations were performed simultaneously, also lymphogram, TST and chest X-ray were performed. ITL was defined when the TST and / or any IGRA was positive. Results: 156 patients had Crohn disease, 42 ulcerative colitis and 6 non-specific colitis. 34 were treated with 5-aminosalicylic acid, 63 with immunomodulators, 32 anti-TNF-α, 27 corticosteroids and 47 a combination of them. 14 were positive QFT, 24 for the T-SPOT and 55 for the TST. The lymphogram showed an association between TSPOT + and QTF + and the amount of circulating CD8 (> 500 cells) while QFT- SPOT + results have the amount of CD8 reduced (<500). Moreover, their treatment modified all lymphocyte populations particularly the IMS and corticosteroids. Conclusion: The immunomodulatory treatment of patients with IBD altered lymphocyte profile which, in turn, is related to the result of testing LTBI. A correct interpretation of the results for the study of LTBI needs to know the treatment received and requires an assessment of lymphocyte populations that verifies its normality. If the lymphocytes are low, particularly CD8, the effectiveness of IGRA (specially the QTF), is very small and require every test possible to rule out LTBI.

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