IGRA testing in patients with immune-mediated inflammatory diseases: which factors influence the results?

Diagnosis of latent tuberculosis infection in patients with immune-mediated inflammatory chronic diseases (IMIDs) can be challenged as diagnostic test reliability could be impaired by immunosuppression. We retrospectively analyzed the Quantiferon Gold-Test in-Tube (QFT-G-IT) results of all patients with IMIDs seen at the Department of Internal Medicine of Son Llàtzer Hospital, Palma de Mallorca (Spain), looking for the factors related to QFT-G-IT indeterminate results. During the study period (2008-2015), 520 patients met the inclusion criteria. Factors associated with indeterminate QFT-G-IT results in a univariate analysis were inflammatory bowel disease, disease activity, lymphopenia, and medium-to-high doses of corticosteroids. In a subsequent multivariate analysis, only lymphopenia (defined as < 1500 cells) was associated with indeterminate QFT-G-IT results. Lymphocyte count was the only factor independently associated with an increased number of indeterminate QFT-G-IT results in patients with different autoimmune diseases. Others factors such as the use of medium-to-high doses of corticosteroids should be considered before testing with QFT-G-IT.

Use of Quantiferon-TB-Gold in Tube(®) test for detecting latent tuberculosis in patients considered as candidates for anti-TNF therapy in routine clinical practice.

BACKGROUND/METHODS: Quantiferon-TB-Gold in Tube(®) test (QFT-G-IT) may have advantages if combined with TST when screening for Latent Tuberculosis Infection (LTBI) prior to initiating anti-TNF therapy in an area of intermediate tuberculosis incidence such as Spain. In a small-scale prospective study, we evaluate the use of QFT-G-IT in combination with the screening recommended in Spain (Tuberculin-Skin Test, TST retest, clinical data, and Chest X-Ray (CXR)) for LTBI in patients considered as candidates for anti-TNFα treatment. RESULTS: From June 2008 to October 2010, 123 patients from a 300-bed hospital in Palma de Mallorca (Spain) were included in the study. The majority of patients were under immunosuppressive therapy. A positive TST and TST booster were found in 22 and 17 patients, respectively. Thus 39 (31.7%) of the 123 patients had a positive TST. QFT-G-IT was positive in 16 patients (13.6%), indeterminate in 4 (3.2%), and negative in 103 (83.7%). One of the two tests was positive and LTBI was diagnosed in 34.1% of patients. The agreement between TST and QFT-G-IT among vaccinated patients was low and not statistically significant (Kappa=0.15) and was almost perfect among non-BCG vaccinated patients (K=0.81). TST positive responses were significantly related to BCG-vaccination (p<0.05) and QFT-G-IT positive response rates were related to older age (p<0.05). CONCLUSION: QFT-G-IT may have advantages when combined with TST in immunosuppressed patients especially in older patients with a negative TST; in BCG vaccinated patients with a positive TST, QFT-G-IT could avoid unnecessary treatments and toxicities related to a false-positive TST result.

Ribavirin-resistant chronic norovirus infection-associated enteropathy in common variable immunodeficiency. Case report and review of the literature.

Chronic Norovirus infection is particularly challenging in patients with common variable immunodeficiency (CVID) because of their inability to achieve viral clearance and the risk of developing enteropathy leading to intestinal villous atrophy and malabsorption. To date, therapeutic options to eliminate the virus are limited and only ribavirin has been shown to induce viral clearance in norovirus enteropathy associated with CVID. We report a case of a 48-year-old female patient diagnosed with CVID enteropathy possibly related to norovirus infection who failed a ribavirin-based therapy despite dosage optimization through drug plasma level monitoring.