Positive IGRA Test Research Articles

1438. Latent tuberculosis infection (LTBI) in hematopoietic stem cell transplantation (HSCT) recipients: a retrospective Italian cohort study in Tor Vergata University Hospital, Rome.

Abstract Background Patients undergoing haematopoietic stem cell transplantation (HSCT) have severe and prolonged immunodeficiency and the incidence of tuberculosis (TB) disease in those patients is 10 to 40 times higher than the general population Methods This retrospective study performed at Tor Vergata University Hospital in Rome (Italy) included all adult patients who underwent a HSCT in the Hematologic Transplant Unit from January 2015 to December 2019. Data on TB screening, performed through interferon-γ release assay (IGRA), were collected; patients were observed for TB reactivation in a follow up period of at least 3 years Results 323 HSCT recipients were enrolled in this study. Patients’ characteristics are summarized in table 1. 63 patients (19.5%) were not screened for TB, of which 6.3% were born overseas. 260 HSCT recipients (80.5%) were screened: 228 patients (87.7%) had a negative IGRA result, 21 (8.1%) tested positive, and 11 (4.2%) had an indeterminate result. 98.5% were screened before the HSCT. Of the 21 patients with a positive pre-HSCT IGRA test, 14 (66.7%) were males and significantly (p< 0.001) older (median age 60 [IQR] 58-65 years) than those with negative or indeterminate results. Almost all patients (95.2%) were Italian. Patients with a positive IGRA showed a higher monocyte count compared to the other groups (p=0.044), while those with indeterminate IGRA showed a tendence to lower lymphocyte absolute counts, compared to the other groups (p=0.060) (Table 2). All the 21 patients with a pre-HSCT positive IGRA test were radiologically and clinically screened for active TB and, once it was ruled out, treated for latent TB (LTBI) with isoniazid (INH) for 6 months. No events of toxicity or treatment interruption were reported. None of the patients was treated with rifampin. None of the 21 patients with pre-HSCT positive IGRA test developed active TB during the follow up period. Table 1.Characteristics of the study population, overall and divided according to IGRA testingTable 2.Characteristics of the IGRA tested patients, overall and divided by IGRA test results Conclusion To our knowledge, this is the first Italian study on the prevalence of LTBI in patients undergoing HSCT. 8.1% of the 260 patients screened with an IGRA tested positive. The great majority (95.2%) of LTBI patients were Italian and significantly older than IGRA-negative patients. All LTBI HSCT patients received INH treatment and no drug toxicity, nor TB reactivation was observed during the follow-up period Disclosures All Authors: No reported disclosures.

Tuberculosis of the eye, case series study.

Tuberculosis of the eye represents a challenge throughout the world, and there is a continuous debate about its pathophysiology, diagnosis, and treatment. The present research represents an interventional prospective study focusing on the variable clinical presentations, and the diagnostic and therapeutic characteristics of ocular tuberculosis. Fifteen eyes from nine cases were diagnosed with ocular tuberculosis, treated, and followed up between 2010 and 2020. The diagnosis was based on (1) a compatible clinical picture, (2) highly positive Tuberculin skin test or a positive IGRA test (Interferon-Gamma Release Assays), (3) a dramatic response to anti-tuberculous drugs without systemic steroid. Mean age was 41.22±13.64 years; eight cases were females 89.8%, one male 11.1%. Only one case had preexisting pulmonary tuberculosis. Bilateral ocular involvement occurred in two thirds of cases (66.7%). The most common clinical presentation was intermediate uveitis (33.3%), followed by multifocal choroiditis (20%). All cases were cured without relapse for the 2–10 years of follow-up, after taking oral anti-tuberculous drugs for 6–12 months. No systemic steroids were given, only topical steroid drops, as indicated. In conclusion, ocular tuberculosis is a mysterious condition with a wide-range of clinical presentations and should be considered in the differential diagnoses of any type of intraocular inflammation, or any unexplained reduction in vision. Oral anti-tuberculous drugs with or without topical steroids are sufficient to improve vision, produce, cure, and prevent relapse.

Abnormal Complex Karyotyping in A Patient Suspected of Acute Myeloblastic Leukemia (AML-M5): A Case Study

Hemophagocytic Lymphohistiocytosis (HLH) is a condition of immune dysregulation characterized by severe organ damage induced by a hyperinflammatory response and uncontrolled T-cell and macrophage activation. Patients with Acute Myeloblastic Leukemia (AML) may be prone to develop HLH. Hemophagocytic lymphohistiocytosis syndrome in AMLpatients with an abnormal complex karyotyping can worsen the patients' prognosis and outcome. A 47-year-old-female presented with prolonged fever, chills, fatigue, weight loss, productive cough, and anemia (blood transfusion (+)). Laboratory findings: hemoglobin 8.5 g/dL, WBC 151.99x103/μL, and platelet count 28x103/μL, peripheral blood 13% blast like cells, 19% promonocytes, 43% atypical (bizarre) monocytes, 25% neutrophils. Levels of CRP>150 mg/L and procalcitonin 82.67 ng/mL, negative HBsAg, and positive IGRA test. Bone marrow morphology showed hypercellularity, decreased thrombopoiesis and erythropoiesis, increased granulopoiesis, macrophages, and hemophagocytosis. Karyotyping results: abnormal karyotypes: 46: XX (9 cells), 44: X (-18), 45: XX (-4), 45: XX (+7, -2, -16), 46: XX (chtb (3), chtb (4), chtb (5), chtb (9), chtb (12), chtb (22)), 46: XX (chtb (5), chtb (7)), 46: XX (chtb (6), chtb (12)), 46: XX (dic 2), 46: XX (chtb (1) (q12), chtb (3) (p21)), 46: XX (chtb (X) (q25) ), 46: XX (der (9), dic (9)), t (9:22)), 46: XX ((+ 21), (-13) chtb (2), p (23), t ( 9:22)). The conclusion was abnormal complex karyotyping. High concentrations of inflammatory cytokines (interleukin-1, interleukin-6, TNF-alpha, and interferon-gamma) secreted by malignant cells and increased phagocytic function of leukemic cells play an important role in the pathogenesis of HLH. Monocytic components (subtypes AML4 and AML5 of the FAB classification) are predisposing factors in cases of AML-related HLH. Cytogenetic abnormalities involving 8p11 and 16p13 are more common in AML-related HLH. Complex genetic abnormalities exacerbate the prognosis of AML, especially in treatment failure. A concluded that was diagnosed with HLH due to AML-M5 with genetic abnormalities of BCR ABL (+), monosomy, trisomy, and multiple chromatid breakage with high mortality. Karyotyping examination is important to determine the prognosis of the disease.

Isolated spleen tuberculosis in an immunocompetent patient, a rare case report.

IntroductionTuberculosis (TB), as a major public health concern, is affecting almost 10 million people globally. At present, diagnostic and screening efforts mainly focus on positive smear results. Therefore, the number of extra pulmonary and negative sputum TB is rising and hampering the diagnosis and treatment process due to the large number of false negatives. Rare cases such as solitary splenic TB are usually seen in patients with splenic abnormalities, spleen trauma, immunosuppression, sickle cell disease, pyogenic infections, etc.Presentation of caseA 40-year-old female with no comorbidity came with chief complaint of early satiety every mealtime and epigastric pain in the last 6 months prior to admission. There was no significant positive examination except for positive IGRA test and enlargement of spleen with multiple cystic lesions on abdominal CT. We performed laparotomy with splenectomy followed by a histopathology examination which showed features of primary tubercular abscess.DiscussionIn the immunocompromised patient, the visceral abdomen is usually involved and a part of miliary TB. However, this case revealed the rare possibility of a healthy person with primary isolated tubercular splenic abscess while being immunocompetent and lacking any comorbidity.ConclusionSplenic TB diagnosis is difficult in patients lacking pulmonary involvement and without specific symptoms. Thorough examinations and clinical expertise are needed to provide accurate diagnosis and treat uncommon forms of TB and cases with negative smear results in consideration of rising prevalence and difficult disease control.

Tuberculosis and Leprosy Co-Infection: A Perspective on Diagnosis and Treatment

BackgroundThe Marshall Islands are known to be endemic for both leprosy and tuberculosis (TB). Active TB needs to be ruled out in all cases of leprosy, as treatment will lead to rifampin monotherapy of undiagnosed TB co-infection. The use of protein based interferon gamma release assays (IGRAS) to test for latent TB in leprosy endemic areas is confounded by the crossreactivity of T-cell response to the antigenic homologs of these proteins in Mycobacterium leparae.MethodsThe Purified Protein Derivative (PPD) skin test may have some utility in the diagnosis of latent TB in the setting of paucibacillary leprosy, however “giant reactions” to PPD testing have been documented in monoinfection with multibacillary leprosy.ResultsA 32-year-old Marshallese woman presented to the surgical department with symptoms concerning for osteomyelitis of the third distal phalanx, multiple burn wounds on both hands, and hypoaesthetic- hypopigmented skin lesions. She was referred to the National Hansen’s institute where a limited disarticulation of the distal phalanx and a slit skin biopsy was performed. Fite stain was negative, but PCR was positive for Mycobacterium leprae. The patient also had a strongly positive IGRA test for TB, and a positive PPD skin test. A chest x-ray showed a subtle infiltrate in the right middle lobe, three induced sputa were AFB negative by smear - however 1/3 was culture positive for drug-susceptible TB. The patient then underwent standard drug therapy for TB with the addition of dapsone for the treatment of Hanson’s. Repeat sputum cultures were negative at one month, and the patient had improvement in her skin hypopigmentation within four months of therapy.ConclusionThe immunological milieu of the host appears to paradoxically influence susceptibility to mycobacterial coinfection, with no consensus regarding whether prior exposure to one offers protection or predisposition to the other. The clinical implications of failure to identify active TB in a case of leprosy can not be understated, and positive IGRA or PPD testing in leprosy should not be considered falsely positive without further investigation. If treatment for paucibacillary leprosy is to be considered before ruling out active TB then minocycline may temporarily replace Rifampin.Disclosures All authors: No reported disclosures.

Tuberculose latente em profissionais de saúde: concordância entre 2 testes diagnósticos

The diagnosis of latent tuberculosis infection (LTBI), namely in healthcare workers, has been done by tuberculin skin test (TST). Recently, Interferon‐ʎ Release Assays (IGRA tests) have been introduced. Unlike TST, they do not turn positive after BCG vaccine or after most of non‐tuberculous mycobacteria infections.In the absence of a gold standard for the diagnosis of LTB, the aim of this study was to analyze the correlation between the two LTB diagnostic techniques, by determining Kappa coefficient and concordance rate between TST and IGRA test, in healthcare workers of a Portuguese university hospital.We carried out a cross‐sectional and retrospective study, and we analysed TST and IGRA tests records, that are performed simultaneously (up to 15 days apart) in Occupational Health Department, in 2010 and 2011 (n137).Most of the sample did BCG and 44.5% did two or more inoculations. The average diameter of PT was 17.5mm (SD 4.3). Only two subjects reported TST<10mm, both showing a negative IGRA test. Only 53 (39.3%) of the 135 participants with positive PT had a positive IGRA test too.The level of agreement between TST and the IGRA test was determined by Kappa coefficient. Respectively to a cut off for PT of 10mm, 15mm and 20mm, the degree of agreement was 0.019 (p=0.26), 0,19 (p=0.001) and 0.26 (p=0.003). Concordance rates were respectively 40%, 54% and 65%.It was found that the concordance between the two methods increased as the cut off for TST also increased. Nevertheless, a higher concordance rate would be expected with cut off of 15mm, and particularly of 20mm, since BCG vaccine administered in childhood usually induce smaller reactions. The existence of more than one BCG inoculation in the sample, especially after childhood, can be partly responsible for the low concordance between the two methods. Nevertheless, we cannot also exclude IGRA test's false negatives.In the decision to treat LTB, it is necessary to take into account the limitations of both tests, their level of agreement and weighting individual, occupational and epidemiological factors.

No added value of interferon-γ release to a prediction model for childhood tuberculosis.

The predictive value of a combination of clinical and radiological features with interferon-γ release assay (IGRA) for diagnosis of active tuberculosis (TB) disease among TB-exposed children is unknown.150 symptomatic HIV-negative children (aged 3 months to 14 years), prospectively recruited through active contact tracing, were included. Backward stepwise logistic regression and bootstrapping techniques were used for the development and internal validation of a clinical prediction model for active TB disease. Model discrimination and incremental value of a positive IGRA test were assessed by area under the receiver operating characteristic curve (AUC).35 (23%) children were diagnosed with active TB disease and started on treatment and 115 (77%) had other respiratory tract infections. A final parsimonious clinical model, comprising age <5 years (adjusted (a)OR 4.8, 95% CI 2.0-11.5) and lymphadenopathy on clinical examination (aOR 4.9, 95% CI 1.8-13.0) discriminated active TB disease from other disease with an AUC of 0.70 (95% CI 0.61-0.80). A positive IGRA result did not improve the discriminatory ability of the clinical model (c-statistic 0.72 versus 0.70; p=0.644).A clinical algorithm, including age <5 years and lymphadenopathy classified 70% of active TB disease among symptomatic TB-exposed children. IGRA does not add any discriminatory value to this prediction model.

Comparison of retinal and choroidal involvement in tuberculous chorioretinitis in a non‐endemic area

PurposeTo assess the respective involvement of retina versus choroid in presumed ocular tuberculosis (POT) in a non‐endemic area using dual fluorescein (FA) and indocyanine green angiography (ICGA).MethodsRetrospective study on patients with the diagnosis of POT seen in the Centre for Ophthalmic Specialized Care, Lausanne, Switzerland. Angiography signs were quantified according to an established FA and ICGA scoring system for uveitis (Int Ophthalmol. 2010;30:539–52 and Ocul Immunol Inflamm 2010;18:385–9).ResultsAmong the 1739 uveitis patients seen from 1995 to 2014, 53 patients were diagnosed as POT (3%) of which 28 had sufficient data to be included in the study. The choroid was predominantly involved in 22 patients and the retina in 6 patients. The mean angiographic score was 6.19/36 ± 4.11 for the retina versus 13.48/36 ± 7.06 for the choroid. For patients having sufficient angiographic follow‐up, the scores decreased from 6.19 to 2.40 ± 2.39 for FA and from 13.48 to 7.87 ± 5.37 for ICGA after combined antituberculous and inflammation suppressive therapy.ConclusionsThis study shows for the first time the respective involvement of retina and choroid in POT. Choroid is preferentially involved for which ICGA is the examination of choice. By looking only at FA, there is a risk of underestimating global ocular involvement and to miss the diagnosis. To evaluate correctly intraocular inflammation in POT and to have a better follow‐up, the use of dual FA &amp; ICG angiography is recommended. On the other hand, in case of a compatible uveitis having a positive IGRA test, in a non‐endemic area, dual FA &amp; ICGA should be performed to avert or help the diagnosis of ocular tuberculosis.

P36 Autoimmune hepatitis in a patient with hiv and hepatitis b co-infection along with latent tb: a therapeutic dilemma

Background/introduction Liver disease is an important cause of morbidity and mortality in patients infected with HIV infection. Abnormal liver function tests are frequently encountered in these patients and often attributed to HAART. Autoimmune Hepatitis is a rare disease with unclear pathogenesis; several viruses have been proposed to act as triggering agents for the inflammatory process of the disease. Case presentation We present a 46 year old afro Caribbean gentleman who presented with lethargy, weight loss and jaundice. He was diagnosed to be co-infected with HIV and Hepatitis B with a positive autoimmune screen. His persistently elevated liver enzymes warranted a liver biopsy which revealed interface hepatitis, necrosis with lymphocytes and plasma cell infiltrates with variable degree of fibrosis. A picture difficult to interpret in the light of HIV and Hepatitis B infections. His persistently high ALT made it challenging to initiate antiretroviral therapy and the need for steroids to suppress the autoimmune Hepatitis raised a concern regarding the reactivation of the latent TB infection as diagnosed by a positive IGRA test. A review of literature revealed 12 cases of HIV with AIH, but none co-infected with Hepatitis B. Conclusion There are no clear guidelines for management of autoimmune Hepatitis in HIV and treatment is with immunosuppressive agents. A multidisciplinary approach helped in the management of this gentlemen who now stable on antiretroviral therapy and tapering doses of steroids, along with chemoprophylaxis against latent TB.

Aktuelle Fragestellungen zum Tuberkulose-Screening mit Interferon-Gamma-Release Assays (IGRAs)

A positive IGRA test does not always indicate a latent tuberculosis infection (LTBI); the prevalence of LTBI in the tested collective must be carefully considered in test interpretation. When IGRAs are performed repeatedly in healthcare workers (BiG), variabilities of test results (conversions and reversions of the respective previous negative or positive result) can be expected. Therefore only individuals for whom there is an established risk of being infected by Mycobacterium tuberculosis (M.tb.), i.e. significantly prolonged direct exposure to an infectious TB case, should be tested. Positive IGRA results alone do not reliably predict subsequent progression to active TB disease. According to the current body of scientific knowledge, IGRAs are not superior to the tuberculin skin test (TST) in the case of young children.

Early Identification of Progressive TB Disease Using Host Biomarkers

Identification and evaluation of diagnostic biomarkers that predict TB disease progression are elaborate and complicated undertakings, since the number of incident cases even in high risk study populations is usually low and the definition of latent M.tb infection through a positive TST or IGRA test result is inaccurate. Using a retrospective case–control study approach embedded in the Amsterdam Cohort Studies on HIV infection and AIDS (van den Hoek et al., 1988), Sloot et al. (in press) identify a transcriptional signature within Peripheral Blood Mononuclear Cells, which identifies HIV-positive subjects who are later diagnosed with active TB disease. 55 to 250 days prior to TB diagnosis, IL13 transcription was detected in six out of 14 TB progressors and linked to differential expression of 50 additional genes, including type I IFN signature genes, while no subject in the control group expressed IL13. It can be assumed that this signature is part of an early host immune response to mycobacterial replication in vivo. Whether it is a hallmark of deficient immunological control of the pathogen invariably linked to progressive disease or rather reflective of pathogen activity independent of subsequent disease progression remains unclear. The study by Sloot et al. supports the concept that a diagnostic approach based on host biomarkers cannot only improve the diagnosis of active TB in populations where a conventional sputum-based diagnosis is difficult (e.g. in children, HIV-positives, extra-pulmonary TB), but might further allow identification of subjects with sub-clinically active M.tb replication. Other recent articles also highlighted the potential of host biomarkers based on transcriptional (Anderson et al., 2014, Joosten et al., 2012) or novel T cell signatures (Portevin et al., 2014, Harari et al., 2011, Schuetz et al., 2011) to improve diagnosis of active TB and possibly also allow early detection of TB disease progression. It is widely accepted that often a substantial time interval exists between infection with M.tb, and diagnosis of symptomatic disease. Individuals who develop active TB disease after primary infection frequently do so within the first two years (Marais et al., 2004). This specific characteristic of M.tb infection provides a window of opportunity for more accurate identification of individuals currently progressing to active TB using such novel biomarkers and to target them for early therapeutic intervention. Particularly in high risk populations such as HIV-positives, TB-contacts or IFN-gamma release assay converters (or TST skin-test converters) this approach might be more attractive than the current suboptimal algorithms with very limited specificity to trigger isoniazid preventive treatment, which likely result in overtreatment (American Thoracic Society, 2000). The use of novel host biomarkers in such a strategy would not only help to significantly reduce TB disease morbidity by detection of those subjects with the highest risk of active TB development in a “pre-clinical” stadium and motivating them and the treating medical staff to adhere to preventive treatment, but could also help to abrogate the MTB transmission chain and hence contribute to the EndTB Strategy by WHO and to the vision of a world free of TB in 2050 (WHO, 2014). Future research in the field of host biomarkers predictive of TB disease should be aiming at simplifying current diagnostic approaches into affordable products applicable on a large scale. Simultaneously, prospective large scale studies on early detection of progressive TB disease will be necessary (even though complicated to conduct) to further confirm the diagnostic accuracy and feasibility of these novel biomarkers in the field. Especially, the specificity for progressive versus non-progressive/latent M.tb infection needs to be assessed, as well as the biomarkers ability to distinguish between TB and other inflammatory diseases. An assessment of host biomarkers would require validation work in patient populations with different genetic backgrounds, as ethnicity can influence the composition of the host response, making such studies even larger. Significant effort is still required until the application of such novel diagnostic strategies on a large scale could be achieved. Nonetheless, new diagnostic host markers for early identification of progressive TB disease might herald a new era in TB diagnosis and early treatment.

Non-tuberculous mycobacteria and the performance of interferon gamma release assays in Denmark.

BackgroundThe QuantiFERON-TB-Gold Test (QFT) is more specific than the Mantoux skin-test to discriminate between Mycobacterium tuberculosis (MTB) and non-tuberculous mycobacterial (NTM) infections. Here we study the performance of the QFT in patients with NTM disease.MethodsFrom 2005 to 2011, nationwide patient data on positive NTM cultures (n = 925) were combined with nationwide data on QFT results (n = 16,133), both retrieved from the International Reference Laboratory of Mycobacteriology, Denmark. A total of 112 patients with NTM infections had a QFT performed, 53 patients had definite NTM disease, 10 had possible disease and 49 had NTM colonization.ResultsQFT was positive in 8% (4/53) of patients with definite disease, 40% (4/10) with possible disease and 31% (15/49) with colonization. Positivity rate was lowest among patients with definite disease infected with NTM without the RD1 region 4% (2/50). None of the 15 children with MAC lymphadenitis had a positive QFT.ConclusionThis study is one of the largest assessing IGRAs in patients with NTM disease in a TB low-incidence setting. Our study showed that the QFT holds potential to discriminate between NTM and MTB infections. We found no positive IGRA test results among children with NTM not sharing the RD1-region of MTB resulting in a 100% specificity and we suggest that a QFT in a child presenting with cervical lymphadenitis may be helpful in distinguishing NTM from TB lymphadenitis.

FRI0414 The risk of tuberculosis in patients with ankylosing spondylitis during anti-tnf therapy: data from national database in slovakia

BackgroundTNF-alfa blockers are highly effective for signs and symptoms in patients with ankylosing spondylitis (AS). Many clinical studies and data from various national registries assign concerns about serious infections, especially...

Secondary choriocapillaritis in infectious chorioretinitis

To analyse the indocyanine green angiography (ICGA) patterns of hypofluorescence that are compatible with choriocapillaritis that occur secondarily to toxoplasmic retinochoroiditis (ToRC), ocular tuberculosis (including tuberculous choroiditis, TuCR and multifocal serpiginoid choroiditis, TMSC) and syphilitic chorioretinitis (SyCR). This was a single centre, retrospective case review study. Patients with a diagnosis of ToRC, TuCR, TMSC or SyCR were identified, their charts were reviewed and fundus photographs, fluorescein angiography (FA) and ICGA pictures were assessed. Indocyanine green angiography was performed at the initial presentation in 63 of the 105 patients with ToRC, in 37 of the 38 patients with TuCR, in six of six patients with TMSC and in two of four patients with SyCR. The following four ICGA patterns indicated choriocapillaritis: extension of hypofluorescence beyond the hypofluorescence of the actual infectious focus as seen on fundus photography or FA (seen only in ToRC and TuCR); small dark dots around the infectious focus (seen only in ToRC); multiple 'confetti-like' hypofluorescent areas or hypofluorescent geographical confluent areas (seen only in TMSC); and widespread areas of nonperfusion visible only in ICGA (seen only in SyCR). Patients with secondary choriocapillaritis have distinct typical ICGA findings. ICGA is thus an important diagnostic tool that can provide an explanation for otherwise obscure visual loss and that might have diagnostic value for specific conditions like ToRC and SyCR.

Latent tuberculosis infection is associated with an increased frequency of Treg cells in the bronchoalveolar lavage

Background: A positive Interferon-γ release assay (IGRA+) after exposure to tuberculosis (TB) patients indicates a systemic immune response to M. tuberculosis (MTB). This condition defines latent infection with MTB (LTBI) and is associated with a higher risk of progression to active TB. However, only a minority of individuals has a positive IGRA-test result after exposure. Pulmonary clearance of MTB after infection may prevent a systemic immune response. In mice, pulmonary regulatory T-lymphocytes (T reg cells) can delay the clearance in early infection. In humans T reg cells are recruited to the site of infection in active TB.

Risk of developing tuberculosis after brief exposure in Norwegian children: results of a contact investigation

ObjectiveProlonged exposure to adults with pulmonary tuberculosis is a risk factor for infecting children. We have studied to what extent a brief exposure may increase the risk of being infected...

Zum Stellenwert der neuen In-vitro-Bluttests für das Tuberkulosescreening vor Gabe von TNF-α-Inhibitoren bei Psoriasis

Aufgrund des erhöhten Tuberkuloserisikos beim Einsatz von TNF-α-Inhibitoren bei der Behandlung der Psoriasis vulgaris bzw. der Psoriasisarthritis sollte bei allen Patienten eine aktive TB ausgeschlossen werden und ein Screening auf Vorliegen einer latenten TB (LTBI) vor TNF-α-Therapie erfolgen. Das Screening sollte eine Röntgen-Thorax-Aufnahme, eine sorgfältigen Anamnese und die Durchführung eines hochspezifischen Interferon-Gamma Release Assays (IGRA) umfassen. Da sowohl falsch positive als auch falsch negative Tuberkulinhauttest (THT)-Ergebnisse in diesen Patientengruppen erwartet werden können, wird der früher häufig durchgeführte THT nicht mehr empfohlen. Die Behandlung der LTBI bei positivem IGRA umfasst grundsätzlich eine Chemoprävention mit Isoniazid (INH) über 9 Monate.