Detection and management of latent tuberculosis in liver transplant patients

Safety and outcome of treatment of latent tuberculosis infection in liver transplant recipients

PURPOSE

Liver transplant (LT) recipients have an increased risk of tuberculosis (TB), which is associated with higher mortality rates. This retrospective cohort study assessed the outcome and tolerability of screening and treatment of latent tuberculosis infection (LTBI) in LT recipients.

METHODS

Between March 2020 and February 2022, all adult LT candidates at our institution were screened for LTBI. The candidates who tested positive for interferon-γ-releasing assay or met epidemiological or clinical-radiological criteria for LTBI were treated and monitored.

RESULTS

Among the 857 LT recipients, 199 (23.2%) were diagnosed with LTBI, of which 171 (85.9%) initiated LTBI treatment. The median duration of follow-up was 677 days. Adequate LTBI treatment occurred in 141/171 (82.5%) patients and was discontinued prematurely in 30/171 (17.5%) patients. The most common reason for discontinuation was liver enzyme elevation (11/30, 36.7%), although only five discontinued treatment due to suspicion of isoniazid-associated hepatotoxicity. None of the LTBI-treated patients developed active TB during the follow-up period, while 3.6% (1/28) of untreated LTBI patients and 0.6% (4/658) of patients without LTBI developed TB.

CONCLUSION

These findings demonstrate that LTBI screening and treatment is a safe and effective strategy to prevent TB in LT recipients. However, monitoring for adverse events and liver enzyme elevation is recommended.

Infections After Liver Transplant -Timeline, Management and Prevention

Liver transplantation (LT) is the standard treatment for end- stage liver disease. Patient and graft survival have improved significantly in the last three decades owing to improvement in surgical technique, better perioperative management and better immunosuppressive regimens. However, LT recipients are at increased risk of infections, particularly in the first year after transplantation. The risk of infection is directly proportional to immunosuppressive regimen and graft function. In this review, we will briefly discuss the timeline of infections after liver transplant, preventive strategies and management of infectious complications.

Screening for Latent Tuberculosis Infection in Solid Organ Transplant Recipients to Predict Active Disease: A Systematic Review and Meta-Analysis of Diagnostic Studies

BACKGROUND

This is a systematic review and meta-analysis of diagnostic test accuracy studies to assess the predictive value of both tuberculin skin test (TST) and interferon-gamma release assays (IGRA) for active tuberculosis (TB) among solid organ transplantation (SOT) recipients.

METHODS

Medline, Embase, and the CENTRAL databases were searched from 1946 until June 30, 2022. Two independent assessors extracted data from studies. Sensitivity analyses were performed to investigate the effect of studies with high or low risk of bias. Methodological quality of each publication was assessed using QUADAS-2.

RESULTS

A total of 43 studies (36 403 patients) with patients who were screened for latent TB infection (LTBI) and who underwent SOT were included: 18 were comparative and 25 noncomparative (19 TST, 6 QuantiFERON-TB Gold In-Tube [QFT-GIT]). For IGRA tests taken together, positive predictive value (PPV) and negative predictive value (NPV) were 1.2% and 99.6%, respectively. For TST, PPV was 2.13% and NPV was 95.5%. Overall, PPV is higher when TB burden is higher, regardless of test type, although still low in absolute terms. Incidence of active TB was similar between studies using LTBI prophylaxis (mean incidence 1.22%; 95% confidence interval [CI], .2179-2.221) and those not using prophylaxis (mean incidence 1.045%; 95% CI, 0.2731-1.817; P = .7717). Strengths of this study include the large number of studies available from multiple different countries; limitations include absence of gold standard for diagnosis of latent TB and low incidence of active TB.

CONCLUSIONS

We found both TST and IGRA had a low PPV and high NPV for the development of active TB posttransplant. Further studies are needed to better understand how to prevent active TB in the SOT population.

Assessing anti-SARS-CoV-2 cellular immunity in 571 vaccines by using an IFN-γ release assay

Memory T cell responses have been analyzed only in small cohorts of COVID-19 vaccines. Herein, we aimed to assess anti-SARS-CoV-2 cellular immunity in a large cohort using QuantiFERON assays, which are IFN-γ release assays (IGRAs) based on short-term whole blood culture. The study included 571 individuals receiving the viral spike (S) protein-expressing BNT162b2 mRNA vaccine. QuantiFERON assays revealed antigen-specific IFN-γ production in most individuals 8 weeks after the second dose. Simultaneous flow cytometric assays to detect T cells expressing activation-induced markers (AIMs) performed for 28 randomly selected individuals provided data correlating with the QuantiFERON data. Simultaneous IFN-γ enzyme-linked immunospot and AIM assays for another subset of 31 individuals, based on short-term peripheral blood mononuclear cell culture, also indicated a correlation between IFN-γ production and AIM positivity. These observations indicated the acquisition of T cell memory responses and supported the usability of IGRAs to assess cellular immunity. The QuantiFERON results were weakly correlated with serum IgG titers against the receptor-binding domain of the S protein and were associated with pre-vaccination infection and adverse reactions after the second dose. The present study revealed cellular immunity after COVID-19 vaccination, providing insights into the effects and adverse reactions of vaccination.

Isoniazid prophylaxis in liver transplant recipient with latent tuberculosis; Is it harmful for transplanted liver?

BACKGROUND

Liver transplantation (LT) is considered the only treatment for patients with end-stage liver disease and, despite its incredible impacts on the patients' health status, places them in an immunocompromised state in which opportunistic infection would find a way to present. Latent Tuberculosis Infection (LTBI) is the most common form of TB and can be diagnosed through Tuberculin Skin Test (TST) or Interferon-Gamma Release Assays (IGRA). LT recipients are at significant risk of TB activation. There is no strict guideline to approaching these cases though, in most centers, Isoniazid (INH) would be prescribed prophylactically. INH is a hepatotoxic medication and can have adverse effects on the transplanted liver. There is no consensus on this issue; therefore, we aimed to survey the potential hepatotoxic effects of INH among LT recipients in Shiraz, Iran.

METHODS

A retrospective cohort study was conducted among LT candidates and recipients at Abu Ali Sina Organ Transplantation Center between 1993 and 2019. All the cases underwent TST and chest X-ray to detect LTBI. All the LTBI were treated with INH from six to nine months and followed by the level of liver enzymes for quick detection of hepatotoxicity. A control group was selected among LT recipients and matched for age, gender, MELD score, and donor age.

RESULTS

Among 4895 medical records reviewed, 55 (1.12%) cases had LTBI. Neither INH-related hepatotoxicity, nor signs and symptoms that were suspicious to TB reactivation were reported. Overall, three deaths were reported, two because of myocardial infarction and one due to pneumonia. Ten patients (18.2%) experienced acute rejection as confirmed with pathology and responded to methylprednisolone. Aspartate aminotransferase (AST) was diminished from pre-LT time to the first time after transplantation; after that, it showed a steady pattern. Meanwhile, Alanine transaminase (ALT) was constant before and one stage later and decreased after that. Statistical analyses only showed significant changes in the total bilirubin titer between the case and control groups.

CONCLUSION

This survey showed prophylactic management of LTBI with INH in LT candidates and recipients was associated with no hepatotoxicity or related death. It seems INH prophylaxis is safe in LT settings and can efficiently prevent TB activation; however, careful monitoring for adverse effects and liver enzymes elevation is highly recommended. This article is protected by copyright. All rights reserved.

Mycobacterial infections in solid organ transplant recipients

Mycobacterium tuberculosis (MTB) infection in solid organ transplant (SOT) recipients remains a major challenge for physicians and surgeons. Active tuberculosis (TB) is associated with increased morbidity and mortality in SOT recipients. MTB usually develops after transplantation in a recipient with latent TB infection (LTBI) before transplantation and may also be transmitted from the donor or acquired from the community. Therefore, screening for LTBI in donors and recipients before transplantation is very important in preventing active disease after transplantation. This review article is based on recently published data, case series, and expert recommendations. We reviewed updated information about the epidemiology, diagnosis, and treatment of latent and active TB before and after transplantation. We also reviewed recent treatments for multidrug-resistant TB.

Latent tuberculosis: Risk factors, screening and treatment in liver transplantation recipients from an endemic area

BACKGROUND

Patients undergoing solid organ transplantation, particularly those who live or have lived in tuberculosis (TB) endemic areas, are at a high risk of developing TB. The majority of post-transplantation TB cases are associated with reactivation of latent TB infection (LTBI). Brazil is in a single position with overlapping areas of high TB endemicity and high transplant activity. In liver transplant (LT), one should be aware of the potential hepatotoxicity associated with the treatment regimens for LTBI.

AIM

To evaluate the frequency of LTBI in LT patients and treatment-related issues.

METHODS

This was a retrospective analysis of a cohort of cirrhotic patients aged ≥ 18 years, who underwent LT at a high-complexity teaching hospital from January 2005 to December 2012.

RESULTS

Overall, 429 patients underwent LT during the study period. Of these, 213 (49.7%) underwent the tuberculin skin test (TST) during the pre-transplant period, and 35 (16.4%) of them had a positive result. The treatment for LTBI was initiated after LT in 12 (34.3%) of the TST-positive patients; in 3 (25.0%), treatment was maintained for at least 6 mo.

CONCLUSION

The prevalence of LTBI was lower than expected. Initiation and completion of LTBI treatment was limited by difficulties in the management of these special patients.

Drug-Induced Liver Injury After Liver Transplantation

Drug-induced liver injury (DILI) is an adverse reaction to many drugs in common use that in a liver transplantation (LT) recipient may cause graft dysfunction and may even lead to graft loss and the need for retransplantation. However, several potential clinical scenarios, such as graft rejection and infection, can confound the diagnosis of suspected DILI in the setting of LT. This makes causal assessment of a new liver injury more uncertain and has traditionally precluded collection of bona fide cases of DILI affecting LT patients in prospective DILI registries and cohorts. Although no studies have yet determined a greater susceptibility of the transplant patient to DILI, these patients nevertheless present certain risk factors that can theoretically increase the risk of DILI. These include the fact that these patients are polymedicated, use drugs that are potentially hepatotoxic, and can have coexisting hepatitis B or C viruses in addition to other factors found in nontransplant patients, such as genetic variants. Therefore, awareness is crucial of any potential hepatotoxic effect of drugs used in the LT recipient and their possible implication in any case of liver dysfunction. In the present article, we review the most common drugs used in LT recipients from a liver safety perspective and address the main pitfalls in attributing causality in this clinical setting. We also affirm the need for further research and collaboration in this somewhat neglected topic in the field of DILI.

Prevention and treatment of tuberculosis in solid organ transplant recipients

Introduction: Tuberculosis (TB) in solid organ transplant (SOT) recipients is associated with significant morbidity and mortality. Its management in transplant recipients is difficult and highly complex, given the underlying immunosuppression and the risks of drug-drug interactions imposed by immunosuppressive drugs that are needed to maintain the transplant allograft.Areas covered: We provide a brief review of TB in SOT and discuss the clinical indications, mechanisms of action and drug resistance, drug-drug interactions, and adverse effects of anti-TB drugs. We provide a summary of recent clinical trials, which serve as the foundation for current recommendations. We further include relevant updates on new agents being evaluated for clinical use in TB management.Expert commentary: TB causes significant morbidity in SOT recipients. The drugs used in the treatment for latent TB and active disease in SOT are similar to the regimens used in the general population. However, TB disease in transplant recipients is more difficult to manage because of the potential for hepatotoxicity and the complex drug-drug interactions with immunosuppressive drugs. We believe that alternative regimens suited for the vulnerable transplant population, and more therapeutic drug options are needed given the adverse toxicities associated with currently approved anti-TB drugs.

Treatment of latent TB Infection and the risk of tuberculosis after solid organ transplantation: Comprehensive review

BACKGROUND

Mycobacterium tuberculosis disease may occur after treatment of latent TB infection (LTBI). Prompted by a case of reactivation TB disease in a solid organ transplant (SOT) recipient who received LTBI treatment, we reviewed the literature to examine outcomes, adverse effects, resistance, and treatment choices of tuberculosis after LTBI therapy.

METHODS

MEDLINE and Web of Science from inception to 5/2019 were reviewed using key words "latent tuberculosis infection" and "SOT" or "transplantation." The search yielded nine cases, 41 cohort studies and six randomized controlled trials (RCT).

RESULTS

Cohort and RCT demonstrated significant reduction in TB disease among transplanted patients who received LTBI therapy; only 56/2651 (2.1%) SOT patients developed TB after LTBI therapy. Adverse drug reactions occurred in 149/1148 (12.9%) and 73/641 (11.4%) of cohort and RCT patients, respectively. Among liver recipients, 56/266 (21%) developed side effects, of which half (29/56, 51.8%) was INH-related. There was no reported INH resistance.

CONCLUSIONS

Latent TB infection treatment is efficacious in SOT recipients at risk of TB disease. However, tuberculosis may still occur despite LTBI treatment. Hepatotoxicity associated with LTBI therapy is infrequent, although more commonly observed among liver recipients.

Fluoroquinolones for the treatment of latent Mycobacterium tuberculosis infection in liver transplantation

Solid organ transplantation (SOT) is the best treatment option for end-stage organ disease. Newer immunosuppressive agents have reduced the incidence of graft rejection but have increased the risk of infection, particularly due to the reactivation of latent infections due to opportunistic agents such as Mycobacterium tuberculosis. Active tuberculosis (TB) after SOT is a significant cause of morbidity and mortality. Most cases of posttransplant TB are secondary to reactivation of latent tuberculosis infection (LTBI) due to the effects of long-term immunosuppressive therapy. Risk minimization strategies have been developed to diagnose LTBI and initiate treatment prior to transplantation. Isoniazid with vitamin B6 supplementation is the treatment of choice. However, liver transplantation (LT) candidates and recipients have an increased risk of isoniazid-induced liver toxicity, leading to lower treatment completion rates than in other SOT populations. Fluoroquinolones (FQs) exhibit good in vitro antimycobacterial activity and a lower risk of drug-induced liver injury than isoniazid. In the present review, we highlight the disease burden posed by posttransplant TB and summarize the emerging clinical evidence supporting the use of FQs for the treatment of LTBI in LT recipients and candidates.

Mycobacterium tuberculosis infections in solid organ transplantation: Guidelines from the infectious diseases community of practice of the American Society of Transplantation

These updated guidelines from the Infectious Diseases Community of Practice of the American Society of Transplantation review the diagnosis, prevention, and management of tuberculosis in the pre- and post-transplant period. The challenges of screening for both latent and active TB in the setting of transplantation are reviewed. The use of interferon gamma release assays for detection of latent tuberculosis is discussed and compared to tuberculin skin testing. Given the limitations of both testing modality, it is important to consider exposure history and chest imaging. The clinical manifestations of active tuberculosis in transplantation are covered. New recommendations for treatment of latent tuberculosis and active tuberculosis are included.

Latent tuberculosis infection in transplant candidates: a systematic review and meta-analysis on TST and IGRA

INTRODUCTION

The diagnostic accuracy of interferon-gamma release assays (IGRAs) and the tuberculin skin test (TST) for latent tuberculosis infection (LTBI) in transplant candidates is uncertain.

METHODS

Pubmed, Embase and Cochrane library were searched to identify relevant studies. Quality of included studies was assessed with RevMan5 software (via GUADAS2 checklist). Accuracy measures of IGRAs and TST assays (sensitivity, specificity and others) were pooled with random effects model. Data were analyzed by STATA and Meta-DiSc.

RESULTS

Twenty-eight studies were selected for full review, and 16 were included in the final analysis. The pooled sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), positive likelihood ratio (PLR), negative likelihood ratio (NLR) and diagnostic odds ratio (DOR) for TST were 46% [95% confidence interval (CI) 38-54%], 86% (95% CI 75-93%), 46.3% (95% CI 40-52), 88.7% (95% CI 87-89), 3.3 (95% CI 1.6-6.4), 0.63 (95% CI 0.52-0.77) and 5 (95% CI 2-12), respectively. For QFT-G, the pooled sensitivity, specificity, PPV, NPV, PLR, NLR, and DOR were 58% (95% CI 41-73%), 89% (95% CI 77-95%), 72.7% (95% CI 68-76), 80.6% (95% CI 78-82), 5.3 (95% CI 2.0-14.0), 0.47 (95% CI 0.30-0.75) and 11 (95% CI 3-46), respectively. Likewise, for T-SPOT.TB, the pooled sensitivity, specificity, PPV, NPV, PLR, NLR, and DOR were 55% (95% CI 40-70%), 92% (95% CI 87-95%), 60.4% (95% CI 47-72), 90.2% (95% CI 86-92), 6.7 (95% CI 4.0-11.1), 0.52 (95% CI 0.31-0.85) and 16 (95% CI 7-37), respectively.

CONCLUSIONS

IGRAs were more sensitive and specific than the TST with regard to the diagnosis of LTBI in the transplant candidates. They have added value and can be complementary to TST.

Prevalence of latent tuberculosis infection in transplant candidates: A systematic review and meta-analysis

INTRODUCTION

Tuberculosis (TB) is considered as a serious complication for organ transplant recipients; therefore, the detection and appropriate treatment of latent infection are recommended for preventing active TB infections in the future. The objective of this review is to conduct a systematic review and meta-analysis of studies assessing the prevalence of latent TB infection (LTBI) in transplant candidates.

METHODS

Electronic databases, including MEDLINE (via PubMed), SCOPUS were searched until 30 June 2017. The prevalence of LTBI was estimated using the random effects meta-analysis. Heterogeneity was evaluated by subgroup analysis. Data were analyzed by STATA version 14.

RESULTS

The pooled prevalence of LTBI based on tuberculin skin test (TST) in different transplant types was as follows: liver 24% (14%-33%, 95% CI), lung 22% (18%-26%), renal 21% (16%-27%, 95% CI) and hematopoietic stem cell transplantation (HCT) 14% (9%-19%). The prevalence of LTBI based on Interferon Gamma Release Assay (IGRA) tests in renal transplant candidates was 31% (95% CI; 25-37%), which was much higher than the prevalence of LTBI in liver transplant candidates (25%, 95% CI; 17-33%) and HCT transplant candidates (13%, 95% CI; 10-16%) and there was statistically significant differences between them. The pooled prevalence of indeterminate results based on IGRAs test in different transplant types was as follows: renal 6% (4%-8%, 95% CI) and liver 12% (2%-21%, 95% CI). Subgroup analysis revealed that there were statistically significant differences between the overall prevalence of indeterminate results by using IGRA tests in liver transplant candidates (12%, 95% CI; 2-21%) and renal transplant candidates (6%, 95% CI; 4-8%). The pooled prevalence of post-transplant TB was 2% (1%-2%, 95% CI) and its occurrence was more common in renal recipients (4% (2%-7%, 95% CI)) than in the liver transplant patients (1% (0%-2%, 95% CI)). The prevalence of LTBI in the subgroup (i.e. the patients' mean age was <50 years) was significantly higher than the prevalence of LTBI by using TST/IGRAs in the other subgroup (i.e. the patients' mean age was ≥50 years).

CONCLUSION

Our study suggests fair overall agreement between IGRAs and TST in patients requiring liver and HCT transplantation, while a superiority of IGRAs over TST in patients requiring renal transplantation was seen.

Isoniazid Prophylaxis for Latent Tuberculosis Infections in Liver Transplant Recipients in a Tuberculosis-Endemic Area

Background

Isoniazid (INH) prophylaxis (Px) has good efficacy for preventing tuberculosis (TB) in the general population. However, its use for the treatment of latent TB infections (LTBI) in liver transplant (LT) recipients is challenging because little is known about INH-induced hepatotoxicity in graft recipients. We evaluated the efficacy and safety of INH Px in LT recipients.

Material/Methods

From March 2008 to December 2012, we retrospectively reviewed data on 277 patients who received LT at a single center. We examined the results of tuberculin skin tests and interferon-γ release assays, use of INH, INH-induced hepatotoxicity, and post-LT TB occurrence.

Results

Among 277 recipients, 7 cases of post-transplant TB were detected (2.52%). Seventeen patients received post-transplant INH Px. Among INH Px recipients, post-LT TB infection did not occur. Hepatotoxicity after INH Px was significantly lower in the patients who received INH Px at an aspartate aminotransferase (AST) level that was less than 50 U/L than in those who received INH Px at an AST level that was more than 50 U/L (P=0.046, 0.002).

Conclusions

INH is likely to be effective for preventing post-LT TB recurrence in LTBI. However, because of INH-induced hepatotoxicity, it is better to avoid using it in the early post-LT period and to wait to initiate INH Px until liver function is stable in LT recipients.

Three months of weekly rifapentine plus isoniazid for latent tuberculosis treatment in solid organ transplant candidates

BACKGROUND

Isoniazid daily for 9 months is the recommended regimen for latent tuberculosis infection (LTBI) in solid organ transplant (SOT) candidates, but its use is controversial, due to reports of hepatotoxicity and low treatment completion rates. A 12-week course of once weekly directly observed therapy (DOT) with isoniazid plus rifapentine (3HP) is a new LTBI treatment regimen. Tolerability and safety data of 3HP LTBI treatment in SOT candidates are limited.

METHODS

Twelve consecutive SOT candidates who underwent DOT with 3HP for LTBI at Westchester Medical Center, Valhalla, New York, USA, between January 2013 and August 2016 were prospectively evaluated for tolerability and safety of 3HP. The diagnosis of LTBI was made in a person with a positive interferon-gamma release test, without a history of previously treated active or latent tuberculosis infection, and without signs, symptoms, or radiographic evidence of active tuberculosis. Patients were followed up 1 month after treatment completion and at routine follow-up visits with their transplant providers.

RESULTS

Eleven patients were men, and the median age was 60 years (range 44-72). Eight patients were liver, and four kidney transplant candidates. The median Model for End-Stage Liver Disease (MELD score) was 17 (range 10-31). All patients completed treatment. Only a single patient developed transaminitis greater than twice the baseline value. Three patients underwent liver transplantation. None of them developed tuberculosis at 9, 22, or 40 months following transplantation.

CONCLUSION

Directly observed 3HP LTBI treatment was not associated with hepatotoxicity, even in patients with higher MELD scores. Further studies are needed to confirm the safety and efficacy of this LTBI treatment regimen in the SOT population.

Drug Metabolism, Drug Interactions, and Drug-Induced Liver Injury in Living Donor Liver Transplant Patients

Living donor liver transplant (LDLT) fills a critically needed gap in the number of livers available for transplant. However, little is known about the functional recovery of the liver in the donor and in the recipient after surgery. Given that both donor and recipients are treated with several drugs, it is important to characterize the time course of recovery of hepatic synthetic, metabolic, and excretory function in these patients. In the absence of data from LDLT, information on the effect of liver disease on the pharmacokinetics of medications can be used as guidance for drug dosing in LDLT patients.

Demographics and prevalence of positive QuantiFERON-TB Gold In-Tube test in renal transplant candidates

BACKGROUND

Latent tuberculosis infection (LTBI) screening prior to solid organ transplantation is standard of care. QuantiFERON-TB Gold In-Tube (QFT-GIT) test is the preferred diagnostic test for renal transplant candidates (RTC). QFT-GIT reversions and the potential delay of living-donor kidney transplantation (LDKT) because of QFT-GIT positivity have not been examined previously in RTC.

METHODS

We evaluated the prevalence of positive QFT-GIT in RTC from January 1 through December 31, 2011. In addition, we examined the demographic and renal disease data differences between QFT-GIT-positive and -negative patients, changes in QFT-GIT results, and positive QFT-GIT results reverting to negative. Lastly, we evaluated if QFT-GIT-positive patients were less likely to undergo LDKT within 6 months of QFT-GIT testing.

RESULTS

In total, 722 RTC were analyzed, 16% of whom had positive QFT-GIT. The QFT-GIT-positive patients were more likely to be older and foreign-born, P < 0.0001. Haitians had the highest prevalence. Of the 119 QFT-GIT-positive patients, 25% had low/intermediate-positive results and were more likely to revert to negative, compared with patients with high-positive QFT-GIT results (50% vs. 0%, P = 0.01). A trend was seen toward fewer QFT-GIT-positive patients undergoing LDKT, compared with QFT-GIT-negative patients (0% vs. 3%, P = 0.09).

CONCLUSIONS

Our high prevalence was likely a result of the high number of foreign-born RTC. Half of our small subset of low/intermediate-positive QFT-GIT patients reverted to negative. QFT-GIT-positive patients were more likely to have their LDKT delayed.

Mycobacterial infections in solid organ transplant recipients

Mycobacterial infections represent a growing challenge for solid organ transplant recipients (SOT). The adverse effects of tuberculosis (TB) therapy present a major difficulty, due to the interactions with immunosuppressive drugs and direct drug toxicity. While TB may be donor-transmitted or community-acquired, it usually develops at a latent infection site in the recipient. Pre-transplant prevention efforts will improve transplant outcomes and avoid the complications associated with post-transplant diagnosis and treatment. The present review and consensus manuscript is based on the updated published information and expert recommendations. The current data about epidemiology, diagnosis, new regimens for the treatment of latent TB infection (LTBI), the experience with rifamycins for the treatment of active TB in the post-transplant period and the experience with isoniazid for LTBI in the liver transplant population, are also reviewed. We attempt to provide useful recommendations for each transplant period and problem concerning mycobacterial infections in SOT recipients.

Latent tuberculosis in kidney and liver transplant patients: a review of treatment practices and outcomes

BACKGROUND

The standard treatment of latent tuberculosis infection (LTBI) is associated with toxicities and data are limited on tolerability among patients with advanced organ disease listed for transplant. Alternate options are available, but they have yet to be studied in this population.

METHODS

A retrospective review of the treatment of LTBI among kidney and/or liver transplant candidates was conducted to assess factors impacting therapy initiation, tolerability, and completion of therapy.

RESULTS

Of 174 eligible patients, treatment of LTBI was initiated in 129, of which 91 were listed for kidney transplant and 38 were listed for liver or liver/kidney transplant. Infectious Diseases consultation was independently associated with treatment initiation when controlling for waitlisted organ and receipt of hemodialysis (odds ratio [OR] 81.14, 95% confidence interval [CI] 23.94-274.94, P < 0.001). Documented completion of first-line therapy was 47% overall, and 49% and 39%, respectively, among kidney and liver/kidney candidates (P = not significant). On multivariable analysis, controlling for baseline aspartate aminotransferase and waitlisted organ, first-line receipt of rifampin was associated with lower rates of treatment completion (OR 0.19, 95% CI 0.05-0.77, P = 0.02).

CONCLUSION

Based on medical record documentation, completion of first-line therapy was <50% in this cohort, although this is likely an underestimate, as 34% of patients had no chart documentation that therapy was completed. Approximately 20% of patients did not complete first-line therapy because of adverse effects.

Immunodiagnostic Tests' Predictive Values for Progression to Tuberculosis in Transplant Recipients: A Prospective Cohort Study

BACKGROUND

Little is known about the predictive value for progression to tuberculosis (TB) of interferon-γ release assays and how they compare with the tuberculin skin test (TST) in assessing the risk of TB infection in transplant recipients.

METHODS

We screened 50 liver transplant (LT) and 26 hematopoietic stem cell transplant (HSCT) recipients with both QuantiFERON-TB Gold In-tube (QFT-GT) and TST and prospectively followed them for a median of 47 months without preventive chemoprophylaxis.

RESULTS

In the LT cohort, 1 in 22 (4.5%) QFT-GT-positive patients developed posttransplant TB, compared with none of the QFT-GT-negative patients. In the HSCT cohort, none of the 7 QFT-GT-positive patients developed TB, whereas 1 case (5.3%) progressed to active TB among the 19 QFT-GT-negative patients. Comparable results were obtained with the TST: in the LT group, 1 of 23 TST-positive and none of the 27 TST-negative patients developed TB; and in the HSCT group, none of the 8 TST-positive and one of the 18 TST-negative patients progressed to active TB.

CONCLUSIONS

In this cohort of transplant recipients, the positive predictive value of QFT-GT for progression to active TB was low and comparable to that of TST. Although the risk of developing TB in patients with negative results at baseline is very low, some cases may still occur.

Outcome of latent tuberculosis infection in solid organ transplant recipients over a 10-year period

BACKGROUND

Screening and therapy of latent tuberculosis infection (LTBI) is recommended in solid organ transplant (SOT). However, there are limited data on the tolerability of LTBI therapy pretransplant and posttransplant. We studied the tolerability of LTBI therapy and effectiveness of a centralized LTBI treatment program in a low-risk population.

METHODS

Provincial TB and transplant databases were retrospectively reviewed for LTBI therapy referrals in SOT candidates and recipients over a 10-year period. Using univariate logistic regression, we examined factors associated with failure to complete therapy and followed patients for active TB.

RESULTS

From 2001 to 2010, 200/461 SOT candidates referred to the TB program (43.4%) were eligible for therapy for LTBI. Eleven patients refused therapy. The remaining patients (n=189) were initially prescribed isoniazid (73%), rifampin (12.7%), or another regimen (14.3%). Adequate LTBI therapy occurred in 122 (64.5%). Patients who were liver transplant candidates or recipients were less likely to complete therapy than nonliver transplant patients (OR, 0.20; P<0.001) as were patients treated in the posttransplant phase (OR, 0.47; P=0.034). Liver enzyme elevation led to discontinuation of therapy more often in liver transplant candidates and recipients (OR, 10.48; P<0.001) and posttransplant treatment (OR, 3.50; P=0.019). In 599.4 patient-years of follow-up posttransplant (mean, 4.9 year/patient), there were no cases of active TB.

CONCLUSION

A centralized referral program for LTBI therapy in transplant candidates is effective to prevent TB reactivation posttransplant. A significant proportion of liver transplant candidates and recipients do not tolerate standard LTBI therapy. Alternative therapies for these patients should be evaluated.

High Proportion of Indeterminate QuantiFERON-TB Gold In-Tube Results in an Inpatient Population Is Related to Host Factors and Preanalytical Steps

Background

 QuantiFERON-TB Gold In-Tube test (QFT-GIT) can be used as an alternative to tuberculin skin testing (TST) for the targeted testing of latent tuberculosis. Due to many shortcomings with TST, QFT-GIT usage is increasing. QFT-GIT implementation in the inpatient setting remains unclear.

Methods

 We retrospectively identified patients admitted to a tertiary care academic center who received either a TST or a QFT-GIT in the 18 months prior to and after QFT-GIT implementation in March 2012. Risk factors associated with indeterminate results were evaluated.

Results

 The proportion of inpatients receiving a test for tuberculosis infection doubled following QFT-GIT implementation (1.4% vs 2.9%). After QFT-GIT became available, 75% of tested people received a QFT-GIT and 25% received a TST. We found indeterminate test results in 19.8%. Independent predictors of indeterminate results were female sex (adjusted odds ratio [AOR], 1.64), lymphopenia (AOR, 2.21), hypoalbuminemia (AOR, 6.81) and sample collection by nonphlebotomists (AOR, 3.0, vs phlebotomists). Of patients who had indeterminate results, 42% had a subsequent indeterminate result on repeat testing. All indeterminate results were due to a low mitogen response.

Conclusions

 QFT-GIT testing in the inpatient setting is associated with a high proportion of indeterminate results that is associated with host factors and preanalytical errors. Careful selection of patients to be tested and training on sample processing for QFT-GIT testing should be considered to decrease indeterminate results.

Drug-drug interactions with oral anti-HCV agents and idiosyncratic hepatotoxicity in the liver transplant setting

Studies of boceprevir and telaprevir based antiviral therapy in liver transplant (LT) recipients with hepatitis C genotype 1 infection have demonstrated dramatic increases in tacrolimus, cyclosporine, and mTOR inhibitor exposure. In addition to empiric dose reductions, daily monitoring of immunosuppressant blood levels is required when initiating as well as discontinuing the protease inhibitors to maximize patient safety. Although improved suppression of HCV replication is anticipated, 20 to 40% of treated subjects have required early treatment discontinuation due to various adverse events including anemia (100%), infection (30%), nephrotoxicity (20%) and rejection (5 to 10%). Simeprevir and faldaprevir will likely have improved efficacy and safety profiles but potential drug interactions with other OATP1B1 substrates and unconjugated hyperbilirubinemia are expected. In contrast, sofosbuvir and daclatasvir based antiviral therapy are not expected to lead to clinically significant drug-drug interactions in LT recipients but confirmatory studies are needed. Liver transplant recipients may also be at increased risk of developing drug induced liver injury (DILI). Establishing a diagnosis of DILI in the transplant setting is very difficult with the variable latency, laboratory features and histopathological manifestations of hepatotoxicity associated with a given drug, the need to exclude competing causes of allograft injury, and the lack of an objective and verifiable confirmatory test. Nonetheless, a heightened awareness of the possibility of DILI is warranted in light of the large number of medications used in LT recipients and the potential adverse impact that DILI may have on patient outcomes.

Challenging issues in tuberculosis in solid organ transplantation

Solid organ transplant (SOT) recipients are at risk for opportunistic infections including tuberculosis. Although guidelines on the management of latent tuberculosis and active tuberculosis are available, there remain a number of clinical areas with limited guidance. We discuss challenges in the diagnosis, management, and treatment of latent and active tuberculosis in SOT candidates and recipients who reside in low-tuberculosis-prevalence areas. We discuss the diagnosis of latent tuberculosis in SOT candidates/recipients using tuberculin skin tests and interferon-γ release assays and risk stratification of SOT candidates/recipients that would identify individuals at high risk for latent tuberculosis despite negative test results. Through a careful review of posttransplant tuberculosis cases, we identify a history of treated tuberculosis in SOT recipients as a risk factor for development of posttransplant active tuberculosis. Finally, we include comparisons of recommendations by several large transplant organizations and identify areas for future research.

Hepatotoxicity of antibiotics: a review and update for the clinician

Collectively, the various classes of antibiotics are a leading cause of drug-induced liver injury (DILI). However, acute antibiotic-associated DILI can be difficult to diagnose, as the course of therapy is usually brief, and other confounding factors are often present. In addition to the broad clinicopathologic spectrum of hepatotoxicity associated with the antimicrobials, the underlying infectious disease being treated may itself be associated with hepatic dysfunction and jaundice. This review provides summarized information on several classes of antimicrobial agents, highlighting new agents causing DILI and updating information on older agents.

Risk factors for pulmonary tuberculosis in Croatia: a matched case-control study

Background

Mycobacterium tuberculosis is a necessary, but not sufficient, cause of tuberculosis. A number of studies have addressed the issue of risk factors for tuberculosis development. Croatia is a European country with an incidence rate of 14/100 000 which is slowly decreasing. The aim of this study is to evaluate the potential demographic, socioeconomic, behavioural and biological risk factors for tuberculosis in Croatia in comparison to other high-income, low-incidence European countries.

Methods

A total of 300 tuberculosis patients were matched for age, sex and county of residence to 300 controls randomly selected from general practitioners’ registers. They were interviewed and their medical records were evaluated for variables broadly described as potential risk factors.

Results

In multiple logistic regression, the following factors were significant: parents born in a particular neighbouring county (Bosnia and Herzegovina) (OR = 3.90, 95% CI 2.01-7.58), the lowest level of education (OR = 3.44, 95% CI 1.39-8.50), poor household equipment (OR = 4.72, 95% CI 1.51-14.76), unemployment (OR = 2.69, 95% CI 1.18-6.16), contact with tuberculosis (OR = 2.19, 95% CI 1.27-3.77), former (OR = 2.27, 95% CI 1.19-4.33) and current smoking habits (OR = 2.35, 95% CI 1.27-4.36), diabetes (OR = 2.38, 95% CI 1.05-5.38), a malignant disease (OR = 5.79, 95% CI 1.49-22.42), being underweight in the previous year (OR = 13.57, 95% CI 1.21-152.38).

Conclusion

In our study, the identified risk groups for tuberculosis reflect a complex interaction between socioeconomic conditions, lifestyle and non-communicable diseases. Interventions focused on poverty will undoubtedly be useful, but not sufficient. Tuberculosis control would benefit from a combination of broad public health activities aimed at the prevention and control of risky lifestyles and non-communicable diseases, interventions outside the health sector, and efforts to constantly improve the Croatian national tuberculosis programme.

Review article: prescribing medications in patients with cirrhosis - a practical guide

BACKGROUND

Most drugs have not been well studied in cirrhosis; recommendations on safe use are based largely on experience and/or expert opinion, with dosing recommendations often based on pharmacokinetic (PK) changes.

AIM

To provide a practical approach to prescribing medications for cirrhotic patients.

METHODS

An indexed MEDLINE search was conducted using keywords cirrhosis, drug-induced liver injury, pharmacodynamics (PDs), PKs, drug disposition and adverse drug reactions. Unpublished information from the Food and Drug Administration and industry was also reviewed.

RESULTS

Most medications have not been adequately studied in cirrhosis, and specific prescribing information is often lacking. Lower doses are generally recommended based on PK changes, but data are limited in terms of correlating PD effects with the degree of liver impairment. Very few drugs have been documented to have their hepatotoxicity potential enhanced by cirrhosis; most of these involve antituberculosis or antiretroviral agents used for HIV or viral hepatitis. Paracetamol can be used safely when prescribed in relatively small doses (2-3 g or less/day) for short durations, and is recommended as first-line treatment of pain. In contrast, NSAIDs should be used cautiously (or not at all) in advanced cirrhosis. Proton pump inhibitors have been linked to an increased risk of spontaneous bacterial peritonitis (SBP) in cirrhosis and should be used with care.

CONCLUSIONS

Most drugs can be used safely in cirrhosis, including those that are potentially hepatotoxic, but lower doses or reduced dosing frequency is often recommended, due to altered PKs. Drugs that can precipitate renal failure, gastrointestinal bleeding, SBP and encephalopathy should be identified and avoided.

Use of rifabutin for the treatment of a latent tuberculosis infection in a patient after solid organ transplantation

Latent tuberculosis infection is an important problem for solid organ transplant recipients because of the frequency of its occurrence and its potential for reactivation. Because of the high mortality rate associated with active tuberculosis infections in transplant recipients, guidelines from the American Thoracic Society recommend treatment for latent tuberculosis in this population. However, the choice of treatments is often difficult because liver transplant recipients may be more sensitive to isoniazid hepatotoxicity, and rifampin has significant drug interactions with the calcineurin inhibitors used for immunosuppression. Two prior case reports described success with the use of rifabutin, a rifampin alternative, as part of a multidrug treatment regimen for active tuberculosis in posttransplant patients; however, there is no prior literature describing any experience with rifabutin for the treatment of latent tuberculosis in the posttransplant setting. We present a summary of tacrolimus drug levels and corresponding dose requirements for a single posttransplant patient during the administration of 3 different latent tuberculosis drug regimens: rifampin alone, rifampin plus ketoconazole, and rifabutin. In this patient's case, rifabutin allowed the maintenance of adequate tacrolimus levels, although an approximate 2.5-fold increase in the dose was required. Rifampin alone was associated with inadequate immunosuppressant levels, and rifampin plus ketoconazole was associated with a problematically prolonged QT interval and concerns about inadequate tuberculosis treatment.

Relevance of latent TB infection in areas of high TB prevalence

About one-third of the world population has latent TB infection (LTBI), the majority of which is distributed in 22 high-burden countries. Early diagnosis and treatment of active TB remains the top priority in resource-poor countries with high TB prevalence. Notwithstanding, because LTBI contributes significantly to the pool of active TB cases later on, its diagnosis and treatment is essential, especially in high-risk groups. The lack of a gold standard and several limitations of currently available tools, namely the tuberculin skin test and interferon-γ release assays, are major constraints for LTBI diagnosis. In areas with high TB prevalence, interferon-γ release assays have not shown superiority over the conventional tuberculin skin test and are yet to be systematically studied. Decisions regarding LTBI treatment with isoniazid preventive therapy should be made, keeping in mind the high prevalence of isoniazid resistance in these settings. Although efforts to shorten the LTBI treatment duration are encouraging, most trials have focused on adherence and toxicity. Future trials on short-duration regimens in high-burden settings should address drug efficacy issues as well. LTBI management, therefore, should comprise a targeted screening approach and individualization of LTBI treatment protocols. In addition, efforts should focus on airborne infection control measures in high-burden countries. A high prevalence of drug-resistant TB, the HIV epidemic, and delays in the diagnosis of active TB cases are other major concerns in areas of high TB prevalence. There is ample space for further research in these countries, whose outcomes may strengthen future national guidelines.

Chemoprophylaxis with isoniazid in liver transplant recipients

A patient receiving a liver graft needs to be treated with immunosuppressive drugs to avoid rejection. These kinds of drugs predispose the patient to the reactivation of latent infections such as tuberculosis (TB). Therefore, it is necessary to establish treatment regimens to prevent this. We retrospectively analyzed all consecutive patients undergoing liver transplantation (LT) at our center between January 1, 2000 and December 31, 2010. Latent tuberculosis infections (LTBIs) were diagnosed with positive tuberculin skin test results. After LT, infected patients were treated with isoniazid for 6 months; the treatment began soon after transplantation, and the patients were followed until the end of the study. During this period, 53 patients had LTBI data. All these patients were treated with isoniazid after LT. The median observation period after LT was 52 months (range = 12-129 months). No cases of TB reactivation were reported during follow-up. Only 4 patients presented alterations in liver enzymes related to this treatment, and they showed clear improvement after the treatment was stopped. None of these patients showed severe graft dysfunction. In conclusion, preventive isoniazid appears to be a safe drug for use in LTBI patients after LT. The treatment may be established just after LT without important graft dysfunction or severe consequences for the patient.

Comparison of the 2-step tuberculin skin test and the quantiFERON-TB Gold In-Tube Test for the screening of tuberculosis infection before liver transplantation

The ability of interferon-gamma release assays (IGRAs) to detect latent tuberculosis (TB) infection before liver transplantation (LT)is not well established. The aims of this study were (1) to compare the ability of the tuberculin skin test (TST) and the QuantiFERON-TB Gold In-Tube (QFT-IT) test (a whole-blood IGRA) to diagnose latent TB infections in patients awaiting LT and (2) to correlate the results with the severity of liver disease. We conducted a prospective, cross-sectional study of patients who were evaluated for LT between July 2008 and July 2010. The 95 patients who were included underwent the 2-step TST and the QFT-IT test. The mean Model for End-Stage Liver Disease (MELD) score was 13.8. Forty-four patients (46.3%) had positive TST results, 42 (44.2%) had positive QFT-IT results, and 2 (2.1%) had indeterminate QFT-IT results. Simultaneous TST and QFT-IT testing yielded a positivity rate of 55.8% [95% confidence interval (CI) = 45.3-65.9] with either test, and the 2-step TST yielded a positivity rate of 46.3% (95% CI = 36.1-56.8); the difference was 9.5% (P = 0.004). In an adjusted analysis, the rates for positive TST results were lower in patients with MELD scores > or = 18 [odds ratio (OR) = 0.2, 95% CI = 0.04-0.7], lower in Child-Pugh-Turcotte (CPT) class C patients versus CPT class A patients (OR = 0.1, 95% CI = 0.02-0.6), and higher in males (OR = 6.4, 95% CI = 1.9-22.0). In contrast, only being male (OR = 3.5, 95% CI = 1.1-11.0) was associated with positive QFT-IT results; no association was found with the MELD score (OR = 0.8, 95% CI = 0.2-2.8) or the CPT class (OR = 0.3; 0.05-1.4). In conclusion, the QFT-IT test is better than the TST for detecting latent TB infection in patients with more advanced liver disease. Our results support the regular use of the QFT-IT test for screening patients with end-stage liver disease for latent TB infection before LT.