Latent Mycobacterium tuberculosis Infection in Liver Transplant Recipients-Controversies in Current Diagnosis and Management

The prevalence of latent/chronic infection in liver transplant candidates in Taleghani Hospital of Tehran, Iran, from 2020 until 2021

Aim

The present study aimed to study the prevalence of various latent infections in pre-transplanted patients.

Background

Due to chronic immunosuppressive therapy, patients receiving organ transplants are at risk for reactivation of various infections. Due to the complications in the course of diagnosing and treating the post-transplant infection, screening transplant recipients and donors is vital.

Methods

This retrospective cohort study was performed between March 2020 and 2021. A total of 193 patients receiving a liver transplant in Taleghani Hospital, Tehran, Iran were enrolled.

Results

One-hundred and three (53.4%) patients were men, with an average age of 48.4 ± 13.3 years. Among viruses, 177 (91.7%) patients had a positive IgG titer for CMV. Anti-EBV IgG was positive in 169 (87.6%) patients. One-hundred and seventy-five (90.7%) patients had a positive IgG titer for the VZV. One-hundred and sixty-six (86.0%) cases had positive IgG anti-HSV antibodies. According to our findings, none of the patients were infected with HIV, but 9 (4.7%) cases and 141 (73.1%) had positive anti-HCV and anti-HAV IgG antibodies, respectively. HBV surface (HBs) antigen was also reported positive in 17 (8.8%) patients, while the HBs antibody was positive in 29 (15.0%) patients.

Conclusion

In our study, most of the patients had positive serology for latent viral infections such as CMV, EBV, VZV, and HSV, but the prevalence of latent tuberculosis and viral hepatitis was low among transplant candidates.

The potential liver donor with tuberculosis: A fresh look at international recommendations based on a survey of practice in Indian liver transplant centres

Background The western recommendations for the use of organs from liver donors with tuberculosis (TB) come from an environment where the burden of disease is low and cadaveric organ donation rates are high-in complete contrast to the Indian scenario, where these recommendations may be too restrictive. Methods A questionnaire relating to current practice on the use of organs from liver donors with TB was sent to all liver transplant centres in India. Results Responses were obtained from 94% of centres. Two-thirds accepted organs from deceased donors with TB in the elective setting, especially for recipients with a high MELD (Model for end-stage liver disease) score. The proportion rose by 1.5 times in the setting of acute liver failure. Two-thirds advised anti-TB treatment (ATT) for corresponding recipients, and the remaining advised isonicotinic acid hydrazide (INH) prophylaxis. Untreated living donors with TB were not accepted. Half the respondents accepted living donors after completion of ATT, and did not treat recipients postoperatively. The remainder accepted them after 8 weeks of treatment and advised INH prophylaxis or ATT for recipients. Conclusions That this practice has not impacted recipient outcomes suggests that the guidelines for management of liver donors and recipients may need to be altered for populations endemic for TB.

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.

Incidence and Risk Factors for Tuberculosis After Liver Transplantation in an Endemic Area: A Nationwide Population-Based Matched Cohort Study

Morbidity and mortality from tuberculosis (TB) are high in Taiwan. We conducted a nationwide population-based matched cohort study using data retrieved from the Taiwan's National Health Insurance Research Database to determine the impact of TB after liver transplantation (LT). During 2000-2011, we identified 3202 liver transplant recipients and selected subjects from the general population matched for age, sex, and comorbidities on the same index date of recognition of LT with a 1:10 ratio. The data were analyzed using Cox proportional hazards models. Compared to the matched cohort, liver transplant patients had a higher risk for TB (adjusted HR 2.25, 95% CI 1.65-3.05, p < 0.001), and those with TB showed higher mortality (HR 2.27, 95% CI 1.30-3.97, p = 0.004). Old age (HR 2.64, 95% CI 1.25-5.54, p = 0.011) and mammalian target of rapamycin inhibitors (mTORis) (HR 3.09, 95% CI 1.68-5.69, p < 0.001) were significant risk factors for TB in LT; mTORis were also associated with mortality after adjusting for confounders (HR 2.13, 95% CI 1.73-2.62, p < 0.001). Therefore, regular surveillance of TB and treatment of latent TB infection in high-risk patients after LT are important, especially in TB-endemic areas.

A guide to the management of tuberculosis in patients with chronic liver disease

Tuberculosis remains one of the 'Captains of the Men of Death' even today, particularly in the developing world. Its frequency is increased 14-fold in patients with chronic liver diseases (CLD) and liver cirrhosis, more so in those with decompensated disease, probably due to the cirrhosis-associated immune dysfunction syndrome, and case-fatality rates are high. The diagnosis of tuberculosis, particularly the interpretation of the Mantoux test, is also fraught with difficulties in CLD, especially after previous BCG vaccination. However, the greatest challenge in the patient with CLD or liver cirrhosis and tuberculosis is managing their therapy since the best first-line anti-tuberculosis drugs are hepatotoxic and baseline liver function is often deranged. Frequency of hepatotoxicity is increased in those with liver cirrhosis, chronic hepatitis B and chronic hepatitis C, possibly related to increased viral loads and may be decreased following antiviral therapy. If hepatotoxicity develops in those with liver cirrhosis, particularly decompensated cirrhosis, the risk of severe liver failure is markedly increased. Currently, there are no established guidelines for anti-tuberculosis therapy (ATT) in CLD and liver cirrhosis although the need for such guidelines is self-evident. It is proposed that ATT should include no more than 2 hepatotoxic drugs (RIF and INH) in patients with CLD or liver cirrhosis and stable liver function [Child-Turcotte-Pugh (CTP) ≤7], only a single hepatotoxic drug (RIF or INH) in those with advanced liver dysfunction (CTP 8-10) and no hepatotoxic drugs with very advanced liver dysfunction (CTP ≥11). A standard protocol should be followed for monitoring ATT-related hepatotoxicity and for stop rules and reintroduction rules in all these patients, on the lines proposed here. It is hoped that these proposals will introduce uniformity and result in streamlining the management of these difficult patients.