Mycobacterium tuberculosis infection following renal transplantation in Taiwan.

BACKGROUND

Tuberculosis (TB) is one of the major causes of morbidity and mortality worldwide. Post-transplant (post-Tx) TB is a problem in successful long-term outcome of renal transplantation recipients. It is a life-threatening opportunistic infection that is frequently encountered, but the diagnosis is often delayed. With the emergence of newer potent immunosuppressive regimens and an increased incidence of TB in the general population, post-Tx TB among transplant recipients can be anticipated. Our objective was to describe the pattern and risk factors of TB infection, and the prognosis in an endemic area.

METHODS

This study was a retrospective review of the records of 756 renal transplant recipients in our hospital during the period from January 1983 to December 2003. The demographic data, transplant characteristics, clinical manifestations, diagnostic criteria, treatment protocol, and long-term outcome of this cohort of patients were analyzed.

RESULTS

Thirty-one episodes developed into TB in 29 patients (3.8%) with a mean age of 45.5 (range: 24.2-66.2) years and a mean post-Tx period of 57.9 (range: 1.2-145.2) months. The forms of the diseases were pulmonary in 22/31 (71%), disseminated in 1/31 (3%), miliary in 1/31 (3%), and extrapulmonary in 7/31 (23%). All patients initially received 4-drug combination therapy, and then dosage was adjusted based on clinical condition. Because of drug interaction, a mean 2-fold increase in the dose of calcineurium inhibitor, but no change in steroid, was required. Twenty-two patients (71%) had an elevated creatinine (Cr) level, and 6 (19%) patients did not recover owing to tissue-proof acute rejection (3 cases) and chronic allograft nephropathy (3 cases), respectively, after treatment. The serum Cr level on diagnosis of TB was 1.9+/-0.7 mg/dL; it then deteriorated to 2.4+/-1.5 mg/dL (P=0.134). Hepatotoxicity developed in 11 patients (35.5%) during treatment. Twenty-five patients were successfully treated, 2 patients remain under treatment, and 4 (12.9%) died. Based on univariate analysis, we found the post-Tx TB risk factors were diabetes and more than 3 episodes of rejection, modalities for acute rejection (high-dose steroid and anti-lymphocyte globulin), and maintenance therapy with steroid.

CONCLUSION

Post-Tx TB is a serious problem worldwide, and a high index of suspicion is warranted to ensure early diagnosis and prompt initiation of treatment for TB among renal transplant patients. The use of optimal immunosuppressive agents to minimize acute rejection seems reasonable to prevent TB infection in endemic areas like Taiwan. More than 9 months of treatment may be necessary to prevent recurrence.