Introduction: TB is a diagnostic and therapeutic challenge in K/ KP Tx. Pharmacokinetic interaction between rifampin (RFP) and mTOR /calcineurin  inhibitors (CNI) led to use of alternative regimens for TB treatment in this group of patients. Results obtained in TB treatment with RFP-free regimens in K/KP TX patients are presented. 

Methods: Retrospective review of confirmed TB cases in K /KP Tx patients. (Jan 2006-Jul 2019), defined by M.tuberculosis positive culture or PCR; o elevated adenosine deaminase (ADA) and/or characteristic histopathology findings with clinical evolution consistent with  TB. Cases defined by response to empiric treatment were excluded. 

Results: 57 TB cases (50 in 2297adults with KTx (2.2%) /7 in 364 KPTx (1.92%),  Two were postmortem diagnosis (excluded from analysis). “De novo” Treatment with RFP-free regimens: 30 patients (pts) (25 KTx, 5 KPTx). Mean age: 49.24 (∓11.50) years. Induction immunosuppression (IS): 22 pts. Maintenance IS: tacrolimus-mycofenolate (MF)-steroids (E) in 13 (43%), sirolimus-MF-E in  6 (20%), Other IS regimens: 11(36%). Belatacept in 4 patients. (13%). 22 pts without rejections (R) prior to TB, (8 pts with R: Rejection rate prior to TB 0.15 episodes/year/patient. TB onset after TX: Median 28 (range 2.4- 242.3) months. Late onset (> 6 months): 24 cases (80%). TB: pulmonary = 13 (43%); Diseminated = 7 (23%) Extrapulmonary = 10 (33%). All patients were treated with  isoniazid (IHN), ethambutol (EMB), levofloxacin (L), 12 patientes also received pyrazinamide (PZN) during the first 2 months. 27 (90%) patients completed treatment with  IHN-EMB-L x 6 months (1), 9 months (3) o 12 months (23). In these patients, graf function had no change (mean initial creatinine 1.5 mg%, mean creatinine at end of treatment 1.5 mg%, p=NS). One patient returned to dialysis at 4th month of treatment, and completed with IHN-RFP. 2 (7%) patients died while on treatment. Among the 28 patients who completed treatment, median (range) follow-up was 32 (8-150) months. No TB relapses were observed. 

Conclusions: Rifampin-free TB treatment in K/KP Tx was safe and effective. Mortality was less than observed in series with a larger number of patients treated with rifampin. The use of RFP-free regimens also avoided cumbersome pharmacokinetic interactions with CNI/mTOR, with excellent results in grafts function.