Antigen-specific Immunoprofiling in a Patient With Eisenmenger Syndrome, Treated Tuberculosis, and Atypical Non-tubercular Mycobacteria (NTM) Isolation Prior to Bilateral Lung Transplant

Abstract Non-tubercular mycobacteria (NTM) present a serious challenge in managing lung transplant candidates and recipients. Pretransplant NTM isolation has been associated with post-transplant NTM infection and significantly increased mortality risk. Strategies for managing pre-transplant NTM isolation vary widely in clinical practice. We present a 35-year-old lung transplant candidate from a tuberculosis-endemic country with severe pulmonary hypertension and Eisenmenger Syndrome due to unrepaired atrial septal defect, who underwent bilateral lung transplantation. Two years prior to transplant, she was successfully treated for pulmonary tuberculosis with six months of an unknown regimen in her home country. After moving to the U.S., she received M. tuberculosis (MTB) clearance from her state tuberculosis board, with three negative sputum samples six months prior to transplant. During her transplant evaluation, multi-drug-resistant M. fortuitum complex was isolated from one mycobacterial sputum culture. There was no clinical or radiographic evidence of active lung infection, and no targeted therapies were added. Standard peri-transplant antibiotics (vancomycin, cefepime, and caspofungin) were given. The patient received basilixamab for induction immunosuppression, and tacrolimus, mycophenolate mofetil, and prednisone for maintenance immunosuppression. Explant pathology showed necrotizing granuloma in the right upper lobe with acid-fast bacilli (AFB). The differential diagnosis included non-viable MTB, viable MTB despite prior clearance, or M. fortuitum. Three bronchoscopy washings were obtained in the first week post-transplant and returned negative for MTB by PCR, AFB stain, and culture. In collaboration with the Mycobacteriology laboratory, broad-range PCR testing was performed on the formalin-fixed paraffin-embedded samples from the explanted right lung, which was positive for MTB complex DNA. In total, the patient completed six sputum samples within the year pre-transplant and six respiratory samples within a month post-transplant, all of which returned negative for MTB by PCR, AFB stain, and culture. Blood flow cytometric (FC) immunoprofiling with mycobacterial antigens and controls was conducted (Escalante et al. 2015). The patient's FC antigen-specific activated T-cell profiling was consistent with a reduced risk of latent TB infection (FC CD4+ CD25+CD134+ T-cells (RD1-peptides-nil) = 0.19%). T-cell reactivity to MTB300 and PPD antigens suggested prior MTB, NTM, and/or BCG vaccination exposures. She progressed well without any preventive therapy for LTBI. FC immunoprofiling one year after transplantation showed similar results. She continues to have good pulmonary function and quality of life in her second-year post-transplant without evidence of NTM or MTB infection. Escalante P, et al. Combinatorial Immunoprofiling in Latent Tuberculosis Infection. Am J Respir Crit Care Med. 2015;192(5):605-17. PMCID: PMC4595688.