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The number of cases of tuberculosis (TB) in the United States declined by 45% between 1993 and 2006. This decline occurred disproportionately among United States–born persons (66%) compared to foreign-born individuals, among whom the number of cases actually increased by 5%. In solid-organ transplant recipients, the incidence of Mycobacterium tuberculosis (MTB) infection worldwide ranges between 0.35% and 15%, depending on the level of endemicity. This rate can be 36to 74-fold greater than that in the general population. The majority of MTB cases after transplantation represent reactivation of latent tuberculosis infection (LTBI), although acquisition of primary TB infection posttransplant and transmission of MTB via the transplanted organ are infrequent possibilities. Active TB in the posttransplantation setting can pose a number of challenges: atypical presentation leading to a delay in diagnosis, therapy associated with drug interactions and toxicities, graft rejection, and formidable morbidity and mortality. This is of particular concern in both patients with end-stage liver disease awaiting liver transplantation and liver transplant recipients, given the hepatotoxicity of several anti-TB medications and their associated drug interactions with immunosuppressants. In this issue of Liver Transplantation, Holty et al. present a systematic review and meta-analysis of TB in liver transplant recipients. They included cases of active MTB infection following liver transplantation as well as transplant candidates or recipients who received 6 months of therapy for LTBI prior to transplantation. The prevalence of active TB in liver transplant recipients was 1.3%. Extrapulmonary infection was seen in 67%, multiorgan involvement was seen in 27%, and 31% died. Tuberculin skin test (TST) results were as follows: a) Among 38 cases of posttransplant active TB with known pretransplant TST status, 37% were TST-positive, 53% were negative, and 11% were anergic; among 17 of these patients who had a posttransplant TST, only 35% were positive. b) In 3 studies with 2972 patients who underwent liver transplantation, 31% of the patients had a pretransplant TST, and 13% of these were positive. None of the TST-positive patients who received isoniazid therapy for at least 6 months developed active TB, whereas 7 TST-positive patients developed active disease without such therapy (mean follow-up, 54 months). Short-term mortality in patients with active posttransplant TB was 31%, with 65% of deaths directly attributed to MTB infection. Because reactivation of LTBI represents the majority of posttransplant cases of active TB, it is prudent to screen and identify such patients before transplantation for consideration of appropriate therapy for LTBI. Until recently, TST was the only test available for LTBI diagnosis. As noted previously, TST was notoriously insensitive: 64% of patients with posttransplant active TB were either TST-negative or anergic prior to transplantation, and 65% of patients had a negative posttransplant TST in the setting of active TB. TST has

JC virus (JCV), BK virus (BKV) and simian virus 40 (SV40) are deoxyribonucleic acid (DNA) viruses, members of the family Polyomaviridae. These viruses establish persistent infections, and reactivate from latency in their host under immunosuppression. During the last few years there has been recognition of the morbidity related to polyomaviruses, particularly BKV in kidney transplant recipients. More importantly, recent studies indicate the potential implication of JCV, BKV, and SV40 in renal dysfunction among nonrenal organ transplant patients. Polyomaviruses are tumor-inducing viruses and animal models have provided evidence of the oncogenicity of these pathogens. Although data are not conclusive, molecular studies suggest an association of BKV and SV40 with malignancies among solid organ transplant patients. As new and potent immunosuppressive agents are introduced into clinical practice, it is believed that the incidence of polyomavirus-related diseases in organ transplantation might increase. This review evaluates the biologic and epidemiologic features of these 3 viruses, the data regarding their infections in nonkidney organ transplant patients and describes future directions in the management and research of these opportunistic pathogens. Liver Transpl 12:1457-1463, 2006. © 2006 AASLD.

1. Recurrent and de novo malignancies are the second leading causes of late death in liver transplant recipients, following age-related cardiovascular complications. 2. The increased incidence of de novo malignancies in liver transplant recipients compared with the general population reflects their demographic makeup, known preexistent risk factors for cancer, greater rate of chronic viral infection, and actions of exogenous immunosuppression. 3. The greatest incidence of de novo malignancies is seen in cancers associated with chronic viral infections, such as Epstein-Barr virus-associated posttransplant lymphoproliferative disease, and skin cancers, including squamous cell carcinoma and Kaposi's sarcoma. 4. Although a greater incidence of such malignancies as oropharyngeal malignancy and colorectal cancer was noted, there did not appear to be an increased risk for liver transplant recipients matched for age, sex, and length of follow-up using modified life-table technique and Surveillance Epidemiology End Result data with a similar at-risk group. However, they may present with more advanced stages of disease. 5. An increased incidence of de novo cancers in chronically immunocompromised liver transplant recipients demands careful long-term screening protocols to help facilitate diagnosis at an earlier stage of disease.

Background In 2004, four recipients of kidneys, a liver, and an arterial segment from a common organ donor died of encephalitis of an unknown cause. Methods We reviewed the medical records of the organ donor and the recipients. Blood, cerebrospinal fluid, and tissues from the recipients were tested with a variety of assays and pathological stains for numerous causes of encephalitis. Samples from the recipients were also inoculated into mice. Results The organ donor had been healthy before having a subarachnoid hemorrhage that led to his death. Encephalitis developed in all four recipients within 30 days after transplantation and was accompanied by rapid neurologic deterioration characterized by agitated delirium, seizures, respiratory failure, and coma. They died an average of 13 days after the onset of neurologic symptoms. Mice inoculated with samples from the affected patients became ill seven to eight days later, and electron microscopy of central nervous system (CNS) tissue demonstrated rhabdovirus particles. Rabies-specific immunohistochemical and direct fluorescence antibody staining demonstrated rabies virus in multiple tissues from all recipients. Cytoplasmic inclusions consistent with Negri bodies were seen in CNS tissue from all recipients. Antibodies against rabies virus were present in three of the four recipients and the donor. The donor had told others of being bitten by a bat. Conclusions This report documenting the transmission of rabies virus from an organ donor to multiple recipients underscores the challenges of preventing and detecting transmission of unusual pathogens through transplantation. (Liver Transpl 2005;11:1295–1297.)