M. Codeluppi

Performance of tests for latent tuberculosis in different groups of immunocompromised patients.

BACKGROUND Immunocompromised persons infected with Mycobacterium tuberculosis (MTB) have increased risk of tuberculosis (TB) reactivation, but their management is hampered by the occurrence of false-negative results of the tuberculin skin test (TST). The T-cell interferon (IFN)-gamma release blood assays T-SPOT.TB (TS.TB) [Oxford Immunotec; Abingdon, UK] and QuantiFERON-TB Gold In-Tube (QFT-IT) [Cellestis Ltd; Carnegie, VIC, Australia] might improve diagnostic accuracy for latent TB infection (LTBI) in high-risk persons, although their performance in different groups of immunocompromised patients is largely unknown. METHODS AND RESULTS Over a 1-year period, we prospectively enrolled patients in three different immunosuppressed groups, as follows: 120 liver transplantation candidates (LTCs); 116 chronically HIV-infected persons; and 95 patients with hematologic malignancies (HMs). TST, TS.TB, and QFT-IT were simultaneously performed, their results were compared, and intertest agreement was evaluated. Overall, TST provided fewer positive results (10.9%) than TS.TB (18.4%; p < 0.001) and QFT-IT (15.1%; p = 0.033). Significantly fewer HIV-infected individuals had at least one positive test (9.5%) compared with LTCs (35.8%; p < 0.001) and patients with HMs (29.5%; p < 0.001). Diagnostic agreement between tests was moderate (kappa = 0.40 to 0.65) and decreased in the HIV-infected group when the results of the TS.TB were compared with either TST (kappa = 0.16) or QFT-IT (kappa = 0.19). Indeterminate blood test results due to low positive control values were significantly more frequent with QFT-IT (7.2%) than with TS.TB (0.6%; p < 0.001). CONCLUSIONS Blood tests identified significantly more patients as being infected with MTB than TST, although diagnostic agreement varied across groups. Based on these results, we recommend tailoring application of the new blood IFN-gamma assays for LTBI in different high-risk groups and advise caution in their current use in immunosuppressed patients.

Early Withdrawal of Calcineurin Inhibitors and Everolimus Monotherapy in de novo Liver Transplant Recipients Preserves Renal Function

We designed a randomized trial to assess whether the early withdrawal of cyclosporine (CsA) followed by the initiation of everolimus (Evr) monotherapy in de novo liver transplantation (LT) patients would result in superior renal function compared to a CsA‐based immunosuppression protocol. All patients were treated with CsA for the first 10 days and then randomized to receive Evr in combination with CsA up to day 30, then either continued on Evr monotherapy (Evr group) or maintained on CsA with/without mycophenolate mofetil (CsA group) in case of chronic kidney disease (CKD). Seventy‐eight patients were randomized (Evr n = 52; CsA n = 26). The 1‐year freedom from efficacy failure in Evr group was 75% versus 69.2% in CsA group, p = 0.36. There was no statistically significant difference in patient survival between the two groups. Mean modification of diet in renal disease (MDRD) was significantly better in the Evr group at 12 months (87.7 ± 26.1 vs. 59.9 ± 12.6 mL/min; p < 0.001). The incidence of CKD stage ≥3 (estimated glomerular filtration rate <60 mL/min) was higher in the CsA group at 1 year (52.2% vs. 15.4%, p = 0.005). The results indicate that early withdrawal of CsA followed by Evr monotherapy in de novo LT patients is associated with an improvement in renal function, with a similar incidence of rejection and major complications.

HHV-6A in Syncytial Giant-Cell Hepatitis

Syncytial giant-cell hepatitis is a rare but severe form of hepatitis that is associated with autoimmune diseases, drug reactions, and viral infections. We used serologic, molecular, and immunohistochemical methods to search for an infectious cause in a case of syncytial giant-cell hepatitis that developed in a liver-transplant recipient who had latent infection with variant B of human herpesvirus 6 (HHV-6B) and who had received the organ from a donor with variant A latent infection (HHV-6A). At the onset of the disease, the detection of HHV-6A (but not HHV-6B) DNA in plasma, in affected liver tissue, and in single micromanipulated syncytial giant cells with the use of two different polymerase-chain-reaction (PCR) assays indicated the presence of active HHV-6A infection in the patient. Expression of the HHV-6A-specific early protein, p41/38, but not of the HHV-6B-specific late protein, p101, was demonstrated only in liver syncytial giant cells in the absence of other infectious pathogens. The same markers of HHV-6A active infection were documented in serial follow-up samples from the patient and disappeared only at the resolution of syncytial giant-cell hepatitis. Neither HHV-6B DNA nor late protein was identified in the same follow-up samples from the patient. Thus, HHV-6A may be a cause of syncytial giant-cell hepatitis.

Outcome, incidence, and timing of infectious complications in small bowel and multivisceral organ transplantation patients.

Background. Infectious complications still represent a major cause of morbidity and mortality in patients with organ transplantation. In particular, small bowel or multivisceral transplantation is complicated to a greater extent than other grafts as a consequence of infectious complications including sepsis. Methods. This prospective study assessed outcome, incidence, and timing of infections in sequential patients undergoing small bowel or multivisceral transplantation (SB/MVTx) performed at a university transplant center between January 2001 and October 2003. Nineteen patients underwent transplantation during this period, 13 of whom (68%) undergoing isolated SB and 6 (32%) MV grafts with or without liver. Results. The median follow up was 524 days (interquartile range=252–730) with an overall 24.4 person/year of observation. Postoperative mortality rate was 0.1 death/person/year; all patients, except one who died intraoperatively, were alive 6 months postsurgery. There were 100 documented infections including: 59 bacterial (2.4 events/person/year), 35 viral (1.4 events/person/year) and 6 fungal (0.2 events/person/year). Patients developed at least one episode of bacterial infection in 94% of the cases, viral infection in 67%, and fungal infection in 28%. Conclusions. This cohort describes the very common and complex nature of infectious complications in this challenging group of transplantation patients. Larger cohorts are needed to specifically address infection risk factors and longer term outcomes.

Characterization of Specific Immune Responses to Different Aspergillus Antigens during the Course of Invasive Aspergillosis in Hematologic Patients

Several studies in mouse model of invasive aspergillosis (IA) and in healthy donors have shown that different Aspergillus antigens may stimulate different adaptive immune responses. However, the occurrence of Aspergillus-specific T cells have not yet been reported in patients with the disease. In patients with IA, we have investigated during the infection: a) whether and how specific T-cell responses to different Aspergillus antigens occur and develop; b) which antigens elicit the highest frequencies of protective immune responses and, c) whether such protective T cells could be expanded ex-vivo. Forty hematologic patients have been studied, including 22 patients with IA and 18 controls. Specific T cells producing IL-10, IFN-γ, IL-4 and IL-17A have been characterized through enzyme linked immunospot and cytokine secretion assays on 88 peripheral blood (PB) samples, by using the following recombinant antigens: GEL1p, CRF1p, PEP1p, SOD1p, α1–3glucan, β1–3glucan, galactomannan. Specific T cells were expanded through short term culture. Aspergillus-specific T cells producing non-protective interleukin-10 (IL-10) and protective interferon-gamma (IFN-γ) have been detected to all the antigens only in IA patients. Lower numbers of specific T cells producing IL-4 and IL-17A have also been shown. Protective T cells targeted predominantly Aspergillus cell wall antigens, tended to increase during the IA course and to be associated with a better clinical outcome. Aspergillus-specific T cells could be successfully generated from the PB of 8 out of 8 patients with IA and included cytotoxic subsets able to lyse Aspergillus hyphae. Aspergillus specific T-cell responses contribute to the clearance of the pathogen in immunosuppressed patients with IA and Aspergillus cell wall antigens are those mainly targeted by protective immune responses. Cytotoxic specific T cells can be expanded from immunosuppressed patients even during the infection by using the above mentioned antigens. These findings may be exploited for immunotherapeutic purposes in patients with IA.

Mucorales -specific T cells emerge in the course of invasive mucormycosis and may be used as a surrogate diagnostic marker in high-risk patients

Mucorales-specific T cells were investigated in 28 hematologic patients during the course of their treatment. Three developed proven invasive mucormycosis (IM), 17 had infections of known origin but other than IM, and 8 never had fever during the period of observation. Mucorales-specific T cells could be detected only in patients with IM, both at diagnosis and throughout the entire course of the IM, but neither before nor for long after resolution of the infection. Such T cells predominantly produced IL-4, IFN-γ, IL-10, and to a lesser extent IL-17 and belonged to either CD4(+) or CD8(+) subsets. The specific T cells that produced IFN-γ were able to directly induce damage to Mucorales hyphae. None of the 25 patients without IM had Mucorales-specific T cells. Specific T cells contribute to human immune responses against fungi of the order Mucorales and could be evaluated as a surrogate diagnostic marker of IM.

Prevalence of Human Herpesvirus-6 Chromosomal Integration (CIHHV-6) in Italian Solid Organ and Allogeneic Stem Cell Transplant Patients

The unique phenomenon of human herpesvirus‐6 (HHV‐6) chromosomal integration (CIHHV‐6) may account for clinical drawbacks in transplant setting, being misinterpreted as active infection and leading to unnecessary and potentially harmful treatments. We have investigated the prevalence of CIHHV‐6 in 205 consecutive solid organ (SO) and allogeneic stem cell transplant (alloSCT) Italian patients. Fifty‐two (38.5%) of 135 solid organ transplant (SOT) and 16 (22.8%) of 70 alloSCT patients resulted positive for plasma HHV‐6 DNA by real‐time polymerase chain reaction. Seven SOT and three alloSCT patients presented HHV‐6‐related diseases, requiring antivirals. Two further patients (0.9%) were identified, presenting high HHV‐6 loads. The quantification of HHV‐6 on hair follicles disclosed the integrated state, allowing the discontinuation of antivirals. Before starting specific treatments, CIHHV‐6 should be excluded in transplant patients with HHV‐6 viremia by the comparison of HHV‐6 loads on different fluids and tissues. Pretransplantation screening of donors and recipients may further prevent the misdiagnosis of CIHHV‐6.

Gastric involvement in AIDS associated cryptosporidiosis

Background—Cryptosporidiosis has been shown to be a common cause of diarrhoea in both immunocompetent and immunosuppressed individuals. There are very few data on the distribution of Cryptosporidium parvumalong the gastrointestinal tract. Aims—To evaluate the location ofCryptosporidium parasites in the digestive tract of patients with AIDS. Methods—Gastrointestinal localisation ofC parvum was studied in 71 patients with AIDS who underwent upper and/or lower endoscopy with biopsy for chronic diarrhoeal illness and/or other gastrointestinal disorders of unexplained origin. Results—Twenty four individuals (33.8%) were positive for C parvum, of which 16 (88.9%) had parasites in the gastric epithelium. Most patients with gastric localisation of C parvum did not show specific symptoms indicating the presence of this parasite in the stomach. Conclusions—Gastric involvement in AIDS related cryptosporidiosis is more frequent than expected, but no clear correlation between gastric location and related clinical and pathological features was observed.

Diagnosis of invasive aspergillosis by tracking Aspergillus-specific T cells in hematologic patients with pulmonary infiltrates.

Invasive aspergillosis (IA) is a leading cause of infection-related mortality in hematologic patients, with death rate ranging from 50 to 90%.1 The reason for this extremely poor outcome is because of the difficulties in a timely and undoubted diagnosis, which still relies on a very high degree of suspicion. The current diagnostic tools are limited by invasiveness, slowness, relative insensitiveness, lack of standardization and unpredictable kinetics.2 The most widely studied test, Galctomannan antigenemia (GM), has been demonstrated to be highly variable in performance, with sensitivity ranging between 29 and 100%, and is affected by several factors related either to the fungus or to the host.2 Furthermore, the detection of Aspergillus DNA through polymerase chain reaction (PCR) is still hampered by the difficulties in understanding the fungal DNA release and kinetics other than by technical barriers.2 For all these reasons, establishing an early diagnosis of IA remains a challenge.1, 2

Fusarium verticillioides fungemia in a liver transplantation patient: successful treatment with voriconazole ☆

Fusarium is an opportunistic fungal pathogen which is emerging as a significant cause of morbidity and mortality in immunocompromised hosts. We present a rare case of F. verticillioides fungemia that occurred in a patient who underwent a second orthotopic liver transplantation for chronic rejection and completely responded to treatment with voriconazole.