Katia Boggian

Cytomegalovirus Serology and Replication Remain Associated With Solid Organ Graft Rejection and Graft Loss in the Era of Prophylactic Treatment

Background Cytomegalovirus (CMV) replication has been associated with more risk for solid organ graft rejection. We wondered whether this association still holds when patients at risk receive prophylactic treatment for CMV. Methods We correlated CMV infection, biopsy-proven graft rejection, and graft loss in 1,414 patients receiving heart (n=97), kidney (n=917), liver (n=237), or lung (n=163) allografts reported to the Swiss Transplant Cohort Study. Results Recipients of all organs were at an increased risk for biopsy-proven graft rejection within 4 weeks after detection of CMV replication (hazard ratio [HR] after heart transplantation, 2.60; 95% confidence interval [CI], 1.34–4.94, P<0.001; HR after kidney transplantation, 1.58; 95% CI, 1.16–2.16, P=0.02; HR after liver transplantation, 2.21; 95% CI, 1.53–3.17, P<0.001; HR after lung transplantation, 5.83; 95% CI, 3.12–10.9, P<0.001. Relative hazards were comparable in patients with asymptomatic or symptomatic CMV infection. The CMV donor or recipient serological constellation also predicted the incidence of graft rejection after liver and lung transplantation, with significantly higher rates of rejection in transplants in which donor or recipient were CMV seropositive (non-D−/R−), compared with D− transplant or R− transplant (HR, 3.05; P=0.002 for liver and HR, 2.42; P=0.01 for lung transplants). Finally, graft loss occurred more frequently in non-D− or non-R− compared with D− transplant or R− transplant in all organs analyzed. Valganciclovir prophylactic treatment seemed to delay, but not prevent, graft loss in non-D− or non-R− transplants. Conclusion Cytomegalovirus replication and donor or recipient seroconstellation remains associated with graft rejection and graft loss in the era of prophylactic CMV treatment.

IL1B and DEFB1 Polymorphisms Increase Susceptibility to Invasive Mold Infection After Solid Organ Transplantation

BACKGROUND Single-nucleotide polymorphisms (SNPs) in immune genes have been associated with susceptibility to invasive mold infection (IMI) among hematopoietic stem cell but not solid-organ transplant (SOT) recipients. METHODS Twenty-four SNPs from systematically selected genes were genotyped among 1101 SOT recipients (715 kidney transplant recipients, 190 liver transplant recipients, 102 lung transplant recipients, 79 heart transplant recipients, and 15 recipients of other transplants) from the Swiss Transplant Cohort Study. Association between SNPs and the end point were assessed by log-rank test and Cox regression models. Cytokine production upon Aspergillus stimulation was measured by enzyme-linked immunosorbent assay in peripheral blood mononuclear cells (PBMCs) from healthy volunteers and correlated with relevant genotypes. RESULTS Mold colonization (n = 45) and proven/probable IMI (n = 26) were associated with polymorphisms in the genes encoding interleukin 1β (IL1B; rs16944; recessive mode, P = .001 for colonization and P = .00005 for IMI, by the log-rank test), interleukin 1 receptor antagonist (IL1RN; rs419598; P = .01 and P = .02, respectively), and β-defensin 1 (DEFB1; rs1800972; P = .001 and P = .0002, respectively). The associations with IL1B and DEFB1 remained significant in a multivariate regression model (P = .002 for IL1B rs16944; P = .01 for DEFB1 rs1800972). The presence of 2 copies of the rare allele of rs16944 or rs419598 was associated with reduced Aspergillus-induced interleukin 1β and tumor necrosis factor α secretion by PBMCs. CONCLUSIONS Functional polymorphisms in IL1B and DEFB1 influence susceptibility to mold infection in SOT recipients. This observation may contribute to individual risk stratification.

An uncommon reason for dyspnoea: phrenic paresis secondary to alveolar echinococcosis

To the Editors: We describe the presentation of an Echinococcus multilocularis (EM) infection (alveolar echinococcosis (AE)) with progressive massive orthopnoea and progressive dyspnoea on exertion due to infiltration of the diaphragm and phrenic nerves. Diagnosis was proved using a combination of computed tomography (CT), lung function in the supine and sitting position, sniff test during radioscopy and AE serology. Because of diffuse infiltration of the retroperitoneal and mediastinal space a surgical intervention was inapplicable. Thus, medical treatment was initiated using albendazole. Noninvasive ventilation (NIV) resolved orthopnoea and the patient was discharged. AE occurs in the northern hemisphere but in Switzerland it is classified as a rare disease. To our knowledge this is the first described case of this rare infection with a consecutive bilateral paresis of the diaphragm. But despite its unique entity, this case report demonstrates that clinical findings and routine diagnostic methods may lead to the correct diagnosis. Progressive phrenic paresis is a rare cause of orthopnoea and dyspnoea on exertion [1]. Relevant paresis is often overseen and diagnosed late in the course of the disease. The main reasons for bilateral phrenic paresis are traumatic, inflammatory, neuropathic, idiopathic or tumour related [1]. We present a case of a non-malignant compression caused by AE leading to bilateral phrenic paresis. A 60-yr-old farmer’s wife presented to a district hospital with progressive dyspnoea on exertion for 2 yrs. A cardiologic consultation at that time including echocardiography and exercise testing was unremarkable. Within the last year, the patient complained about weight …

KIR-associated protection from CMV replication requires pre-existing immunity: a prospective study in solid organ transplant recipients.

Previous studies have associated activating Killer cell Immunoglobulin-like Receptor (KIR) genes with protection from cytomegalovirus (CMV) replication after organ transplantation. Whether KIR-associated protection is operating in the context of primary infection, re-activation, or both, remains unknown. Here we correlated KIR genotype and CMV serostatus at the time of transplantation with rates of CMV viremia in 517 heart (n=57), kidney (n=223), liver (n=165) or lung (n=72) allograft recipients reported to the Swiss Transplant Cohort Study. Across the entire cohort we found B haplotypes—which in contrast to A haplotypes may contain multiple activating KIR genes—to be protective in the most immunosuppressed patients (receiving anti-thymocyte globulin induction and intensive maintenance immunosuppression) (hazard ratio after adjustment for covariates 0.46, 95% confidence interval 0.29–0.75, P=0.002). Notably, a significant protection was detected only in recipients who were CMV-seropositive at the time of transplantation (HR 0.45, 95% CI 0.26–0.77, P=0.004), but not in CMV seronegative recipients (HR 0.59, 95% CI 0.22–1.53, P=0.28). These data indicate a prominent role for KIR—and presumably natural killer (NK) cells—in the control of CMV replication in CMV seropositive organ transplant recipients treated with intense immunosuppression.

Delayed diagnosis of atypical mycobacterial skin and soft tissue infections in non-immunocompromized hosts.

Relapsing or persisting skin and soft tissue infections after injury with biological materials should prompt consideration of atypical mycobacteria, even in non-immunocompromized hosts. We report 3 cases where diagnosis was delayed for 3–10 months. Insidiously, Mycobacterium marinum infection can occur without any contact to fish tank or swimming pool.

A traveller presenting with severe melioidosis complicated by a pericardial effusion: a case report

BackgroundBurkholderia pseudomallei, the etiologic agent of melioidosis, is endemic to tropic regions, mainly in Southeast Asia and northern Australia. Melioidosis occurs only sporadically in travellers returning from disease-endemic areas. Severe clinical disease is seen mostly in patients with alteration of immune status. In particular, pericardial effusion occurs in 1-3% of patients with melioidosis, confined to endemic regions. To our best knowledge, this is the first reported case of melioidosis in a traveller complicated by a hemodynamically significant pericardial effusion without predisposing disease.Case presentationA 44-year-old Caucasian man developed pneumonia, with bilateral pleural effusions and complicated by a hemodynamically significant pericardial effusion, soon after his return from Thailand to Switzerland. Cultures from different specimens including blood cultures turned out negative. Diagnosis was only accomplished by isolation of Burkholderia pseudomallei from the pericardial aspirate, thus finally enabling the adequate antibiotic treatment.ConclusionsMelioidosis is a great mimicker and physicians in non-endemic countries should be aware of its varied manifestations. In particular, melioidosis should be considered in differential diagnosis of pericardial effusion in travellers , even without risk factors predisposing to severe disease.

Preventive Strategies Against Cytomegalovirus and Incidence of α‐Herpesvirus Infections in Solid Organ Transplant Recipients: A Nationwide Cohort Study

We assessed the impact of antiviral preventive strategies on the incidence of herpes simplex virus (HSV) and varicella‐zoster virus (VZV) infections in a nationwide cohort of transplant recipients. Risk factors for the development of HSV or VZV infection were assessed by Cox proportional hazards regression. We included 2781 patients (56% kidney, 20% liver, 10% lung, 7.3% heart, 6.7% others). Overall, 1264 (45%) patients received antiviral prophylaxis (ganciclovir or valganciclovir, n = 1145; acyclovir or valacyclovir, n = 138). Incidence of HSV and VZV infections was 28.9 and 12.1 cases, respectively, per 1000 person‐years. Incidence of HSV and VZV infections at 1 year after transplant was 4.6% (95% confidence interval [CI] 3.5–5.8) in patients receiving antiviral prophylaxis versus 12.3% (95% CI 10.7–14) in patients without prophylaxis; this was observed particularly for HSV infections (3% [95% CI 2.2–4] versus 9.8% [95% CI 8.4–11.4], respectively). A lower rate of HSV and VZV infections was also seen in donor or recipient cytomegalovirus‐positive patients receiving ganciclovir or valganciclovir prophylaxis compared with a preemptive approach. Female sex (hazard ratio [HR] 1.663, p = 0.001), HSV seropositivity (HR 5.198, p < 0.001), previous episodes of rejection (HR 1.95, p = 0.004), and use of a preemptive approach (HR 2.841, p = 0.017) were significantly associated with a higher risk of HSV infection. Although HSV and VZV infections were common after transplantation, antiviral prophylaxis significantly reduced symptomatic HSV infections.

Clostridium difficile Infection is Associated with Graft Loss in Solid Organ Transplant Recipients.

Clostridium difficile infection (CDI) is a leading cause of infectious diarrhea in solid organ transplant recipients (SOT). We aimed to assess incidence, risk factors, and outcome of CDI within the Swiss Transplant Cohort Study (STCS). We performed a case‐control study of SOT recipients in the STCS diagnosed with CDI between May 2008 and August 2013. We matched 2 control subjects per case by age at transplantation, sex, and transplanted organ. A multivariable analysis was performed using conditional logistic regression to identify risk factors and evaluate outcome of CDI. Two thousand one hundred fifty‐eight SOT recipients, comprising 87 cases of CDI and 174 matched controls were included. The overall CDI rate per 10 000 patient days was 0.47 (95% confidence interval ([CI] 0.38‐0.58), with the highest rate in lung (1.48, 95% CI 0.93‐2.24). In multivariable analysis, proven infections (hazard ratio [HR] 2.82, 95% CI 1.29‐6.19) and antibiotic treatments (HR 4.51, 95% CI 2.03‐10.0) during the preceding 3 months were independently associated with the development of CDI. Despite mild clinical presentations, recipients acquiring CDI posttransplantation had an increased risk of graft loss (HR 2.24, 95% CI 1.15‐4.37; P = .02). These findings may help to improve the management of SOT recipients.

Relevance of cohort studies for the study of transplant infectious diseases.

Purpose of reviewThe debate on the merits of observational studies as compared with randomized trials is ongoing. We will briefly touch on this subject, and demonstrate the role of cohort studies for the description of infectious disease patterns after transplantation. The potential benefits of cohort studies for the clinical management of patients outside of the expected gain in epidemiological knowledge are reviewed. The newly established Swiss Transplantation Cohort Study and in particular the part focusing on infectious diseases will serve as an illustration. Recent findingsA neglected area of research is the indirect value of large, multicenter cohort studies. These benefits can range from a deepened collaboration to the development of common definitions and guidelines. Unfortunately, very few data exist on the role of such indirect effects on improving quality of patient management. SummaryThis review postulates an important role for cohort studies, which should not be viewed as inferior but complementary to established research tools, in particular randomized trials. Randomized trials remain the least bias-prone method to establish knowledge regarding the significance of diagnostic or therapeutic measures. Cohort studies have the power to reflect a real-world situation and to pinpoint areas of knowledge as well as of uncertainty. Prerequisite is a prospective design requiring a set of inclusive data coupled with the meticulous insistence on data retrieval and quality.

LILRB1 polymorphisms influence posttransplant HCMV susceptibility and ligand interactions

UL18 is a human CMV (HCMV) MHC class I (MHCI) homolog that efficiently inhibits leukocyte immunoglobulin-like receptor subfamily B member 1 (LILRB1)+ NK cells. We found an association of LILRB1 polymorphisms in the regulatory regions and ligand-binding domains with control of HCMV in transplant patients. Naturally occurring LILRB1 variants expressed in model NK cells showed functional differences with UL18 and classical MHCI, but not with HLA-G. The altered functional recognition was recapitulated in binding assays with the binding domains of LILRB1. Each of 4 nonsynonymous substitutions in the first 2 LILRB1 immunoglobulin domains contributed to binding with UL18, classical MHCI, and HLA-G. One of the polymorphisms controlled addition of an N-linked glycan, and that mutation of the glycosylation site altered binding to all ligands tested, including enhancing binding to UL18. Together, these findings indicate that specific LILRB1 alleles that allow for superior immune evasion by HCMV are restricted by mutations that limit LILRB1 expression selectively on NK cells. The polymorphisms also maintained an appropriate interaction with HLA-G, fitting with a principal role of LILRB1 in fetal tolerance.