Fever, Human Herpesvirus-6 (HHV-6) Seroconversion, and Acute Rejection Episodes as a Function of the Initial Seroprevalence for HHV-6 in Renal Transplant Recipients

Herpes Virus Infection in Lung Transplantation: Diagnosis, Treatment and Prevention Strategies

Lung transplantation is an ultimate treatment option for some end-stage lung diseases; due to the intense immunosuppression needed to reduce the risk of developing acute and chronic allograft failure, infectious complications are highly incident. Viral infections represent nearly 30% of all infectious complications, with herpes viruses playing an important role in the development of acute and chronic diseases. Among them, cytomegalovirus (CMV) is a major cause of morbidity and mortality, being associated with an increased risk of chronic lung allograft failure. Epstein-Barr virus (EBV) is associated with transformation of infected B cells with the development of post-transplantation lymphoproliferative disorders (PTLDs). Similarly, herpes simplex virus (HSV), varicella zoster virus and human herpesviruses 6 and 7 can also be responsible for acute manifestations in lung transplant patients. During these last years, new, highly sensitive and specific diagnostic tests have been developed, and preventive and prophylactic strategies have been studied aiming to reduce and prevent the incidence of these viral infections. In this narrative review, we explore epidemiology, diagnosis and treatment options for more frequent herpes virus infections in lung transplant patients.

Virus-Associated Nephropathies: A Narrative Review

While most viral infections cause mild symptoms and a spontaneous favorable resolution, some can lead to severe or protracted manifestations, specifically in immunocompromised hosts. Kidney injuries related to viral infections may have multiple causes related to the infection severity, drug toxicity or direct or indirect viral-associated nephropathy. We review here the described virus-associated nephropathies in order to guide diagnosis strategies and treatments in cases of acute kidney injury (AKI) occurring concomitantly with a viral infection. The occurrence of virus-associated nephropathy depends on multiple factors: the local epidemiology of the virus, its ability to infect renal cells and the patient's underlying immune response, which varies with the state of immunosuppression. Clear comprehension of pathophysiological mechanisms associated with a summary of described direct and indirect injuries should help physicians to diagnose and treat viral associated nephropathies.

Human herpes simplex virus-6 (HHV-6) detection and seroprevalence among Qatari nationals and immigrants residing in Qatar

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The prevalence of anti-human herpes virus-6 immunoglobulin G (IgG) was 71.7% among healthy donors in Qatar.

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One-quarter (24.3%) of healthy donors in Qatar had detectable viraemia.

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No strong association was found between viraemia and IgG positivity.

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A significant association was found between viraemia and the nationality of healthy donors.

Background

Human herpes simplex virus-6 (HHV-6) is the causative agent of exanthema subitum. Transmission mainly occurs through salivary secretions, yet blood transfusions and organ transplantations have also been reported as routes of transmission. Studies of seroprevalence of HHV-6 in the Middle East and North Africa (MENA) region and other parts of Asia are scarce. As such, this study aimed to estimate the seroprevalence of HHV-6 among healthy blood donors in Qatar.

Methods

In total, 620 healthy blood donors from different nationalities residing in Qatar, mainly from the MENA region and Southeast Asia, were tested using a commercial anti-HHV-6 immunoglobulin G (IgG) enzyme-linked immunosorbent assay kit. In addition, HHV-6 DNA from randomly selected samples was tested and quantified using quantitative reverse transcriptase polymerase chain reaction.

Results

Anti-HHV-6 IgG was detected in 71.7% (445/620) [95% confidence interval (CI) 68.2–75.3%] of the tested samples, while 24.3% (61/251) (95% CI 20.0–29.6%) had detectable HHV-6 viraemia. Only 22.5% of individuals with positive IgG status had detectable HHV-6 DNA in their blood, indicating a weak association between viraemia and IgG positivity (P=0.08). Furthermore, no significant difference was associated between HHV-6 viraemia and demographic characteristics, except for nationality.

Conclusion

The seroprevalence of HHV-6 in Qatar was found to be similar to rates reported in other parts of the world.

Detection of human herpes virus type-6 in patients undergoing hemodialysis

Aim: To investigate the epidemiology of human herpes virus type-6 (HHV-6) among hemodialysis (HD) patients. Materials & methods: DNA was extracted from plasma samples of 149 patients undergoing HD with no history of organ transplantation from 2011 to 2013. Presence of HHV-6 was investigated by using real-time PCR. Results: Diabetes (36.2%) and hypertension (28.8%) were two major factors for HD. The HHV-6 DNA was identified in eight patients (5.37%). Conclusion: This study is one of the few reports of HHV-6 infection among HD patients. In HD patient population, it is critical to improve standards of infection control in dialysis and expand treatment coverage. Furthermore, studies on clinical implications of HHV-6 infection in HD patients are crucial.

Early HHV-6 replication is associated with morbidity non-related to CMV infection after kidney transplantation

Human herpesvirus type 6-(HHV-6) has been associated with morbidity after liver transplantation.

OBJECTIVE

The aim of this study was to determine the HHV-6 seroprevalence among donor-recipient pairs, analyze the incidence of early active infection, its clinical manifestation, interaction with CMV, and the related morbidity in the first year after kidney transplantation.

METHODS

46 donor-recipient pairs had IgG evaluated by ELISA before transplantation: HHV-6(Pambio - USA) and CMV-(Roche - USA). A frozen whole blood sample collected weekly (from the 1st to the 6th week) was retrospectively tested for HHV-6 viral load (VL) determination by real time quantitative PCR (qPCR, Nanogen - Italy). Patients were preemptively surveyed for CMV by pp65 antigenemia (Ag, APAAP, immunohistochemistry, Biotest - Germany) from the 4th to the 12th week after transplantation. Active infection was defined as qPCR-HHV6+ (viral-load/mL-VL) and Ag+ (+cells/100.000 granulocytes), for HHV-6 and CMV, respectively. DCMV was defined as simultaneous positive antigenemia and suggestive signs/symptoms. Concerning +qPCR-HHV6, associated factors, clinical manifestation, interaction with CMV and morbidity were searched.

RESULTS

Pre-transplant HHV-6 seroprevalence was significantly higher among kidney recipients compared to their donors (82.6x54.8%; p = 0.005 [3.9 (1.4-10.4)]). Active infection by this virus occurred in 26.1% (12/46), with no association with previous IgG (p = 0.412). Median VL was 125 copies/mL (53-11.264), and the median Ag was 21 +cells (2-740). There was no association between HHV-6 and CMV activation after transplantation (p = 0.441), neither concerning DCMV (p = 0.596). Median highest Ag+ and days of ganciclovir treatment were similar between qPCR-HHV6 + or - (p = 0.206 and p = 0.124, respectively). qPCR-HHV6+ was associated with higher incidence of bacterial (p = 0.009) and fungal (p = 0.001) infections, and higher number (p = 0.001) of hospital admission and longer duration of hospitalization over the first 6 and 12 months post-transplantation (p = 0.033 and p = 0.001).

CONCLUSION

Latent HHV-6 infection is more common among recipients than donors before transplantation. Early active infection by this pathogen after transplantation does not increase DCMV incidence or severity during the first 3 months of follow-up. However, early HHV-6 replication is associated with other infections and hospitalizations in the first year.

Human Herpesvirus 6 Infection in Hemodialysis and Peritoneal Dialysis Patients

Background

Human herpesvirus 6 (HHV-6) infection occurs worldwide and can be reactivated from latency during periods of immunosuppression, especially after organ transplantation. No previous study has evaluated the influence of dialysis type on HHV-6 infection. The aim of the present study was to determine the prevalence of HHV-6 antibodies in hemodialysis (HD) and peritoneal dialysis (PD) patients.

Methods

W e studied 36 PD patients, 35 HD patients, and 20 healthy subjects, all with no history of organ transplantation. After systematic inquiries and a physical examination, blood was drawn for determination of biochemical parameters, cytomegalovirus immunoglobulin M (IgM) and immunoglobulin G (IgG), hepatitis B surface antigen, and the hepatitis C and human immunodeficiency virus antibodies. Titers of HHV-6 IgM and IgG antibodies were determined by ELISA.

Results

Titers for HHV-6 IgM antibody were positive in 9 HD patients (25.7%), 8 PD patients (22.2%), and 2 control subjects (10.0%, p > 0.05). More HD patients (20.0%) than PD patients (5.6%, p = 0.07) or control subjects (0.0%, p =0.03) were positive for HHV-6 IgG antibody. In HD patients, HHV-6 IgG seropositivity and duration of dialysis were positively correlated (R = 0.33, p = 0.05).

Conclusions

Infection with HHV-6 is not rare in PD and HD patients. In addition, HHV-6 IgG seropositivity was significantly higher in H D patients than in control subjects and approached significance when compared with seropositivity in PD patients. Moreover, in HD patients, HHV-6 IgG seropositivity correlated with duration on HD. These preliminary findings provide insight into the pre-transplantation period for patients and may aid our understanding of how to best protect patients against HHV-6 after transplantation.

Viral infections in lung transplant recipients

Viral infections, including beta-herpes viruses and community respiratory viruses, are frequent pathogens in lung transplant recipients. These pathogens have become increasingly recognized as having a significant role in long-term outcomes of lung transplantation, which has been limited by the frequent development of infections, and chronic allograft dysfunction. Community respiratory viruses, such as influenza and respiratory syncytial virus have been associated with both acute rejection and chronic allograft dysfunction, particularly if early treatment was not administered. beta-herpes viruses, particularly cytomegalovirus (CMV), have long been associated with increased mortality in lung transplant recipients, although the advent of effective antiviral strategies has led to improved morbidity and mortality. Because these pathogens have been associated with altered immune responses against the allograft, a better understanding of immunopathogenesis of viral infections may lead to a broader approach to limit the morbidity from these pathogens.

HHV-6 infection in a pediatric kidney transplant patient

Human herpesvirus 6 (HHV-6) infection can induce unusual complications in transplant patients, such as interstitial pneumonitis, encephalitis and marrow aplasia. We describe the clinical course of HHV-6 infection in a girl with renal transplantation. She presented with diarrhea and poor feeding on day 36 post-transplantation (Tx), after a 5-day steroid pulse for clinical signs of acute rejection. A week later she developed fever and had elevated plasma creatinine and lactic dehydrogenase levels, but a physical examination did not reveal any anomalies with respect to suggest rash, pneumonitis, encephalitis or lymphadenopathy. Two weeks later, the patient developed anemia and leucopenia. HHV-6 was the only pathogen detected by the PCR assay of the serum and marrow aspiration. The patient had a successful recovery without specific treatment. This case report highlights the wide spectrum of complications resulting from HHV-6 infection in immunosuppressed patients.

Lack of association between beta-herpesvirus infection and bronchiolitis obliterans syndrome in lung transplant recipients in the era of antiviral prophylaxis

BACKGROUND

Cytomegalovirus (CMV), human herpesvirus-6 and -7 (HHV-6 and -7) are beta-herpesviruses that commonly reactivate and have been proposed to trigger acute rejection and chronic allograft injury. We assessed the contribution of these viruses in the development of bronchiolitis obliterans syndrome (BOS) after lung transplantation.

METHODS

Quantitative real-time polymerase chain reaction of bronchoalveolar lavage samples were performed for CMV, HHV-6 and -7 in a prospective cohort of lung transplant recipients. A time-dependent Cox regression analysis was used to correlate the risk of BOS and acute rejection in patients with and without beta-herpesviruses infection.

RESULTS

Ninety-three patients were included in the study over a period of 3 years. A total of 581 samples from bronchoalveolar lavage were obtained. Sixty-one patients (65.6%) had at least one positive result for one of the beta-herpesviruses: 48 patients (51.6%) for CMV and 19 patients (20.4%) for both HHV-6 and -7. Median peak viral load was 3419 copies/mL for CMV, 258 copies/mL for HHV-6, and 665 copies/mL for HHV-7. Acute rejection (>or=grade 2) occurred in 46.2% and BOS (>or=stage 1) in 19.4% of the patients. In the Cox regression model the relative risk of acute rejection or BOS was not increased in patients with any beta-herpesviruses reactivation. Acute rejection was the only independently associated risk factor for BOS.

CONCLUSIONS

In lung transplant recipients receiving prolonged antiviral prophylaxis, reactivation of beta-herpesviruses within the allograft was common. However, despite high viral loads in many patients, virus replication was not associated with the development of rejection or BOS.

Hyperthermia alters kidney function and renal scintigraphy

BACKGROUND/AIM

Fever can be caused by different reasons such as environmental conditions, acute rejection after kidney transplantation and bacterial diseases including kidney and urinary tract infections. The present study represents a novel idea of investigating the direct effect of body temperature elevation on kidney function to determine whether hyperthermia alters the kidney function transiently leading to inaccurate findings and possible misinterpretation of the radionuclide (99mTc-MAG-3) renography studies.

METHODS

Renography studies were performed on New Zealand White rabbits weighing approximately 3-3.5 kg. Each rabbit was inject with 48.1 MBq (1.3 mCi) technetium-99m-mercaptoacetyltriglycine (99mTc-MAG-3). Studies were acquired using a gamma camera equipped with a low-energy, high-resolution collimator interfaced with a computer. Dynamic images were acquired as 2-s frames for the first 1 min and every 30 s for the next 30 min on a matrix of 64 x 64. Regions of interest were drawn over the whole kidneys. Radioactivity time curves were generated from the regions of interest. Time to peak activity (Tmax), time from peak to 50% activity (T1/2), and the uptake slope of each kidney were calculated from the renograms. Three days later the same protocol was repeated for the same rabbit but with a higher body temperature by 2 degrees C. Then it was repeated with a higher body temperature by 3 degrees C, then 4 degrees C with the same interval period. Blood pressure was measured using a catheter inserted into the femoral artery connected to a Lectromid recorder at normal temperature and during increasing the temperature by 2, 3 and 4 degrees C. Renal blood flow was also measured via the renal artery using an electromagnetic blood flow sensor connected to a flowmeter. Creatinine and blood urea nitrogen (BUN) in blood were measured in control and hyperthermic rabbits.

RESULTS

During hyperthermia the experimental curves shifted to the right of the control curves indicating that there was a delayed renal uptake of 99mTc-MAG-3 and clearance of radioactivity. This delay was proportional to body temperature. Calculated averages were: Tmax 1.6 +/- 0.1, 2.8 +/- 0.3, 8.8 +/- 1, 15 +/- 4 min; T1/2 2.77 +/- 0.2, 3 +/- 0.4, 8.9 +/- 1.1, 20 +/- 3.4 min, and perfusion index 190 +/- 5, 201 +/- 4, 218 +/- 7, 224 +/- 9 of control and hyperthermic (elevation of temperature 2, 3, and 4 degrees C) rabbits, respectively (n = 6; p < 0.05). Mean arterial pressure and renal blood flow did not significantly change during hyperthermia. Creatinine and BUN were proportionally elevated to high temperature.

CONCLUSIONS

Our results indicate that hyperthermia causes a transient alteration in the function of the kidney and scintigraphic pattern on radionuclide renography. Radionuclide renography studies may be performed at normothermic temperature since interpretation at higher body temperature could lead to misleading results, and temperature should be checked and recorded for single and follow-up radionuclide renography studies.