Relationship between beta-herpesviruses reactivation and development of complications after autologous peripheral blood stem cell transplantation

Human herpesvirus-6 in hematopoietic stem cell transplant recipients: a prospective cohort study in Egypt

BACKGROUND

Immunocompromised patients face reactivation of latent viruses that increase the risk of morbidity.

AIM

The study aimed to detect human herpes virus 6 (HHV-6) reactivation among allogeneic (allo) and autologous (auto) hematopoietic stem cell transplant (HSCT) recipients and to correlate potentially attributed clinical manifestations to HHV-6 DNA plasma level.

METHODS

A prospective study included all (forty) patients undergoing allo and auto-HSCT from Jan 2020 till June 2022. Plasma samples were collected for HHV-6 serology, and for HHV-6 quantitative PCR at post-transplantation weeks 2, 4, 6. Demographic and clinical data were recorded.

RESULTS

Out of 40 peripheral blood stem cell transplant (PBSCT) recipients, 34 (85%) were HHV-6 IgG positive pre-HSCT. Of which, fourteen patients (14/34, 41.2%) showed positive HHV-6 DNaemia. HHV-6 DNAemia (15/40, 37.5%) was significantly higher among allo (8/12, 66.7%) versus auto (7/28, 25%) HSCT recipients (p = 0.030). Patients with HHV-6 DNAemia developed fever, delayed engraftment and bone marrow suppression in 6/15, 40%, thrombocytopenia (5/15, 33.3%), rash and pneumonitis (2/15, 13.3%), acute GVHD (aGVHD) (1/15, 6.7%). HHV-6 DNAemia ranged from 101 to 102,000 copies/mL. Univariate analysis identified conditioning with busulfan-cyclophosphamide as a significant risk (p = 0.043), while receiving BEAM protocol was a protective factor (p = 0.045). In multivariate analysis, receiving BEAM protocol retained significance (p = 0.040).

CONCLUSION

Frequent HHV-6 reactivation was detected after HSCT, especially in allo-HSCT recipients with clinical manifestations which could not be otherwise explained. To our best knowledge this is the first study of HHV6 reactivation in HSCT recipients from Egypt. Raising awareness for HHV-6 reactivation manifestations and screening in HSCT recipients could be lifesaving.

Risk factors and outcome of concurrent and sequential multiviral cytomegalovirus, Epstein-Barr virus, BK virus, adenovirus and other viral reactivations in transplantation

PURPOSE OF REVIEW

Reactivation of viral infections occurs frequently in immunosuppressed populations, particularly in solid organ (SOT) or allogeneic haematopoietic cell (HCT) transplant patients. Concurrent and sequential multivirus infections are common, yet risk factors and outcomes remain unclear. This review aims to identify the patients vulnerable to multivirus infections and characterize the impact of increased viral burden to formulate prevention and treatment strategies.

RECENT FINDINGS

Incidences of up to 89% in SOT and 36% in HCT have been reported for two viruses, and 32% in SOT and 28% in HCT for at least three viruses. Risk factors appear related to an increased burden of immunosuppression, with most viral coinfections occurring within 12 months of transplantation. Direct viral complications such as cytomegalovirus disease are more frequent in coinfected patients, with documented prolonged duration of viraemia, higher viral load and increased end-organ disease. Graft dysfunction, acute rejection and graft-vs.-host disease (GVHD) have also been associated. Increased mortality is reported in the HCT population.

SUMMARY

Multivirus infections occur in a significant proportion of transplant patients and is linked to immunosuppressive burden. There is increasing evidence that this leads to worse graft and patient outcomes. Further prospective studies are required to further comprehensively characterise viral epidemiology, mechanisms and treatment strategies to ameliorate this risk.

Temporal lobe epilepsy associated with human herpes virus 6

Human herpes virus 6 (HHV-6) is a ubiquitous and most common pathogen that affects humans. Human herpes virus 6B (HHV-6B) is a wide spread human herpesvirus that infects most people when they are children, establishes latent infections in the central nervous system (CNS), especially in the hippocampus and amygdala, and induces neurologic diseases. HHV-6 can establish a latent infection and be reactivated by various stimuli. Recently, viral genomic DNA of HHV-6B has been detected in surgically removed brain tissues of intractable epilepsy patients, suggesting the involvement of HHV-6B in the pathogenesis of epilepsy. Temporal lobe epilepsy (TLE) has been shown to be closely related with HHV-6B. TLE patients with HHV-6B in their brains suffer from reiterative attacks of febrile seizures and hippocampal sclerosis. However, the mechanisms underlying the contribution of this virus to the development of TLE remains unknown. The direct damage and immune activation caused by the virus are involved in the process of neuron damage, abnormal neural circuit formation and glial cell proliferation. In addition, some cytokines like interleukin-17A (IL-17A), nuclear factor-kappa B (NF-κb), transforming growth factor-β (TGF-β), mitogen-activated protein kinase (MAPK) and phospholipase A2 are up-regulated and involved in the pathological process of TLE. More studies are needed to clarify the mechanisms underlying the link between HHV-6B and epilepsy, and identify biomarkers to recognize different patient groups for anti-inflammatory or immunomodulatory therapies.

Human herpesvirus 6 infection after autologous stem cell transplantation: A multicenter prospective study in adult patients

OBJECTIVES

to prospectively evaluate the incidence and the clinical relevance on hematopoietic reconstitution of HHV-6 infection in autologous hematopoietic stem cell transplantation (ASCT) recipients.

METHODS

HHV-6 DNA load was measured in whole blood specimens once during the 7 days before stem cell re-infusion and once a week after transplantation until hematopoietic recovery. Active HHV-6 infection was defined by 2 consecutive positive DNA loads.

RESULTS

from July 2012 to February 2015, 196 adult patients undergoing ASCT were enrolled. Twenty-two (11.2%) patients developed active HHV-6 infection with a cumulative incidence of 19% at 40 days after transplantation. The onset of active HHV-6 infection occurred with a median of 13 days after stem cell re-infusion. HHV-6 infection was associated with an increased frequency of non-infectious complications (OR = 5.05; 95%CI 1.78-14.32; P < 0.001). Moreover, the severity of these non-infectious complications was higher in recipients exhibiting HHV-6 infection (OR = 4.62; 95%CI 1.32-16.2; p < 0.01). Delayed neutrophils 10 (IQR: 8-14) vs 8 (IQR: 6-11) days and platelets recoveries 15 (IQR: 11.8-18.5) vs 8 (IQR: 4-14) days were observed in patients with active HHV-6 infection compared to non-infected ones.

CONCLUSIONS

in this study, 11.2% ASCT recipients presented active HHV-6 infection associated with significantly delayed hematologic reconstitution.

Human herpes virus 6 reactivation following autologous hematopoietic cell transplantation - a single-center experience

Data regarding presentation and management of human herpes virus 6 (HHV-6) reactivation among autologous hematopoietic cell transplantation (HCT) recipients are limited. We retrospectively reviewed medical charts of all autologous HCT patients tested for HHV-6 reactivation due to suspected clinical presentation between 1/2012 and 8/2017. Among 328 autologous HCT recipients, 44 patients were tested for HHV-6 reactivation. Thirty patients tested positive; 29 (97%) had sustained fever, six (20%) had rash and four (13%) had pneumonia. Median C-reactive protein was significantly lower in HHV-6 positive patients compared to negative patients (3.6 (range, 0.4-11) vs. 9.6 (range, 3.2-30) mg/dL, respectively, p = .004). Ganciclovir formulations were administrated in 29 (97%) patients with median time to fever resolution of one (range, 1-2) day. HHV-6 should be considered as an important cause of post engraftment fever in autologous HCT. Larger studies are warranted to evaluate incidence of HHV-6 reactivation and optimal treatment regimen.

Genomic Integration of HHV-6 Mimicking Viral Reactivation after Autologous Stem Cell Transplantation

The monitoring of Human Herpesvirus 6 (HHV-6) after allogeneic stem cell transplantation has proven to be useful in preventing life-threatening complications; however, the pathogenic role of HHV-6 after autologous transplantation is not well-characterized, although viral reactivation might be responsible for significant complications even after this type of transplant. Here we report, for the first time to our knowledge, the case of a patient with chromosomally integrated HHV-6 (ciHHV-6), presenting with high titers of HHV-6 DNA copies after autologous transplantation, mimicking HHV-6 reactivation. The presence of viral DNA in the follicle bulb confirmed the ciHHV-6 and allowed for the discontinuation of the antiviral treatment. Due to the increasing awareness of HHV-6 potential pathogenicity and the fact that ciHHV-6 is expected in 1–2% of the population, such a case might be helpful in recognizing ci HHV-6, thus avoiding unnecessary and potentially toxic antiviral therapy once the viral genomic integration is confirmed.

HHV-6 reactivation as a cause of fever in autologous hematopoietic stem cell transplant recipients

OBJECTIVES

We report the biological and clinical impacts possibly associated with HHV-6 reactivation in autologous hematopoietic stem cell transplant (AHSCT) recipients after intensive chemotherapy regimen for lymphoma.

METHODS

We retrospectively reviewed clinical, biological, radiological, treatment and outcomes of patients with positive HHV-6 DNA in whole blood following autologous hematopoietic stem cell transplantation.

RESULTS

Blood HHV-6 reactivation was reported in 27 (8.5%) patients among 316 AHSCT recipients after high dose therapy for lymphoma. Thirteen (4.1%) patients were symptomatic with fever (100%), diarrhea (61.5%), skin rash (46.1%), and pneumonia (23.1%). Antiviral treatment was administered in 9 (69%) patients and outcome was favorable in all cases.

CONCLUSION

Our study suggests a possible pathogenic role of HHV-6 in AHSCT recipients and suggests an impact of antiviral treatments on viral replication and clinical signs resolution.

Roseolovirus-associated encephalitis in immunocompetent and immunocompromised individuals

The roseoloviruses, human herpesvirus (HHV)-6A, HHV-6B, and HHV-7, can cause severe encephalitis or encephalopathy. In immunocompetent children, primary HHV-6B infection is occasionally accompanied by diverse clinical forms of encephalitis. Roseolovirus coinfections with heterologous viruses and delayed primary HHV-7 infection in immunocompetent adults result in very severe neurological and generalized symptoms. Recovery from neurological sequelae is slow and sometimes incomplete. In immunocompromised patients with underlying hematological malignancies and transplantation, frequent single or simultaneous reactivation of roseoloviruses elicit severe, lethal organ dysfunctions, including damages in the limbic system, brain stem, and hippocampus. Most cases have been due to HHV-6B with HHV-6A accounting for 2-3%. The most severe manifestation of HHV-6B reactivation is post-transplantation limbic encephalitis. Seizures, cognitive problems, and abnormal EEG are common. Major risk factors for HHV-6B-associated encephalitis include unrelated cord blood cell transplantation and repeated hematopoietic stem cell transplantation. Rare genetic disorders, male gender, certain HLA constellation, and immune tolerance to replicating HHV-6 in persons carrying chromosomally integrated HHV-6 might also predispose an individual to roseolovirus-associated brain damage. At this time, little is known about the risk factors for HHV-7-associated encephalitis. Intrathecal glial cell destruction due to virus replication, overexpression of proinflammatory cytokines, and viral mimicry of chemokines all contribute to brain dysfunction. High virus load in the cerebrospinal fluid, hippocampal astrogliosis, and viral protein expression in HHV-6B-associated cases and multiple microscopic neuronal degeneration in HHV-7-associated cases are typical laboratory findings. Early empirical therapy with ganciclovir or foscarnet might save the life of a patient with roseolovirus-associated encephalitis.

Human Herpesvirus 6 replication predicts Cytomegalovirus reactivation after allogeneic stem cell transplantation from haploidentical donor

BACKGROUND AND OBJECTIVES

Since HHV-6 reactivation after transplant has been reported to increase the risk of CMV infection, we tested this hypothesis in the HLA-haploidentical hematopoietic stem cell transplantation setting.

STUDY DESIGN

From February 2011 to October 2015, 75 patients received hematopoietic stem cell transplantation using a T-cell replete graft from a HLA-haploidentical donor at our Institution.

RESULTS

Interestingly, 87% of HHV-6 reactivations were followed by a CMV reactivation, at a median of 15days between the two viruses. Incidence of CMV reactivation was 14.5-fold higher in those patients with prior HHV-6 reactivation vs. those without it (p-value<0.001).

CONCLUSION

The present results suggest that HHV-6 can be considered as a predicting indicator of cellular immunosuppression preceding the onset of CMV infection.

Virus reactivations after autologous hematopoietic stem cell transplantation detected by multiplex PCR assay

Several studies have indicated that viral reactivations following allogeneic hematopoietic stem cell transplantation (allo-HSCT) are frequent, but viral reactivations after autologous HSCT (auto-HSCT) have not been investigated in detail. We performed multiplex polymerase chain reaction (PCR) assay to examine multiple viral reactivations simultaneously in 24 patients undergoing auto-HSCT between September 2010 and December 2012. Weekly whole blood samples were collected from pre- to 42 days post-HSCT, and tested for the following 13 viruses; herpes simplex virus 1 (HSV-1), HSV-2, varicella-zoster virus (VZV), Epstein-Barr virus (EBV), cytomegalovirus (CMV), human herpesvirus 6 (HHV-6), HHV-7, HHV-8, adeno virus (ADV), BK virus (BKV), JC virus (JCV), parvovirus B19 (B19V), and hepatitis B virus (HBV).  Fifteen (63%) patients had at least one type of viral reactivation. HHV6 (n = 10; 41.7%) was most frequently detected followed by EBV (n = 7; 29.2%). HHV-6 peaked on day 21 after HSCT and promptly declined. In addition, HBV, CMV, HHV7, and B19V were each detected in one patient. HHV6 reactivation was detected in almost half the auto-HSCT patients, which was similar to the incidence in allo-HSCT patients. The incidence of EBV was unexpectedly high. Viral infections in patients undergoing auto-HSCT were higher than previously reported in other studies. Although there were no particular complications of viral infection, we should pay attention to possible viral reactivations in auto-HSCT patients. J. Med. Virol. 89:358-362, 2017. © 2016 Wiley Periodicals, Inc.

Analysis of the shedding of three β-herpesviruses DNA in Polish patients subjected to allogeneic hematopoietic stem cell transplantation: Six-year follow up

BACKGROUND

Infections with human β-herpesviruses are common worldwide and are still frequent in patients after hematopoietic stem cell transplantation. Some data suggest that HHV-6 and HHV-7 could take part in CMV reactivation from latency and/or progression of CMV disease in immunosupressed patients.

OBJECTIVES

The aims of this study were: (1) to summarise retrospectively the results of β-herpesviruses DNA detection in a large group of adult allogeneic haematopoietic stem cell transplant recipients; and (2) to find a potential correlation between viruses belonging to this subfamily.

STUDY DESIGN

AlloHSCT recipients (N=142) were examined in the early post-transplant period (median=89 days). The presence of CMV, HHV-6 and HHV-7 was confirmed through detection and quantification of viral DNA, isolated from 1679 sera samples.

RESULTS

CMV DNA alone was detected in 23.9% of patients, while single HHV-6 and HHV-7 were detected in 14.8% and 9.9% of individuals, respectively. The reactivation of more than one virus was identified in 31% of analysed patients. In cases of concurrent infection, HHV-7 was detected at the same time as HHV-6, and both of them were usually reactivated before CMV. The kinetics of virus reactivation and measured viral load may suggest a potential role of HHV-6 and HHV-7 as co-factors in CMV reactivation.

CONCLUSIONS

The observed kinetics of virus reactivation may strongly suggest a potential role of HHV-6 and/or HHV-7 as co-factors of CMV reactivation. The co-infection with these β-herpesviruses could predispose patients after hematopoietic stem cell transplantation to a longer and more severe CMV infection.

Detection frequency of human herpesviruses-6A, -6B, and -7 genomic sequences in central nervous system DNA samples from post-mortem individuals with unspecified encephalopathy

In this autopsy-based study, human herpesvirus-6 (HHV-6) and -7 (HHV-7) genomic sequence frequency, HHV-6 variants, HHV-6 load and the expression of HHV-6 antigens in brain samples from the individuals, with and without unspecified encephalopathy (controls), using nested and real-time polymerase chain reactions, restriction endonuclease, and immunohistochemical analysis were examined. GraphPad Prism 6.0 Mann-Whitney nonparametric and chi-square test and Fisher's exact test were used for statistical analysis. The encephalopathy diagnoses were shown by magnetic resonance imaging made during their lifetime and macro- and microscopically studied autopsy tissue materials. Widespread HHV-6 and/or HHV-7 positivity was detected in the brain tissue of various individuals with encephalopathy, as well as in controls (51/57, 89.4 % and 35/51, 68.6 %, respectively; p = 0.009). Significantly higher detection frequency of single HHV-6 and concurrent HHV-6 + HHV-7 DNA was found in pia mater meninges, frontal lobe, temporal lobe, and olfactory tract DNAs in individuals with encephalopathy compared to the control group. HHV-6 load and higher frequency of the viral load >10 copies/10(6) cells significantly differed in samples from individuals with and without encephalopathy. The expression of HHV-6 antigens was revealed in different neural cell types with strong predominance in the encephalopathy group. In all HHV-6-positive autopsy samples of individuals with and without encephalopathy, HHV-6B was revealed. Significantly higher detection frequency of beta-herpesvirus DNA, more often detected HHV-6 load >10 copies/10(6) cells, as well as the expression of HHV-6 antigens in different brain tissue samples from individuals with encephalopathy in comparison with control group indicate on potential involvement of these viruses in encephalopathy development.

Optimisation of a quantitative polymerase chain reaction-based strategy for the detection and quantification of human herpesvirus 6 DNA in patients undergoing allogeneic haematopoietic stem cell transplantation

Human herpesvirus 6 (HHV-6) may cause severe complications after haematopoietic stem cell transplantation (HSCT). Monitoring this virus and providing precise, rapid and early diagnosis of related clinical diseases, constitute essential measures to improve outcomes. A prospective survey on the incidence and clinical features of HHV-6 infections after HSCT has not yet been conducted in Brazilian patients and the impact of this infection on HSCT outcome remains unclear. A rapid test based on real-time quantitative polymerase chain reaction (qPCR) has been optimised to screen and quantify clinical samples for HHV-6. The detection step was based on reaction with TaqMan^® hydrolysis probes. A set of previously described primers and probes have been tested to evaluate efficiency, sensitivity and reproducibility. The target efficiency range was 91.4% with linearity ranging from 10-10⁶ copies/reaction and a limit of detection of five copies/reaction or 250 copies/mL of plasma. The qPCR assay developed in the present study was simple, rapid and sensitive, allowing the detection of a wide range of HHV-6 loads. In conclusion, this test may be useful as a practical tool to help elucidate the clinical relevance of HHV-6 infection and reactivation in different scenarios and to determine the need for surveillance.

Inhibitors of nucleotidyltransferase superfamily enzymes suppress herpes simplex virus replication

Herpesviruses are large double-stranded DNA viruses that cause serious human diseases. Herpesvirus DNA replication depends on multiple processes typically catalyzed by nucleotidyltransferase superfamily (NTS) enzymes. Therefore, we investigated whether inhibitors of NTS enzymes would suppress replication of herpes simplex virus 1 (HSV-1) and HSV-2. Eight of 42 NTS inhibitors suppressed HSV-1 and/or HSV-2 replication by >10-fold at 5 μM, with suppression at 50 μM reaching ∼1 million-fold. Five compounds in two chemical families inhibited HSV replication in Vero and human foreskin fibroblast cells as well as the approved drug acyclovir did. The compounds had 50% effective concentration values as low as 0.22 μM with negligible cytotoxicity in the assays employed. The inhibitors suppressed accumulation of viral genomes and infectious particles and blocked events in the viral replication cycle before and during viral DNA replication. Acyclovir-resistant mutants of HSV-1 and HSV-2 remained highly sensitive to the NTS inhibitors. Five of six NTS inhibitors of the HSVs also blocked replication of another herpesvirus pathogen, human cytomegalovirus. Therefore, NTS enzyme inhibitors are promising candidates for new herpesvirus treatments that may have broad efficacy against members of the herpesvirus family.

Classification of HHV-6A and HHV-6B as distinct viruses

Shortly after the discovery of human herpesvirus 6 (HHV-6), two distinct variants, HHV-6A and HHV-6B, were identified. In 2012, the International Committee on Taxonomy of Viruses (ICTV) classified HHV-6A and HHV-6B as separate viruses. This review outlines several of the documented epidemiological, biological, and immunological distinctions between HHV-6A and HHV-6B, which support the ICTV classification. The utilization of virus-specific clinical and laboratory assays for distinguishing HHV-6A and HHV-6B is now required for further classification. For clarity in biological and clinical distinctions between HHV-6A and HHV-6B, scientists and physicians are herein urged, where possible, to differentiate carefully between HHV-6A and HHV-6B in all future publications.

Co-infections with cytomegalovirus and human herpesvirus type 7 in adult Polish allogeneic haematopoietic stem cell transplant recipients

Human herpesvirus 7 (HHV-7) is widespread around the world and may also be a possible cofactor for cytomegalovirus (CMV) infection in haematopoietic stem cell transplant (HSCT) recipients. In case of viral diseases where specific treatment is available, real-time PCR assays constitute reliable diagnostic tools enabling timely initiation of appropriate therapy and rapid assessment of the efficacy of antiviral treatment strategies. The presence of CMV and HHV-7 was confirmed by the detection of viral DNA isolated from 1,027 plasma samples. A group of 69 allogeneic HSCT (alloHSCT) recipients was examined in early post-transplant period using quantitative real-time PCR methods. Within the study period, 62 % of patients had at least once CMV DNA-emia, while HHV-7 DNA was found in 43 % of subjects. Co-infection between these β-herpesviruses was detected in the plasma samples collected from 18 patients (26 %). Patients with concomitant HHV-7 DNA-emia had significantly higher number of CMV DNA copies compared with those without HHV-7 infection (1986 vs. 432 copies/ml, p < 0.001) but there was no difference in duration of CMV DNA-emia between these groups. On the other hand, while the load of HHV-7 DNA was comparable between patients with CMV DNA-emia and without CMV DNA-emia, the duration of HHV-7 DNA-emia was significantly longer in the first group (38.5 vs. 14 days, p < 0.001). HHV-7 DNA-emia is very frequently detected in Polish alloHSCT recipients. In those, who have subsequent CMV reactivation, the coexistence of the viruses may negatively affect the kinetics of infection with either of them. Therefore the investigation of concomitant HHV-7 DNA-emia could affect the prognosis of post-transplant patients suffering from CMV reactivation.