Reduced risk for extensive chronic graft-versus-host disease in patients receiving transplants with human leukocyte antigen-identical sibling donors given polymerase chain reaction-based preemptive therapy against cytomegalovirus

Cytomegalovirus infection is associated with thymic dysfunction and chronic graft-versus-host disease after pediatric hematopoietic stem cell transplantation

Pediatric hematopoietic stem cell transplantation (HSCT) is challenged by chronic graft-versus-host disease (cGvHD) significantly affecting survival and long-term morbidity, but underlying mechanisms including the impact of post-HSCT CMV infection are sparsely studied. We first investigated the impact of CMV infection for development of cGvHD in 322 children undergoing standard myeloablative HSCT between 2000 and 2018. Clinically significant CMV infection (n = 61) was an independent risk factor for chronic GvHD in a multivariable Cox regression analysis (HR = 2.17, 95% CI = 1.18-3.97, P = 0.013). We next explored the underlying mechanisms in a subcohort of 39 children. CMV infection was followed by reduced concentration of recent thymic emigrants (17.5 vs. 51.9 × 106/L, P = 0.048) and naïve CD4+ and CD8+ T cells at 6 months post-HSCT (all P < 0.05). Furthermore, CD25highFOXP3+ Tregs tended to be lower in patients with CMV infection (2.9 vs. 9.6 × 106/L, P = 0.055), including Tregs expressing the naivety markers CD45RA and Helios. CD8+ T-cell numbers rose after CMV infection and was dominated by exhausted PD1-expressing cells (66% vs. 39%, P = 0.023). These findings indicate that post-HSCT CMV infection is a main risk factor for development of chronic GvHD after pediatric HSCT and suggest that this effect is caused by reduced thymic function with a persistently impaired production of naïve and regulatory T cells in combination with increased peripheral T-cell exhaustion.

SARS-CoV-2 Infection and Active, Multiorgan, Severe cGVHD After HSCT for Adolescent ALL: More Luck Than Understanding? A Case Report

Graft-vs. -host disease (GvHD) is a serious and complex immunological complication of haematopoietic stem cell transplantation (HSCT) and is associated with prolonged immunodeficiency and non-relapse mortality. Standard treatment of chronic GvHD comprises steroids in combination with other immunosuppressive agents. Extracorporeal photopheresis (ECP), with its immunomodulatory mechanism, is applied as part of steroid-sparing regimens for chronic GvHD. Immunocompromised, chronically ill patients are at particular risk of severe disease courses of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. T-cell immunity in SARS-CoV-2 infection is well-described but the role of the humoral immune responses is not fully understood. This case report describes a moderate course of SARS-CoV-2 infection in a patient <9 months after HSCT who was suffering from active, severe, chronic GvHD treated with prednisone and ECP. Following HSCT from a matched unrelated donor to cure acute lymphoblastic leukaemia, the 25-year-old male patient experienced multiple infectious complications associated with cytopenia, B-cell dyshomeostasis and autoantibody production followed by development of severe chronic GvHD thereafter at day +212. The steroid-sparing treatment plan consisted of supportive care, topical treatment, prednisone and ECP. He was diagnosed with SARS-CoV-2 infection at day +252, experiencing loss of smell and taste as well as a cough. The patient's oxygen saturation was between 94 and 97% on room air, and computed tomography images showed evolution of typical of SARS-CoV-2 infiltrates. In addition to cytopenia and immune dyshomeostasis, laboratory tests confirmed macrophage activating syndrome, transaminitis and Epstein-Barr virus viraemia. At that time, anti-SARS-CoV-2 monoclonal antibodies were not available in Austria and remdesivir seemed contraindicated. Surprisingly, despite severe lymphopenia the patient developed SARS-CoV-2-specific antibodies within 15 days, which was followed by clearance of SARS-CoV-2 and EBV with resolution of symptoms. Thereafter, parameters of immune dysregulation such as lymphopenia and B-cell dyshomeostasis, the latter characterised by elevated CD21low B cells and autoantibody expression, normalised. Moreover, we observed complete response of active chronic GvHD to treatment.

Posttransplant cyclophosphamide is associated with increased cytomegalovirus infection: a CIBMTR analysis

Prior studies suggest increased cytomegalovirus (CMV) infection after haploidentical donor transplantation with posttransplant cyclophosphamide (HaploCy). The role of allograft source and posttransplant cyclophosphamide (PTCy) in CMV infection is unclear. We analyzed the effect of graft source and PTCy on incidence of CMV infection, and effects of serostatus and CMV infection on transplant outcomes. We examined patients reported to the Center for International Blood and Marrow Transplantation Research between 2012 and 2017 who had received HaploCy (n = 757), matched related (Sib) with PTCy (SibCy, n = 403), or Sib with calcineurin inhibitor-based prophylaxis (SibCNI, n = 1605). Cumulative incidences of CMV infection by day 180 were 42%, 37%, and 23%, respectively (P < .001). CMV disease was statistically comparable. CMV infection risk was highest for CMV-seropositive recipients (R+), but significantly higher in PTCy recipients regardless of donor (HaploCy [n = 545]: hazard ratio [HR], 50.3; SibCy [n = 279]: HR, 47.7; SibCNI [n = 1065]: HR, 24.4; P < .001). D+/R- patients also had increased risk for CMV infection. Among R+ or those developing CMV infection, HaploCy had worse overall survival and nonrelapse mortality. Relapse was unaffected by CMV infection or serostatus. PTCy was associated with lower chronic graft-versus-host disease (GVHD) overall, but CMV infection in PTCy recipients was associated with higher chronic GVHD (P = .006). PTCy, regardless of donor, is associated with higher incidence of CMV infection, augmenting the risk of seropositivity. Additionally, CMV infection may negate the chronic GVHD protection of PTCy. This study supports aggressive prevention strategies in all receiving PTCy.

How I treat CMV reactivation after allogeneic hematopoietic stem cell transplantation

Cytomegalovirus (CMV) reactivation remains one of the most common and life-threatening infectious complications following allogeneic hematopoietic stem cell transplantation, despite novel diagnostic technologies, several novel prophylactic agents, and further improvements in preemptive therapy and treatment of established CMV disease. Treatment decisions for CMV reactivation are becoming increasingly difficult and must take into account whether the patient has received antiviral prophylaxis, the patient's individual risk profile for CMV disease, CMV-specific T-cell reconstitution, CMV viral load, and the potential drug resistance detected at the time of initiation of antiviral therapy. Thus, we increasingly use personalized treatment strategies for the recipient of an allograft with CMV reactivation based on prior use of anti-CMV prophylaxis, viral load, the assessment of CMV-specific T-cell immunity, and the molecular assessment of resistance to antiviral drugs.

Human Cytomegalovirus Latency and Reactivation in Allogeneic Hematopoietic Stem Cell Transplant Recipients

Human cytomegalovirus (HCMV) reactivation is a major infectious cause of morbidity and mortality after allogeneic hematopoietic stem cell transplantation (HSCT). HCMV is a ubiquitous beta-herpesvirus which asymptomatically infects immunocompetent individuals but establishes lifelong latency, with the potential to reactivate to a life-threatening productive infection when the host immune system is suppressed or compromised. Opportunistic HCMV reactivation is the most common viral complication following engraftment after HSCT and is associated with a marked increase in non-relapse mortality, which appears to be linked to complex effects on post-transplant immune recovery. This minireview explores the cellular sites of HCMV latency and reactivation in HSCT recipients and provides an overview of the risk factors for HCMV reactivation post-HSCT. The impact of HCMV in shaping post-transplant immune reconstitution and its relationship with patient outcomes such as relapse and graft-versus-host disease will be discussed. Finally, we survey current and emerging strategies to prevent and control HCMV reactivation in HSCT recipients, with recent developments including adoptive T cell therapies to accelerate HCMV-specific T cell reconstitution and new anti-HCMV drug therapy for HCMV reactivation after HSCT.

Cytomegalovirus-Specific CD8+ T-Cells With Different T-Cell Receptor Affinities Segregate T-Cell Phenotypes and Correlate With Chronic Graft-Versus-Host Disease in Patients Post-Hematopoietic Stem Cell Transplantation

Virus-specific T-cell responses are crucial to control cytomegalovirus (CMV) infections/reactivation in immunocompromised individuals. Adoptive cellular therapy with CMV-specific T-cells has become a viable treatment option. High-affinity anti-viral cellular immune responses are associated with improved long-term immune protection against CMV infection. To date, the characterization of high-affinity T-cell responses against CMV has not been achieved in blood from patients after allogeneic hematopoietic stem cell transplantation (HSCT). Therefore, the purpose of this study was to describe and analyze the phenotype and clinical impact of different CMV-specific CD8+ cytotoxic T-lymphocytes (CMV-CTL) classes based on their T-cell receptor (TCR) affinity. T-cells isolated from 23 patients during the first year following HSCT were tested for the expression of memory markers, programmed cell death 1 (PD-1), as well as TCR affinity, using three different HLA-A*02:01 CMVNLVPMVATV-Pp65 tetramers (wild-type, a245v and q226a mutants). High-affinity CMV-CTL defined by q226a tetramer binding, exhibited a higher frequency in CD8+ T-cells in the first month post-HSCT and exhibited an effector memory phenotype associated with strong PD-1 expression as compared to the medium- and low-affinity CMV-CTLs. High-affinity CMV-CTL was found at higher proportion in patients with chronic graft-versus-host disease (p < 0.001). This study provides a first insight into the detailed TCR affinities of CMV-CTL. This may be useful in order to improve current immunotherapy protocols using isolation of viral-specific T-cell populations based on their TCR affinity.

Infections as a cause of autoimmune rheumatic diseases

Exogenous and endogenous environmental exposures and particularly infections may participate in the breakage of tolerance and the induction of autoimmunity in rheumatic diseases. Response to infections apparently occurs years before clinical manifestations and features of autoimmunity, such as autoantibodies, are detected years before clinical manifestations in autoimmune rheumatic diseases. In this review, we summarize the current evidence for a potential causal link between infectious agents and rheumatoid arthritis, systemic lupus erythematosus, systemic sclerosis, Sjogren’s syndrome and ANCA-associated vasculitis.

CMV in Hematopoietic Stem Cell Transplantation

Due to its negative impact on the outcome of stem cell transplant (SCT) and solid organ transplant patients (SOT) CMV has been called “the troll of transplantation”. One of the greatest advances in the management of SCT has been the introduction of the preemptive strategy. Since its introduction, the incidence of the viremia, as expected, remains unchanged but there has been a marked decline in the incidence of early CMV disease. However, in spite of the advances in prevention of CMV disease, CMV is still today an important cause of morbidity and mortality. Late CMV disease is still occurring in a significant proportion of patients and the so-called indirect effects of CMV are causing significant morbidity and mortality. Fortunately there have been several advances in the development of new antivirals, adoptive immunotherapy and DNA-CMV vaccines that might transform the management of CMV in the near future.

Infectomics and autoinfectomics: a tool to study infectious-induced autoimmunity

The exposome represents all exogenous and endogenous environmental exposures that begin at preconception and carry on throughout life, while the microbiome reflects the microbial component of the exposome. We recently introduced the concept of infectome and autoinfectome as a means of studying the totality of infections throughout life that participate in the induction as well as the progression of autoimmune diseases in an affected individual. The investigation of the autoinfectome could help us understand why some patients develop more than one autoimmune disease, a phenomenon also known as mosaic of autoimmunity. It could also explain the infectious and autoantibody burden of various autoimmune rheumatic diseases. The close interplay between infections and the immune system should be studied over time, long before the onset of autoaggression and autoimmunity. Tracking down each individual's exposure to infectious agents (as defined by the autoinfectome) would be important for the establishment of a causative link between infection and autoimmunity.

Risk factors for cytomegalovirus DNAemia following haploidentical stem cell transplantation and its association with host hepatitis B virus serostatus

BACKGROUND

The risk factors associated with CMV DNAemia are not well known after haploidentical stem cell transplantation (SCT).

OBJECTIVES

This study investigated the risk factors and prognosis for CMV DNAemia among CMV seromatched donors and recipients (D+/R+).

STUDY DESIGN

A retrospective study of patients undergoing haploidentical stem cell transplantation (SCT) between January 2010 and January 2012 was conducted. Cox regression analysis was performed to identify the risk factors for CMV DNAemia. These possible factors included recipient/donor age, recipient/donor gender, gender disparity, recipient HBsAg serostatus, diagnosis, risk stratification, anti-thymocyte globulin (ATG) dose (6mg/kg,10mg/kg), early neutrophil engraftment (≤12 days, >12 days), absolute lymphocyte count on day 30 (ALC30) and the occurrence of acute GVHD before CMV DNAemia.

RESULTS

The total number of patients was 248 with median age of 31 years (range, 14-56). The cumulative incidence of CMV DNAemia (146/248) was 59.5%. CMV DNAemia was first detected after a median of +35 days (range,12-82). Seventeen patients (17/146, 11.6%) developed CMV disease. Multivariate analysis identified HBsAg seropositivity (P=0.002, hazard ratio (HR)=1.833; 95%CI=1.257-2.673) and the occurrence of acute GVHD before CMV DNAemia (P=0.014; HR=1.520; 95%CI=1.088-2.124) as risk factors for CMV DNAemia. CMV DNAemia was associated with subsequent II-IV acute graft-versus-host disease (GVHD) (P=0.014), III-IV aGVHD (P=0.013) and chronic GVHD (P=0.008). Totally, CMV DNAemia was found to be a poor prognostic factor in terms of non-relapse mortality (NRM) (P=0.003, HR=2.730; 95%CI=1.406-5.197), and overall survival (OS) (P=0.045, HR=1.654; 95%CI=1.012-2.701).

CONCLUSIONS

Our data showed HBsAg seropositivity was associated with an increased risk of cytomegalovirus DNAemia. Detection of CMV DNAemia proved to be a poor prognostic factor for haploidentical patients.

Infections and autoimmunity: role of human cytomegalovirus in autoimmune endothelial cell damage

Molecular mimicry between infectious agents and normal human host cell proteins represents one of the possible mechanisms responsible for autoimmunity. Among infectious agents, human cytomegalovirus (HCMV) is an ideal candidate for involvement in autoimmune disorders because of its lifelong persistence through periods of reactivation and latency and because of the extensive manipulation of innate and adaptive immunity. HCMV has been implicated in the pathogenesis of vascular damage in systemic sclerosis (SSc) and atherosclerosis. Based on our data, which demonstrate a cause-and-effect relationship between HCMV and endothelial cell aggression in SSc and atherosclerosis, we propose that immune responses to particular HCMV proteins may result in autoaggression through a mechanism of molecular mimicry of normally expressed endothelial cell surface molecules.

Comparison of outcomes of hematopoietic stem cell transplantation without chemotherapy conditioning by using matched sibling and unrelated donors for treatment of severe combined immunodeficiency

BACKGROUND

Patients with severe combined immunodeficiency disease who have matched sibling donors (MSDs) can proceed to hematopoietic cell transplantation (HCT) without conditioning chemotherapy.

OBJECTIVE

We sought to determine whether the results of HCT without chemotherapy-based conditioning from matched unrelated donors (URDs), either from volunteer adults or umbilical cord blood, are comparable with those from MSDs.

METHODS

We performed a multicenter survey of severe combined immunodeficiency transplantation centers in North America, Europe, and Australia to compile retrospective data on patients who have undergone unconditioned HCT from either URDs (n = 37) or MSDs (n = 66).

RESULTS

Most patients undergoing URD HCT (92%) achieved donor T-cell engraftment compared with 97% for those with MSDs; however, estimated 5-year overall and event-free survival were worse for URD recipients (71% and 60%, respectively) compared with MSD recipients (92% and 89%, respectively; P < .01 for both). URD recipients who received pre-HCT serotherapy had similar 5-year overall survival (100%) to MSD recipients. The incidences of grade II to IV acute and chronic graft-versus-host disease were higher in URD (50% and 39%, respectively) compared with MSD (22% and 5%, respectively) recipients (P < .01 for both). In the surviving patients there was no difference in T-cell reconstitution at the last follow-up between the URD and MSD recipients; however, MSD recipients were more likely to achieve B-cell reconstitution (72% vs 17%, P < .001).

CONCLUSION

Unconditioned URD HCT achieves excellent rates of donor T-cell engraftment similar to that seen in MSD recipients, and reconstitution rates are adequate. However, only a minority will have myeloid and B-cell reconstitution, and attention must be paid to graft-versus-host disease prophylaxis. This approach might be safer in children ineligible for intense regimens to spare the potential complications of chemotherapy.

Antibodies against human cytomegalovirus late protein UL94 in the pathogenesis of scleroderma-like skin lesions in chronic graft-versus-host disease

Human cytomegalovirus (hCMV) infection and its reactivation correlate both with the increased risk and with the worsening of graft-versus-host disease (GVHD). Because scleroderma-like skin lesions can occur in chronic GVHD (cGVHD) in allogeneic stem-cell transplant (HCT) patients and hCMV is relevant in the pathogenesis of systemic sclerosis (SSc), we evaluated the possible pathogenetic link between hCMV and skin cGVHD. Plasma from 18 HCT patients was tested for anti-UL94 and/or anti-NAG-2 antibodies, identified in SSc patients, by direct ELISA assays. Both donors and recipients were anti-hCMV IgG positive, without autoimmune diseases. Patients' purified anti-UL94 and anti-NAG-2 IgG binding to human umbilical endothelial cells (HUVECs) and fibroblasts was performed by FACS analysis and ELISA test. HUVECs apoptosis and fibroblasts proliferation induced by patients' anti-NAG-2 antibodies were measured by DNA fragmentation and cell viability, respectively. About 11/18 patients developed cGVHD and all of them showed skin involvement, ranging from diffuse SSc-like lesions to limited erythema. Eight of eleven cGVHD patients were positive for anti-UL94 and/or anti-NAG-2 antibodies. Remarkably, 4/5 patients who developed diffuse or limited SSc-like lesions had antibodies directed against both UL94 and NAG-2; their anti-NAG-2 IgG-bound HUVECs and fibroblasts induce both endothelial cell apoptosis and fibroblasts proliferation, similar to that induced by purified anti-UL94 and anti-NAG-2 antibodies obtained from SSc patients. In conclusion, our data suggest a pathogenetic link between hCMV infection and scleroderma-like skin cGVHD in HCT patients through a mechanism of molecular mimicry between UL94 viral protein and NAG-2 molecule, as observed in patients with SSc.

Cytomegalovirus-induced immunopathology and its clinical consequences

Human cytomegalovirus (CMV) is a ubiquitous DNA virus that causes severe disease in patients with immature or impaired immune systems. During active infection, CMV modulates host immunity, and CMV-infected patients often develop signs of immune dysfunction, such as immunosuppression and autoimmune phenomena. Furthermore, active viral infection has been observed in several autoimmune diseases, and case reports have linked primary CMV infection and the onset of autoimmune disorders. In addition, CMV infection promotes allograft rejection and graft-versus-host disease in solid organ and bone marrow transplant recipients, respectively, further implicating CMV in the genesis and maintenance of immunopathological phenomena. The mechanisms by which CMV could induce inhibition of host defense, inflammation, and autoimmunity are discussed, as is the treatment of virus-induced immunopathology with antivirals.

Evidence for a bidirectional relationship between cytomegalovirus replication and acute graft-versus-host disease

Cytomegalovirus (CMV) infection and graft-versus-host disease (GVHD) are important complications after allogeneic hematopoietic stem cell transplantation (HSCT) with a clear link. Multiple studies show that GVHD and its treatment put patients at risk for CMV replication. Data on CMV replication as a cause of GVHD, in contrast, are controversial. We analyzed the reciprocal association of CMV replication with acute GVHD (aGVHD) in 515 patients treated with allogeneic HSCT between 1993 and 2008. Cumulative incidences at day 100 were 17% for CMV replication, 68% for aGVHD grade I-IV, and 48% for GVHD grade II-IV. Multivariate time-dependent analyses revealed that the presence of GVHD increased the risk of CMV replication in a dose-dependent manner: hazard ratio (HR) for CMV replication for patients with aGVHD grade I was 1.35 (95% confidence interval [CI] 0.82-2.21); HR for patients with aGVHD grade II-IV was 1.61 (95% CI 1.11-2.36, P-value for trend = .01). During phases of CMV replication, patients were at increased risk of developing aGVHD (HR 2.18, 95% CI 1.30-3.65, P < .01). These data confirm that GVHD and its therapy can induce CMV replication. They further demonstrate the reciprocal novel finding that patients are at significantly increased risk of developing aGVHD during CMV replication.

How we treat cytomegalovirus in hematopoietic cell transplant recipients

Cytomegalovirus (CMV) continues to cause major complications after hematopoietic cell transplantation (HCT). Over the past decade, most centers have adopted preemptive antiviral treatment or prophylaxis strategies to prevent CMV disease. Both strategies are effective but also have shortcomings with presently available drugs. Here, we review aspects of CMV treatment and prevention in HCT recipients, including currently used drugs and diagnostics, ways to optimize preemptive therapy strategies with quantitative polymerase chain reaction assays, the use of prophylaxis, management of CMV disease caused by wild-type or drug-resistant strains, and future strategies.

Bone marrow transplantation from a pediatric donor with a high frequency of cytomegalovirus-specific T-cells

A recent study reported that quantitation of cytomegalovirus (CMV)-specific CD8+ T lymphocytes in the graft and monitoring of these T cells might identify hematopoietic stem cell transplantation-recipients at the risk for progressive CMV infection. A 6-year-old girl underwent bone marrow transplantation from an HLA-identical sibling with a very high frequency of CMV specific tetramer-positive CD8+ T-cells. CMV-specific T-cell immunity was prospectively evaluated using a peptide (HLA-A2, NLVPMVATV). Tetramer assay showed that the frequency of CMV-specific CD8+ T cells of the donor in the peripheral blood was 5.3%, higher than average amongst young children. The frequency of CMV-specific CD8+ T cells of the donor in the graft was 3.7% of CD8+ T-cells. Before transplantation, the frequency of CMV specific CD8+ T cells of the recipient was 0.1% in the peripheral blood. Surprisingly, the frequency of CMV specific CD8+ T cells increased up to 30% of CD8+ T-cells at day 27 after transplantation. IFN-gamma enzyme-linked immunospot assay showed the recipient-T cells had strong responses to the A2-specific NLVPMVATV peptide. Although the phenotypic pattern of the CMV-specific T cells of the recipient was different from those of the donor before transplantation, the phenotype of the donor-derived cells retained their original phenotype in the recipient after transplantation. These finding suggested that active transferred immunity from the graft with a high frequency of CMV-specific CTL could induce a rapid reconstitution of CMV-specific T-cell mediated immunity in pediatric HLA-identical allogenetic bone marrow transplantation. The screening of peripheral blood using HLA-peptide tetramer staining might be beneficial to select donors.

Physiopathologie de la sclérodermie systémique: état des lieux sur une affection aux multiples facettes

Systemic sclerosis is a rare disease characterized by vascular hyperreactivity and collagen deposition. Endothelial cell, fibroblast and lymphocyte abnormalities have been reported in systemic sclerosis. Fibroblast dysfunction is characterized by uncontrolled activation of the transforming growth factor-beta (TGF-beta) pathway and excess synthesis of both connective tissue growth factor (CTGF) and free radicals. These promote the accumulation of extracellular matrix. Endothelial cells produce excess quantities of endothelin 1 and inducible NO synthase. They also undergo early apoptosis. Oxidative stress appears to play a major role in disease progression. Increased levels of interleukin 4, a profibrotic cytokine, have been detected in plasma and skin of systemic sclerosis patients. Autoantibodies are detectable in the serum of almost all systemic sclerosis patients. Some are directed against well-identified ubiquitous nuclear proteins and have no demonstrated pathogenic role. Other autoantibodies bind to endothelial cells or fibroblasts and may have a pathogenic role.

Antibodies against human cytomegalovirus in the pathogenesis of systemic sclerosis: a gene array approach

BACKGROUND

Systemic sclerosis is an autoimmune disease characterized by immunological abnormalities, vascular damage, and fibroblast proliferation. We have previously shown that a molecular mimicry mechanism links antibodies against the human-cytomegalovirus-derived protein UL94 to the pathogenesis of systemic sclerosis. The UL94 epitope shows homology with NAG-2, a surface molecule highly expressed on endothelial cells. Anti-UL94 peptide antibodies purified from patients' sera induce apoptosis of endothelial cells upon engagement of the NAG-2-integrin complex.

METHODS AND FINDINGS

We show here that NAG-2 is expressed on dermal fibroblasts and that anti-UL94 antibodies bind to fibroblasts. We have used the gene array strategy (Affimetrix oligonucleotide microarrays) to analyze the transcriptional profile in response to a 4-h and an 8-h treatment with antibodies against the UL94 peptide in endothelial cells and dermal fibroblasts. Exposure of endothelial cells to anti-UL94 antibodies had a profound impact on gene expression, resulting in the upregulation of 1,645 transcripts. Several gene clusters were upregulated including genes encoding adhesion molecules, chemokines, colony-stimulating factors (CSFs), growth factors, and molecules involved in apoptosis. Following antibody stimulation, dermal fibroblasts showed an upregulation of 989 transcripts and acquired a "scleroderma-like" phenotype. Indeed, genes involved in extracellular matrix deposition, growth factors, chemokines, and cytokines were upregulated. We confirmed the microarray results by real-time quantitative polymerase chain reaction and by measuring some of the corresponding proteins with ELISA and Western blotting.

CONCLUSION

Our results show that anti-human-cytomegalovirus antibodies may be linked to the pathogenesis of systemic sclerosis not only by inducing endothelial cell activation and apoptosis but also by causing activation of fibroblasts, one of the hallmarks of the disease.

The influence of the conditions of hematopoietic cell transplantation on infectious complications

PURPOSE OF REVIEW

The multitude of factors that influence the risk of infection after hematopoietic cell transplantation has been further complicated by the rapid evolution of this therapy in the past 5 years. The degree to which functional immune reconstitution has been achieved reflects the equilibrium reached by the immune systems of the recipient and donor in the context of host non-hematopoietic tissue. Thus immunomodulatory influences on the recipient and the transplanted graft, both before and after hematopoietic cell transplantation, have a profound influence on the incidence and severity of infection. This review of the recent literature contributes to our understanding of how the conditions of hematopoietic cell transplantation influence the timing and nature of infectious complications.

RECENT FINDINGS

The main themes of published primary research from 2004 to the present focus on non-myeloablative conditioning regimens and their effects on immune reconstitution after hematopoietic cell transplantation.

SUMMARY

A plethora of clinical trials are ongoing, focused on the outcome after conditioning regimens designed to result in less regimen-related toxicity while preserving or enhancing the graft-versus-tumor effect. Given the infancy of these new approaches, it is not possible to make definitive statements regarding the relative risk of serious infection with each therapy. It is clear that a reduction in regimen-related non-infectious complications or mortality does not necessarily ensure a reduction in clinically significant infections. Improvements in early diagnostic and therapeutic options for these infections now bring us to an era of understanding pathogens as probes of the functional reconstitution of immunity.