An Association between BK Virus Replication in Bone Marrow and Cytopenia in Kidney-Transplant Recipients. J Transplant. 2014;2014:252914. [PMID: 24868448 PMCID: PMC4020201 DOI: 10.1155/2014/252914]

Characteristics, risk factors, and outcomes of neutropenia after liver or kidney transplantation in children

BACKGROUND

While prior adult studies have shown that approximately 20%-38% of subjects undergoing solid-organ transplant develop neutropenia, similar analyses in pediatric subjects are scarce.

METHODS

We conducted a retrospective chart review of liver transplant (LT) and kidney transplant (KT) recipients at our center during the period 2008-2018. All of the KT and none of the LT subjects during this time period had induction with either anti-thymocyte globulin (ATG) or basiliximab at time of transplant. Neutropenia was defined as absolute neutrophil count (ANC) value ≤1000/mm3 .

RESULTS

One hundred subjects with LT and 82 subjects with KT were included. The incidence of neutropenia within the first year of transplant in KT was higher compared to LT (54.8% vs 39%, p = .01). The median number of hospitalizations (p = .001) and infectious complications (p = .04) was significantly higher only in the KT subjects who developed neutropenia (compared to those who did not). Multivariate analysis identified factors associated with severity of liver disease at transplant, namely h/o upper gastrointestinal bleeding (p = .02), weight deficit (p = .01), and pre-LT ANC (p = .01), along with high or moderate risk cytomegalovirus status (p = .05) as predictors of neutropenia in LT subjects. Female gender (p = .03) predicted neutropenia, while BK virus infection was protective for neutropenia (p = .04) in KT subjects.

CONCLUSIONS

The incidence of and morbidity associated with neutropenia within 1 year post-transplant is higher in KT subjects compared to LT subjects. The likely reason for this is the use of induction therapy (ATG, basiliximab) at the time of transplant in KT subjects.

The Human Bone Marrow Is Host to the DNAs of Several Viruses

The long-term impact of viruses residing in the human bone marrow (BM) remains unexplored. However, chronic inflammatory processes driven by single or multiple viruses could significantly alter hematopoiesis and immune function. We performed a systematic analysis of the DNAs of 38 viruses in the BM. We detected, by quantitative PCRs and next-generation sequencing, viral DNA in 88.9% of the samples, up to five viruses in one individual. Included were, among others, several herpesviruses, hepatitis B virus, Merkel cell polyomavirus and, unprecedentedly, human papillomavirus 31. Given the reactivation and/or oncogenic potential of these viruses, their repercussion on hematopoietic and malignant disorders calls for careful examination. Furthermore, the implications of persistent infections on the engraftment, regenerative capacity, and outcomes of bone marrow transplantation deserve in-depth evaluation.

Epidemiology of parvovirus B19 and anemia among kidney transplant recipients: A meta-analysis

Background

Persistent anemia has been described in kidney transplant (KTx) recipients with parvovirus B19 virus infection. However, the epidemiology of parvovirus B19 and parvovirus B19-related anemia after KTx remains unclear. We conducted this systematic review (1) to investigate the incidence of parvovirus B19 infection after KTx and (2) to assess the incidence of parvovirus B19 among KTx patients with anemia.

Materials and Methods

A systematic review was conducted in EMBASE, MEDLINE, and Cochrane databases from inception to March 2019 to identify studies that reported the incidence rate of parvovirus B19 infection and/or seroprevalence of parvovirus B19 in KTx recipients. Effect estimates from the individual studies were extracted and combined using random-effects, generic inverse variance method of DerSimonian and Laird. The protocol for this systematic review is registered with PROSPERO (no. CRD42019125716).

Results

Nineteen observational studies with a total of 2108 KTx patients were enrolled. Overall, the pooled estimated seroprevalence of parvovirus B19 immunoglobulin G was 62.2% (95% confidence interval [CI]: 45.8%-76.1%). The pooled estimated incidence rate of positive parvovirus B19 DNA in the 1^st year after KTx was 10.3% (95% CI: 5.5%-18.4%). After sensitivity analysis excluded a study that solely included KTx patients with anemia, the pooled estimated incidence rate of positive parvovirus B19 DNA after KTx was 7.6% (95% CI: 3.7%-15.0%). Among KTx with anemia, the pooled estimated incidence rate of positive parvovirus B19 DNA was 27.4% (95% CI: 16.6%-41.7%). Meta-regression analysis demonstrated no significant correlations between the year of study and the incidence rate of positive parvovirus B19 DNA (P = 0.33). Egger's regression asymmetry test was performed and demonstrated no publication bias in all analyses.

Conclusion

The overall estimated incidence of positive parvovirus B19 DNA after KTX is 10.3%. Among KTx with anemia, the incidence rate of positive parvovirus B19 DNA is 27.4%. The incidence of positive parvovirus B19 DNA does not seem to decrease overtime.

BK virus: Current understanding of pathogenicity and clinical disease in transplantation

BK polyomavirus (BKV) is an important cause of graft loss in renal transplant recipients that continues to pose a significant challenge to clinicians due to its frequently unpredictable onset, persistence, and the lack of effective antiviral agents or prevention strategies. This review covers our current understanding of epidemiology, viral transmission and disease progression, and treatment and prevention strategies that have been used to manage this disease.

Alloimmunity But Not Viral Immunity Promotes Allograft Loss in a Mouse Model of Polyomavirus-Associated Allograft Injury

Background

The interplay between viral infection and alloimmunity is known to influence the fate of transplanted organs. Clarifying how local virus-associated inflammation/injury and antiviral immunity can alter host alloimmune responses in transplantation remains a critical question.

Methods

We used a mouse model of polyomavirus (PyV) infection and kidney transplantation to investigate the roles of direct viral pathology, the antiviral immune response, and alloimmunity in the pathogenesis of PyV-associated allograft injury. We have previously shown that an effective primary T cell response is required in PyV-associated graft injury.

Results

Here we show that the transfer of primed antidonor, but not antiviral, T cells results in PyV-associated allograft injury. In further studies, we use a surrogate minor antigen model (ovalbumin) and show that only antidonor specific T cells and not antiviral specific T cells are sufficient to mediate injury. Lastly, we demonstrate that local but not systemic virus-mediated inflammation and injury within the graft itself are required.

Conclusions

These data suggest that in this mouse model, the predominant mechanism of allograft injury in PyV-associated injury is due to an augmented alloimmune T cell response driven by virus-induced inflammation/injury within the graft. These studies highlight the important interplay between viral infection and alloimmunity in a model system.

BK nephropathy in the native kidneys of patients with organ transplants: Clinical spectrum of BK infection

Nephropathy secondary to BK virus, a member of the Papoviridae family of viruses, has been recognized for some time as an important cause of allograft dysfunction in renal transplant recipients. In recent times, BK nephropathy (BKN) of the native kidneys has being increasingly recognized as a cause of chronic kidney disease in patients with solid organ transplants, bone marrow transplants and in patients with other clinical entities associated with immunosuppression. In such patients renal dysfunction is often attributed to other factors including nephrotoxicity of medications used to prevent rejection of the transplanted organs. Renal biopsy is required for the diagnosis of BKN. Quantitation of the BK viral load in blood and urine are surrogate diagnostic methods. The treatment of BKN is based on reduction of the immunosuppressive medications. Several compounds have shown antiviral activity, but have not consistently shown to have beneficial effects in BKN. In addition to BKN, BK viral infection can cause severe urinary bladder cystitis, ureteritis and urinary tract obstruction as well as manifestations in other organ systems including the central nervous system, the respiratory system, the gastrointestinal system and the hematopoietic system. BK viral infection has also been implicated in tumorigenesis. The spectrum of clinical manifestations from BK infection and infection from other members of the Papoviridae family is widening. Prevention and treatment of BK infection and infections from other Papovaviruses are subjects of intense research.

Severe neutropenia in children after renal transplantation: incidence, course, and treatment with granulocyte colony-stimulating factor

BACKGROUND

Infections are an important cause of morbidity and mortality in solid organ transplant recipients. Neutrophils play a crucial role in the initial host defense against bacterial pathogens. Neutropenia is not uncommon after renal transplantation in adults; however, there are scarce published data in children. We conducted a historical cohort study to evaluate the incidence, clinical course, and management of severe neutropenia after renal transplantation in children.

METHODS

In a single-center study, we collected clinical and laboratory data on all children (<20 years) who underwent renal transplantation from January 2005 to March 2014. All post-transplantation blood counts were reviewed; the lowest absolute neutrophil count was recorded and correlated with clinical information and other laboratory findings.

RESULTS

Of the 72 patients studied, 46 (64%) had at least one episode of neutropenia [absolute neutrophil count (ANC) <1500/μl] during the study period, 16 of whom (22%) had severe neutropenia (ANC < 500/μl), 2-11 months (median, 3.5) after renal transplantation. Work-up for viral infection or malignancy was performed. Initial management included dose decrease and subsequent discontinuation of antimetabolite, stopping co-trimoxazole and valganciclovir. Bone marrow aspiration in four children revealed normal marrow cellularity in all cases, with myelocyte maturational arrest in two. Eight children (11%) were treated with granulocyte colony-stimulating factor (G-CSF) (5 mcg/kg/day) 1-4 doses (median, 2), with excellent response in all and no adverse effects. Eight children presented with fever during severe neutropenia, and were treated with empiric antibiotics. Mycophenolate/azathioprine were resumed in all patients unless contraindicated (pre-existing BK viremia -1, PTLD -1). Recurrence of neutropenia was seen in five patients, only one of whom required further treatment with G-CSF. Graft function was preserved during and after resolution of neutropenia. Post-transplant neutropenia in children is common, and mostly occurs in the first few months. Its etiology is probably primarily a result of the combination of immunosuppressive agents and prophylactic treatment of infections in the early post-transplant period.

CONCLUSIONS

Decreasing immunosuppressive or antimicrobial medications carries the risk of acute rejection or infection. Off-label treatment with G-CSF may present a safe and effective alternative.