Human parvovirus B19 infection in organ transplant recipients

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.

Parvovirus b19-Induced Acute Hepatitis With Hepatosplenomegaly and Polyarthropathy

Parvovirus B19 infection can present with myriads of clinical diseases and syndromes; hepatitis and polyarthropathy are a few of these examples. Parvovirus frequently affects children but this condition has also been reported in adults. 

The present case report discusses a case of a 43-year-old female who presented to the outpatient department (OPD) with complaints of high-grade fever and pain in multiple joints of her body for three days.

On examination, stiffness and swelling of the hand, knees, wrist, and ankles were noted. Laboratory investigations showed highly elevated aspartate transaminase (AST), alanine transaminase (ALT), and bilirubin. Electrocardiogram (ECG) and echocardiogram (ECHO) findings were unremarkable. PCR testing showed the presence of parvovirus. Parvovirus B19 infection led to the development of acute hepatitis, which appeared as yellowing of skin (jaundice) and led to hepatosplenomegaly. Parvovirus-induced polyarthropathy was also observed in the patient. The patient was managed with a parenteral course of ceftriaxone, paracetamol, and a normal saline infusion. Anti-viral drugs were also prescribed to the patient including ribavirin and pegylated interferon. This case study will explore how the patient was diagnosed and managed with conventional therapy and anti-viral to relieve parvovirus-induced hepatitis with hepatosplenomegaly and polyarthritis.

Acute hepatitis can be caused by viruses and other noninfectious causes, all of which must be cleared out to avoid chronic disease development. When patients present with joint pain and skin rashes, a thorough workup for viral indicators, medication histories, autoimmune and metabolic illnesses, and parvovirus b19 infection is required.

The detection, treatment of parvovirus B19 infection induced anemia in solid organ transplants: a case series and literature review of 194 patients

BACKGROUND

There are no optimal diagnostic, treatment and post-infection surveillance strategies for parvovirus B19 infection in solid organ transplantation (SOT) recipients.

METHODS

We conducted a retrospective review of all PVB19 infected cases confirmed by qPCR among SOT recipients at our institution over a 3-year period and reviewed the literature from 1990 to 2021.

RESULTS

Eight kidney and two heart transplant patients with refractory anemia had PVB19 infection. The viral DNA load in peripheral blood ranged from 2.62 × 10² to 8.31 × 10⁶ copies/mL. Two patients with the lowest PVB19 DNA load only reduced the use of immunosuppressants and anemia was relieved. Eight received intravenous immunoglobulin (IVIG) (ranging from 0.25 to 0.5 g/kg/day). The median time to anemia improvement (hemoglobulin>100g/L) was 16 days (8-70 days) after treatment. One patient had a PVB19 relapse and viral DNA load > 1.00 × 10⁸ copies/mL at diagnosis. A total of 86 studies involving 194 SOTs were screened from the literature, and the most common symptom was anemia and low reticulocyte count. PVB19 DNA was detected in all cases. Of that, 91.4% of cases received IVIG, 53.8% received IVIG and immunosuppression reduction, 6.5% of cases showed reduced immunosuppression without IVIG, and 2.1% did not receive any special treatment. The recurrence rate was 17.5%.

CONCLUSION

PVB19 infection is a cause of anemia after SOT, and treatment mainly relies on IVIG and/or immunosuppression reduction.

Purpuric rash in an adolescent with fever, pancytopenia, and an hemophagocytic lymphohistiocytosis-like syndrome due to parvovirus B19

A rare case of parvovirus B19 infection associated with fever, hemorrhagic rash, and a clinical course resembling an incomplete HLH syndrome is presented. Parvovirus B19 should be included in the evaluation of febrile purpura and HLH-like syndrome.

Successful Treatment of Anemia With Anaplastic and Microangiopathic Characteristics in a Kidney Transplant Recipient With Parvovirus B19 Infection: A Case Report

BACKGROUND

The prevalence of parvovirus B19 infection in renal transplantation ranges from 2% to 30%. The age and immune status of the patient influence the severity of the clinical picture. A diagnosis is made by taking as evidence the giant proerythroblasts on a bone marrow sample and the parvovirus B19 viral replication with a polymerase chain reaction (PCR) technique at the blood level. Clinically, parvovirus B19 may appear with fever and severe anemia, which can be followed by pancytopenia and thrombotic microangiopathy in some cases. The literature reports a graft dysfunction rate ranging from 10% to 36%. An infection relapse may happen in 30% of cases.

CASE PRESENTATION

We report the case of a 33-year-old patient who underwent a kidney transplant in January of 2018. After transplantation, he reached a creatinine value of 1.1 mg/dL and a hemoglobin (Hb) level of 14 g/dL. In April 2019, he developed mycoplasma pneumonia, with signs of hemolytic anemia on bone marrow aspiration. Eventually, he was admitted because of fever, arthralgia, and anemia, with serologic and bone marrow biopsy evidence of red cell aplasia secondary to parvovirus B19 infection. He was treated with 400 mg/kg intravenous immunoglobulin (IVIg) for 10 days; 18 days after the end of treatment, he reached a creatinine value of 1.15 mg/dL, an Hb of 12.5 g/dL, and a reduction of the viral load from 25,000,000 copies/mL to 1,600,000 copies/mL.

CONCLUSIONS

Anemia with both an aplasic and hemolytic component was successfully treated using immunoglobulin therapy, with a significant fall in the parvovirus B19 viral load.

The immunophenotyping of different stages of BK virus allograft nephropathy

Objectives: To investigate the immunohistochemical features of different stages of BK virus allograft nephropathy (BKVN) and further elucidate the underlying immunological mechanism involved in the evolution of BKVN. Methods: Fifty-two renal transplant recipients with biopsy proven BKVN were retrospectively selected. According to the third edition of the American Society of Transplantation Infection guidelines, 10 patients were categorized as having mild BKVN (stage A), 25 were moderate (stage B) and 17 were severe (stage C). The differential infiltrations of CD3+ (T lymphocytes), CD4+ (helper T lymphocytes), CD8+ (cytotoxic T lymphocytes), CD20+ (B lymphocytes), CD68+ (macrophages) and CD138+ (plasma cells) cells and the expression of interleukin-2 receptor (IL-2R) and human leukocyte antigen DR (HLA-DR) were compared among the three groups. Results: CD3+, CD4+, CD8+, CD20+, CD138+ and CD68+ cells infiltrations, IL-2R and HLA-DR expression were positive in the BKVN patients. Moreover, with increasing stages of BKVN, the numbers of positively stained inflammatory cells and the expression of IL-2R were significantly increased in the severe group compared to the mild group, whereas no statistically significant differences were observed with regard to HLA-DR expression. Eosinophil and neutrophil infiltration could also be observed in moderate to advanced BKVN. Conclusion: Renal allograft damage caused by BKVN involved T lymphocyte-, B lymphocyte- and mononuclear macrophage-mediated immune responses. Inflammatory cell infiltrations in the renal allograft were probably the driving force for BKVN progression. Additionally, eosinophils and neutrophils may be involved in the pathophysiological mechanism of BKVN.

Pure Red Cell Aplasia After Kidney Transplantation: Parvovirus B19 Culprit or Coincidence?

Background

Anemia is present even in long-term observation after kidney transplantation. Observational study results indicate the presence of chronic post-transplantation anemia in 1 in 3 recipients. An extreme form of erythroid line dysfunction is pure red cell aplasia (PRCA). It may be caused by immunosuppressive treatment per se or a side effect, opportunistic pathogen activation. Parvovirus B19 (PV B19) infection is quite likely the cause of refractory normocytic anemia in immunocompromised patients.

Case Report

In this case report we discuss biological and clinical features of this phenomenon and the treatment strategies, based on 2 PRCA cases in kidney transplant recipients. Additionally, a systematic review of published reports of PV B19 related PRCA in kidney recipients is presented.

Conclusions

PV replication should be ruled out in cases of persistent and/or refractory anemia after kidney transplantation. The established first-line treatment of PRCA is passive immunization. Taking into account cost effectiveness, a decrease in immunosuppression load is reasonable under careful control of allograft function.

Update of the human parvovirus B19 biology

Since its discovery, the human parvovirus B19 (B19V) has been associated with many clinical situations in addition to the prototype clinical manifestations, i.e. erythema infectiosum and erythroblastopenia crisis. The clinical significance of the viral B19V DNA persistence in sera after acute infection remains largely unknown. Such data may constitute a new clinical entity and is discussed in this manuscript. In 2002, despite the genetic diversity among B19V viruses has been reported to be very low, the description of markedly distinct sequences showed a new organization into three genotypes. The most recent common ancestor for B19V genotypes was estimated at early 1800s. B19V replication is enhanced by hypoxia and this might to explain the high viral load detected by quantitative PCR in the sera of infected patients. The minimum infectious dose necessary to transmit B19V infection by the transfusion of labile blood products remains unclear. At the opposite, the US Food and Drug Administration proposed a limit of 10(4)IU/mL of viral DNA in plasma pools used for the production of plasma derivatives. Recently, a new human parvovirus (PARV4) has been discovered. The consequences on blood transfusion of this blood-borne agent and its pathogenicity are still unknown.

Parvovirus B19 (B19) and cytomegalovirus (CMV) infections and anti-erythropoietin (anti-EPO) antibodies in patients on dialysis hyporesponsive to erythropoietin therapy

BACKGROUND

Approximately 10% of patients receiving recombinant human erythropoietin (rHuEPO) do not respond to the treatment. We evaluated parvovirus B19 (B19) and cytomegalovirus (CMV) infections and antierythropoietin (anti-EPO) antibodies as potential causes of anemia in dialyzed patients, hyporesponsive to rHuEPO.

METHODS

Data from 120 dialyzed patients, receiving rHuEPO alfa, were collected: demographic characteristics, rHuEPO dose, duration of rHuEPO treatment and time on dialysis, etiology of chronic kidney disease and transfusion history. Serology and PCR were performed to address B19 and CMV infection status. An ELISA was developed to detect anti-EPO antibodies.

RESULTS

rHuEPO resistance correlated with high ferritin levels (p = 0.001) and short time on dialysis (p = 0.012). B19 DNA was found in 10 (8.3%) dialyzed patients and CMV DNA was detected in 33 (27.5%). There was no significant correlation between B19 infection and anemia,while a tendency of correlation between active CMV infection and hemoglobin levels or hematocrit value (p= 0.069 and p= 0.070, respectively) has been observed. Anti-EPO antibodies were not detected in any patient.

CONCLUSIONS

B19 infection is a rare complication in dialyzed patients and should be investigated after exclusion of other common causes, while CMV infection is rather common. The role of CMV infection in the hyporesponsiveness in dialyzed patients should be further evaluated in other studies. Our data suggest that anti-EPO antibodies are not involved in rHuEPO resistance in this population.

Clinical investigation of human parvovirus B19 infection after renal transplantation in China

OBJECTIVE

We investigated the incidence of human parvovirus B19 (HPV B19) infection after renal transplantation as well as the risk of anemia and renal allograft damage among infected transplant recipients in China.

METHODS

We selected 114 patients at 1-18 months after renal transplantation for detection of HPV B19 DNA copies compared with a control population. Renal function and hematopoiesis were compared between infected and noninfected groups.

RESULTS

Twenty-seven patients diagnosed with HPV B19 infection during follow-up (18.75%),which was a significantly higher number than among the general population over the same period. Infected versus nonaffected patients exhibited a significantly higher incidence of anemia and urinary abnormalities in addition to significantly lower values of hemoglobin, higher serum creatinine concentrations, and lower glomerular filtration rates. The 2 groups did not differ in the types or doses of calcineurin inhibitor (CNI) immunosuppressants. Two cases of pure red cell aplasia (PRCA) as confirmed using bone marrow biopsy, were observed in the infected group. They displayed HPV B19 DNA copy numbers >10(7)/mL and segmental mesangial cell proliferation on renal biopsy. The PRCA cases were cured with immunomodulatory therapy.

CONCLUSIONS

The HPV B19 infection rate was significantly higher among renal transplant recipients than normal controls. Infections correlated with damage to the renal allograft, which may in turn cause PRCA. Immunomodulation therapy was effective to treat this complication of HPV B19 infection.

[Parvovirus B19 infection after kidney transplantation]

Prevalence for human parvovirus B19 infection is estimated to be between 2% and 30% in renal transplant recipients. In post-transplant settings, parvovirus B19 infection may occur either as a primary infection or a reactivation. Parvovirus transmission most commonly occurs through respiratory tract but may also result from graft or blood packs contamination. Co-infections with HHV-6 and CMV viruses are frequent. The hallmark symptom is anemia, more rarely pancytopenia and hemophagocytic syndrome. In respect to renal involvement, parvovirus B19 infection has been associated with graft dysfunction in 10% of cases. Both thrombotic microangiopathies and collapsing glomerulopathies have been reported concomitantly with parvovirus B19 infection but the causal link remains unclear. Other complications are seldomly reported, including hepatitis, encephalitis, and myocarditis. Diagnosis is based on pre and post-transplant serological status. In addition, the management of parvovirus B19 infection in immunocompromised patients requires quantitative assessment of blood viral load by PCR. The treatment relies primarily on reduction of immunosuppression combined with intravenous immunoglobulin infusions. Relapses occur in 30% of cases.

Infection and chronic allograft dysfunction

With the advent of more potent immunosuppressive regimens, the incidence of acute rejection following renal transplantation has declined sharply in recent years. In spite of this, long-term graft outcomes remain suboptimal because of relentless attrition by cumulated insults to the allograft. As acute rejection rates have declined, other causes of graft injury and loss have recently emerged. Among these, infectious diseases remain a persistent threat and can be associated with allograft dysfunction. This group includes nephropathy due to polyoma (BK) virus infection, cytomegalovirus disease, and bacterial infection (the latter most commonly arising from the urinary tract). Rarer infectious causes of chronic allograft dysfunction include cryoglobulinemia associated with hepatitis C, Epstein-Barr virus-associated posttransplant lymphoproliferative disease, and direct cytotoxicity from adenoviral infection or parvovirus B19.

Advances in human B19 erythrovirus biology

Since its discovery, human parvovirus B19 (B19V), now termed erythrovirus, has been associated with many clinical situations (neurological and myocardium infections, persistent B19V DNAemia) in addition to the prototype clinical manifestations, i.e., erythema infectiosum and erythroblastopenia crisis. In 2002, the use of new molecular tools led to the characterization of three different genotypes of human B19 erythrovirus. Although the genomic organization is conserved, the geographic distribution of the different genotypes varies worldwide, and the nucleotidic divergences can impact the molecular diagnosis of B19 virus infection. The cell cycle of the virus remains partially unresolved; however, recent studies have shed light on the mechanism of cell entry and the interactions of B19V proteins with apoptosis pathways.

Parvovirus B19-related Anaemia After Renal Transplantation

We describe here the case of a renal transplant recipient treated by sirolimus based immunosuppresive therapy, who developed severe and unusual pancytopenia 2 months after renal transplantation. Parvovirus B19 primo-infection was diagnosed. The first course of intravenous immunoglobulin failed. Bone marrow aspiration confirmed megaloblastic anaemia associated with parvovirus B19. Finally, this infection was succesfully treated by the reduction of immunosuppression combined with a second course of intravenous immunoglobulin.

Antibody-mediated opsonization of red blood cells in parvovirus B19 infection

Red blood cells (RBCs) express abundantly parvovirus B19 receptor, and their role in the dissemination or clearance of B19 infection is unknown. In this study, we report that in early, acute or persistent infection, B19 viremia is mostly associated with RBCs. The capacity of different patients' plasma or IgG to opsonize RBCs collected from patients with early B19 infection, was investigated. The highest opsonization activity was observed with plasma or IgG fractions from patients with past B19 infection. In contrast, IgG samples from patients with acute or persistent infection showed no or little opsonization activity. The depletion of antibodies specific to B19 VP1, but not VP2, from IgG samples, resulted in a significant suppression of opsonization. Furthermore, IgG samples preincubated with heated B19 particles exposing VP1-unique (VP1u) region were unable to opsonize RBCs. These observations clearly suggest a role for anti-VP1u IgG in the opsonization of RBC-bound B19 particles.

Parvovirus-B19-associated complications in renal transplant recipients

Parvovirus B19 is a common human pathogen, causing erythema infectiosum in children, hydrops fetalis in pregnant women, and transient aplastic crisis in patients with chronic hemolytic anemia. Immunosuppressed patients can fail to mount an effective immune response to B19, resulting in prolonged or persistent viremia. Renal transplant recipients can develop symptomatic B19 infections as a result of primary infection acquired via the usual respiratory route or via the transplanted organ, or because of reactivation of latent or persistent viral infection. The most common manifestations of B19 infection in immunosuppressed patients are pure red cell aplasia and other cytopenias. Thus, this diagnosis should be considered in transplant recipients with unexplained anemia and reticulocytopenia or pancytopenia. Collapsing glomerulopathy and thrombotic microangiopathy have been reported in association with B19 infection in renal transplant recipients, but a causal relationship has not been definitively established. Prompt diagnosis of B19 infection in the renal transplant recipient requires a high index of suspicion and careful selection of diagnostic tests, which include serologies and polymerase chain reaction. Most patients benefit from intravenous immunoglobulin therapy and/or alteration or reduction of immunosuppressive therapy. Conservative therapy might be sufficient in some cases.

Parvovirus B19 and the kidney

Infection with parvovirus B19 causes several clinical syndromes (fifth disease, transient aplastic crisis, pure red cell aplasia, and hydrops fetalis) and may contribute to other illnesses. B19 has been linked to renal disease in three settings: As a cause of acute glomerulopathy and as a cause of anemia in ESRD and kidney transplantation. Case reports implicate parvovirus in the pathogenesis of proliferative glomerulonephritis and collapsing glomerulopathy, but a causal relationship has not been established. A proposed role for B19 infection is based on the temporal association of renal findings with viral infection, positive serology, and identification of the viral genome in the glomerulus. Mechanisms may include cytopathic effects on glomerular epithelial cells and/or endothelial cells and glomerular deposition of immune complexes. Patients who require dialysis may have increased susceptibility to acute and chronic anemia after parvoviral infection. Factors that predispose this population to complications of B19 infection include impaired immune response, deficient erythropoietin production, and possibly decreased erythrocyte survival. The clinical burden of parvovirus B19 infection in renal transplant recipients may be underestimated; these individuals may develop persistent viremia as a result of a dysfunctional immune response. Chronic anemia and pure red blood cell aplasia are the most common complications of parvovirus infection in this population; the diagnosis should be considered in transplant recipients with unexplained anemia or pancytopenia. Allograft rejection and dysfunction have been reported in association with infection, but a cause-effect relationship has not been proved. Further investigation of the relationship between B19 and kidney disease is warranted.

Quantification of viral inactivation by photochemical treatment with amotosalen and UV A light, using a novel polymerase chain reaction inhibition method with preamplification

Background. In evaluating a photochemical treatment process for inactivating parvovirus B19, there lacked simple culture methods to measure infectivity. The recently developed enzyme‐linked immunospot (ELISpot) infectivity assay uses late‐stage erythropoietic progenitor cells and is labor intensive and time consuming. We evaluated a novel, efficient polymerase chain reaction (PCR) inhibition assay and examined correlations with reductions in infectivity.

Methods. Contaminated plasma was treated with 150 μmol/L amotosalen and 3 J/cm² ultraviolet A light and then tested for DNA modification using conventional PCR inhibition and a novel preamplification approach. The novel assay subjected the samples to preamplification cycles using long‐template PCR, followed by quantitative PCR (QPCR) inhibition detection. Both approaches were tested for correlations with reductions in viral infectivity by comparing ELISpot assay results of identical samples.

Results. The B19 preamplification inhibition assay showed detection ranges of 2–2.5 log and demonstrated quantitative correlation with up to a 5.8‐log reduction in viral infectivity in ELISpot results. Conventional PCR detected a >5 log reduction in amplification, correlated with a 4.4‐log reduction in viral infectivity. A range of 4‐log inhibition of hepatitis B virus DNA amplification was also achieved.

Conclusions. The results demonstrated that a novel preamplification QPCR assay is a useful tool for predicting reductions in infectivity after photochemical treatment. This assay was extended to show utility in circumstances where practical in vitro assays are unavailable for the determination of the efficacy of pathogen inactivation.

Collapsing and non-collapsing focal segmental glomerulosclerosis in kidney transplants

BACKGROUND

The aetiological and clinical associations of collapsing focal segmental glomerulosclerosis (cFSGS) following kidney transplantation (KTx) are poorly described. In this study, post-transplant cFSGS and non-collapsing FSGS (ncFSGS) were compared in recent KTx recipients. Evidence for intragraft viral infection was sought.

METHODS

Twenty-nine cases of post-KTx FSGS were identified and classified as cFSGS (n = 10) or ncFSGS (n = 19). Biopsies were scored using Banff '97 criteria and subjected to in situ hybridization (ISH) for parvovirus B19 (pvB19), simian virus 40 (SV40) and BK virus (BKV).

RESULTS

cFSGS and ncFSGS patients were comparable for age, gender, weight, delayed function, human leucocyte antigen (HLA) matching, acute rejection and median time to diagnosis. Deceased donor source was more common among cFSGS cases (70 vs 32%, P = 0.05). FSGS was recurrent in 2/10 cFSGS cases compared with 8/19 ncFSGS (P = NS). cFSGS was associated with more proteinuria (11.9 vs 7.2 g/day, P = 0.05) and higher serum creatinine (4.2 vs 1.9 mg/dl, P = 0.0001) at diagnosis. Plasmapheresis was used in two out of 10 cFSGS and seven out of 19 ncFSGS cases with treatment response in 0 of two and three of seven, respectively. Graft loss was more rapid with cFSGS compared with ncFSGS (P = 0.02). Histologically, cFSGS was associated with more severe chronic vascular abnormalities. All biopsies were negative for pvB19, SV40 and BKV by ISH.

CONCLUSIONS

cFSGS following KTx presents with higher proteinuria, diminished renal function, more severe vascular disease and higher rate of graft loss compared with the non-collapsing form. There was no evidence for infection by pvB19 or polyomaviruses.

Parvovirus B19 infection after transplantation: a review of 98 cases

BACKGROUND

Infections with parvovirus B19 (PVB19) can cause significant morbidity in transplant recipients.

METHODS

To characterize the epidemiology and clinical spectrum of posttransplant PVB19 infection, we reviewed all cases at our institution during a 16-year period, summarized the data from 91 cases published in the medical literature, and performed longitudinal molecular surveillance for PVB19 DNAemia among 47 solid organ and hematopoietic stem cell transplant recipients.

RESULTS

The median time to onset of PVB19 disease was 7 weeks after transplantation. Anemia, leukopenia, and thrombocytopenia were present in 98.8%, 37.5%, and 21.0% of patients, respectively. Hepatitis, myocarditis, and pneumonitis were also reported in association with PVB19 disease. Allograft tissue loss or dysfunction was observed at the time of PVB19 disease in 10% of cases. At the onset of disease, PVB19 IgM serological test results were negative in 29% of cases. Almost all patients (96%) with anti-PVB19 IgM had a positive PVB19 polymerase chain reaction assay result. Intravenous immunoglobulin was the most commonly used treatment modality. Three of 98 patients died of myocarditis and cardiogenic shock associated with PVB19 disease. Molecular surveillance throughout the first year after transplantation did not reveal PVB19 DNAemia in 47 anemic solid organ and hematopoietic stem cell transplant patients.

CONCLUSIONS

PVB19 is a rare but clinically significant infection that manifests as refractory anemia during the posttransplantation period. The use of polymerase chain reaction for diagnosis is particularly helpful in immunosuppressed transplant patients who may fail to mount antibodies against PVB19 during active infection.

Intravenous immunoglobulin: striving for appropriate use

BACKGROUND

Intravenous immunoglobulin (IVIG) is the mainstay therapy in human immune deficiency states characterized by qualitative and quantitative reductions in B cells. In addition, however, there is widespread use of IVIG in a number of other areas, including neuroimmunologic, infectious, dermatologic, hematologic, autoimmune, inflammatory and idiopathic disorders. In many of these cases, there are little objective data to support the use.

METHODS

We performed a review of more than 400 publications in PubMed using the key words 'intravenous immunoglobulin' and excluded publications that focused on immune deficiency, for which the indication for IVIG is already clear.

RESULTS

For a number of off-label indications, there is significant evidence of efficacy and IVIG has become the standard of care for many clinical syndromes other than immune deficiency. In some conditions, however, the data have not been well controlled or randomized and are often limited to case reports that are difficult to interpret. Although the critical shortage of IVIG of the last decade is no longer an issue, IVIG is expensive and not without risk. The use of IVIG should be based not only on clinical data, but also, and especially, on the biological rationale for its use.

CONCLUSIONS

The appropriate use of IVIG is an important issue that is difficult to resolve, and will continue to challenge clinicians based on expense and potentially limited supply, including the intrinsic limitations of donor plasma. The establishment of national and international voluntary registries to report use of IVIG in disorders for which evidence is lacking would be a first step toward facilitating randomized, controlled clinical trials.

Plasma Cell-Rich Rejection Processes in Renal Transplantation: Morphology and Prognostic Relevance

BACKGROUND

Renal transplantation is the most effective therapy in end-stage renal disease. The prognosis of transplant survival is still determined by rejection. Morphologically, this involves interstitial rejection with potential development of vascular rejection (VR) and/or glomerular rejection processes, designated as transplant glomerulopathy (TGP). The cellular infiltrates are usually dominated by lymphocytes and macrophages in differing quantity, characterizing the severity of the rejection processes.

METHODS

In 14% of the renal transplant biopsies and explants in our investigation (n = 399) plasma cells (PR) predominate in the cellular infiltrate. To determine whether the enrichment of PR has an impact on graft function or could even constitute an independent parameter for transplant survival, we analyzed 109 cases of transplanted patients matched for AR and CR and divided them into those rich and those nonrich in PR.

RESULTS

In the group rich in PR, PR comprised 30% of all infiltrates in comparison to 5% in the group non-rich in PR. VR and TGP appeared significantly more often in PR-rich rejections (P = 0.0044). The group rich in PR had a significantly more adverse prognosis (P = 0.0024), especially if PR enrichment was observed in the chronic rejection processes (P = 0.0148). In the Cox proportional hazard model the occurrence of VR was the only independent factor.

CONCLUSION

In itself, plasma-cell enrichment is not a prognostic marker, but it is an indicator of a more adverse outcome because it is often accompanied by the appearance or subsequent development of VR +/- TGP. The detection of PR-rich rejection processes should therefore encourage the clinician to intensify the immunosuppressive schedule.

Parvovirus B19-induced anemia in renal transplantation: a role for rHuEPO in resistance to classical treatment

Human parvovirus B19 (PVB 19) is responsible for pure red cell aplasia in immunocompromised patients, and particularly solid organ recipients. Intravenous immunoglobulins (IVIG) have been shown to be efficient to achieve the correction of anemia in association with the reduction of immunosuppression. We report a case of kidney transplant recipient with PVB 19-induced anemia that did not respond to recombinant human erythropoietin (rHuEPO) and to a first course of IVIG. After discontinuation of rHuEPO, a second course of IVIG was successful with the resolution of anemia. We discuss the role of rHuEPO that may facilitate PVB 19 replication in erythropoietin-sensitive human erythroid progenitor cells.

Parvovirus B19 VP2-proteins produced in Saccharomyces cerevisiae: comparison with VP2-particles produced by baculovirus-derived vectors

The capsids of human parvovirus B19 consist of two structural proteins, the minor-capsid protein VP1 and the major-capsid protein VP2. The latter which constitutes for 95% of the capsid are able to form virus-like particles (VLPs) in yeast without the presence of VP1-proteins. VP2-proteins produced in Saccharomyces cerevisiae have the capacity to form VLPs in the absence of VP1-proteins. These yeast-derived VLPs resemble native virus or recombinant VP2-VLPs produced by baculovirus systems in respect of size, molecular weight and of antigenicity as shown by antigen-capture ELISA and T-cell proliferation tests. Regarding costs, yield and ease of handling particle production in yeast represents an alternative to the recombinant baculovirus expression system which is so far the source for VP2-VLPs of human parvovirus B19.

A cluster of parvovirus B19 infections in renal transplant recipients: a prospective case series and review of the literature

Up to 9% of renal transplant recipients have severe multifactorial erythropoietin-resistant anemia. Human parvovirus B19 (PVB19) infection can cause severe anemia and is likely underreported. Sparse information on epidemiology and management in this population exists. To address these issues, after our first index case, we modified our clinical practice to prospectively screen patients with persistent hemoglobin (Hb) <10 mg/dL for PVB19 infection after excluding common causes of anemia including erythropoietin resistance. Potentially infected patients were further evaluated by serology, qualitative polymerase chain reaction (quPCR) and bone marrow biopsy (BMB) for cytomegalovirus, Epstein-Barr virus, PVB19 and other etiologies. Over 3 months, 212 kidney recipients visited outpatient clinics. Of 52 recipients with anemia, 8 had an Hb <10 mg/dL with erythropoietin resistance and were screened for PVB19 infection. Three cases had PVB19 infection by quPCR and often-inconclusive serology/BMB results. Cases had immunosuppression reduced and received IVIG (0.5 gm/kg x 4 doses) with recovery from anemia, viral clearance in two cases and one recurrence. PVB19-mediated anemia occurred in up to three out of eight (38%) screened kidney recipients with Hb <10 mg/dL resistant to erythrypoietin. We recommend prospective risk stratification for this population, high indices of suspicion using at least qualitative techniques for diagnosis and treatment goal for viral eradication.

Exposure of hematologic patients to parvovirus B19 as a contaminant of blood cell preparations and blood products

BACKGROUND

Patients with hematologic malignancies often require blood products, and parvovirus B19 is known to be transmitted by this route. Primary infection with parvovirus B19 shows a wide variety of disease manifestation. In immunocompromised patients, symptoms are severe and viral clearance is delayed or missing.

STUDY DESIGN AND METHODS

A total of 2123 blood products given to all patients of a hematologic ward over a period of 6 months were retrospectively examined for the presence of parvovirus B19 DNA by an in-house real-time polymerase chain reaction (PCR; TaqMan). Patients who had received B19 DNA-positive blood products were further investigated serologically and by PCR for the presence of parvovirus B19 antibodies and DNA.

RESULTS

Twenty-one (1%) of 2123 blood products tested positive for the presence of B19 DNA (2% of pooled products, 0.7% of single-donor products, and 17.6% of allogeneic peripheral blood progenitor cells), the median viral load was 700 genome equivalents per mL. During the study period, 114 patients were treated on the ward, and 14 (12%) of them received B19 DNA-positive blood components. None of them developed symptoms of an acute B19 infection, although one had a short low-level viremia.

CONCLUSIONS

Although B19 DNA was detected in 1 percent of blood products given to hematologic patients, the exposure of 12 percent of patients did not result in symptomatic infections.

Renal Anemia Aggravated by Long-Term Parvovirus B19 and Cytomegalovirus Infection in a Renal Transplant Patient: Case Report and Evaluation of B19 Seroprevalence in Dialysis Patients

Due to viral replication in erythroid precursor cells, severe anemia represents a major complication of B19 infection. However, cytomegalovirus (CMV) is the leading cause of virus-induced complications with a significant impact on graft outcome of renal transplant patients. Herein, we present a long-term B19 infection in a 45-year-old female renal transplant patient, which aggravated the renal anemia associated with a concomitant CMV infection. Since no data were available on the seroprevalence of this virus in pretransplant patients, we determined the B19 serostatus of 90 dialyzed pretransplant adult subjects.

Abundance of interstitial eosinophils in renal allografts is associated with vascular rejection

BACKGROUND

The authors investigated the possible relevance of significant interstitial graft eosinophilic infiltrate (SIGEI) to the pathologic diagnosis of renal transplants.

METHODS

The authors performed a clinical and pathologic review of 29 consecutive patients with renal allograft failure and nephrectomy. As a result of their size, such specimens are more conducive than biopsies to the investigation of large blood vessels. SIGEI was diagnosed when eosinophils represented 10% or more of the interstitial inflammatory infiltrate. Vascular rejection was graded according to the Banff criteria. Risk for allergic interstitial nephritis and immunosuppression at the time of the nephrectomy-high dose, minimal, or none-was determined from the clinical history.

RESULTS

SIGEI was observed in 13 of the 29 patients and was absent in 16. Vascular (Banff type II) rejection was present in 11 of 13 cases with SIGEI and in 9 of 16 cases without SIGEI. The relation between SIGEI and Banff type II rejection was statistically significant: in 14 patients on high-dose immunosuppression, vascular rejection was present in all 5 cases with SIGEI, whereas in the 9 grafts without SIGEI, only 3 had vascular rejection (P=0.04). The authors did not find an association between SIGEI and risk for iatrogenic interstitial nephritis: SIGEI was seen in only 4 of 15 patients with high or moderate iatrogenic risk.

CONCLUSIONS

In this series of allograft nephrectomies, SIGEI was significantly associated with vascular rejection (Banff type II) but not with risk of allergic iatrogenic nephritis, suggesting that the presence of SIGEI may be a helpful criterion in the pathologic diagnosis of renal allografts.

Danger signals derived from stressed and necrotic epithelial cells activate human eosinophils

Eosinophilic granulocytes are found in tissues with an interface with the external environment, such as the gastrointestinal, genitourinary and respiratory tracts. These leucocytes have been associated with tissue damage in a variety of diseases. The aim of this study was to evaluate whether necrotic epithelial cells can activate eosinophils. The danger theory postulates that cells of the innate immune system primarily recognize substances that signal danger to the host. We damaged epithelial cell lines derived from the genital (HeLa cells), respiratory (HEp-2 cells) and intestinal tracts (HT29 cells) and assessed their capacity to cause eosinophilic migration, release of putative tissue-damaging factors, such as eosinophil peroxidase (EPO) and eosinophil cationic protein (ECP), as well as secretion of tissue-healing factors, e.g. fibroblast growth factors (FGF)-1 and -2 and transforming growth factor (TGF)-beta1. We found that necrotic intestinal cells induced chemotaxis in human eosinophils. EPO release was elicited in eosinophils stimulated with necrotic cells derived from all cell lines, as well as from viable HEp-2 and HT29 cells. Release of ECP was only seen in eosinophils incubated with necrotic intestinal or genital cells, not viable ones. Both necrotic intestinal and genital cells elicited FGF-2 secretion from eosinophils. TGF-beta1 was released from eosinophils exposed to viable and necrotic HT29 cells. These findings indicate that eosinophils are able to recognize and be activated by danger signals released from damaged epithelial cells, which may be of importance in understanding the role of eosinophils in the various inflammatory conditions in which they are involved.

Persistent human parvovirus B19 infection in children under maintenance chemotherapy for acute lymphocytic leukemia

OBJECTIVE

To report on B19 infection management and chemotherapy schedule consequences in five children treated for acute lymphocytic leukemia (ALL).

PATIENTS AND METHODS

Between May 2001 and February 2002, five patients between 4 and 12 years of age, receiving maintenance chemotherapy for ALL, presented with symptoms suggesting B19 infection (pallor, fatigue, petechiae and pancytopenia in four patients; generalized rash in two patients; acute hepatitis in one patient). Qualitative polymerase chain reaction (PCR) on peripheral blood was used for diagnosis and follow-up of infection; quantitative PCR was used for viral load measurement. Intravenous nonspecific high-dose immunoglobulin therapy was administered until PCR was negative.

RESULTS

Qualitative B19 DNA was found in the peripheral blood of all patients, confirming the infection. Viral load at diagnosis ranged from 10 to 10 particles/mL blood. B19 DNA was detectable in four patients at 45, 21, 40, and 44 weeks, respectively. Chemotherapy was delayed in all patients. No clear benefit of intravenous immunoglobulin was noted.

CONCLUSIONS

Infection with B19 is rarely reported in patients with ALL, but it should be suspected when unexplained pancytopenia occurs during chemotherapy. Persistent B19 infection remains a challenge in the management of patients receiving maintenance chemotherapy for ALL, as no specific therapy such as a specific immunoglobulin or vaccine exists. The role of viral load measurement needs to be established in terms of its use in follow-up and evaluation of the therapeutic response.

Histopathologic findings and classification of feline renal transplants

Seventy-seven feline transplant kidney specimens, obtained from 1 to 3,183 days (9 years) after transplantation, were reevaluated histologically and classified on the basis of the Banff '97 guidelines for human renal transplant kidneys. Overall, this classification system appeared useful in detecting rejection reactions and confirmed the finding in humans that biopsies can diagnose subclinical rejection and therefore are an important diagnostic tool for the follow up of renal transplants. However, on the basis of serum creatinine values, the severity of the acute or active and chronic lesions was not accurately reflected by this scoring system. This is thought to be due to the significant differences in histologic rejection patterns, especially in acute or active rejection, in cats when compared with humans. Tubulitis, lymphocytic glomerulitis, and vasculitis, which are the main pillars of the Banff '97 acute or active rejection scoring system, are either rare or not found in cats. The presence of significant necrotizing glomerulitis and vasculitis in feline renal transplants might imply that the rejection is complicated by acute antibody-mediated rejection. Alternatively, cyclosporine toxicity also should be considered because some of these kidneys show other signs of cyclosporine toxicity. Finally, the significance of subcapsular and interlobular phlebitis, rarely described in human rejection reactions but a distinct entity in cats, is unknown. From this study, it is clear that there are significant differences in the histology of acute or active rejection between humans and cats and that a better understanding of the histologic appearance of renal allografts will be especially beneficial for treatment and prognostic purposes.

Recurrent high level parvovirus B19/genotype 2 viremia in a renal transplant recipient analyzed by real-time PCR for simultaneous detection of genotypes 1 to 3

Organ transplant recipients infected with parvovirus B19 frequently develop persistent viremia associated with chronic anemia and pure red cell aplasia. In this study, a male renal transplant recipient who had been infected with parvovirus B19/genotype 2 after renal transplantation at the age of 34 years is described. The patient was repeatedly treated with high dose intravenous immunoglobulin (IVIG) that resulted in the resolvement of symptoms but not in virus eradication. During an observation period of 33 months after transplantation three phases associated with high parvovirus B19 viremia were observed. Both the first and the second viremic phases were combined with severe anemia. Parvovirus B19 specific IgM-antibodies were initially detected at the beginning of the second phase in continually rising concentrations. Initially eradication of the virus by immunoglobulin therapy was reported after the first viremic phase [Liefeldt et al. (2002): Nephrol Dial Transplant 17:1840-1842]. Retrospectively this statement has to be corrected. It was based on the use of a qualitative PCR assay specific for parvovirus B19 genotype 1 associated with reduced sensitivity for detection of genotype 2. After sequence analysis of the viral DNA and adjustment of a real-time PCR assay (TaqMan) for quantitative detection of all three B19 virus genotypes analysis of consecutive serum samples allowed the demonstration of long lasting phases with reduced viral loads following IVIG-treatment. These results demonstrate that IVIG treatment of parvovirus B19-triggered anemia in transplant recipients offers an opportunity to resolve symptoms, but does not guarantee eradication of the virus. Since reactivation of parvovirus B19 infection can result in high virus load associated with the recurrence of symptoms repeated screening for viral DNA is recommended using the TaqMan system established for quantitative detection of all three genotypes of parvovirus B19.

Frequent detection of parvovirus B19 genome in the myocardium of adult patients with idiopathic dilated cardiomyopathy

Aside from enteroviruses and other viruses, e.g., adenoviruses, which are known to be associated with idiopathic dilated cardiomyopathy (IDC), a cardiac tropism is also attributed to parvovirus B19 (PVB19). The purpose of the present study was to determine the prevalence of enterovirus, adenovirus and PVB19 genomes in the myocardium of adult patients with IDC and to analyze the significance of PVB19 with regard to the course of the disease, as compared to the other cardiotropic viruses. In 52 adult patients with IDC and 10 control patients with normal left ventricular ejection fraction (> or =55%) undergoing coronary artery bypass surgery, myocardial tissue samples were investigated for enteroviral RNA using polymerase chain reaction (PCR) and Southern blot hybridization of the PCR product. Specific nested PCR was used to assess the prevalence of adenovirus and PVB19 DNA, in addition to sequencing of the latter. The clinical and echocardiographic course of the disease was followed for a mean (+/- SD) period of 21.1+/-9.5 months. Fourteen of the 52 patients (27%) were enterovirus-positive, 2/52 (4%) patients were adenovirus-positive, 14/52 (27%) patients were PVB19-positive, 8/52 (15%) patients were enterovirus plus PVB19-positive, and in 14/52 (27%) patients no viral genomes were found. Six patients died during the follow-up period, without any significant difference between the patient groups: 1/14 (7%) in the enterovirus-positive, 0/2 (0%) in the adenovirus-positive, 2/14 (14%) in the PVB19-positive, 1/8 (12.5%) in the enterovirus plus PVB19-positive, and 2/14 (14%) in the virus-negative group. PVB19 genome was found in 4 of the 10 (40%) control patients, but no enterovirus or adenovirus genomes were detected in these patients. In conclusion, in the myocardium of patients with IDC, PVB19 is detectable as frequently as enteroviral genome. PVB19-positive patients with IDC have a rather favorable prognosis and do not differ significantly from the other virus-positive or virus-negative patient groups with respect to survival. Finally, the pathogenetic and prognostic significance of PVB19 in IDC still remains unclear.

B19 virus infection in renal transplant recipients

BACKGROUND

B19 virus infection with persistent anaemia has been reported in organ transplant recipients. Detection of B19 virus DNA in serum is the best direct marker of active infection.

OBJECTIVE

The present study evaluated the incidence and clinical role of active B19 virus infection in renal transplant recipients presenting with anaemia.

STUDY DESIGN

Forty-eight such recipients were investigated by nested PCR on serum samples. The controls were 21 recipients without anaemia. Active HCMV infection was also investigated as a marker of high immunosuppression.

RESULTS AND CONCLUSIONS

In 11/48 (23%) patients B19 virus DNA was demonstrated in serum versus only 1/21 (5%) of the controls. Ten of these 11 patients had already been seropositive at transplantation and active infection occurred in eight of them during the first 3 months after transplantation. The remaining patient experienced a primary infection 9 months after transplantation. Eight (73%) of these 11 patients displayed a concomitant HCMV infection and four (36%) showed increasing serum creatinine levels but none developed glomerulopathy; 3/11 (27%) recovered spontaneously from anaemia whereas 8/11 (73%) needed therapy. In conclusion, the relatively high occurrence (23%) of B19 virus infection in patients presenting with anaemia, suggests that it should be considered in the differential diagnosis of persistent anaemia in renal transplant recipients. Presence of the viral DNA should be assessed early from transplantation and the viral load should be monitored to follow persistent infection and better understand the relation between active infection and occurrence of anaemia, and to assess the efficacy of IVIG therapy and/or immunosuppression reduction in clearing the virus.

A case of persistent anemia in a renal transplant recipient: association with parvovirus B19 infection

We report an unexplained anemia that persisted for 4 months in a renal transplant patient who was receiving immunosuppression therapy that included prednisolone, tacrolimus and azathioprine. A bone marrow biopsy demonstrated pure erythroid hypoplasia and occasional giant pronormoblasts with intranuclear inclusions, characteristic of a parvovirus B19 infection. Both the serum and bone marrow cells were positive by parvovirus B19 DNA PCR. The anemia resolved 6 weeks after the administration of intravenous immunoglobulin (IVIG). Four months later, anemia redeveloped and IVIG was infused again. Hemoglobin levels were, however, still subnormal after 1 month of treatment and tacrolimus was then switched to cyclosporin A, resulting in a clear improvement. A parvovirus B19 infection should be included in the differential diagnosis of renal transplant recipients who present with anemia associated with a low reticulocyte count. Tacrolimus may possibly impair the clearance of a parvovirus B19 infection.

Donor-transmitted parvovirus infection in a kidney transplant recipient presenting as pancytopenia and allograft dysfunction

Parvovirus B19 is a nonenveloped single-stranded DNA virus that commonly causes a benign childhood infection typically manifesting as a "slapped-cheek" rash. In immunodeficient hosts, this infection can cause persistent anemia and occasionally pancytopenia. Recently, direct renal involvement has been reported in renal transplant recipients leading to various forms of glomerulopathy and allograft dysfunction. Most cases are primary infections and are donor transmitted through the transplanted organ. Clinical and virological response to intravenous immunoglobulin (Ig) is usually excellent. We describe a case of donor-transmitted parvovirus infection in a 23-year-old male who received his first cadaver renal transplant. The patient had an uncomplicated postoperative course with immediate graft function. Eight weeks after transplantation, he presented with fever, polyarthralgia, pancytopenia, and allograft dysfunction. Serological studies revealed elevated IgM titers against parvovirus B19. A renal biopsy was performed, which showed no evidence of acute rejection but with moderate degree of tubular damage. Parvovirus B19 viral DNA was detected in the renal tissue via polymerase chain reaction (PCR). The patient received a 10-day course of intravenous Ig (400 mg/kg/day) with excellent response. His blood count normalized and the allograft improved to baseline function. The incidence of parvovirus infection in renal transplant patients is probably underestimated, because patients are not routinely screened for it and anemia and/or pancytopenia in these patients are often ascribed to immunosuppressive drugs. Because this infection is treatable, we conclude that parvovirus B19 infection should be actively considered in transplant patients presenting with pancytopenia and allograft dysfunction.

[Pure red cell aplasia in a lung transplant patient]

Aplastic anemia secondary to infection by parvovirus B19 is normally an extremely rare problem in patients with no prior history. However, the presence of certain risks, such as receiving chronic immunosuppressant therapy, may facilitate its appearance. Very few cases have been published concerning red cell aplasia due to parvovirus B19 infection in patients receiving a transplanted lung. We report the case of a 24-year-old woman with cystic fibrosis who had received a double lung transplant. The patient developed red cell aplasia secondary to parvovirus B19 infection; severe anemia requiring multiple transfusions. Five days of intravenous immunoglobulin therapy resolved the anemia. We discuss the difficulty of serological diagnosis in such cases, the importance of using techniques that identify the virus and taking measures that may prevent recurrence.

Opportunistic infections after renal transplantation

Opportunistic infection is a serious clinical complication in patients receiving immunosuppressive therapy after kidney transplantation. This article deals with some of the possible infectious agents that were recently encountered at our transplantation centre in Düsseldorf, Germany. Opportunistic organsims such as human herpesviruses 6-8, polyomavirus, parvovirus B19, varicella zoster virus, Nocardia and Listeria monocytogenes are rare but severe complications that are presented in this overview. As a result of the use of new immunosuppresive drugs like tacrolimus and mycophenolate mofetil these infections are now seen more frequently, so they should always be included in differential diagnostic considerations. New diagnostic procedures and new treatment strategies should allow early detection and successful treatment of opportunistic infections in the majority of kidney transplant recipients.

Parvovirus B19 infection in pediatric solid-organ and bone marrow transplantation

The clinical significance of parvovirus B19 infection in pediatric solid-organ and bone marrow transplanted patients is unclear. The overall prevalence of parvovirus B19 infection in these patients is about 1-2% during the first year after transplantation. The most common symptom is anemia, but leukopenia and thrombocytopenia have also been observed. Rare cases of hepatic dysfunction, myocarditis, vasculitis and respiratory failure have also been reported. Whereas serology is of limited value around the time of transplantation, it is recommended that a search for B19 DNA is included in first-line investigations in any transplanted patient with unexplained anemia. Specific antiviral therapy is not available, however, intravenous immunoglobulin produces rapid improvement in most cases. Although relatively rare, the severe complications following parvovirus B19 infection in the transplant setting can be avoided by early diagnosis and treatment.

Infections in recipients of kidney transplants

A review of infections in kidney transplant recipients is presented in this article, beginning with a discussion of the pretransplant infectious diseases evaluation and an overview of the timing of infectious posttransplant, and then focusing on individual types of infection.

Reconstituted immunity against persistent parvovirus B19 infection in a patient with acquired immunodeficiency syndrome after highly active antiretroviral therapy

We discovered a patient with AIDS with persistent B19 infection who had slow resolution of anemia after he commenced receiving HAART without intravenous immunoglobulin. The patient's anemia recurred when the initial course of HAART failed, but it remitted slowly after salvage therapy was instituted. However, circulating B19 was still detectable by nested polymerase chain reaction 1 year after commencement of salvage therapy. Immunoglobulin G and immunoglobulin M antibodies against B19 were not detected by means of enzyme-linked immunosorbent assay when the anemia initially resolved, but they were detected after the patient commenced receiving salvage therapy. The absence of antibody response after the initial remission of parvovirus B19 infection suggested that cellular immunity was an important component of reconstituted immune function against B19 after the patient received HAART. The humoral response that was restored later was abnormal; it had strong reactivity to nonstructural protein NS-1 and poor generation of neutralizing antibodies against linear epitopes unique to minor capsid protein VP1.

Viral infections after renal transplantation

Viral infections are a leading cause of posttransplantation morbidity and mortality. A number of recent developments have altered our understanding and management of these disorders. The pathogenetic roles of several viruses, including human herpesviruses 6 and 8, have been newly established. Molecular-based diagnostic tests now make more rapid diagnosis possible. The licensing of new potent antiviral agents offers a wider choice of drugs for viral prophylaxis and treatment. The use of more potent immunosuppressive agents is responsible in part for the increasing incidence of some viral infections, but this varies among drugs, and individual viruses differ in their sensitivity to immunosuppressive agents. This review summarizes the natural history, diagnosis, prevention, and treatment of many common viral infections after renal transplantation.

Cytokine cross-talk between tubular epithelial cells and interstitial immunocompetent cells

Immunostaining of renal biopsies of patients with interstitial rejection of allografts or other forms of interstitial inflammation has demonstrated the presence of activated T cells and monocytes/macrophages in the tubulointerstitial area. Cytokines that are produced by infiltrating cells are capable of activating tubular epithelial cells. In turn tubular epithelial cells can produce a wide variety of inflammatory mediators, including chemokines, which further regulate cellular influx. Interfering in this cross-talk between tubular epithelial cells and infiltrating cells might provide new options for therapeutic intervention.