Thrombotic microangiopathy and cytomegalovirus disease in patients infected with human immunodeficiency virus

Renal Involvement in Congenital Cytomegalovirus Infection: A Systematic Review

Background: Congenital cytomegalovirus (cCMV) infection is the most frequent mother-to-child transmitted infection worldwide and a prevalent cause of neonatal disease and long-term morbidity. The kidney is a target organ for CMV, which replicates in renal tubules and is excreted in large quantities in urine for years in children with cCMV infection. Nonetheless, kidney disease has rarely been reported in cCMV-infected patients. Objective: We aimed to describe the available data on renal involvement in patients with cCMV infection at the pathologic, functional, anatomical, and/or clinical levels. Methods: A systematic search was performed in the MEDLINE/PubMed, SCOPUS, and Cochrane databases. Studies describing any renal involvement in fetuses or neonates aged ≤3 weeks at diagnosis of microbiologically confirmed cCMV infection were eligible. Results: Twenty-four articles were included, with a very low level of evidence. Pathologic findings in autopsy studies universally described CMV typical inclusion bodies in tubular cells. No functional studies were identified. cCMV infection was not associated with an increased risk of kidney malformations. Congenital nephrotic syndrome was the most common clinical condition associated with cCMV, but a causal relationship cannot be established. Conclusions: Typical pathological features of cCMV infection are very common in renal tissue, but they do not seem to entail significant consequences at the anatomical or clinical levels.

Thrombotic microangiopathy in the setting of human immunodeficiency virus infection: High incidence of severe thrombocytopenia

BACKGROUND

Human immunodeficiency virus (HIV) infection increases the risk of thrombotic microangiopathy (TMA), but TMA in the setting of HIV infection is not well characterized. The experience with TMA in the setting of HIV infection at the University of Maryland Medical Center was reviewed.

STUDY DESIGN AND METHODS

Patients undergoing therapeutic plasma exchange (TPE) for TMA from January 1, 2000 through December 31, 2012 were reviewed. Those with known HIV-positive and -negative status were compared.

RESULTS

Among 102 patients with known HIV status, 28 (27%) were HIV-positive, including 3 with previously undiagnosed HIV. HIV-positive patients had a median viral load of 89 500 copies/mL (range, 0->750 000 copies/mL) and a median CD4 count of 58 cells/µL (range, 2-410 cells/µL). Compared to HIV-negative patients, HIV-positive patients more frequently presented with concurrent infections (60.7% vs. 23.7%; P = .0007), had a trend toward lower median platelet counts (3000/µL vs. 15 000/µL; P = .07) and more frequently had platelet counts less than 10 000/mcL (P = .02). Nevertheless, number of TPE procedures required for remission, remission rate, mortality, and relapse incidence were similar in HIV-positive and HIV-negative patients.

CONCLUSIONS

The incidence described herein of HIV infection among TMA patients is the highest reported outside of South Africa. More severe thrombocytopenia in HIV-positive patients may reflect TMA in the setting of preexisting HIV-associated thrombocytopenia. HIV should be considered in patients with TMA, and TMA should be considered in HIV-positive patients with severe thrombocytopenia.

Transplantation-Associated Thrombotic Microangiopathy in Patients Treated With Sirolimus and Cyclosporine as Salvage Therapy for Graft-Versus-Host Disease

Background: Transplantation-associated thrombotic microangiopathy (TA-TMA) is a rare complication of hematopoietic stem cell transplantation. Because sirolimus (SIR) and calcineurin inhibitor—either cyclosporine (CsA) or tacrolimus—have become more common as graft-versus-host disease (GVHD) prophylaxis, we are witnessing a higher frequency of this complication. Objective: To analyze the incidence, timing, and management of TA-TMA in patients who received the combination of CsA and SIR as therapy for uncontrolled GVHD in one single center. Methods: This was a retrospective analysis from February 2002 to June 2014 of the combination of SIR and CsA as salvage therapy in 61 patients with treatment-refractory or relapsed acute GVHD (n = 24) or chronic GVHD (n = 37) in a tertiary hospital. Results: A total of 61 patients received CsA and SIR as salvage therapy for acute (n = 16), late acute (n = 8), overlap syndrome (n = 22), or classic chronic (n = 15) GVHD. We identified 13 patients with TA-TMA (21.3%), and the status of GVHD was active in 11 of 13 patients. Only 1 patient showed high CsA levels, and 6 of 13 patients had very high concentrations of SIR in blood. We used an enzyme inducer in 6 patients, which proved effective in 3. Overall survival for TA-TMA patients was inferior compared to that for non TA-TMA patients at 12 months (42.9% vs 51.9%) and 24 months (34.3% vs 49.1%), although this difference was not significant. Conclusion: Prompt identification and good management of TA-TMA, with better control of GVHD, may contribute to a decrease in patient mortality that would result from this complication.

Review: Viral infections and mechanisms of thrombosis and bleeding

Viral infections are associated with coagulation disorders. All aspects of the coagulation cascade, primary hemostasis, coagulation, and fibrinolysis, can be affected. As a consequence, thrombosis and disseminated intravascular coagulation, hemorrhage, or both, may occur. Investigation of coagulation disorders as a consequence of different viral infections have not been performed uniformly. Common pathways are therefore not fully elucidated. In many severe viral infections there is no treatment other than supportive measures. A better understanding of the pathophysiology behind the association of viral infections and coagulation disorders is crucial for developing therapeutic strategies. This is of special importance in case of severe complications, such as those seen in hemorrhagic viral infections, the incidence of which is increasing worldwide. To date, only a few promising targets have been discovered, meaning the implementation in a clinical context is still hampered. This review discusses non‐hemorrhagic and hemorrhagic viruses for which sufficient data on the association with hemostasis and related clinical features is available. This will enable clinicians to interpret research data and place them into a perspective. J. Med. Virol. 84:1680–1696, 2012. © 2012 Wiley Periodicals, Inc.

Cytomegalovirus-induced cutaneous microangiopathy manifesting as lower limb ischemia in a human immunodeficiency virus-infected patient

Cutaneous infections by cytomegalovirus (CMV) are rare and often difficult to diagnose both clinically and histopathologically. A wide range of different clinical manifestations have been described in the literature, especially in immunosuppressed patients. CMV-induced thrombosis has also been reported in these patients, and various mechanisms have been proposed to explain the role of CMV in the thrombotic process, including direct damage of the endothelial cells, activation of coagulation factors and inducing the production of antiphospholipid antibodies. We present the case of a human immunodeficiency virus (HIV)-infected woman who developed distal ischemic lesions of the lower extremities during a generalized CMV infection. We discuss the role of CMV and antiphospholipid antibodies in the pathogenesis of thrombosis in immunosuppressed patients.

Case of anti-glomerular basement membrane antibody-induced glomerulonephritis with cytomegalovirus-induced thrombotic microangiopathy

Although the involvement of cytomegalovirus (CMV) infections in the development of thrombotic microangiopathy (TMA) in HIV patients and transplant recipients has been reported, it is still controversial whether CMV itself can cause TMA. We report herein a rare case with rapid improvement of TMA by ganciclovir treatment in a patient who is neither HIV-positive nor a transplant recipient, suggesting a pathogenic role for CMV in TMA.

Viral-associated thrombotic microangiopathies

Thrombotic microangiopathies encompass a group of disorders characterized by microangiopathic hemolytic anemia, thrombocytopenia associated with hyaline thrombi (comprised primarily of platelet aggregates in the microcirculation), and varying degrees of end-organ failure. Many primary (genetic) and secondary etiological predisposing factors have been described-namely pregnancy, autoimmune disorders, cancer, drugs and antineoplastic therapy, bone marrow transplantation/solid organ transplantation, and infections. In the setting of infectious diseases, the association with Shiga or Shiga-like exotoxin of Escherichia coli 0157:h7 or Shigella dysenteriae type 1-induced typical hemolytic uremic syndrome is well known. Recently however, an increasing body of evidence suggests that viruses may also play an important role as trigger factors in the pathogenesis of thrombotic microangiopathies. This is a comprehensive review focusing on the current understanding of viral associated/induced endothelial stimulation and damage that ultimately leads to the development of this life-threatening multisystemic disorder.

BK virus encephalitis with thrombotic microangiopathy in an allogeneic hematopoietic stem cell transplant recipient

BK virus (BKV) infection occurs most often in immunocompromised hosts, in the setting of renal or bone marrow transplantation. Hemorrhagic cystitis is the commonest manifestation but in recent years infections in other organ systems have been reported. We report an unusual case of biopsy-proven BKV encephalitis in a hematopoietic stem cell transplant patient who subsequently developed thrombotic microangiopathy. As far as we know, this is the first report of such an association in a transplant patient.

Thrombotic microangiopathy in haematopoietic cell transplantation: an update

Allogeneic hematopoietic cell transplantation (HCT) represents a vital procedure for patients with various hematologic conditions. Despite advances in the field, HCT carries significant morbidity and mortality. A rare but potentially devastating complication is transplantation-associated thrombotic microangiopathy (TA-TMA). In contrast to idiopathic TTP, whose etiology is attributed to deficient activity of ADAMTS13, (a member of the A Disintegrin And Metalloprotease with Thrombospondin 1 repeats family of metalloproteases), patients with TA-TMA have > 5% ADAMTS13 activity. Pathophysiologic mechanisms associated with TA-TMA, include loss of endothelial cell integrity induced by intensive conditioning regimens, immunosuppressive therapy, irradiation, infections and graft-versus-host (GVHD) disease. The reported incidence of TA-TMA ranges from 0.5% to 75%, reflecting the difficulty of accurate diagnosis in these patients. Two different groups have proposed consensus definitions for TA-TMA, yet they fail to distinguish the primary syndrome from secondary causes such as infections or medication exposure. Despite treatment, mortality rate in TA-TMA ranges between 60% to 90%. The treatment strategies for TA-TMA remain challenging. Calcineurin inhibitors should be discontinued and replaced with alternative immunosuppressive agents. Daclizumab, a humanized monoclonal anti-CD25 antibody, has shown promising results in the treatment of TA-TMA. Rituximab or the addition of defibrotide, have been reported to induce remission in this patient population. In general, plasma exchange is not recommended.

CKD in HIV-infected patients other than HIV-associated nephropathy

A spectrum of kidney diseases in HIV-infected patients has been reported both before and after the introduction of highly active antiretroviral therapy (HAART). Kidney syndromes affecting HIV-infected patients include CKD as well as proteinuria, nephrotic syndrome, and acute nephritic syndrome. Thrombotic microangiopathy should be considered in patients with kidney disease and typical clinical characteristics. As the HIV-infected population ages, there is increased concern regarding the incidence of vascular and metabolic disease, leading to an increased burden of CKD. Although HIV-associated nephropathy is still the major cause of nephrotic syndrome in HIV-infected patients, immune complex glomerulonephritis (ICGN) still comprises a substantial proportion of the disease burden, especially in people of European origin. Genetic investigations into the underpinnings of the various histologic expressions of HIV-associated kidney disease hold great promise. The single most important diagnostic test to differentiate various forms of kidney disease in HIV-infected patients is a kidney biopsy. The results of treating kidney disease in HIV-infected patients remain unclear, and properly designed randomized controlled trials of the treatment of ICGN with HAART and other approaches are desperately needed.

Thrombotic Microangiopathy and Hypothermia in an HIV-positive Patient: Importance of Cytomegalovirus Infection

Cytomegalovirus (CMV) infection is a well-known frequent complication in HIV-infected patients. We report a case of thrombotic microangiopathy and severe hypothermia in a 21-y-old woman positive for HIV infection. CMV infection was diagnosed by PCR. The symptoms completely resolved after ganciclovir therapy which supports the role of CMV as a causative agent.

[Kidney diseases in HIV-infected patients]

HIV infection has become a global disease, both in geographic terms, since it has spread worldwide, and at the individual level since it affects every organ of the human body. Antiretroviral treatments, in countries where they are easily available, have modified HIV infection into a systemic chronic disease, the life expectancy of which is yet to be determined precisely. Treatments have dramatically changed the pattern of the disease and clinicians now have to face a number of new challenges. Kidneys, like all the other organs, can be involved in a great number of diseases in HIV-infected patients. We have voluntarily chosen to present "kidney diseases in HIV-infected patients" in their wider meaning, with a discussion of renal diseases that are directly caused by the virus, nephropathies due to frequent viral co-infections in HIV-infected patients such as HCV and HBV, nephropathies induced by anti-HIV, HBV and HCV therapies. Physicians in charge of HIV-infected patients should be aware of the key role they have to play in the screening for kidney abnormalities. This participates not only in improving patients' kidney prognosis but also their long-term general outcome. Renal screening strategies must refer to simple routine laboratory tests. Enclosed at the end of this article are a few suggestions for the renal management of situations that frequently occur in HIV infected patients (kidney dysfunction screening, serum creatinine increase and discovery of a proteinuria).

Thrombotic microangiopathy and other glomerular disorders in the HIV-infected patient

SUMMARY

Various forms of kidney disease have been related directly to human immunodeficiency virus (HIV) viral infection, including HIV-associated nephropathy (HIVAN), immune complex diseases, and thrombotic microangiopathy (TMA). HIVAN and HIV immune complex glomerulonephritides are the most common HIV-specific nephropathies. HIV-associated TMA, although far less common, remains an important consideration. The diagnosis of TMA in HIV, which has a poorly understood pathogenesis, can be suggested by thrombocytopenia, microangiopathic hemolytic anemia, and acute renal failure, but only definitively diagnosed by kidney biopsy. Not surprisingly, the incidence and prevalence of the HIV-specific entities have declined with the advent of highly active antiretroviral therapy. With this decline, however, other glomerular diseases are of increasing importance in this high-risk population. The differential diagnosis of glomerular disease in an HIV-positive patient is therefore broad. Glomerular diseases seen in this population include classic focal segmental glomerulosclerosis, IgA nephropathy, postinfectious glomerulonephritis, hepatitis B- and C-related glomerulonephritides, and membranous nephropathy. In addition, as the HIV-infected population ages, diabetic and hypertensive nephropathies are likely to become more prevalent. With overlapping presentations of these entities, definitive diagnosis often is difficult, necessitating kidney biopsy. As a consequence of establishing an accurate diagnosis, improved patient outcome can best be accomplished through disease-specific intervention.

Viruses and kidney disease: beyond HIV

SUMMARY

Human immunodeficiency virus (HIV)-infected patients may acquire new viral co-infections; they also may experience the reactivation or worsening of existing viral infections, including active, smoldering, or latent infections. HIV-infected patients may be predisposed to these viral infections owing to immunodeficiency or risk factors common to HIV and other viruses. A number of these affect the kidney, either by direct infection or by deposition of immune complexes. In this review we discuss the renal manifestations and treatment of hepatitis C virus, BK virus, adenovirus, cytomegalovirus, and parvovirus B19 in patients with HIV disease. We also discuss an approach to the identification of new viral renal pathogens, using a viral gene chip to identify viral DNA or RNA.

HIV-1 infection and the kidney: an evolving challenge in HIV medicine

With the advent of highly active antiretroviral therapy (HAART), the incidence of opportunistic infections has declined substantially, and cardiovascular, liver, and renal diseases have emerged as major causes of morbidity and mortality in individuals with human immunodeficiency virus (HIV). Acute renal failure is common in HIV-infected patients and is associated with acute infection and medication-related nephrotoxicity. HIV-associated nephropathy is the most common cause of chronic kidney disease in HIV-positive African American populations and may respond to HAART. Other important HIV-associated renal diseases include HIV immune complex kidney diseases and thrombotic microangiopathy. The increasing importance of non-HIV-associated diseases, such as diabetes mellitus, hypertension, and vascular disease, to the burden of chronic kidney disease has been recognized, focusing attention on prevention and control of these diseases in HIV-positive individuals. HIV-positive individuals who experience progression to end-stage renal disease and who have undetectable HIV-1 viral loads while receiving HAART should be evaluated for renal transplant. Emerging evidence suggests that HIV-positive individuals may have graft and patient survival comparable to HIV-negative individuals. Several studies suggest that HIV-1 can potentially infect renal cells, and HIV transgenic mice have clarified the roles of a number of HIV proteins in the pathogenesis of HIV-associated renal disease. Host factors may modify disease expression at the level of cytokine networks and the renal microvasculature and contribute to the pathogenic effects of HIV-1 infection on the kidney.

Thrombotic microangiopathy after kidney transplantation

Two forms of post-transplant thrombotic microangiopathy (TMA) may be recognized: recurrent TMA and de novo TMA. Recurrent TMA may occur in patients who developed a nondiarrhoeal form of haemolytic uraemic syndrome (HUS) being particularly frequent in patients with autosomal recessive or dominant HUS. The recurrence is almost the rule in patients with mutation in complement factor H gene. Most patients eventually lose the graft. Treatment with plasma infusions or plasmapheresis is often disappointing, but few cases may be rescued. Intravenous immunoglobulins and rituximab have also been successful in anedoctic cases. De novo TMA is rarer. A number of factors including viral infection may be responsible of de novo TMA, but in most cases TMA is triggered by calcineurin inhibitors or mTOR inhibitors. The clinical presentation of de novo TMA may be variable with some patients showing clinical and laboratory features of HUS while others showing only a progressive renal failure. The prognosis is less severe than with recurrent TMA. Complete withdrawal of the offending drug may lead to improvement in many cases. The addition of plasma exchange may result in graft salvage in about 80% of cases.

Risk Factors and Severe Outcome in Thrombotic Microangiopathy After Allogeneic Hematopoietic Stem Cell Transplantation

BACKGROUND

Thrombotic microangiopathy (TMA) has been described as severe complication after hematopoietic stem cell transplantation (HSCT). The principal aim of this study was to focus the incidence and the outcome of TMA in the era of more complex HSCTs.

METHODS

We analyzed the role of some predicting factors for the incidence and the outcome of TMA after HSCT. We enrolled 539 consecutive patients (307 males, median age 31 years) undergoing HSCT from match or mismatch human leukocyte antigen family donor (314) or match/mismatch unrelated (195) and haploidentical donor (30) for malignant or nonmalignant diseases. TMA diagnosis was performed by homogeneous clinical and laboratory criteria.

RESULTS

Sixty-four of 539 patients presented TMA (11,87%) and the five-year cumulative incidence of TMA was 14% (HR=0.13). Fifty nine of 64 patients were affected by malignant and 5/64 by non-malignant diseases. On multivariate analysis, TMA occurrence was influenced by graft versus host disease >grade II (P=0.0001), donor type (P=0.029), gender (P=0.0233), total body irradiation based conditioning regimen (P=0.0041). Three factors for TMA outcome proved to be statistically significant by multivariate analysis: age (P=0.009), donor type (P=0.0187) and TMA index (P=0.029). The TMA mortality rate was 50%. The outcome was influenced by defibrotide (P=0.02 in univariate analysis).

CONCLUSIONS

The study underlines the possibility of finding out which patients are more prone to developing post-HSCT TMA, and identifies which risk factors are more frequently associated with a dismal outcome after TMA.

Acute cytomegalovirus infection and venous thrombosis: role of antiphospholipid antibodies

Cytomegalovirus (CMV)-induced thrombosis has been reported in immunocompromised patients, such as transplant recipients and patients with AIDS. Recent cases also describe thrombotic phenomena in immunocompetent patients with CMV infection. Various mechanisms may explain the role of CMV in thrombosis: this virus can damage endothelial cells, activate coagulation factors, and induce production of antiphospholipid (aPL) antibodies. We present a case report of a previously healthy white woman with a pulmonary embolism associated with CMV infection and the presence of aPL antibodies, and we discuss the role of the aPL antibodies associated with CMV infection in the pathogenesis of thrombosis.

Thrombotic Microangiopathy after Lung Transplantation

BACKGROUND

Thrombotic microangiopathy (TMA) is a well-recognized complication after transplantation. The purpose of this study was to describe our center's experience with this complication after lung transplantation.

METHODS

We retrospectively reviewed cases of TMA among patients who underwent lung transplantation between January 1, 1999 and December 31, 2003 (n = 257). The cases were characterized and the outcomes were analyzed. Univariate and multivariate Cox regression models were constructed to identify potential risk factors for TMA.

RESULTS

Twenty-four cases of TMA developed in 20 recipients. Thirteen cases occurred in the setting of another illness and 11 cases were isolated complications. Multivariate Cox regression models identified female gender, history of TMA, and the immunosuppressive regimen as independent predictors of TMA. Maintenance immunosuppression with the combination of a calcineurin inhibitor and sirolimus carried a significantly higher risk of TMA than a calcineurin inhibitor alone. After the diagnosis of TMA, calcineurin inhibitors were stopped in 18 cases; however, in 6 cases in which the onset of TMA coincided with the addition of sirolimus to a calcineurin inhibitor, only sirolimus was discontinued. Plasmapheresis was performed for severe cases (n = 10). TMA remitted in all cases, and an alternate calcineurin inhibitor was introduced in 14 cases. TMA recurred in 4 recipients, a median 253 days after the initial episode. The median survival after the onset of TMA was 377 days.

CONCLUSION

TMA is a serious complication after lung transplantation, and the risk is highest when sirolimus is used in combination with a calcineurin inhibitor.

Thrombotic Microangiopathy Syndrome in the ICU

Major studies designed to improve our understanding of the pathophysiology of TMA have been conducted over recent years. This improved knowledge opens up new perspectives for more targeted treatment. However, until these innovative treatments become available, early diagnosis of these diseases is essential in order to rapidly initiate specific treatment, as the interval between diagnosis and initiation of plasma exchange is a decisive element in the prognosis of TTP. Treatment must not be stopped too early or too rapidly and must take into account the various associated factors, especially the presence of infection.

Blood and marrow transplant clinical trials network toxicity committee consensus summary: thrombotic microangiopathy after hematopoietic stem cell transplantation

The syndrome of microangiopathic hemolysis associated with renal failure, neurologic impairment, or both is a recognized complication of hematopoietic stem cell transplantation. This entity is often called hemolytic uremic syndrome (HUS) or thrombotic thrombocytopenic purpura (TTP), yet it is clear that the pathophysiology of transplant-associated HUS/TTP is different from that of classic HUS or TTP. Furthermore, the incidence of this syndrome varies from 0.5% to 76% in different transplant series, primarily because of the lack of a uniform definition. The toxicity committee of the Blood and Marrow Transplant Clinical Trials Network has reviewed the current literature on transplant-related HUS/TTP and recommends that it be henceforth renamed posttransplantation thrombotic microangiopathy (TMA). An operational definition for TMA based on the presence of microangiopathic hemolysis and renal and/or neurologic dysfunction is proposed. The primary intervention after diagnosis of TMA should be withdrawal of calcineurin inhibitors. Plasma exchange, although frequently used in this condition, has not been proven to be effective. In the absence of definitive trials, plasma exchange cannot be considered a standard of care for TMA. It is hoped that these positions will improve the identification and reporting of this devastating complication after hematopoietic stem cell transplantation and facilitate future clinical studies for its prevention and treatment.

[Portal vein thrombosis in HIV-infected patients: report of four cases]

Portal vein thrombosis (PVT) seems rare among HIV infected patients. Even though, the report of such cases is of great interest because it may help to determine the factors of occurrence. We describe cases of PVT in 4 HIV-infected men, aged 32 - 64. Two of them were co-infected with hepatitis C virus (HCV). The four patients had a history of disseminated mycobacterial infection (one case of tuberculosis, 3 cases of mycobacterium avium complex infection) with abdominal lymphadenitis. Despite HAART, their immunodeficiency was profound (CD4: 65 to 216/mm(3)). At the time of diagnosis, two patients were treated with protease-inhibitor containing regimen: indinavir (one case), ritonavir-saquinavir (one case). PVT was revealed by haematemesis (one case), abdominal pain (ome case), anasarca (2 cases). In three patients, the diagnosis of PVT was confirmed by imagery (echo-doppler or angio- RMI), and for the last patient, PVT was found during the transjugular intrahepatic portosystemic shunt setup. A low level of C protein was diagnosed in one case. Cirrhosis was not found in HIV-HCV co-infected patients. Two patients died early after diagnosis, one patient died 3 years after the onset of symptoms. Various factors may cause the development of a PVT in HIV infected patient. Serious immunodeficiency, opportunistic infections such as tuberculosis and mycobacterium avium complex related infection with abdominal lymphadenitis can further the development of PVT. Protease-inhibitor might have facilitated the process. Due to the severe prognosis of advanced cases, early evocation of diagnosis is needed.

Tacrolimus-Related Encephalopathy following Allogeneic Stem Cell Transplantation in Children

Tacrolimus is a potent immunosuppressive drug widely used to prevent and treat graft-versus-host disease (GVHD) in stem cell transplantation (SCT). Among 49 patients receiving tacrolimus who underwent SCT from January 2000 to July 2003, 10 patients (20%) developed encephalopathy. The commonly observed symptoms were convulsions and drowsiness, and most patients complained of signal symptoms such as headache, nausea, and cortical blindness before onset. The most common abnormality on neuroimages was high-intensity lesions in white matter on magnetic resonance imaging T2-weighted or fluid-attenuated inversion recovery images. At onset, all patients were receiving treatment for acute GVHD (grade II/III) or extensive chronic GVHD and demonstrated an abrupt increase in blood pressure from baseline levels. The serum tacrolimus concentration was generally within acceptable levels at onset. Symptoms gradually improved in all patients when the blood pressure was lowered with antihypertensive medication, regardless of continued tacrolimus administration following a short-term suspension. The pathogenesis of tacrolimus-related encephalopathy is multifactorial, although refractory GVHD and a sudden increase in blood pressure seem to be major predisposing factors. Because the withdrawal of tacrolimus or switching to less potent anti-GVHD agents usually worsens the GVHD, the administration of tacrolimus should be managed by closely monitoring serum levels and controlling blood pressure.

Thrombotic thrombocytopenic purpura-hemolytic uremic syndrome following allogeneic HPC transplantation: a diagnostic dilemma

BACKGROUND

Thrombotic thrombocytopenic purpura-hemolytic uremic syndrome (TTP-HUS) has been described as a specific sequela of allogeneic HPC transplantation (HPCT). Nevertheless, because multiple transplant-related sequela can cause the characteristic clinical features of TTP-HUS, the diagnosis is difficult.

STUDY DESIGN AND METHODS

All English-language articles describing patients with TTP-HUS following HPCT were identified. Articles reporting five or more total patients, including at least one patient diagnosed with TTP-HUS following allogeneic HPCT, were reviewed. All articles describing autopsies of patients diagnosed with TTP-HUS following allogeneic HPCT were also reviewed.

RESULTS

Thirty-five articles reporting 5 or more total patients described 447 patients diagnosed with TTP-HUS following allogeneic HPCT. The frequency of diagnosis of TTP-HUS following allogeneic HPCT varied by 125-fold (0.5%-63.6%). Twenty-eight different sets of diagnostic criteria were described in the 35 articles; 25 articles included both RBC fragmentation and increased serum LDH. Many risk factors described as correlating with the diagnosis of TTP-HUS also predict greater risk for multiple transplant-related complications. Benefit of plasma exchange treatment could not be documented. Survival information was reported for 379 patients, 232 (61%) died, and reported mortality rates varied from 0 to 100 percent. Autopsies have been reported for 35 patients who were diagnosed with TTP-HUS following allogeneic HPCT; none had systemic thrombotic microangiopathy, the diagnostic abnormality of TTP-HUS; and infection (19 patients) was the most commonly reported cause of death.

CONCLUSIONS

The clinical features of TTP-HUS following allogeneic HPCT may be caused by common transplant-related complications; the benefit from plasma exchange treatment is uncertain.

Porcine cytomegalovirus and coagulopathy in pig-to-primate xenotransplantation

BACKGROUND

A rapidly progressive disorder termed consumptive coagulopathy (CC) has been observed frequently in pig-to-baboon renal xenotransplantation. CC may be initiated by endothelial activation and induction of procoagulant factors after immunologic injury or infection, or by molecular incompatibilities between porcine coagulation proteins and primate clotting factors. The activation of porcine (P) cytomegalovirus (PCMV) and baboon (B) CMV infections has been documented in pig-to-primate xenotransplantation. The purpose of this study was to determine the contribution of PCMV and BCMV to CC.

METHODS

Endothelial activation was assessed by means of measurement of porcine tissue factor (pTF) in a functional assay in primary porcine aortic endothelial cells (PAEC) in vitro. Renal xenografts and native kidneys were studied by immunohistochemistry in immunosuppressed swine and baboons. BCMV and PCMV DNA was measured by quantitative molecular assays using real-time polymerase chain reaction.

RESULTS

In vitro, infection of PAEC with PCMV resulted in a significant increase of pTF expression. In vivo, pTF increase occurred without the activation of PCMV in two xenografts, and in four grafts no pTF was detected despite PCMV activation. All animals with graft pTF increase developed CC. BCMV activation in the baboon xenograft recipients did not correlate with CC or pTF increase. Control pigs and baboons had activation of PCMV and BCMV, respectively, but without coagulation abnormalities.

CONCLUSIONS

PCMV induces endothelial cell activation in vitro with procoagulant expression. However, in vivo, CC and pTF induction has an uncertain relationship to increased replication of PCMV within a xenograft. Although the data do not exclude a contributory role of PCMV in CC, other mechanisms are also likely to contribute to coagulopathies observed in pig-to-primate xenotransplantation.

Thrombotic microangiopathy and cytomegalovirus in liver transplant recipients: a case-based review

BACKGROUND

Thrombotic microangiopathy (TMA) is a rare but potentially lethal complication encountered in solid organ and bone marrow transplant recipients, requiring rapid recognition, diagnosis, and initiation of therapy. Several potential causes have been identified in this setting, including viral infections and medications.

METHODS

We report a case of TMA in a liver transplant recipient with active cytomegalovirus (CMV) gastritis. A 41-year-old female presented 3 months after liver transplantation with a 5-week history of nausea, vomiting, anorexia, and diarrhea. CMV serology was donor seropositive and recipient seronegative (D+/R-). The immunosuppressive regimen consisted of tacrolimus, mycophenolate mofetil, and prednisone. Evaluation revealed CMV viremia with a high viral load and intravenous ganciclovir was started. A decline in hemoglobin and platelets with an increase in lactate dehydrogenase (LDH) warranted hematologic evaluation, which revealed findings consistent with microangiopathic hemolytic anemia. Ganciclovir and tacrolimus were discontinued. Intravenous immunoglobulin was administered and daily plasmapheresis was initiated. As the patient's blood counts and LDH started to improve, ganciclovir was cautiously reinstituted. The patient's gastrointestinal symptoms gradually resolved and her blood counts continued to improve with prolonged plasmapheresis (a total of 23 plasmapheresis sessions). Tacrolimus and possibly CMV infection were suspected to be the cause for her TMA, and cyclosporine was substituted.

CONCLUSIONS

TMA is an important entity in the differential diagnosis of acute hemolytic anemia in liver transplant recipients. Many cases seem to be medication-induced. However, in treatment-resistant or relapsing cases, a possibility of concomitant CMV infection should be considered.

Posttransplantation thrombotic thrombocytopenic purpura: a single-center experience and a contemporary review

OBJECTIVE

To assess the activity of von Willebrand factor-cleaving protease (vWF-CP) in patients with thrombotic thrombocytopenic purpura (TTP) complicating bone marrow transplantation (BMT) and peripheral blood stem cell transplantation (PBSCT).

PATIENTS AND METHODS

From March 1, 1999, to June 30, 2001, allogeneic and autologous hematopoietic stem cell transplantation was performed in 118 and 400 patients, respectively. We reviewed risk factors for development of posttransplantation TTP and measured vWF-CP activity during active TTP in 10 recipients.

RESULTS

The incidence of TTP after allogeneic and autologous transplantation was 6.8% (8/118) and 0.25% (1/400), respectively. Among the allogeneic transplant recipients, the incidence of TTP after nonmyeloablative (NMA) PBSCT, matched unrelated donor BMT, and sibling BMT or PBSCT was 15.4% (2/13), 11.8% (2/17), and 4.5% (4/88), respectively. Of the 10 patients with TTP, 9 (90%) had received extensive prior therapy, including autologous transplantation in both NMA recipients. Acute graft-vs-host disease (GVHD) prophylaxis consisted of cyclosporine and methotrexate in most affected patients. The vWF antigen level was elevated in all patients, and no patients showed evidence of vWF-CP deficiency. During active TTP, 6 patients had grade II-IV acute GVHD, 1 had extensive chronic GVHD, and 4 had cytomegalovirus viremia. Risk factor analysis for development of TTP showed that transplant type (NMA and matched unrelated donor) and source of stem cells (bone marrow vs peripheral blood stem cell) were significant.

CONCLUSIONS

Posttransplantation TTP was not found to be associated with severe vWF-CP deficiency. The elevated levels of vWF antigen are consistent with diffuse endothelial injury likely because of multiple interacting factors such as extensive prior therapy, GVHD, cyclosporine, and reactivation of cytomegalovirus. The disorder appears to be more frequent among patients with, or at risk for, acute GVHD, suggesting a possible role in the pathogenesis. Nonmyeloablative transplantation does not appear to confer a lesser risk, possibly for these reasons.

Cytomegalovirus infection and thrombosis: a causative association?

Venous thrombosis is a well-organised complication of hospitalisation and has often been reported in the context of HIV infection. Less frequently cytomegalovirus (CMV) has been implicated in the development of thrombosis, although usually in the context of immunosuppression. We report the case of a young, immunocompetent individual who developed pulmonary emboli as a complication of CMV infection and describe the three proposed mechanisms by which this is thought to occur. The probable mechanism in our patient is discussed.

Thrombotic microangiopathy in patients with acquired immunodeficiency syndrome before and during the era of introduction of highly active antiretroviral therapy

The incidence of thrombotic microangiopathy (TMA) was retrospectively evaluated in a cohort of 1223 patients with acquired immunodeficiency syndrome (AIDS) who were observed from January 1985 through December 1996 (before the era of highly active antiretroviral therapy [HAART]), and the incidence was prospectively assessed for 347 patients with AIDS during the period of January 1997 through December 2000 (during the HAART era). Seventeen cases were reported in the former cohort (1.4%). The increased risk of developing TMA was statistically significant in patients with cryptosporidiosis or AIDS-related cancer but not in those with other diseases. In the 1997-2000 cohort, no cases were observed during follow-up. TMA is associated with conditions observed in the advanced phases of human immunodeficiency virus infection. The disappearance of TMA during the HAART era may be explained by the lower percentage of patients with long-lasting CD4+ T cell depletion, advanced AIDS, or cryptosporidiosis or who have undergone multiple courses of chemotherapy for treatment of cancer.

Renal Dysfunction in HIV-1-infected Patients

Improved therapy directed against opportunistic infection and HIV-1 itself has resulted in greatly enhanced patient survival in the past decade among patients infected with HIV-1. Since patients are living longer, HIV-1 infection is associated with a rising burden of kidney disease. Approximately 14% of black patients and 6% of white patients dying with HIV-1 infection in 1999 in the United States had renal disease. Overall, 10% of patients dying with HIV-1 infection had renal failure. The most common glomerular diseases are focal segmental glomerulosclerosis and immune complex glomerulonephritis. Appropriate therapy for focal segmental glomerulosclerosis includes effective antiretroviral therapy and angiotensin antagonist medication. Drug toxicity is also common, often manifesting as electrolyte abnormalities, acute renal failure, interstitial nephritis, or nephrolithiasis. In particular, indinavir is associated with crystalluria, nephrolithiasis, interstitial nephritis, and lower urinary tract inflammation. Appropriate screening for renal disease and appropriate intervention will likely reduce the morbidity and mortality associated with progressive renal disease.

Valaciclovir: a review of its long term utility in the management of genital herpes simplex virus and cytomegalovirus infections

Valaciclovir is an aciclovir prodrug used to treat infections caused by herpes simplex virus (HSV) and varicella zoster virus, and for prophylaxis against cytomegalovirus (CMV). Oral valaciclovir provides significantly better oral bioavailability than oral aciclovir itself, contributing to the need for less frequent administration. Several studies have demonstrated the efficacy of long term (> 90 days) therapy with valaciclovir for the suppression of genital HSV disease in otherwise healthy individuals with HSV infection. In 1 randomised, double-blind trial, once daily valaciclovir (1000 mg, 500 mg and 250 mg) produced statistically significant suppression of disease recurrence, as did twice daily valaciclovir 250 mg and aciclovir 400 mg. Valaciclovir dosages of > or = 500 mg daily are recommended for suppression of genital herpes recurrences in immunocompetent individuals. This disease occurs frequently in patients with human immunodeficiency virus (HIV) infection and, in a single randomised double-blind trial, prophylactic valaciclovir (1000 mg once daily or 500 mg twice daily) and aciclovir (400 mg twice daily) were found to be of similar efficacy in the suppression of genital herpes. However, a higher than expected dropout rate indicated that more studies of valaciclovir in patients with HIV are required. In a randomised trial of patients undergoing renal transplant, valaciclovir 2 g 4 times daily for 90 days significantly reduced the incidence and delayed the onset of CMV disease: the incidence in valaciclovir-treated patients who were CMV-seronegative at baseline, and recieived a kidney from a CMV-seropositive donor, was 3% versus 45% for placebo after 90 days of treatment. Acute graft rejection was also reduced in the valaciclovir-treated group. A small study in heart transplant patients compared valaciclovir (2 g 4 times daily) with aciclovir (200 mg 4 times daily) and found a significant reduction in CMV antigenaemia favouring valacilovir at the end of the treatment period. Additional reductions in other indices of CMV in those given valaciclovir compared with aciclovir were also noted. In a preliminary study of prophylaxis for CMV disease in bone marrow transplant recipients valaciclovir (2 g 4 times daily) was superior to aciclovir (800 mg 4 times daily) in terms of time to CMV viraemia or viruria. Although valaciclovir (8 g/day for approximately 30 weeks) reduced the incidence and time to CMV disease compared with aciclovir (3.2 g/day) in patients with advanced HIV disease, valaciclovir was associated with more gastrointestinal complaints and an increased risk of death, leading to premature termination of the study. As yet, no trials comparing the efficacy of valaciclovir with famciclovir (the oral prodrug for penciclovir) in the suppression of recurrent episodes of genital herpes have been published, nor have direct comparisons been made, between valaciclovir with ganciclovir in patients with CMV disease. Valaciclovir is well tolerated at dosages used to suppress recurrent episodes of genital herpes (500 to 1000 mg/day) in immunocompetent and HIV seropositive individuals, with headache being reported most often. However, a potentially fatal thrombotic microangiopathy (TMA)-like syndrome has been reported in some immunocompromised patients receiving high-dose prophylactic valaciclovir therapy (8 g/day) for CMV disease for prolonged periods, and the risk of this syndrome appears to be higher in patients with advanced HIV disease. While the clinical benefits of valaciclovir in some immunocompromised patients may outweigh the risk of TMA, close monitoring for symptoms of TMA is indicated in all immunocompromised patients receiving high-dose valaciclovir.

CONCLUSION

Oral valaciclovir is an effective drug for the suppression of recurrent episodes of genital herpes in immunocompetent and immunocompromised individuals. (ABSTRACT TRUNCATED)

Hemolytic uremic syndrome. Recurrence after renal transplantation. Groupe Coopératif de l'Ile-de-France (GCIF)

Hemolytic uremic syndrome (HUS) is an uncommon cause of end-stage renal failure in adults, and few data are available concerning the outcome of renal transplantation in these patients. We conducted this retrospective multicentric study to appreciate the outcome of adult renal transplant recipients whose primary disease was HUS. Sixteen patients, transplanted between 1975 and 1995, were included in the study. In each case, initial diagnosis of HUS was documented by a kidney biopsy. These 16 patients received a total of 25 allografts: 1 graft for 9 patients, 2 grafts for 5 patients, and 3 grafts for 2 patients. Nine patients (56%) developed definite clinical and pathologic evidence of recurrence on at least 1 graft. Four additional patients (25%) demonstrated only some clinical or pathologic evidence of recurrence which could not be distinguished from acute vascular rejection. Three patients had no sign of recurrence of the initial disease. The 1-year graft survival rate was 63% and the 5-year graft survival rate was 18.5%. In the group of patients with proven or possible recurrence (n = 13), the 1-year and 5-year graft survival rates were 49% and less than 10%, respectively. The recurrence was an early event, occurring before the end of the first month after transplantation in half the cases. The recurrence rate was 92% in non-nephrectomized patients and 50% in patients with bilateral nephrectomy. In the literature, 71 adult patients with primary HUS had received a total of 90 kidney grafts. Among them, 54% had a recurrence on their graft, which was diagnosed in 52% of the kidney transplants. It is note-worthy that when data from the literature are pooled with our results, the rate of recurrence appears to be significantly lower in binephrectomized patients than in patients with their native kidneys at the time of transplantation (5 of 14 versus 27 of 35 patients, respectively, p = 0.0155). By univariate analysis, no other risk factor for recurrence could be identified. Treatment with cyclosporine A did not influence the recurrence rate. We conclude that recurrence of HUS after renal transplantation is a frequent, early, and severe complication, leading rapidly to graft loss. Prospective studies are needed to confirm that bilateral nephrectomy prior to transplantation decreases the rate of recurrence.

Thrombotic microangiopathy in the HIV-2-infected macaque

Thrombotic microangiopathy (TMA) has been increasingly reported in human immunodeficiency virus (HIV)-infected humans over the past decade. The pathogenesis is unknown. We prospectively analyzed the renal pathology and function of 27 pigtailed macaques (Macaca nemestrina), infected intravenously with a virulent HIV-2 strain, HIV-2(287), in addition to that of four uninfected control macaques. Necropsies were performed between 12 hours and 28 days after infection. HIV-2 antigen was detectable in peripheral blood mononuclear cell (PBMC) cocultures in all animals after 10 days of HIV-2 infection; a rapid decline in CD4(+) PBMC (<350/microliter) was seen in five of six animals 21 days and 28 days after infection. No macaque developed features of clinical AIDS. Typical lesions of human HIV-associated nephropathy were undetectable. Six of the 27 HIV-2-infected macaques demonstrated both histological TMA lesions (thrombi in glomerular capillary loops and small arteries, mesangiolysis) and ultrastructural lesions (mesangiolysis, subendothelial lucency, platelet thrombi in glomerular capillary lumina). Extrarenal thrombi were detected in the gastrointestinal and adrenal microvasculature of macaques that had developed renal TMA. None of the control animals demonstrated features of renal TMA at necropsy. In a retrospective analysis of kidneys obtained from 39 additional macaques infected with HIV-2(287), seven cases demonstrated TMA. In situ hybridization showed no detectable HIV-2 RNA in kidney sections of 65/66 HIV-2-infected macaques, including all 13 TMA cases. Expression of the chemokine receptor CXCR4, the putative coreceptor for HIV-2(287), was absent in intrinsic renal cells in all HIV-2-infected macaques. The HIV-2-infected macaque may be a useful model of human HIV-associated TMA. Our data do not support a role of direct HIV-2 infection of intrinsic renal cells as an underlying mechanism.

Thrombotic microangiopathy in association with cytomegalovirus infection in a renal transplant patient: a new treatment strategy

BACKGROUND

Cytomegalovirus (CMV) associated with thrombotic microangiopathy (TMA) in transplant patients has not been extensively described. This case illustrates an association between CMV and TMA in a transplant patient with resolution of the latter after treatment of the CMV.

METHODS AND RESULTS

At 6 weeks after renal transplantation, a 57-year-old woman presented with TMA. Cyclosporine was discontinued, and plasmapheresis was started. However, the patient continued to deteriorate and developed CMV pneumonitis. Plasmapheresis was discontinued, and intravenous ganciclovir was initiated. Both the TMA and the CMV resolved after initiation of the ganciclovir.

CONCLUSION

This case identifies another potential etiological factor in the development of TMA after renal transplantation. It is the first reported case of TMA being cured with treatment of CMV.