Unusual viral infections (progressive multifocal leukoencephalopathy and cytomegalovirus disease) after high-dose chemotherapy with autologous blood stem cell rescue and peritransplantation rituximab

Hypogammaglobulinemia, late-onset neutropenia, and infections following rituximab

Rituximab is a chimeric anti-CD20 monoclonal antibody that targets CD20-expressing B lymphocytes, has a well-defined efficacy and safety profile, and is broadly used to treat a wide array of diseases. In this review, we cover the mechanism of action of rituximab and focus on hypogammaglobulinemia and late-onset neutropenia-2 immune effects secondary to rituximab-and subsequent infection. We review risk factors and highlight key considerations for immunologic monitoring and clinical management of rituximab-induced secondary immune deficiencies. In patients treated with rituximab, monitoring for hypogammaglobulinemia and infections may help to identify the subset of patients at high risk for developing poor B cell reconstitution, subsequent infections, and adverse complications. These patients may benefit from early interventions such as vaccination, antibacterial prophylaxis, and immunoglobulin replacement therapy. Systematic evaluation of immunoglobulin levels and peripheral B cell counts by flow cytometry, both at baseline and periodically after therapy, is recommended for monitoring. In addition, in those patients with prolonged hypogammaglobulinemia and increased infections after rituximab use, immunologic evaluation for inborn errors of immunity may be warranted to further risk stratification, increase monitoring, and assist in therapeutic decision-making. As the immunologic effects of rituximab are further elucidated, personalized approaches to minimize the risk of adverse reactions while maximizing benefit will allow for improved care of patients with decreased morbidity and mortality.

JC polyomavirus: a short review of its biology, its association with progressive multifocal leukoencephalopathy, and the diagnostic value of different methods to manifest its activity or presence

INTRODUCTION

JC polyomavirus is the causative agent of progressive multifocal leukoencephalopathy (PML), a demyelinating disease resulting from the lytic infection of oligodendrocytes that may develop in immunosuppressed individuals: HIV1 infected or individuals under immunosuppressive therapies. Understanding the biology of JCPyV is necessary for a proper patient management, the development of diagnostic tests, and risk stratification.

AREAS COVERED

The review covers different areas of expertise including the genomic characterization of JCPyV strains detected in different body compartments (urine, plasma, and cerebrospinal fluid) of PML patients, viral mutations, molecular diagnostics, viral miRNAs, and disease.

EXPERT OPINION

The implementation of molecular biology techniques improved our understanding of JCPyV biology. Deep sequencing analysis of viral genomes revealed the presence of viral quasispecies in the cerebrospinal fluid of PML patients characterized by noncoding control region rearrangements and VP1 mutations. These neurotropic JCPyV variants present enhanced replication and an altered cell tropism that contribute to PML development. Monitoring these variants may be relevant for the identification of patients at risk of PML. Multiplex realtime PCR targeting both the LTAg and the archetype NCCR could be used to identify them. Failure to amplify NCCR should indicate the presence of a JCPyV prototype speeding up the diagnostic process.

Metagenomic next-generation sequencing restores the diagnosis of a rare infectious complication of B cell depletion

A 45-year-old female patient receiving rituximab for B cell non-Hodgkin follicular lymphoma presented unexplained recurrent fever, abdominal discomfort, and pollakiuria. We performed shotgun metagenomic sequencing from peri-kidney collection that identified a co-infection with Mycoplasma hominis and Ureaplasma urealyticum. The patient recovered with sequelae after appropriate antibiotic treatment was given.

Practical guidance for the diagnosis and management of secondary hypogammaglobulinemia: A Work Group Report of the AAAAI Primary Immunodeficiency and Altered Immune Response Committees

Secondary hypogammaglobulinemia (SHG) is characterized by reduced immunoglobulin levels due to acquired causes of decreased antibody production or increased antibody loss. Clarification regarding whether the hypogammaglobulinemia is secondary or primary is important because this has implications for evaluation and management. Prior receipt of immunosuppressive medications and/or presence of conditions associated with SHG development, including protein loss syndromes, are histories that raise suspicion for SHG. In patients with these histories, a thorough investigation of potential etiologies of SHG reviewed in this report is needed to devise an effective treatment plan focused on removal of iatrogenic causes (eg, discontinuation of an offending drug) or treatment of the underlying condition (eg, management of nephrotic syndrome). When iatrogenic causes cannot be removed or underlying conditions cannot be reversed, therapeutic options are not clearly delineated but include heightened monitoring for clinical infections, supportive antimicrobials, and in some cases, immunoglobulin replacement therapy. This report serves to summarize the existing literature regarding immunosuppressive medications and populations (autoimmune, neurologic, hematologic/oncologic, pulmonary, posttransplant, protein-losing) associated with SHG and highlights key areas for future investigation.

Rituximab for the treatment of multiple sclerosis: a review

In the last decades, evidence suggesting the direct or indirect involvement of B cells on multiple sclerosis (MS) pathogenesis has accumulated. The increased amount of data on the efficacy and safety of B-cell-depleting therapies from several studies has suggested the addition of these drugs as treatment options to the current armamentarium of disease modifying therapies (DMTs) for MS. Particularly, rituximab (RTX), a chimeric monoclonal antibody directed at CD20 positive B lymphocytes resulting in cell-mediated apoptosis, has been demonstrated to reduce inflammatory activity, incidence of relapses and new brain lesions on magnetic resonance imaging (MRI) in patients with relapsing-remitting MS (RRMS). Additional evidence also demonstrated that patients with progressive MS (PMS) may benefit from RTX, which also showed to be well tolerated, with acceptable safety risks and favorable cost-effectiveness profile.Despite these encouraging results, RTX is currently approved for non-Hodgkin's lymphoma, chronic lymphocytic leukemia, several forms of vasculitis and rheumatoid arthritis, while it can only be administered off-label for MS treatment. Between Northern European countries exist different rules for using not licensed drug for treating MS. The Sweden MS register reports a high rate (53.5%) of off-label RTX prescriptions in relation to other annually started DMTs to treat MS patients, while Danish and Norwegian neurologists have to use other anti-CD20 drugs, as ocrelizumab, in most of the cases.In this paper, we review the pharmacokinetics, pharmacodynamics, clinical efficacy, safety profile and cost effectiveness aspects of RTX for the treatment of MS. Particularly, with the approval of new anti-CD20 DMTs, the recent worldwide COVID-19 emergency and the possible increased risk of infection with this class of drugs, this review sheds light on the use of RTX as an alternative treatment option for MS management, while commenting the gaps of knowledge regarding this drug.

Natalizumab-associated progressive multifocal leukoencephalopathy (PML) in multiple sclerosis (MS): "a case report from Ireland with review of literature, clinical pitfalls and future direction"

Background

Progressive multifocal leukoencephalopathy (PML) is one of the most serious treatment-related complications that is encountered in patients with multiple sclerosis (MS). PML is a serious complication of MS treatment which is most commonly related to natalizumab.

Case presentation

We report clinical course of progressive multifocal leukoencephalopathy (PML) in a 40-year-old man who was on treatment for highly active relapsing-remitting multiple sclerosis with natalizumab (Nz). He was treated with steroids, cidofovir, and mirtazapine and went on to develop long-term disability. The case describes the evolution of PML from diagnosis up till 5 months with changes on sequential brain scans and clinical symptoms in our patient.

Conclusion

Patients who are on natalizumab should be aware and consented for the risk of PML. They should be periodically re-assessed for their relative PML risk. There is a growing body of evidence that suggests switching patients from natalizumab who have a higher risk of PML to other safer treatment options.

Infectious Complications of Biological and Small Molecule Targeted Immunomodulatory Therapies

The past 2 decades have seen a revolution in our approach to therapeutic immunosuppression. We have moved from relying on broadly active traditional medications, such as prednisolone or methotrexate, toward more specific agents that often target a single receptor, cytokine, or cell type, using monoclonal antibodies, fusion proteins, or targeted small molecules. This change has transformed the treatment of many conditions, including rheumatoid arthritis, cancers, asthma, and inflammatory bowel disease, but along with the benefits have come risks. Contrary to the hope that these more specific agents would have minimal and predictable infectious sequelae, infectious complications have emerged as a major stumbling block for many of these agents. Furthermore, the growing number and complexity of available biologic agents makes it difficult for clinicians to maintain current knowledge, and most review articles focus on a particular target disease or class of agent. In this article, we review the current state of knowledge about infectious complications of biologic and small molecule immunomodulatory agents, aiming to create a single resource relevant to a broad range of clinicians and researchers. For each of 19 classes of agent, we discuss the mechanism of action, the risk and types of infectious complications, and recommendations for prevention of infection.

Human Polyomavirus JCPyV and Its Role in Progressive Multifocal Leukoencephalopathy and Oncogenesis

The human neurotropic virus JCPyV, a member of the Polyomaviridiae family, is the opportunistic infectious agent of Progressive Multifocal Leukoencephalopathy (PML), a fatal disease seen in severe immunosuppressive conditions and, during the last decade, in patients undergoing immunotherapy. JCPyV is a ubiquitous pathogen with up to 85% of the adult population word-wide exhibiting antibodies against it. Early experiments demonstrated that direct inoculation of JCPyV into the brain of different species resulted in the development of brain tumors and other neuroectodermal-derived neoplasias. Later, several reports showed the detection of viral sequences in medulloblastomas and glial tumors, as well as expression of the viral protein T-Antigen. Few oncogenic viruses, however, have caused so much controversy regarding their role in the pathogenesis of brain tumors, but the discovery of new Polyomaviruses that cause Merkel cell carcinomas in humans and brain tumors in racoons, in addition to the role of JCPyV in colon cancer and multiple mechanistic studies have shed much needed light on the role of JCPyV in cancer. The pathways affected by the viral protein T-Antigen include cell cycle regulators, like p53 and pRb, and transcription factors that activate pro-proliferative genes, like c-Myc. In addition, infection with JCPyV causes chromosomal damage and T-Antigen inhibits homologous recombination, and activates anti-apoptotic proteins, such as Survivin. Here we review the different aspects of the biology and physiopathology of JCPyV.

Lower gamma globulin level before conditioning is a risk factor for cytomegalovirus antigenemia after pediatric allogeneic stem cell transplantation

BACKGROUND

Despite the development of early detection methods and new antiviral drugs, cytomegalovirus (CMV) infection remains a persistent and sometimes severe complication of stem cell transplantation (SCT). CMV antigenemia has become widely used for early detection of CMV infection after SCT.

PROCEDURE

We retrospectively analyzed risk factors for CMV antigenemia in pediatric patients following allogeneic SCT. We analyzed 74 pediatric patients who received allogeneic SCT at Sapporo Hokuyu Hospital between April 2007 and March 2018 and were alive over three months after SCT.

RESULTS

Of the 74 patients, 22 (29.7%) were CMV antigenemia positive. On univariate analyses, many patients with CMV antigenemia tested positive for CMV antibody before SCT (P < 0.001), and had lower gamma globulin levels before conditioning (P = 0.014). Multivariate analysis additionally confirmed that pre-SCT CMV antibody positivity (P < 0.001) and preconditioning gamma globulin levels under 655 mg/dL (P = 0.004) were independent risk factors for post-SCT CMV antigenemia.

CONCLUSIONS

These results indicate the importance of assessing gamma globulin levels in pediatric patients prior to SCT.

Amebic Encephalitis in a Patient with Chronic Lymphocytic Leukemia on Ibrutinib Therapy

Chronic lymphocytic leukemia (CLL) is the most common type of leukemia in Western countries. A common first-line therapy offered to qualifying patients includes ibrutinib, an oral covalent inhibitor of Bruton's tyrosine kinase. Treatment of CLL with ibrutinib therapy is generally well tolerated; however, serious opportunistic infections are being reported in patients treated with ibrutinib. In this report, we present a patient with CLL on ibrutinib therapy who developed rapidly declining neurological status concerning for the central nervous system (CNS) process related to his immunocompromised status. Despite multiple testing modalities, no evidence was found to explain the acute changes the patient was experiencing, and he had no improvement with common antimicrobial coverage. The patient ultimately expired, and autopsy of the brain revealed granulomatous amebic encephalitis due to opportunistic infection by Acanthamoeba species. As evidenced by this case, ibrutinib therapy, despite being generally well tolerated, has the potential to predispose patients to opportunistic infections like amebic encephalitis. Amebic encephalitis is a highly lethal CNS infection, and it is important for clinicians to recognize early on the potential for infection in patients on ibrutinib therapy presenting with CNS symptoms.

Progressive multifocal leukoencephalopathy after allogeneic stem cell transplantation: Case report and review of the literature

Progressive multifocal leukoencephalopathy (PML) is a rare, yet typically fatal complication of allogeneic stem cell transplantation. It is caused by reactivation of the John Cunningham (JC) virus in an immunocompromised host. This report describes an unfortunate case of PML in a recipient of an allogeneic stem cell transplant for acute myelogenous leukemia. The JC virus was undetectable in the patient's cerebrospinal fluid by polymerase chain reaction (PCR); however, a positive diagnosis was made after a brain biopsy. This and other published cases demonstrate that recipients of allogeneic stem cells can develop PML. Moreover, early diagnosis of the disease is often difficult and, as demonstrated in this case, screening with PCR does not appear to have strong diagnostic significance. With no effective treatment presently available, restoration of immune function is the only intervention that can affect prognosis. Further prospective studies are needed to understand the pathophysiology and treatment of this disease.

T cell deficiencies as a common risk factor for drug associated progressive multifocal leukoencephalopathy

Progressive multifocal leukoencephalopathy (PML) is a disease of the central nervous system caused by neuropathogenic prototypes of ubiquitous community-acquired JC virus (JCV). The disease became of particular concern following its association with certain therapies that modulate immune system function without heavy immunosuppression. Due to lack of prophylactic/treatment options and poor outcomes, which often include severe disability or death, PML is a considerable concern for development of new drugs that interfere with immune system functions. In this review of clinical and research findings, we discuss the evidence that deficiencies in CD4⁺ T helper cells, cytotoxic CD8⁺ T cells, and interferon gamma are of crucial importance for development of PML under a variety of circumstances, including those associated with use of various drugs, regardless of differences in their mechanisms of action. These deficiencies apparently enable transformation of the harmless JCV archetype into neuropathogenic prototypes, but the site(s), and the mechanisms, of this transformation are yet to be elucidated. Here we discuss the evidence for brain as one of the sites of this transformation, and propose a model of PML pathogenesis that emphasizes the central role of T cell deficiencies in the two life cycles of the JCV, one non-pathogenic and one neuropathogenic. Finally, we conclude that the development of clinical grade T cell functional tests and more consistent use of already available laboratory tests for T cell subset analysis would greatly aid the effort to more accurately predict and assess the magnitude of PML risk for concerned therapeutic interventions.

Clinical and microbiological characteristics of the infections in patients treated with rituximab for autoimmune and/or malignant hematological disorders

INTRODUCTION

Rituximab is commonly used for the treatment of hematological malignancies and autoimmune diseases. Despite a reputation for good tolerance, case-series and registries reported rituximab-related infections of variable severity including opportunistic infections. We aimed at describing the natural history of infectious events (IE) after treatment by rituximab providing clinical and microbiological features and outcome.

PATIENTS AND METHODS

We retrospectively analyzed the medical records of patients treated with rituximab in an internal medicine department of a tertiary hospital between 2007 and 2015, and identified all IE after this therapy. Events' severity was assessed using the Common Terminological Criteria of Adverse Events (version 4.3) definitions.

RESULTS

Among 101 patients treated with rituximab, we identified 228 IE in 74 (73.3%) of these patients (median follow-up 30.4months). Indication for rituximab was either autoimmune disease (AID) (52.5% of patients), or monoclonal hematological disease (MHD) (47.5%). Patients received an overall median number of 5 rituximab infusions [interquartile range: 4-8], representing a cumulative dose of 4340mg [2620-6160]. After last rituximab infusion, IE occurred after 3.1months [0.7-9.4]. Respectively, IE were severe in 28.1% of cases in patients treated for AID vs 58.0% in patients treated for MHD (p<0.001), due to opportunistic pathogens in 7.8% vs 11.0% (p=0.49) and fatal in 4.7% vs 13.0% (p=0.044). Factor associated with mortality were polymicrobial infection (p<0.001), monoclonal hematological disease (p=0.035), use of steroids over 10mg/d within the last two weeks (p=0.003), and rituximab cumulative dose (p<0.001). We identified a group of 10 patients (9.9%) showing life-threatening, polymicrobial, and opportunistic infections constituting a 'catastrophic infectious syndrome', which was lethal in 7 cases.

CONCLUSION

IE after treatment by rituximab can be extremely severe, especially in patients immunocompromised by several other drugs. Further studies should focus on the group with life-threatening polymicrobial infections.

Cytomegalovirus reactivation in lymphoma and myeloma patients undergoing autologous peripheral blood stem cell transplantation

BACKGROUND

Cytomegalovirus reactivation is often diagnosed in allogeneic hematopoietic cell transplant recipients and therefore could lead to CMV-related disease, involving many organs in these immunocompromised patients. In contrast, few studies investigated CMV reactivation and end-organ disease in patients undergoing Autologous Peripheral Blood Stem Cell Transplant (ASCT) since they are considered at low risk for both reactivation and disease.

OBJECTIVES

The primary outcome of the analysis was to understand the difference in incidence of CMV reactivation between MM and Lymphoma patients. Secondary outcomes included the difference between MM and Lymphoma patients when considering the effect of CMV reactivation on transplant related mortality (TRM) overall survival (OS) progression free survival (PFS), risk factors for reactivation, and median time to reactivation.

STUDY DESIGN

In this report, we retrospectively compared the incidence, risk factors, and outcome of CMV reactivation in adult patients with Myeloma (MM) and Lymphoma undergoing ASCT at the American university of Beirut Medical Center in Lebanon (AUBMC). A total of 324 consecutive ASCT were performed between January 2005 and March 2016. Serial weekly monitoring for CMV quantification was done using a quantitative PCR, starting from transplantation until the hospital discharge and afterwards based on the clinical symptoms in cases of clinical suspicion of reactivation after discharge from the hospital.

RESULTS

The cumulative incidence of CMV reactivation was 16% (n=53) with a median time of 16 (range, 4-242) days after ASCT. The incidence of reactivation was significantly higher in the MM (22%) and NHL (20%) groups, when compared to the HL (4%) (P=0.001). There was a higher incidence of CMV reactivation according to age (≥50 vs ≤50 years) with higher incidence in the older population 24% vs 10% respectively (p=0.0043). The mean time to CMV reactivation was significantly higher in the NHL group with a mean of 53.7days when compared to the HL and MM groups with mean 19.75days and 12.66 (range, 4-34) days respectively (P=0.003). Twenty-two patients (76%) and three patients (75%) patients required specific antiviral therapy in the MM group and HL groups respectively; which was significantly higher (P<0.001) then the NHL group with 13 (65%) patients requiring specific antiviral therapy. Five patients (1.5%) developed CMV disease at a median of 60days (range, 7-107) post ASCT: there was significant difference in the mean-time to reactivation based on disease type MM versus lymphoma 10 versus 33days (P=0.007). In multivariate analysis, a higher age was associated with an increased risk of CMV reactivation; MM and NHL had higher risk of CMV reactivation when compared to HL, and progressive disease at transplant was associated with increased risk of CMV reactivation. After a median follow-up of 21.5 months (range: 1-125), there was no significant impact on PFS, however there was significant decrease in OS of lymphoma patients who had CMV reactivation when compared to those without CMV reactivation (204 and 112days respectively P=0.045). TRM increased from 1.1% in patients with no CMV reactivation to 13% in patients with CMV reactivation (P=0.003).

CONCLUSION

Our data suggests that CMV reactivation is not uncommon in ASCT recipients and may contribute to increase TRM. MM patients may have a higher incidence, of CMV reactivation with more anti-viral treatment requirements when compared to lymphoma patients, especially in older population.

Antigen presentation by B cells guides programing of memory CD4+ T-cell responses to a TLR4-agonist containing vaccine in mice

The contribution of B cells to immunity against many infectious diseases is unquestionably important and well characterized. Here, we sought to determine the role of B cells in the induction of T-helper 1 (T_H 1) CD4⁺ T cells upon vaccination with a tuberculosis (TB) antigen combined with a TLR4 agonist. We used B-cell deficient mice (μMT^-/- ), tetramer-positive CD4⁺ T cells, markers of memory "precursor" effector cells (MPECs), and T-cell adoptive transfers and demonstrated that the early antigen-specific cytokine-producing T_H 1 responses are unaffected in the absence of B cells, however MPEC induction is strongly impaired resulting in a deficiency of the memory T_H 1 response in μMT^-/- mice. We further show that antigen-presentation by B cells is necessary for their role in MPEC generation using B-cell adoptive transfers from wt or MHC class II knock-out mice into μMT^-/- mice. Our study challenges the view that B-cell deficiency exclusively alters the T_H 1 response at memory time-points. Collectively, our results provide new insights on the multifaceted roles of B cells that will have a high impact on vaccine development against several pathogens including those requiring T_H 1 cell-mediated immunity.

Drug-associated progressive multifocal leukoencephalopathy: a clinical, radiological, and cerebrospinal fluid analysis of 326 cases

The implementation of a variety of immunosuppressive therapies has made drug-associated progressive multifocal leukoencephalopathy (PML) an increasingly prevalent clinical entity. The purpose of this study was to investigate its diagnostic characteristics and to determine whether differences herein exist between the multiple sclerosis (MS), neoplasm, post-transplantation, and autoimmune disease subgroups. Reports of possible, probable, and definite PML according to the current diagnostic criteria were obtained by a systematic search of PubMed and the Dutch pharmacovigilance database. Demographic, epidemiologic, clinical, radiological, cerebrospinal fluid (CSF), and histopathological features were extracted from each report and differences were compared between the disease categories. In the 326 identified reports, PML onset occurred on average 29.5 months after drug introduction, varying from 14.2 to 37.8 months in the neoplasm and MS subgroups, respectively. The most common overall symptoms were motor weakness (48.6 %), cognitive deficits (43.2 %), dysarthria (26.3 %), and ataxia (24.1 %). The former two also constituted the most prevalent manifestations in each subgroup. Lesions were more often localized supratentorially (87.7 %) than infratentorially (27.4 %), especially in the frontal (64.1 %) and parietal lobes (46.6 %), and revealed enhancement in 27.6 % of cases, particularly in the MS (42.9 %) subgroup. Positive JC virus results in the first CSF sample were obtained in 63.5 %, while conversion after one or more negative outcomes occurred in 13.7 % of cases. 52.2 % of patients died, ranging from 12.0 to 83.3 % in the MS and neoplasm subgroups, respectively. In conclusion, despite the heterogeneous nature of the underlying diseases, motor weakness and cognitive changes were the two most common manifestations of drug-associated PML in all subgroups. The frontal and parietal lobes invariably constituted the predilection sites of drug-related PML lesions.

Cytomegalovirus infection in autologous stem cell transplant recipients in the era of rituximab

The incidence of cytomegalovirus (CMV) reactivation/disease after autologous stem cell transplant (ASCT) is much lower than that after allogeneic stem cell transplantation. With the recent use of rituximab during cancer chemotherapy or conditioning regimens prior to transplantation, there has been an increasing concern of opportunistic infections including CMV. In the present study, we reviewed the patients undergoing ASCT from December 2007 to December 2013 to identify those developing CMV reactivation/disease. Out of the 978 patients who underwent ASCT at the Karmanos Cancer Institute, 239 patients were tested for symptomatic CMV reactivation based on clinical suspicion. Of the tested patients, 7/239 (2.9 %) were documented to have CMV reactivation within 90 days of ASCT. The median time to develop CMV viremia was 32 days from transplantation. Of the 239 patients tested, CMV viremia was detected in 3 out of 72 patients who received rituximab as compared to 4 out of 167 patients who did not. Three of these seven viremic patients were treated with anti-viral drugs; viremia resolved in all patients at a median of 24 days. Three patients were found to develop other bacterial and/or fungal infections following CMV viremia. Two of the seven patients died during 1-year follow-up, due to primary disease progression or Candida sepsis. None of the patients developed proven tissue-invasive CMV disease. The study did not evaluate the incidence of asymptomatic CMV infection/reactivation. Despite prior publications based on limited data, rituximab does not appear to contribute to an increased frequency of symptomatic CMV reactivation following ASCT.

Hepatitis B virus reactivation with a rituximab-containing regimen

Rituximab is currently used not only in the treatment of B-cell lymphoma but also for various other diseases, including autoimmune diseases, post-transplant graft vs host disease, and rejection following kidney transplants. Due to rituximab’s widespread use, great progress has been made regarding research into complications that arise from its use, one of the most serious being the reactivation of hepatitis B virus (HBV), and efforts continue to establish guidelines for preventive treatment against this occurrence. This report discusses preventive measures against rituximab-induced HBV reactivation and future objectives.

Drug-induced progressive multifocal leukoencephalopathy: Lessons learned from contrasting natalizumab and rituximab

Progressive multifocal leukoencephalopathy (PML) has been identified as a serious adverse drug reaction (ADR) of several immunomodulatory biologicals. In this study, we contrasted the reporting patterns of PML for two biologicals for which the risk was identified at different points in their lifecycle: natalizumab (before reapproval) and rituximab (nine years postapproval). We found that, apart from the differences in clinical characteristics (age, gender, indication, time to event, fatality), which reflect the diversity in context of use, PML reports for natalizumab were more complete and were received sooner after occurrence. This study serves as an important reminder that spontaneous reports should only be used with great caution to quantify and compare safety profiles across products over time. The observed variability in reporting patterns and heterogeneity of PML cases presents challenges to such comparisons. Lumping uncharacterized PML reports together without taking these differences into account may result in biased comparisons and flawed conclusions about differential safety.

Diagnosis and treatment of cytomegalovirus 2013

PURPOSE OF REVIEW

Despite significant improvements in the management of patients undergoing allogeneic stem cell transplantation, including anticytomegalovirus (CMV) prophylaxis and treatment, clinical handling of CMV infection remains challenging in the light of high morbidity and mortality rates. Thus, novel strategies and agents to control CMV infection and disease will be discussed.

RECENT FINDINGS

Novel assays to quantify viral load and detect antiviral resistance mechanisms on the basis of next-generation sequencing have been described and will help to earlier and more effectively control CMV infection. In addition, safer and more effective antiviral agents are now available and strategies to boost the CMV-directed immune responses are being explored in the clinic.

SUMMARY

Novel diagnostic tests, novel agents and the increased understanding of the immune response to CMV have and will have a major impact on improving the management of CMV infection in hematological patients.

JC polyomavirus reactivation is common following allogeneic stem cell transplantation and its preemptive detection may prevent lethal complications

Extended application of allogeneic stem cell transplantation (alloSCT) is expected to increase the frequency of JC polyomavirus (JCPyV)-related progressive multifocal leukoencephalopathy (PML). The aim of this study was to assess frequency, risk factors and course of JCPyV reactivation in allografted hematology patients. This retrospective study included consecutive adult patients, treated with alloSCT between January 2008 and December 2011. Quantitative JCPyV-PCR analysis was performed on whole blood DNA samples, originally drawn for cytomegalovirus detection since transplant date. The study included 164 patients diagnosed with hematological malignancies. Patients received reduced-intensity conditioning (n=74) or myeloablative conditioning (n=90), followed by alloSCT. Twenty patients developed transient and 20 had persistent JCPyV reactivation. Two of the patients with persistent reactivation showed a gradual increase in JCPyV levels, preceding PML development by 96 and 127 days. Cessation of immunosuppression resulted in complete resolution of neurological symptoms in one patient, while the other died of PML. Seventy percent of the 'persistently reactivating' patients died. Multivariate analysis confirmed age to be the only significant predictive factor for JCPyV reactivation. In conclusion, JCPyV reactivation occurs in a quarter of allografted patients. Preemptive detection of JCPyV reactivation in high-risk subjects and early discontinuation of immunosuppressive therapy may prevent development of lethal PML.

Immunreconstitution and infectious complications after rituximab treatment in children and adolescents: what do we know and what can we learn from adults?

Rituximab, an anti CD20 monoclonal antibody, is widely used in the treatment of B-cell malignancies in adults and increasingly in pediatric patients. By depleting B-cells, rituximab interferes with humoral immunity. This review provides a comprehensive overview of immune reconstitution and infectious complications after rituximab treatment in children and adolescents. Immune reconstitution starts usually after six months with recovery to normal between nine to twelve months. Extended rituximab treatment results in a prolonged recovery of B-cells without an increase of clinically relevant infections. The kinetic of B-cell recovery is influenced by the concomitant chemotherapy and the underlying disease. Intensive B-NHL treatment such as high-dose chemotherapy followed by rituximab bears a risk for prolonged hypogammaglobulinemia. Overall transient alteration of immune reconstitution and infections after rituximab treatment are acceptable for children and adolescent without significant differences compared to adults. However, age related disparities in the kinetic of immune reconstitution and the definitive role of rituximab in the treatment for children and adolescents with B-cell malignancies need to be evaluated in prospective controlled clinical trials.

Risk of incremental toxicities and associated costs of new anticancer drugs: a meta-analysis

PURPOSE

There are increasing reports of rare but serious toxicities caused by new anticancer drugs, and there are costs associated with their management.

METHODS

We identified anticancer drugs approved by the U.S. Food and Drug Administration from 2000 to 2011 and pivotal trials supporting their registration. Twelve frequent grade 3 to 4 adverse event (AEs) were weighted and pooled in a meta-analysis. Estimates of incremental drug prices and incremental costs for management of AEs were calculated according to type of new agent based on target specificity.

RESULTS

We identified 41 studies comprising 27,539 patients and evaluating 19 experimental drugs. Agents directed against a specific molecular target on cancer cells had a lower incidence of grade 3 to 4 toxicities compared with controls (median risk ratio [RR], 0.67; P = .22), whereas less-specific targeted agents, including angiogenesis inhibitors (median RR, 3.39; P < .001) and chemotherapeutic agents (median RR, 1.73; P < .001), were more toxic. Risk was increased regardless of whether the control arm contained active treatment (RR, 2.11; P < .001) or not (RR, 3.02; P < .001). Median incremental drug price for experimental agents was $6,000 per patient per month. Median cost of managing toxicity was low compared with drug costs but higher than controls for treatment with less-specific targeted agents and chemotherapies.

CONCLUSION

Newly approved anticancer drugs are associated with increased toxicity, except for agents with a specific molecular target on cancer cells. Management of toxicity leads to a small increase in overall cost of treatment. Frequency of toxicity and associated costs are likely higher in less-selected patients treated in general oncologic practice. Development of biomarker-driven agents should be encouraged.

Acute and chronic B cell depletion disrupts CD4+ and CD8+ T cell homeostasis and expansion during acute viral infection in mice

B cells provide humoral protection against pathogens and promote cellular immunity through diverse nonclassical effector functions. To assess B cell function in promoting T cell homeostasis, mature B cells were either acutely or chronically depleted in mice using CD20 mAb. Acute B cell depletion in either 2- or 4-mo-old mice significantly reduced spleen and lymph node CD4(+) and CD8(+) T cell numbers, including naive, activated, and Foxp3(+)CD25(+)CD4(+) regulatory T cell subsets. The numbers of IFN-γ- and TNF-α-producing T cells were also significantly reduced. Chronic B cell depletion for 6 mo in aged naive mice resulted in a 40-70% reduction in activated CD4(+) and CD8(+) T cell numbers and 20-50% reductions in IFN-γ-producing T cells. Therefore, B cells were necessary for maintaining naive CD4(+) and CD8(+) T cell homeostasis for subsequent optimal T cell expansion in young and old mice. To determine the significance of this finding, a week of B cell depletion in 4-mo-old mice was followed by acute viral infection with lymphocytic choriomeningitis virus Armstrong. Despite their expansion, activated and cytokine-producing CD4(+) and CD8(+) T cell numbers were still significantly reduced 1 wk later. Moreover, viral peptide-specific CD4(+) and CD8(+) T cell numbers and effector cell development were significantly reduced in mice lacking B cells, whereas lymphocytic choriomeningitis virus titers were dramatically increased. Thus, T cell function is maintained in B cell-depleted mice, but B cells are required for optimal CD4(+) and CD8(+) T cell homeostasis, activation, and effector development in vivo, particularly during responses to acute viral infection.

Central nervous system infections in cancer patients and hematopoietic stem cell transplant recipients

Central nervous system (CNS) infections in cancer patients present a diagnostic and therapeutic challenge for clinicians. While CNS infections are not frequent complications of cancer, its therapies, or hematopoietic stem cell transplantation, the importance of CNS infections lies in their propensity to result in profound morbidity and substantial mortality in this vulnerable patient population. With an expanding population of patients with malignant disease undergoing more potent and aggressive therapies and with the advent of newer immunomodulatory agents, the incidence of CNS infectious complications is likely to rise. This chapter will summarize the clinical and diagnostic evaluation of potential infections of the CNS in these patients and will discuss particular pathogens of interest with regard to this at-risk patient population.

Hepatitis B virus reactivation with rituximab-containing regimen

Rituximab is recognized as a useful drug for the treatment of B-cell non-Hodgkin’s lymphoma and its use has been extended to such diseases as idiopathic thrombocytopenic purpura, thrombotic thrombocytopenic purpura, chronic rheumatoid arthritis and ANCA-associated vasculitides. One serious complication associated with its use is the reactivation of hepatitis B virus and the search for methods to prevent this occurrence has resulted in the rapid accumulation of knowledge. In this review, we discuss case analyses from our department and other groups and outline the current knowledge on the topic and the remaining issues.

Progressive multifocal leukoencephalopathy: a rare infectious complication following allogeneic hematopoietic cell transplantation (HCT)

Progressive multifocal leukoencephalopathy (PML), a demyelinating disorder caused by brain infection with JC virus, is a neurological complication of immunocompromised states and immunosuppressive therapies. While most commonly seen in the HIV/AIDS population, patients with hematologic malignancies are also at risk following treatment protocols including monoclonal antibodies such as rituximab and after hematopoietic stem cell transplantation. Here, we present the case of PML following allogeneic HCT that highlights potential diagnostic difficulties. We also review the literature regarding PML following HCT and described therapies employed to attempt to treat this disorder.

Progressive multifocal leukoencephalopathy: new concepts

Progressive multifocal leukoencephalopathy (PML) is a demyelinating disease of the CNS caused by reactivation of JC virus (JCV) in a setting of cellular immunosuppression. Originally, PML was observed in patients with advanced HIV infection, lymphoproliferative disorders and transplant recipients. However, the widespread use of HIV antiretroviral drugs and the new selective immunomodulatory and immunosuppressive medications, such as Rituximab and Natalizumab, has recently modified the epidemiology, clinical presentation and prognosis of PML. Herein, we discuss the new concepts on PML, emphasizing the recent modification in the epidemiology; the impact of new immunomodulatory treatments in the disease, PML-IRIS (Immune reconstitution inflammatory síndrome), new treatment strategies and other JCV related CNS diseases.

Rituximab biosimilars

INTRODUCTION

Rituximab is a monoclonal antibody targeting CD20, used to treat B cell malignancies and B cell-mediated autoimmune diseases. Rituximab has the largest market of any monoclonal antibody therapeutic. Its patent will expire within the next few years and several manufacturers have already produced or are developing rituximab biosimilars that aim to match the innovator rituximab as closely as possible.

AREAS COVERED

In this review, we discuss key factors that determine the efficacy of rituximab therapy, potential technical challenges in the manufacture and evaluation of biosimilars, regulatory considerations regarding the review and approval of biosimilars, and the current status of biosimilar rituximab development by various manufacturers. Due to the nature of the topic, literature searches included conference abstracts, regulatory and industry websites as well as peer reviewed literature.

EXPERT OPINION

Cost is a key limitation of current biologics usage and there is a political impetus to the licensing of biosimilars. Concerns regarding potential dissimilarities of biosimilars are legitimate, but surmountable with techniques for in vitro, in vivo and clinical testing and more clearly defined regulatory requirements. These should provide reassurance to prescribers. However, the cost of manufacturing and licensing a biosimilar remains high and the reduction in cost may be more limited than for a non-biologic small molecule drug and its generic version. This cost reduction will be critical to the impact and use of rituximab biosimilars.

Effect of single-dose rituximab on steroid-dependent minimal-change nephrotic syndrome in adults

BACKGROUND

Steroid-dependent minimal-change nephrotic syndrome (MCNS) requires administration of prolonged courses of prednisolone (PSL); therefore, a paradigm shift from such toxic 'non-specific' therapies to selective immunomodulating regimens is necessary for these cases.

METHODS

To assess the therapeutic effects of rituximab (an anti-CD20 antibody) in adult patients with steroid-dependent MCNS, we performed a prospective trial of the effects of a single dose of rituximab administered twice at an interval of 6 months in 25 MCNS patients. We evaluated the biochemical parameters and compared the clinical findings between the 12-month period before and 12-month period after the first rituximab infusion.

RESULTS

A significant reduction in the number of relapses and the total dose and the maintenance dose of PSL administered was observed during the 12-month period after the first rituximab infusion when compared with the findings during the 12-month period before the first rituximab infusion [25 (100%) versus 4 (16%), P < 0.001; 8.2 versus 3.3 g, P < 0.001; 26.4 mg/day at baseline versus 1.1 mg/day at 12-month, P < 0.0001]. Complete remission was achieved/maintained in all patients undergoing B-cell depletion. Four of 17 patients with B-cell repletion developed relapse.

CONCLUSIONS

Our results revealed that rituximab therapy was associated with a reduction in the number of relapses and in the total dose of PSL needed. Therefore, rituximab appears to be a useful therapeutic agent for adult patients with steroid-dependent MCNS. These results suggest that this treatment is rational and should be considered as an important option in the management of adult patients with steroid-dependent MCNS.

Efficacy of prophylactic lamivudine to prevent hepatitis B virus reactivation in B-cell lymphoma treated with rituximab-containing chemotherapy

PURPOSE

Reactivation of hepatitis B virus (HBV) is a common complication in patients with HBV infection who receive cytotoxic chemotherapy. In rituximab-containing chemotherapy for B-cell lymphoma, severe hepatitis due to HBV reactivation occurred. The aim of this study is to estimate the effect of prophylactic lamivudine on the risk of HBV reactivation in patients with HBV infection who receive rituximab-containing chemotherapy.

METHODS

In this study, HBV markers and liver function tests were monitored in 268 consecutive patients with B-cell lymphoma, who received rituximab-containing chemotherapy between January 2008 and November 2011. Sixty-nine patients (25.7 %) with either chronic HBV infection or past HBV infection received prophylaxis with lamivudine 100 mg daily by oral intake.

RESULTS

In the HBsAg-positive group, six (6/38) patients developed hepatitis, only one of which was attributed to HBV reactivation. In the HBsAg-negative and HBcAb-positive group, two (2/31) patients developed hepatitis, none of which was attributed to HBV reactivation.

CONCLUSIONS

These results support that prophylactic lamivudine can prevent HBV reactivation for B-cell lymphoma with HBV infection who was receiving rituximab-containing chemotherapy.

Molecular biology, epidemiology, and pathogenesis of progressive multifocal leukoencephalopathy, the JC virus-induced demyelinating disease of the human brain

Progressive multifocal leukoencephalopathy (PML) is a debilitating and frequently fatal central nervous system (CNS) demyelinating disease caused by JC virus (JCV), for which there is currently no effective treatment. Lytic infection of oligodendrocytes in the brain leads to their eventual destruction and progressive demyelination, resulting in multiple foci of lesions in the white matter of the brain. Before the mid-1980s, PML was a relatively rare disease, reported to occur primarily in those with underlying neoplastic conditions affecting immune function and, more rarely, in allograft recipients receiving immunosuppressive drugs. However, with the onset of the AIDS pandemic, the incidence of PML has increased dramatically. Approximately 3 to 5% of HIV-infected individuals will develop PML, which is classified as an AIDS-defining illness. In addition, the recent advent of humanized monoclonal antibody therapy for the treatment of autoimmune inflammatory diseases such as multiple sclerosis (MS) and Crohn's disease has also led to an increased risk of PML as a side effect of immunotherapy. Thus, the study of JCV and the elucidation of the underlying causes of PML are important and active areas of research that may lead to new insights into immune function and host antiviral defense, as well as to potential new therapies.

Biological agents for the treatment of uveitis

INTRODUCTION

The conventional treatment of uveitis includes corticosteroids and immunosuppressive agents, which are highly efficacious, but can be associated with serious systemic side effects. Over the last two decades, advances in the understanding of the pathogenesis of inflammatory diseases, as well as improved biotechnology, have enabled selective targeting of the chemical mediators of diseases. Recently, a new class of drugs called biologics, that target the various mediators of the inflammation cascade, may potentially provide more effective and less toxic treatment.

AREAS COVERED

This article is a review and summary of the peer-reviewed evidence for biologic agents in the treatment of various forms of ocular inflammation and it focuses on the potential use of other biologic agents that have been tested in experimental autoimmune uveitis. Pubmed was used as our main tool for our literature search. Some additional references were taken from books written on the subject.

EXPERT OPINION

There are a wide variety of new and emerging biological agents currently being used in the treatment of uveitis which has expanded the therapeutic horizons far beyond previous limitations.

Progressive multifocal leukoencephalopathy: an unexpected complication of modern therapeutic monoclonal antibody therapies

Progressive multifocal leukoencephalopathy (PML) is a rare demyelinating disorder of the central nervous system, caused by the reactivation of the ubiquitous JC virus. PML usually occurs during severe immunosuppression, and the most common causes are represented by human immunodeficiency virus infection, lymphoproliferative disorders and other forms of cancer. Recently, the introduction of monoclonal antibodies (e.g. natalizumab, rituximab, efalizumab) in the treatment of several dysimmune diseases such as multiple sclerosis, rheumatoid arthritis, psoriasis and systemic lupus erythematosus, has led to an increased incidence of PML. This phenomenon has had severe consequences, leading, for example, to the withdrawal from the market of Efalizumab, and important restrictions in the use of the other compounds, all of which are characterized by high efficacy in improving prognosis and quality of life. In this review we will discuss clinical, laboratory and imaging findings of PML. In addition, proposed pathogenetic mechanisms promoting the reactivation of JC virus in the context of treatment with monoclonal antibodies will be described.

Low-dose rituximab in adult patients with idiopathic autoimmune hemolytic anemia: clinical efficacy and biologic studies

This prospective study investigated the efficacy, safety, and response duration of low-dose rituximab (100 mg fixed dose for 4 weekly infusions) together with a short course of steroids as first- or second-line therapy in 23 patients with primary autoimmune hemolytic anemia (AIHA). The overall response was 82.6% at month +2, and subsequently stabilized to ∼ 90% at months +6 and +12; the response was better in warm autoimmune hemolytic anemia (WAIHA; overall response, 100% at all time points) than in cold hemagglutinin disease (CHD; average, 60%); the relapse-free survival was 100% for WAIHA at +6 and +12 months versus 89% and 59% in CHD, respectively, and the estimated relapse-free survival at 2 years was 81% and 40% for the warm and cold forms, respectively. The risk of relapse was higher in CHD and in patients with a longer interval between diagnosis and enrollment. Steroid administration was reduced both as cumulative dose (∼ 50%) and duration compared with the patient's past history. Treatment was well tolerated and no adverse events or infections were recorded; retreatment was also effective. The clinical response was correlated with amelioration biologic markers such as cytokine production (IFN-γ, IL-12, TNF-α, and IL-17), suggesting that low-dose rituximab exerts an immunomodulating activity. This study is registered at www.clinicaltrials.gov as NCT01345708.

Progressive multifocal leukoencephalopathy in transplant recipients

OBJECTIVE

Transplant recipients are at risk of developing progressive multifocal leukoencephalopathy (PML), a rare demyelinating disorder caused by oligodendrocyte destruction by JC virus.

METHODS

Reports of PML following transplantation were found using PubMed Entrez (1958-July 2010). A multicenter, retrospective cohort study also identified all cases of PML among transplant recipients diagnosed at Mayo Clinic, Johns Hopkins University, Washington University, and Amsterdam Academic Medical Center. At 1 institution, the incidence of posttransplantation PML was calculated.

RESULTS

A total of 69 cases (44 solid organ, 25 bone marrow) of posttransplantation PML were found including 15 from the 4 medical centers and another 54 from the literature. The median time to development of first symptoms of PML following transplantation was longer in solid organ vs bone marrow recipients (27 vs 11 months, p = 0.0005, range of <1 to >240). Median survival following symptom onset was 6.4 months in solid organ vs 19.5 months in bone marrow recipients (p = 0.068). Case fatality was 84% (95% confidence interval [CI], 70.3-92.4%) and survival beyond 1 year was 55.7% (95% CI, 41.2-67.2%). The incidence of PML among heart and/or lung transplant recipients at 1 institution was 1.24 per 1,000 posttransplantation person-years (95% CI, 0.25-3.61). No clear association was found with any 1 immunosuppressant agent. No treatment provided demonstrable therapeutic benefit.

INTERPRETATION

The risk of PML exists throughout the posttransplantation period. Bone marrow recipients survive longer than solid organ recipients but may have a lower median time to first symptoms of PML. Posttransplantation PML has a higher case fatality and may have a higher incidence than reported in human immunodeficiency virus (HIV) patients on highly-active antiretroviral therapy (HAART) or multiple sclerosis patients treated with natalizumab.

Infections associated with monoclonal antibody and fusion protein therapy in humans

Monoclonal antibodies (mAbs), especially those that interact with immune or hematologic leukocyte membrane targets, have changed the outcome of numerous diseases. However, mAbs can block or reduce immune cells and cytokines, and can lead to increased risk of infection. Some of these risks are predictable and can be explained by their mechanisms of action. Others have been observed only after the mAbs were licensed and used extensively in patients. In this review, we focus on infectious complications that occur upon treatment with mAbs or Fc-containing fusion proteins targeting leukocyte membrane proteins, including CD52, CD20, tumor necrosis factor, VLA4, CD11a and CTLA4. We report their known infectious risks and the recommendations for their use. Although most of these drugs are clinically safe when the indications are respected, we emphasize the need for regular updating of pharmacovigilance data.

Rituximab therapy for autoimmune haematological diseases

Autoimmune haematological diseases are characterized by the production of antibodies against blood proteins or cells, and comprise primary immune thrombocytopenia, autoimmune haemolytic anaemia, acquired haemophilia, and thrombotic thrombocytopenic purpura. Current treatments for these disorders include corticosteroids, cytotoxic drugs and splenectomy, which may be associated with significant systemic toxicity and/or morbility. B cells play a key role in both the development and perpetuation of autoimmunity, since they produce autoantibodies but also function as antigen-presenting cells, and release immunomodulatory cytokines. Rituximab, an anti-CD20 monoclonal antibody that specifically depletes B cells, may be an effective treatment strategy for patients with autoimmune disorders. This article reviews data of the literature, showing that patients with autoimmune haematological diseases can respond to rituximab irrespective of age and number or type of prior treatments. These data suggest that rituximab provides an effective and well-tolerated treatment option for these conditions.

Risk of infection in patients with lymphoma receiving rituximab: systematic review and meta-analysis

BACKGROUND

The addition of Rituximab (R) to standard chemotherapy (C) has been reported to improve the end of treatment outcome in patients affected by CD-20 positive malignant lymphomas (CD20+ ML). Nevertheless, given the profound and prolonged immunosuppression produced by R there are concerns that severe infections may arise. A systematic review and meta-analysis were performed to determine whether or not the addition of R to C may increase the risk of severe infections in adults undergoing induction therapy for CD20+ ML.

METHODS

Only randomised controlled trials comparing R-C to C standard alone in adult patients with CD20+ ML were included. Meta-analysis was performed on overall incidence of severe infection, risk of dying as the consequence of infection, risk of febrile neutropenia, risk of severe leucopenia, risk of severe granulocytopenia and overall response assuming a fixed effect model. Heterogeneity was investigated, if present and I2 >20%, according to several predefined baseline characteristics of the study populations.

RESULTS

Several relevant results have emerged. First, the addition of R to standard C does not increase the overall risk of severe infections (RR = 1.00; 95% CI 0.87 to 1.14) nor does it increase the risk of dying as a consequence of infection (RR = 1.60; 95% CI 0.68 to 3.75). Second, we confirmed that the addition of R to standard C increases the proportion of overall response (RR = 1.12; 95% CI 1.09 to 1.15), but it also increases the risk of severe leucopenia (RR = 1.24; 95% CI 1.12 to 1.37) and granulocytopenia (RR = 1.07; 95% CI 1.02 to 1.12).

CONCLUSIONS

R-C is superior to standard C in terms of overall response and it does not increase the overall incidence of severe infection. However, data on special groups of patients (for example, HIV positive subjects and HBV carriers) are lacking. In our opinion more studies are needed to explore the potential effect of R on silent and chronic viral infections.

[Role of viral infections in immunosuppressed patients]

Ser receptor de un trasplante de órgano sólido, así como recibir tratamiento quimioterápico para una enfermedad hematólógica maligna, predispone claramente a padecer infecciones virales tanto comunes como oportunistas, de origen tanto comunitario como procedentes del donante de órganos y/o de una reactivación de un virus latente endógeno. Herpes virus y más especialmente citomegalovirus y virus de Epstein-Barr son los que con más frecuencia afectan a estos enfermos, así como los virus respiratorios. El tratamiento consiste en la combinación de reducir la inmunodepresión inducida junto con tratamiento antiviral. Se ha realizado una revisión de la literatura pormenorizada y actualizada de la epidemiología, la patogenia, las manifestaciones clínicas y la aproximación terapéutica de las infecciones virales en estos enfermos.

Prevention of hepatitis B virus reactivation under rituximab therapy

Rituximab is a useful drug for the treatment of B-cell non-Hodgkin's lymphoma, and its use has been extended to other diseases such as idiopathic thrombocytopenic purpura and chronic rheumatoid arthritis. One serious complication associated with rituximab use is reactivation of hepatitis B virus, and the search for methods to prevent this occurrence has resulted in a rapid accumulation of knowledge in recent years. In this review, we will discuss case studies from our group, as well as other groups, and outline current knowledge on the topic together with issues that remain to be resolved.

Role of viral infections in immunosuppressed patients

Being a solid organ and hematopoietic stem cell transplant recipient as well as receiving chemotherapy for a malignant hematological disease clearly predispose the subject to a variety of viral infections, both common and opportunistic diseases. The patient may have acquired these infections from the community as well as from the donor organ (donor-derived infections) and/or from reactivation of an endogenous latent virus. Herpes viruses and especially the cytomegalovirus and Epstein-Barr virus are among the most common of the opportunistic viral pathogens affecting these patients, in addition to respiratory viruses. Treatment consists in antiviral drug therapies combined with the reduction in the degree of the induced immunosuppression. A review of the literature has been performed in order to update the epidemiology, pathogenesis, clinical manifestations and therapeutic approach of the viral infections in these immunocompromised patients.

Rituximab administration and reactivation of HBV

Rituximab is a drug used for the treatment of B-cell non-Hodgkin's lymphoma, and its range of use has expanded to the treatment of collagen diseases such as idiopathic thrombocytopenic purpura and rheumatoid arthritis. One serious complication of rituximab use is the reactivation of dormant hepatitis B virus, and prevention of this phenomenon has become an urgent issue. This paper provides a general outline of the problem through an analysis of patient cases that we and other groups have experienced to date.