Fatal reactivation of cytomegalovirus infection after use of rituximab for a post-transplantation lymphoproliferative disorder

CD4+ Cytotoxic T Cells Involved in the Development of EBV-Associated Diseases

Activated cytotoxic CD4 T cells (HLA-DR+) play an important role in the control of EBV infection, especially in cells with latency I (EBNA-1). One of the evasion mechanisms of these latency cells is generated by gp42, which, via peripherally binding to the β1 domain of the β chain of MHC class II (HLA-DQ, -DR, and -DP) of the infected B lymphocyte, can block/alter the HLA class II/T-cell receptor (TCR) interaction, and confer an increased level of susceptibility towards the development of EBV-associated autoimmune diseases or cancer in genetically predisposed individuals (HLA-DRB1* and DQB1* alleles). The main developments predisposing the factors of these diseases are: EBV infection; HLA class II risk alleles; sex; and tissue that is infiltrated with EBV-latent cells, forming ectopic lymphoid structures. Therefore, there is a need to identify treatments for eliminating cells with EBV latency, because the current treatments (e.g., antivirals and rituximab) are ineffective.

Autoimmune Pemphigus: Latest Advances and Emerging Therapies

Pemphigus represents a group of rare and severe autoimmune intra-epidermal blistering diseases affecting the skin and mucous membranes. These painful and debilitating diseases are driven by the production of autoantibodies that are mainly directed against the desmosomal adhesion proteins, desmoglein 3 (Dsg3) and desmoglein 1 (Dsg1). The search to define underlying triggers for anti-Dsg-antibody production has revealed genetic, environmental, and possible vaccine-driven factors, but our knowledge of the processes underlying disease initiation and pathology remains incomplete. Recent studies point to an important role of T cells in supporting auto-antibody production; yet the involvement of the myeloid compartment remains unexplored. Clinical management of pemphigus is beginning to move away from broad-spectrum immunosuppression and towards B-cell-targeted therapies, which reduce many patients’ symptoms but can have significant side effects. Here, we review the latest developments in our understanding of the predisposing factors/conditions of pemphigus, the underlying pathogenic mechanisms, and new and emerging therapies to treat these devastating diseases.

Epstein-Barr Virus and the Origin of Myalgic Encephalomyelitis or Chronic Fatigue Syndrome

Myalgic encephalomyelitis or chronic fatigue syndrome (ME/CFS) affects approximately 1% of the general population. It is a chronic, disabling, multi-system disease for which there is no effective treatment. This is probably related to the limited knowledge about its origin. Here, we summarized the current knowledge about the pathogenesis of ME/CFS and revisit the immunopathobiology of Epstein-Barr virus (EBV) infection. Given the similarities between EBV-associated autoimmune diseases and cancer in terms of poor T cell surveillance of cells with EBV latency, expanded EBV-infected cells in peripheral blood and increased antibodies against EBV, we hypothesize that there could be a common etiology generated by cells with EBV latency that escape immune surveillance. Albeit inconclusive, multiple studies in patients with ME/CFS have suggested an altered cellular immunity and augmented Th2 response that could result from mechanisms of evasion to some pathogens such as EBV, which has been identified as a risk factor in a subset of ME/CFS patients. Namely, cells with latency may evade the immune system in individuals with genetic predisposition to develop ME/CFS and in consequence, there could be poor CD4 T cell immunity to mitogens and other specific antigens, as it has been described in some individuals. Ultimately, we hypothesize that within ME/CFS there is a subgroup of patients with DRB1 and DQB1 alleles that could confer greater susceptibility to EBV, where immune evasion mechanisms generated by cells with latency induce immunodeficiency. Accordingly, we propose new endeavors to investigate if anti-EBV therapies could be effective in selected ME/CFS patients.

Peripheral B Cell Deficiency and Predisposition to Viral Infections: The Paradigm of Immune Deficiencies

In the era of COVID-19, understanding how our immune system responds to viral infections is more pertinent than ever. Immunodeficiencies with very low or absent B cells offer a valuable model to study the role of humoral immunity against these types of infection. This review looks at the available evidence on viral infections in patients with B cell alymphocytosis, in particular those with X-linked agammaglobulinemia (XLA), Good’s syndrome, post monoclonal-antibody therapy and certain patients with Common Variable Immune Deficiency (CVID). Viral infections are not as infrequent as previously thought in these conditions and individuals with very low circulating B cells seem to be predisposed to an adverse outcome. Particularly in the case of SARS-CoV2 infection, mounting evidence suggests that peripheral B cell alymphocytosis is linked to a poor prognosis.

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.

Incidence of Infectious Disease and Malignancies After Rituximab Therapy in Kidney Transplant Recipients: Results From a Cohort in Germany

BACKGROUND

Rituximab is frequently used in solid organ transplantation off-label, especially in patients with renal allografts. Few data are available on the safety aspects of solid organ transplant recipients receiving rituximab. There is a knowledge gap on long-term follow-up data, in particular on infectious complications.

PATIENTS AND METHODS

A retrospective observational registry study (German Registry on Autoimmune Diseases) comprising a total of 681 patients was conducted. The data of 63 adult kidney transplant recipients who received rituximab between 2006 and 2013 were used in this analysis.

RESULTS

Median follow-up was 42 (1-109) months. At least 1 severe infection occurred in 57% of patients. The median time between the first rituximab infusion and the first infection was 4 (1-48) months. Of the overall 88 infections, 74 were severe bacterial infections, 5 were severe viral infections, 3 were severe fungal infections, 2 were combined severe bacterial and fungal infections, and 4 were combined severe viral, fungal and bacterial infections. Seven patients died during the observational period, 2 of them due to infectious complications. In the observational period, 1 case of squamous cell carcinoma but no other malignancies were observed.

CONCLUSION

Consistent with previous data, a high incidence of infections was observed after rituximab treatment in kidney transplant recipients. Most infections occurred within 6 months after rituximab initiation. With more than 3 years of follow-up, we were able to document a low incidence of secondary malignancies after rituximab with only 1 case in our cohort.

Favorable results in ABO-incompatible renal transplantation without B cell-targeted therapy: Advantages and disadvantages of rituximab pretreatment

The effectiveness of desensitization with rituximab in ABO-incompatible renal transplantation (ABO-I) has been widely reported. However, ABO-I outcomes are still worse than those of ABO-identical or ABO-compatible renal transplantation (ABO-Id/C). We retrospectively examined the outcomes in consecutive living donor ABO-Id/C (n = 412) and ABO-I (n = 205) cases to elucidate the causes of inferiority in ABO-I. ABO-I cases included recipients treated with rituximab (RIT, n = 131), splenectomy (SPX, n = 21), or neither because of low anti-A/B antibody titers (NoR/S, n = 53). Graft survival, infection, and de novo HLA antibody production were compared for ABO-I and ABO-Id/C, followed by stratification into RIT and NoR/S groups. Propensity score-based methods were employed to limit selection bias and potential confounders. Overall graft survival for ABO-I was significantly lower than that for ABO-Id/C (92.8% vs 97.2% after 5 years, P = .0037). Graft loss due to infection with ABO-I was significantly more frequent than that with ABO-Id/C, whereas acute antibody-mediated rejection (AMR) caused no graft failure in ABO-I recipients. Stratified analysis demonstrated significantly higher infection risk with RIT than with NoR/S. Safe reduction or avoidance of rituximab in desensitization protocols might contribute to further improvement of ABO-I outcome.

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.

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.

Rituximab Therapy and Infection Risk in Pediatric Renal Transplant Patients

OBJECTIVES

Rituximab is a monoclonal antibody directed against the CD20 molecule on pre-B and mature B cells and is used in transplant recipients for the prevention and treatment of alloantibody-mediated rejection or for the treatment of disease recurrence after transplant. In most patients, rituximab has been safe and well-tolerated, but the long-term adverse effects of rituximab are currently unknown.

MATERIALS AND METHODS

We retrospectively evaluated 78 pediatric renal transplant recipients for the occurrence of infectious disease. Patients who received rituximab therapy were divided into 2 groups: those who developed an infection and those who did not. The 2 groups were compared for serious infections, hospitalization, graft loss, and death rates.

RESULTS

Eighteen transplant patients received rituximab therapy for various causes. The number of rituximab courses given varied according to the cause and ranged from 1 to 8 courses. The dose at each course was 375 mg/m(2). Median age of all recipients was 16.00 years (min-max:, 5.00-22.00 y), and median follow-up time was 2.00 years (min-max:, 1.00-3.00 y). Serious infections (bacterial sepsis, tuberculosis, Cytomegalovirus infection, varicella-zoster virus infection, Polyomavirus-associated nephropathy, and acute pyelonephritis) were observed in 8 patients who received rituximab therapy. We observed that patients with antibody-mediated rejection had significantly increased infection rate. Patients who had used rituximab combined with antithymocyte globulin and higher rituximab course number and higher pretreatment CD19 and CD20 levels had higher risk of infection (P < .05).

CONCLUSIONS

The combined use of rituximab with additional treatments such as antithymocyte globulin, intravenous immunoglobulin, and repeated plasma exchange may be associated with high risk of infectious disease. Especially for those patients who required intensive and repetitive treatment, such as antibody-mediated rejection, rituximab treatment should be used with caution. Infection risk should be closely monitored, although mainly in patients who receive T-cell-depleting agents.

How to reduce lethal infectious complications in ABO-incompatible kidney transplantation

BACKGROUND

ABO-incompatible organ transplants are good options for expanding the living donor pool; however, the necessary pre-conditioning to remove ABO antibodies before surgery can evoke critical infectious complications after surgery.

METHODS

Between February 2009 and July 2013, we performed ABO-incompatible kidney transplantation on 182 patients. We analyzed the first 85 patients for post-operative infectious complications in a cross-sectional cohort of patients (group 1, n = 85) who had received an ABO-incompatible kidney transplant and, in light of the results, amended the pre-conditioning (lower dose of rituximab, selective use of calcineurin inhibitors, anti-metabolite reduction, and prophylactic strategy) given to a prospective cohort (group 2, n = 97).

RESULTS

The characteristics of the two groups did not differ significantly. Infectious complications decreased significantly in group 2, including cytomegalovirus (anti-genemia 64.7% vs 27.8%, P < .001) and BK viremia (35.2% vs 18.6%, P = .008). The acute rejection rate and death-censored graft survival were similar in both groups. Notably, with the modified protocol, there were no deaths (8.2% vs 0.0%, P = .03).

CONCLUSIONS

Pre-conditioning for ABO-incompatible kidney transplantation is a prerequisite for successful outcome; its drawbacks can be limited with the use of a modified immunosuppressive strategy. If immunosuppression is modified according to host conditions, ABO-incompatible kidney transplantation can be performed safely with a successful graft outcome.

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.

Rituximab therapy for primary glomerulonephritis: Report on two cases

The evidence in the medical literature on the efficacy and safety of rituximab therapy for primary glomerulonephritis is limited and controversial. We describe two male Caucasian patients with rapidly progressive kidney failure due to primary proliferative glomerulonephritis. Both of them received high-dose intravenous corticosteroids and oral cyclophosphamide with limited benefit. The first patient (hepatitis C virus-negative mixed cryoglobulinemia) underwent plasma-exchange with intravenous immunoglobulins; he showed significant benefit on kidney function (he became dialysis independent with serum creatinine going back to 1.6 mg/dL) after one rituximab pulse even if urinary abnormalities were still present. No improvement in renal function or urinary changes occurred in the second patient. Both these individuals developed sepsis over the follow-up, the first patient died two months after rituximab therapy. This report is in keeping with the occurrence of severe infections after rituximab therapy in patients with renal impairment at baseline and concomitant high-dose steroids.

The risk of hepatitis B virus reactivation and the role of antiviral prophylaxis in hepatitis B surface antigen negative/hepatitis B core antibody positive patients with diffuse large B-cell lymphoma receiving rituximab-based chemotherapy

The risk factors and the role of prophylactic antiviral therapy of hepatitis B virus (HBV) reactivation in patients with hepatitis B surface antigen (HBsAg) negative/hepatitis B core antibody (HBcAb) positive disease remain controversial. We reviewed 629 patients with diffuse large B-cell lymphoma (DLBCL). Among 629 patients, 150 of 246 patients with resolved HBV (HBsAg negative and HBcAb positive) were treated with rituximab-combined therapy. Among these 150 patients, none of 104 patients (0.0%) who were hepatitis B surface antibody (HBsAb) positive experienced HBV reactivation versus four of 46 patients (8.7%) who were HBsAb negative (p = 0.008). One of 113 patients (0.9%) with International Prognostic Index (IPI) 0-2 suffered HBV reactivation versus three of the remaining 37 patients (8.1%) with IPI 3-5 (p = 0.047). HBsAb and IPI are potential risk factors for HBV reactivation. The use of prophylactic agents may not be recommended for these patients until the occurrence of HBV reactivation.

Hepatitis B reactivation and rituximab: a new boxed warning and considerations for solid organ transplantation

Use of rituximab, a chimeric monoclonal antibody directed at the CD20 antigen, continues to increase in solid organ transplantation (SOT) for several off-label uses. In September 2013, the United States Food and Drug Administration (FDA) issued a Drug Safety Communication to oncology, rheumatology and pharmacy communities outlining a new Boxed Warning for rituximab. Citing 109 cases of fatal hepatitis B virus (HBV) reactivation in persons receiving rituximab therapy with previous or chronic HBV infection documented in their Adverse Event Reporting System (AERS), the FDA recommends screening for HBV serologies in all patients planned to receive rituximab and antiviral prophylaxis in any patient with a positive history of HBV infection. There is a lack of data pertaining to this topic in the SOT population despite an increase in off-label indications. Previous reports suggest patients receiving rituximab, on average, were administered six doses prior to HBV reactivation. Recommendations on prophylaxis, treatment and re-challenging patients with therapy after resolution of reactivation remain unclear. Based on data from the FDA AERS and multiple analyses in oncology, SOT providers utilizing rituximab should adhere to the FDA warnings and recommendations regarding HBV reactivation until further data are available in the SOT population.

Rituximab in the treatment of peripheral neuropathy associated with monoclonal gammopathy

Peripheral neuropathy associated with immunoglobulin (Ig)M gammopathy and anti-myelin-associated glycoprotein antibodies is frequently treatment-resistant and different treatment regimens carry substantial toxicity and side effects. More recently, the chimeric anti-CD20 monoclonal antibody rituximab has shown benefits in the treatment of peripheral neuropathy associated with IgM gammopathy with a favorable side-effect profile. There are no published reports of its use in the treatment of neuropathy associated with IgG and IgA gammopathies. Rituximab is usually given at 375 mg/m(2) intravenously with four weekly doses that may be repeated after 6-12 months. Large controlled studies are still pending but rituximab is an exciting and promising treatment offering another option in the treatment of peripheral neuropathy associated with IgM monoclonal gammopathy.

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.

Cholestatic liver disease after rituximab and adalimumab and the possible role of cross-reacting antibodies to Fab 2 fragments

BACKGROUND

Millions of patients are treated with therapeutic monoclonal antibodies (Tmabs) for miscellaneous diseases. We investigated sera from six patients who received immune globulin, from one patient with refractory anti-neutrophil-cytoplasmic antibody (ANCA)-associated granulomatosis with polyangiitis (GPA) who developed two episodes of acute cholestatic liver disease, one after treatment with rituximab and a second after adalimumab and a healthy control group.

METHODS

Three sera from the patient and six sera from patients who received immune globulin were analyzed for antibodies to rituximab and adalimumab by ELISA. Additionally, sera from the patients and from nine healthy blood donors were coated with the Fab fragment of an unrelated humanized monoclonal antibody, with human Fc proteins as well as a mouse IgG globulin.

RESULTS

Viral serology for hepatitis A, B, C and autoantibodies specific for autoimmune liver disorders were negative. In all three sera from the patient antibodies to rituximab could be detected, but also antibodies to adalimumab were present even at time points when the patient had not yet received adalimumab, indicating cross reactivity between both substances. Testing against an unrelated human Fab fragment revealed positive results, indicating that the patient had antibodies against human Fab fragments in general. The Fc proteins were negative, and patients' sera did also not react with mouse IgG globulins. Remarkably, 2 out of 5 patients which were treated with immune globulin had antibodies against human Fab fragments in general whereas in none of the samples from healthy controls antibodies to Fab fragment could be detected.

CONCLUSION

This is the first study demonstrating cholestatic liver disease induced by two different Tmabs. Cross - reacting antibodies to Fab2 fragments in general are probably involved. Further studies must show if these Fab2 antibodies in general are related with drug-induced side effects and accelerated drug clearance in patients on Tmab therapy.

Rituximab in renal transplantation

Rituximab is a chimeric anti-CD20 monoclonal antibody that leads to B cell depletion. It is not licensed for use in renal transplantation but is in widespread use in ABO blood group incompatible transplantation. It is an effective treatment for post-transplant lymphoproliferative disorder, and is also used in both HLA antibody incompatible renal transplantation and the treatment of acute rejection. Recent evidence suggests rituximab may prevent the development of chronic antibody mediated rejection. The mechanisms underlying its effects are likely to relate both to long-term effects on plasma cell development and to the impact on B cell modulation of T cell responses. Rituximab (in multiple doses or in combination with other monoclonal antibodies and/or other immunosuppressants) may lead to an increase in infectious complications, although the evidence is not clear. Rarely, the drug can cause a cytokine release syndrome, thrombocytopenia and neutropenia. It has been related to an increased risk of progressive multifocal leucoencephalopathy and, recently, deaths from cardiovascular causes. Trials examining the effects of rituximab in induction therapy for compatible renal transplantation and the treatment of chronic antibody mediated rejection are ongoing. These trials should aid greater understanding of the role of B-cells in the alloresponse to renal transplantation.

Reactivation of latent viruses in individuals receiving rituximab for new onset type 1 diabetes

BACKGROUND

Rituximab has been successfully used as an experimental therapy in different autoimmune diseases. Recently, a double-blind placebo-controlled phase-2 study in early onset type 1 diabetes showed that rituximab delayed progression of the disease. However, like with any immunosuppressive therapy, there is a concern of opportunistic viral reactivations with the use of rituximab, including herpes and polyomaviruses.

OBJECTIVES

To study the incidence of new infections and reactivations with BK, JC, Epstein-Barr and cytomegalovirus (BKV, JCV, EBV and CMV) in T1D participants in the phase-2 rituximab study.

STUDY DESIGN

Subjects received 4 weekly doses of rituximab (N = 57) or placebo (N = 30) during the first month of study. Blood samples obtained at weeks 0, 12, 26, 56 and 78 were assayed for CMV, EBV, BKV and JCV by real-time DNA PCR and serology.

RESULTS

EBV reactivations were diagnosed by PCR in 25% of placebo, but none of rituximab recipients (p < 0.01). There were no episodes of CMV viremia in either treatment group. BKV viremias were significantly more common in the rituximab recipients (9%) compared with placebo controls (0, p < 0.01). No JCV reactivations were detected in this study, but among 6 rituximab and 2 placebo recipients who seroconverted for JCV during the study, only one rituximab recipient had detectable viremia. All infections were asymptomatic.

CONCLUSIONS

Four doses of rituximab administered to individuals with early onset T1D decreased the incidence of asymptomatic EBV reactivations, as predicted by the rituximab-mediated elimination of memory B-cells, but increased the frequency of asymptomatic viremias caused by polyomaviruses.

Severe CMV complication following maintenance therapy with rituximab

Cytomegalovirus (CMV) encephalitis is a rare infection that immunodeficient patients, mainly where HIV-positive, may suffer from. Several cases were described when complications with the treatment with monoclonal antibodies, like rituximab, for malignant lymphomas. We will describe here the case of a patient, who has developed CMV gastritis, then CMV encephalitis after the treatment of a CLL with a chemotherapy and maintenance therapy with rituximab.

Hepatitis B virus reactivation associated with anti-neoplastic therapy

Reactivation of hepatitis B virus (HBV) infection is a known complication during and after anti-cancer therapy. This condition can affect two patient populations: it is most commonly seen in patients who are seropositive for hepatitis B surface antigen (HBsAg), but it is also being increasingly reported among patients who are HBsAg-negative but who have prior infection, as evident by seropositive status for antibody to hepatitis B core antigen (anti-HBc), irrespective of their anti-HBs (antibody to HBsAg) status. The clinical course can vary from asymptomatic hepatitis to fulminant hepatic failure that can be potentially fatal. With the increasing use of biological agents in addition to potent cytotoxic chemotherapy in the armamentarium of anti-cancer treatments, reactivation of hepatitis B has become a common clinical situation that is faced by both oncologists and hepatologists especially in HBV endemic areas. In this review, we discuss the clinical course of reactivation in the two HBV-infected sub-populations, and the role of anti-virals in the prevention and management of HBV reactivation in association with cytotoxic chemotherapy and biological therapies.

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.

Epstein-Barr and other herpesvirus infections in patients with early onset type 1 diabetes treated with daclizumab and mycophenolate mofetil

BACKGROUND

We assessed the morbidity of herpesviruses in patients with type 1 diabetes mellitus (T1D) enrolled in immunosuppressive treatment studies.

METHODS

Epstein-Barr virus (EBV), cytomegalovirus (CMV), herpes simplex virus (HSV), and varicella zoster virus (VZV) infections were monitored in 126 participants of a randomized, double-blind, placebo-controlled study of daclizumab (DZB) and mycophenolate mofetil (MMF) including DZB(+)MMF(+), DZB(-)MMF(+), DZB(+)MMF(-), and DZB(-)MMF(-). During the 2-year follow-up, herpesviral infections were monitored clinically, by serology and blood DNA polymerase chain reaction.

RESULTS

Among 57 baseline EBV-seronegative participants, 9 developed EBV primary infections, including 2 with infectious mononucleosis syndrome. There were no appreciable differences in the course of the primary EBV infections across treatment groups. Among 69 baseline EBV-seropositive participants, 22 had virologic reactivations, including 1 symptomatic DZB(-)MMF(+) subject. Compared with 7 DZB(-)MMF(-) EBV reactivators, the 9 DZB(+)MMF(+) reactivators tended to have more prolonged viremia (11.4 vs 4.4 months; P = .06) and higher cumulative viral burden (14.2 vs 12.5 log EBV copies/mL; P = .06). Four of 85 baseline CMV-seronegative subjects developed asymptomatic primary CMV infections. There were no CMV reactivations. Of 30 baseline HSV-seropositive subjects, 8 developed ≥1 episode of herpes labialis; 1 subject had a primary HSV infection; and 1 subject without baseline serology information had a new diagnosis of genital HSV. There were no significant differences in the incidence of HSV recurrences across treatment groups. Of 100 baseline VZV-seropositive subjects, 1 DZB(-)MMF(-) subject developed herpes zoster and 1 DZB(-)MMF(+) subject had Bell's palsy possibly related to VZV.

CONCLUSIONS

The use of DZB alone or in combination with MMF was not associated with increased morbidity due to herpesviruses.

CLINICAL TRIALS REGISTRATION

NCT00100178.

Successful treatment of monomorphic primary central nervous system post-transplantation lymphoproliferative disorder 5 years after kidney transplantation

A 31-year-old man underwent living-related kidney transplantation in 2004 as a consequence of primary focal segmental glomerulosclerosis (FSGS). Four years after the transplantation, we confirmed nephrotic syndrome caused by recurrent FSGS. We performed plasmapheresis and low-density lipoprotein adsorption. We also combined steroid therapy with a reduction in the dose of tacrolimus and an increased dose of mycophenolate mofetil. The nephrotic syndrome improved dramatically with this combined therapeutic approach. However, 10 months after these treatments, he revisited our hospital because of altered consciousness. We detected multiple tumor masses in his brain that were ring enhanced on contrast magnetic resonance imaging. Consequently, we suspected primary central nervous system post-transplantation lymphoproliferative disorder (CNS-PTLD). We performed a craniotomy to biopsy the brain tumors. The biopsy specimen showed Epstein-Barr virus-associated diffuse large B-cell lymphoma. There is no definitive treatment for CNS-PTLD. Therefore, we treated the primary CNS-PTLD successfully with whole-brain radiation and discontinuation of immunosuppression therapy.

Rituximab-induced hepatitis C virus reactivation in rheumatoid arthritis

The B-cell depletion agent rituximab (RTX) is used in lymphoma and rheumatoid arthritis (RA), and there have been several case reports of an RTX-induced reactivation of hepatitis C virus in patients with lymphoma. However, there have been no papers detailing hepatitis C virus reactivation after RTX therapy in a patient with RA. Here we report a case of RTX-induced hepatitis C virus reactivation in a patient with RA. Physicians should be aware that a close follow-up of liver function and viral load is mandatory after RTX therapy in patients with RA and concomitant hepatitis C.

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.

Autoimmunity associated with immunotherapy of cancer

In this age of promise of new therapies for cancer, immunotherapy is emerging as an exciting treatment option for patients. Vaccines and cytokines are being tested extensively in clinical trials, and strategies using monoclonal antibodies and cell transfer are mediating dramatic regression of tumors in patients with certain malignancies. However, although initially advocated as being more specific for cancer and having fewer side effects than conventional therapies, it is becoming increasingly clear that many immunotherapies can lead to immune reactions against normal tissues. Immunotoxicities resulting from treatment can range from relatively minor conditions, such as skin depigmentation, to severe toxicities against crucial organ systems, such as liver, bowel, and lung. Treatment-related toxicity has correlated with better responses in some cases, and it is probable that serious adverse events from immune-mediated reactions will increase in frequency and severity as immunotherapeutic approaches become more effective. This review introduces immunotherapeutic approaches to cancer treatment, provides details of toxicities arising from therapy, and discusses future potential ways to avoid or circumvent these side effects.

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.

Features of Epstein-Barr Virus (EBV) reactivation after reduced intensity conditioning allogeneic hematopoietic stem cell transplantation

This single centre study assessed the incidence, kinetics and predictive factors of Epstein-Barr Virus (EBV) reactivation and EBV-related lymphoproliferative diseases (LPDs) in 175 consecutive patients who received a reduced-intensity conditioning (RIC) before allogeneic hematopoietic stem cell transplantation (allo-HSCT). The cumulative incidence of EBV reactivation at 6 months after allo-HSCT defined as an EBV PCR load above 1000 copies of EBV DNA/10(5) cells was 15%, and none of these patients experienced any sign or symptom of LPD. A total of 17 patients, who had EBV DNA levels exceeding 1000 copies/10(5) cells on two or more occasions, were pre-emptively treated with rituximab. With a median follow-up of 655 (range, 92-1542) days post allo-HSCT, there was no statistically significant difference in term of outcome between those patients who experienced an EBV reactivation and those who did not. In multivariate analysis, the use of antithymocyte globulin as part of the RIC regimen was the only independent risk factor associated with EBV reactivation (relative risk=4.9; 95% confidence interval, 1.1-21.0; P=0.03). We conclude that patients undergoing RIC allo-HSCT using anti-thymocyte globulin as part of the preparative regimen are at higher risk for EBV reactivation. However, this did not impact on outcome, as quantitative monitoring of EBV viral load by PCR and preemptive rituximab therapy allowed for significantly reducing the risk of EBV-related LPD.

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.

Therapeutic targeting of B cells for rheumatic autoimmune diseases

Autoreactive B cells are characterized by their ability to secrete autoantibodies directed against self-peptides. During the last decade, it has become increasingly apparent that B lymphocytes not only produce autoantibodies but also exert important regulatory roles independent of their function as antibody-producing cells. This is especially relevant in the context of autoimmunity, because autoreactive B cells have been shown to possess the ability to activate pathogenic T cells, to produce pro-inflammatory cytokines, and to promote the formation of tertiary lymphoid tissue in target organs. The production of monoclonal antibodies against B-cell-surface molecules has facilitated the characterization of several distinct B lymphocyte subsets. These cell-surface molecules have not only served as useful cell differentiation markers but have also helped to unravel the important biological functions of these cells. Some of these molecules, all of which are expressed on the cell surface, have proven to be effective therapeutic targets. In both animal models and in clinical assays, the efficient elimination of B lymphocytes has been shown to be useful in the treatment of rheumatoid arthritis and other autoimmune diseases. The treatment of most rheumatic autoimmune diseases relies mainly on the use of cytotoxic immunosuppressants and corticosteroids. Although this has resulted in improved disease survival, patients may nonetheless suffer severe adverse events and, in some cases, their relapse rate remains high. The increasing need for safer and more effective drugs along with burgeoning new insights into the pathogenesis of these disorders has fueled interest in biological agents; clinical trials involving the B-cell depletion agent rituximab have been especially promising. This article reviews the current knowledge of B-cell biology and pathogenesis as well as the modern therapeutic approaches for rheumatic autoimmune diseases focusing in particular on the targeting of B-cell-specific surface molecules and on the blocking of B-cell activation and survival.

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.

Reactivation of hepatitis B virus after rituximab-containing treatment in patients with CD20-positive B-cell lymphoma

BACKGROUND

Reactivation of hepatitis B virus (HBV) after rituximab-containing chemotherapy in patients with B-cell lymphoma has been recognized as a potentially serious complication in HBV immune patients.

METHODS

To determine the HBV reactivation in patients treated with rituximab, a retrospective study of HBV-related markers was performed before and after rituximab-containing treatment in 261 consecutive patients with CD20-positive B-cell lymphoma.

RESULTS

Of the 261 patients, 230 patients were tested for both hepatitis B surface antigen (HBsAg) and antibody to hepatitis B core antigen (anti-HBc) before treatment. Fifty-six (24.3%) of 230 patients were anti-HBc positive, and the remaining 174 (75.6%) patients were anti-HBc negative. Among the 56 anti-HBc-positive patients, 5 (8.9%) became HBsAg positive (HBV reactivation), whereas none of the 174 anti-HBc-negative patients became HBsAg positive with a median follow-up of 24 months (P = .001). Among the 5 patients with HBV reactivation, 4 were negative for antibody to HBsAg (anti-HBs), and 1 patient was positive for anti-HBs. All 5 of these patients were treated successfully with entecavir on detection of HBsAg, although 4 of the 5 patients exhibited mild to moderate elevation of alanine aminotransferase. Among 56 anti-HBc-positive patients, those negative for anti-HBs had a higher probability of developing HBV reactivation compared with those positive for anti-HBs (4 of 19; 21.1% vs 1 of 37; 2.7%, P = .014).

CONCLUSIONS

Patients with isolated anti-HBc are at high risk of HBV reactivation and should be monitored closely for HBsAg, anti-HBs, HBV-DNA, and transaminase levels during and after rituximab-containing treatment. Although preemptive use of entecavir enabled successful management of HBV reactivation, mild to moderate hepatic flare was still observed. These approaches should be further evaluated in a prospective study with regard to clinical usefulness, safety, and cost-effectiveness.

Does rituximab increase the incidence of infectious complications? A narrative review

BACKGROUND

Rituximab has increasingly been used for the treatment of hematological malignancies and autoimmune diseases, and its efficacy and safety are well established. Although clinical trials have shown conflicting results regarding the association of rituximab with infections, an increased incidence of infections has recently been reported in patients with lymphomas being treated with rituximab. However, clinical experience regarding the association of rituximab with different types of infection is lacking and this association has not been established in patients with rheumatoid arthritis.

METHODS

All previous studies included in our literature review were found using a PubMed, EMBASE, and Cochrane database search of the English-language medical literature applying the terms 'rituximab', 'monoclonal antibodies', 'infections', 'infectious complications', and combinations of these terms. In addition, the references cited in these articles were examined to identify additional reports.

RESULTS

We performed separate analyses of data regarding the association of rituximab with infection in (1) patients with hematological malignancies, (2) patients with autoimmune disorders, and (3) transplant patients. Recent data show that rituximab maintenance therapy significantly increases the risk of both infection and neutropenia in patients with lymphoma or other hematological malignancies. On the other hand, data available to date do not indicate an increased risk of infections when using rituximab compared with concurrent control treatments in patients with rheumatoid arthritis. However, there is a lack of sufficient long-term data to allow such a statement to be definitively made, and caution regarding infections should continue to be exercised, especially in patients who have received repeated courses of rituximab, are receiving other immunosuppressants concurrently, and in those whose immunoglobulin levels have fallen below the normal range. Few data are available concerning the risk of organ transplant recipients developing infections following rituximab therapy. Data from case reports, case series, and retrospective studies correlate rituximab use with the development of a variety of infections in transplant patients.

CONCLUSIONS

Further studies are needed to clarify the association of rituximab with infection. Physicians and patients should be educated about the association of rituximab with infectious complications. Monitoring of absolute neutrophil count and immunoglobulin levels and the identification of high-risk groups for the development of infectious complications, with timely vaccination of these groups, are clearly needed.

A case of severe acute hepatitis C and delayed antibody production due to rituximab therapy

A 59-year-old male patient underwent surgical treatment for non-Hodgkin's lymphoma of the right scrotum in October 2007. He received a total of 4 courses of two different adjuvant chemotherapy regimens including rituximab from January to April 2008. In June 2008 he was hospitalized due to severe liver dysfunction with an alanine aminotransferase of 2039 IU/l and a prothrombin time of 23.3%. He was diagnosed with acute hepatitis C by the detection of hepatitis C virus (HCV) RNA and negative anti-HCV antibody, and his hepatic function improved with bed rest during hospitalization; however, the production of anti-HCV antibodies was not detected until January 2009. Severe liver dysfunction is uncommon among patients with acute hepatitis C, and the long window (8 months) between HCV infection and the development of anti-HCV antibodies observed in the present case may have been due, at least in part, to a B cell disorder caused by rituximab therapy. In addition to the well-known risk of reactivation of hepatitis B virus infection in patients undergoing chemotherapy, physicians should be aware of the potential effects of chemotherapy on the clinical course of HCV infection.

Immunotherapeutic options for Epstein-Barr virus-associated lymphoproliferative disease following transplantation

Epstein-Barr virus-associated lymphoproliferative diseases (EBV-LPD) after hematopoietic stem cell transplantation or solid-organ transplantation remain a serious and potentially life-threatening complication. In the last decade, outcomes for EBV-LPD have significantly improved. Key to this success was the development of early detection methods, such as serial measurements of EBV-DNA load in the peripheral blood of transplant recipients. Immunotherapeutic interventions for EBV-LPD include reduction of immunosuppression, CD20 monoclonal antibodies (rituximab) as monotherapy or in conjunction with chemotherapy, and adoptive immunotherapy with EBV-specific T cells. Pre-emptive immunotherapeutic interventions can prevent the development of EBV-LPD. As monotherapy, immunotherapy is effective in inducing remissions of EBV-LPD with low-risk features. For high-risk disease, combining immunotherapy with conventional therapies has led to superior outcomes. Current challenges consist of risk stratifying patients so that patients receive the most efficacious therapy without suffering from unwanted side effects.

Epstein-Barr virus-related lymphoproliferative disorder induced by equine anti-thymocyte globulin therapy

Post-transplant lymphoproliferative disorder (PTLD) is generally caused by an uncontrolled B-cell proliferation induced by Epstein-Barr virus (EBV) in the setting of impaired EBV-specific T-cell immunity. PTLD has been described in allogeneic hematopoietic stem cell transplant (HSCT) and rarely in autologous HSCT. Anti-thymocyte globulin (ATG) is being increasingly utilized for acute rejection in organ transplantation, severe autoimmune diseases and aplastic anemia. Mainly, the use of rabbit ATG has been associated with PTLD, which is considered to be more immunosuppressive than equine ATG. The sole administration of equine ATG has rarely been associated with PTLD. Due to the increased use of these potent and novel immunosuppressive agents, it is paramount to be aware of these complications. We present a 55-year-old man with an autologous HSCT who presented with an unusual case of monoclonal plasmacytic PTLD. His lymphoproliferative disorder occurred 3 years after his HSCT and 1 month after the use of equine ATG administered for severe aplastic anemia. We review current concepts of EBV-PTLD, including risk factors, the potential for preemptive therapy and various management strategies.

Rituximab for rescue and maintenance therapy in rapidly progressive life-threatening antineutrophil cytoplasmic autoantibody-associated systemic vasculitis

Antineutrophil cytoplasmic autoantibody (ANCA)-associated systemic vasculitides (AASV) consists of small-vessel systemic inflammatory disorders which commonly affect the kidneys and without treatment have a poor prognosis. Rituximab is a novel biological agent which is being used experimentally in the management of AASV. This report presents the case of a young woman with rapidly progressive life-threatening AASV. Despite prompt diagnosis and initial treatment with steroids and alkylating agents her condition became life threatening. With addition of rituximab therapy she showed an excellent sustained response. Rituximab appears an effective and safe treatment choice for the induction of remission in severe AASV that is not responding to standard agents, at the initial presentation and for maintenance therapy, without the development of common serious side-effects associated with immunosuppression.

[Therapeutic monoclonal antibodies: update on the risk of opportunistic infections]

The large experience accumulated with the therapeutic use of monoclonal antibodies has revealed undesirable effects, among which opportunistic infections when prescribed in inflammatory or hematological diseases. This deleterious effect is a direct consequence of the immunosuppression induced by these antibodies through the blockade of several key pathways involved in both innate and adaptative immune responses, including migration of effector cells, depletion of B or T lymphocytes, inhibition of key cell-cell interactions. Four antibodies are concerned, targeting CD52, CD20, TNF-a and VLA-4, and major risks include activation of latent tuberculosis, or of normally silent viruses. Precise evaluation of these risks and understanding of their mechanisms have now led to the improvement of clinical safety, based on the detection of patients at risk, weighting of the benefit/risk ratio, and a very rigorous detection of latent infections before the onset of treatment by monoclonal antibodies know to induce immunosuppression.