Adverse reactions to biologic agents: focus on autoimmune disease therapies

Programmable chronogenetic gene circuits for self-regulated circadian delivery of biologic drugs

Cells of the body rely on the circadian clock to orchestrate daily changes in physiology that impact both homeostatic and pathological conditions, such as the inflammatory autoimmune disease rheumatoid arthritis (RA). In RA, high levels of proinflammatory cytokines peak early in the morning hours, reflected by daily changes in joint stiffness. Chronotherapy (or circadian medicine) seeks to delivery drugs at optimal times to maximize their efficacy. However, chronotherapy remains a largely unexplored approach for disease modifying, antirheumatic treatment, particularly for cell-based therapies. In this study, we developed autonomous chronogenetic gene circuits that produce the biologic drug interleukin-1 receptor antagonist (IL-1Ra) with desired phase and amplitude. We compared expression of IL-1Ra from circuits that contained different circadian promoter elements (E'-boxes, D-boxes, or RREs) and their ability to respond to inflammatory challenges in murine pre-differentiated induced pluripotent stem cells (PDiPSC) or engineered cartilage pellets. We confirmed that each circuit reliably peaked at a distinct circadian time over multiple days. Engineered cells generated significant amounts of IL-1Ra on a circadian basis, which protected them from circadian dysregulation and inflammatory damage. These programmable chronogenetic circuits have the potential to align with an individual's circadian rhythm for optimized, self-regulated daily drug delivery.

Emerging strategies for nanomedicine in autoimmunity

Autoimmune disorders have risen to be among the most prevalent chronic diseases across the globe, affecting approximately 5-7% of the population. As autoimmune diseases steadily rise in prevalence, so do the number of potential therapeutic strategies to combat them. In recent years, fundamental research investigating autoimmune pathologies has led to the emergence of several cellular targets that provide new therapeutic opportunities. However, key challenges persist in terms of accessing and specifically combating the dysregulated, self-reactive cells while avoiding systemic immune suppression and other off-target effects. Fortunately, the continued advancement of nanomedicines may provide strategies to address these challenges and bring innovative autoimmunity therapies to the clinic. Through precise engineering and rational design, nanomedicines can possess a variety of physicochemical properties, surface modifications, and cargoes, allowing for specific targeting of therapeutics to pathological cell and organ types. These advances in nanomedicine have been demonstrated in cancer therapies and have the broad potential to advance applications in autoimmunity therapies as well. In this review, we focus on leveraging the power of nanomedicine for prevalent autoimmune disorders throughout the body. We expand on three key areas for the development of autoimmunity therapies - avoiding systemic immunosuppression, balancing interactions with the immune system, and elevating current platforms for delivering complex cargoes - and emphasize how nanomedicine-based strategies can overcome these barriers and enable the development of next-generation, clinically relevant autoimmunity therapies.

Adverse drug reactions of Rituximab in patients suffering from autoimmune neurological diseases

BACKGROUND

Rituximab, a chimeric human/mouse monoclonal antibody targeting CD-20 antigens, has been used recently for various rheumatological and autoimmune diseases, including autoimmune neurological disorders.

OBJECTIVES

We aimed to study the frequency, seriousness, causality, and preventability of adverse drug reactions (ADRs) of rituximab in Iranian patients with autoimmune neurological diseases.

METHODS

In this cross-sectional observational study, patients with autoimmune neurological diseases who had an indication for rituximab treatment were enrolled. Naranjo adverse drug reaction probability scale was used to assess the causality of ADRs, and the preventability of the ADRs was determined by P-Method. The seriousness of ADRs was also determined.

RESULTS

A total of 264 ADRs were recorded from 97 patients. The Median (min-max) number of ADRs experienced by patients was 3 (1-7) events. 11.3% of patients experienced serious ADRs. 18.2% and 26.9% of ADRs were Definite and Probable, respectively. Only 5% of the ADRs were ''preventable". The most frequent ADRs were rituximab infusion-related reactions.

CONCLUSION

Rituximab had an acceptable safety profile in our study patients. However, there must be certain cautions regarding the use of the medication for the elderly or patients with a compromised immune system. Timely detection and management of ADRs would also be crucial to prevent severe and permanent damages. Moreover, considering that rituximab is used as an off-label treatment for autoimmune neurological diseases, a risk-benefit assessment would be necessary before deciding on the treatment choice.

Adverse effects of biologic anti-inflammatory agents on the respiratory system: A review

The therapy of autoimmune rheumatological conditions has undergone significant changes with the introduction of biologic antiinflammatory agents including cytokine antagonists and agents that interfere with the function of T and B cells or those that inhibit intracellular enzymes such as Janus kinase (JAK). Although useful to control inflammation, these agents may be associated with druginduced lung disease, which may be difficult to differentiate from pulmonary disorders caused by the underlying autoimmune diseases. This review aims to provide a description of lung disease, both infectious and non-infectious, that may be induced by the administration of biologic anti-inflammatory agents with emphasis on inhibitors of tumour necrosis factor, interleukin-1, interleukin-6 and JAK.

A framework for the use of biological medicines in the free state province, South Africa

PURPOSE

The use of biological medicines (BM) has increased worldwide owing to their effectiveness in the treatment of many chronic diseases. However, in South Africa, access to BM remains limited, hence, there is a need to develop strategies that will enable timely access to BM by all patients who need them.

OBJECTIVE

To develop a framework for the use of BM in South Africa.

METHODS

Using a Delphi questionnaire that was developed by integration of the opinions of newly qualified doctors (<2 years practice), prescribing specialists, and patients using BM, a Delphi method was used to guide an experts' panel into consensus on the different opinions in the questionnaire, and from this, a framework for the use of BM was constructed.

RESULTS

From the surveys, 76.2% of the newly qualified doctors and 91.7% of the prescribing specialists indicated that they had limited knowledge on the pharmacology of BM, and, respectively, 64.5% and 77.8% admitted that their knowledge on BM was not adequate for prescribing and taking care of patients on BM. Also, 58.3% and 75% of the prescribers indicated that the high cost and the tedious procurement process, respectively, were barriers of access to BM. The Delphi panel reached consensus after two rounds, and the resultant framework recommends that, appropriate use of BM requires establishing guidelines for the use of BM, increasing BM content in the medical training programs and information resources used by healthcare professionals, enacting drug regulations and drug policies that will increase availability of BM, offering appropriate patient information and public engagement.

CONCLUSION

The lack of knowledge on BM by health professionals, together with the high cost and a complex procurement processes are the major impediment to access to BM. A framework for the use of BM in South Africa was successfully developed to address these and other challenges.

Ulcerative intestinal tuberculosis case as a complication of treatment by infliximab for intestinal Behçet's disease: A case report

RATIONALE

Intestinal Behçet's disease (BD) is characterized by intestinal ulcerations and gastrointestinal symptoms. Ulcerative intestinal tuberculosis (TB) is usually with dyspepsia, abdominal pain, vomiting, and weight loss. The 2 diseases exhibit similar clinical manifestations, but the most critical aspects of their clinical courses and required treatments are not at all similar.

PATIENT CONCERNS

We present a case in which a patient with intestinal Behçet's disease developed a de novo ulcerative intestinal TB infection after the start of anti-tumor necrosis factor-α treatment. This was despite histopathologic examination without caseous necrosis granuloma and negative for acid-fast staining and latent TB screen.

DIAGNOSES

Intestinal Behçet's disease and intestinal TB.

INTERVENTIONS

The patient was treated with quadruple antituberculous chemotherapy, comprising rifapentine, isoniazid, ethambutol, and pyrazinamide.

OUTCOMES

At follow-up about 3 months, the therapy of oral antituberculous drugs and thalidomide was continued and the patient's condition had stabilized.

LESSONS

This case illustrates the importance of closely monitoring patients who are on infliximab for possible onset of TB, even without abdominal symptoms, and with negative screening results for latent TB.

Adverse Events in Patients With Rheumatoid Arthritis and Psoriatic Arthritis Receiving Long-Term Biological Agents in a Real-Life Setting

Background: Biological agents used for the treatment of psoriatic arthritis (PsA) and rheumatoid arthritis (RA) are associated with serious adverse effects (SAEs). Although several biologics have demonstrated good efficacy and tolerability in short-term trials, treatment guidelines recommend them as third line therapies due to a relative lack of long-term safety data.

Objective: To determine the frequency and severity of adverse effects associated with the long-term use of biologics in the treatment of PsA and RA, and possible risk factors for such events in a real-life setting.

Methods: We conducted a longitudinal study in PsA and RA patients only taking long-term biological agents from 2003 to 2011. Sources of information included dispensing pharmacy data and interviews with patients. Research staff conducted telephone interviews with patients inquiring about any apparent medication-related adverse drug reactions (ADRs) or SAEs. ADR/SAE’s data was based on pharmacy reports. We conducted a multivariate analysis to identify the factors associated with the risk of ADRs.

Results: Of the 305 patients identified, we interviewed 268 patients. Most of these were taking adalimumab 127 (47.4%), 52 (19.4%) etanercept, 42 (15.7%) infliximab, 25 (9.3%) rituximab, 10 (3.7%) abatacept, 9 (3.4%) efalizumab, and 3 (1.1%) tocilizumab. Of the 268 patients, 116 (43.3%) experienced one or more adverse events related to biological agents with 1.6 events per patient, and of these 29 (25%) experienced one or more SAEs, with majority subjected to hospitalizations. The most frequently reported ADRs were administration site reactions as observed in 73 patients (27.2%), infections in 30 patients (11.2%), effects on nervous system in 22 patients (8.2%), and 15 (5.6%) patients withdrew due to ADRs. The use of rituximab was related with less risk of ADR [PR 0.42, 95% CI 0.18–0.96; p = 0.04] than other agents. No other predisposing factors were associated with risk of ADR. The monitoring of patients (medical consultation and laboratory test) was only completed by 48 patients (30.4%).

Conclusion: These data showed the early biological experience in Brazil that were associated with ADRs, withdrawals due to ADRs and SAEs. The quantification of adverse effects (serious or nonserious) considering close monitoring and patients’ perceptions are increasingly important for future decision-making.

Adverse infusion reactions to rituximab in systemic lupus erythematosus: a retrospective analysis

Background

To undertake a retrospective review of patients with SLE who had received Rituximab in order to determine the rates and associated patient characteristics of clinically significant adverse infusion reactions.

Methods

A descriptive analysis was undertaken of each infusion reaction, which was then assessed using the clinical information available to hypothesise on the possible underlying mechanism(s).

Results

Records of 136 SLE patients previously treated with 481 individual infusions of Rituximab were reviewed. A total of 22 patients (17.6%) had 28 (5.8% of total infusions) documented clinically significant adverse infusion reactions. Average age at first Rituximab infusion in patients without a reaction was 37 years (range 16–73) compared with 30 years (range 18–56) in those with a reaction. A high proportion of men (18.2%) experienced an infusion reaction. Severity and type of reaction varied. 6.4% of those who had a reaction were not retreated.

Conclusions

While Rituximab remains an important tool in the treatment of SLE it is important to be aware that rates of infusion reactions may be more significant in SLE than in other diseases. A prospective study is required to better characterise the reactions.

Monoclonal Antibodies: Past, Present and Future

Monoclonal antibodies (mAbs) are immunoglobulins designed to target a specific epitope on an antigen. Immunoglobulins of identical amino-acid sequence were originally produced by hybridomas grown in culture and, subsequently, by recombinant DNA technology using mammalian cell expression systems. The antigen-binding region of the mAb is formed by the variable domains of the heavy and light chains and contains the complementarity-determining region that imparts the high specificity for the target antigen. The pharmacokinetics of mAbs involves target-mediated and non-target-related factors that influence their disposition.Preclinical safety evaluation of mAbs differs substantially from that of small molecular (chemical) entities. Immunogenicity of mAbs has implications for their pharmacokinetics and safety. Early studies of mAbs in humans require careful consideration of the most suitable study population, route/s of administration, starting dose, study design and the potential difference in pharmacokinetics in healthy subjects compared to patients expressing the target antigen.Of the ever-increasing diversity of therapeutic indications for mAbs, we have concentrated on two that have proved dramatically successful. The contribution that mAbs have made to the treatment of inflammatory conditions, in particular arthritides and inflammatory bowel disease, has been nothing short of revolutionary. Their benefit has also been striking in the treatment of solid tumours and, most recently, as immunotherapy for a wide variety of cancers. Finally, we speculate on the future with various new approaches to the development of therapeutic antibodies.

Incidence of Pneumocystis jirovecii and Adverse Events Associated With Pneumocystis Prophylaxis in Children Receiving Glucocorticoids

BACKGROUND

Antimicrobial prophylaxis is indicated to prevent Pneumocystis jirovecii pneumonia (PJP) in profoundly immunosuppressed children. The incidence of PJP infection in children with chronic glucocorticoid exposure is unknown, and PJP prophylaxis has been associated with adverse events. We hypothesized that PJP infection is rare in children without human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS), cancer, or a transplant history who are using chronic glucocorticoids and that those exposed to PJP prophylaxis are more likely to experience a cutaneous hypersensitivity reaction or myelosuppression than unexposed patients.

METHODS

This study involved a retrospective cohort from the Clinformatics Data Mart Database (OptumInsight, Eden Prairie, MN). We identified patients ≤18 years of age who received at least 2 prescriptions for a systemic glucocorticoid within a 60-day period and excluded patients with a history of PJP infection, an oncologic diagnosis, transplant, or HIV/AIDS. PJP prophylaxis exposure was identified by using national drug codes. Cutaneous hypersensitivity reaction or myelosuppression was identified by using International Classification of Diseases, 9th Revision (ICD-9), codes. We used a discrete time-failure model to examine the association between exposure and outcome.

RESULTS

We identified 119399 children on glucocorticoids, 10% of whom received PJP prophylaxis. The incidences of PJP were 0.61 and 0.53 per 10000 patient-years in children exposed and those unexposed to PJP prophylaxis, respectively. In a multivariable model, trimethoprim-sulfamethoxazole was associated with cutaneous hypersensitivity reaction (odds ratio, 3.20; 95% confidence interval, 2.62-3.92) and myelosuppression (odds ratio, 1.85; 95% confidence interval, 1.56-2.20).

CONCLUSIONS

PJP infection was rare in children using glucocorticoids chronically, and PJP prophylaxis-associated cutaneous hypersensitivity reactions and myelosuppression are more common. The use of PJP chemoprophylaxis in children without HIV/AIDS, cancer, or a transplant history who are taking glucocorticoids chronically should be considered carefully.

Biologic response modifiers: Indications, implications, and insights

The field of biologic immune modulators is currently mushrooming at a dizzying pace. Although most of these biologics are tested and approved for one or a few indications, their unanticipated side effects and off-label use have contributed significantly to our understanding of basic immune mechanisms, the involvement of cytokines in several apparently nonimmunologic diseases, and the importance of compartmentalized immune responses. In this review we attempt to give a bird's-eye view of the major biologics and to highlight insights and implications derived from their secondary effects and adverse reactions.

How the immune system responds to therapeutic biological agents

Biological agents target disease mechanisms and have modified the natural history of several immune-mediated disorders. Biological agents are structurally immunogenic, and therefore usually elicit a minor, subclinical and transient phenomenon. Occasionally, however, these drugs induce complete cellular and humoral immune responses, with the main clinical consequences being hypersensitivity reactions or loss of treatment response. This article considers the relative pathogenic mechanisms influencing immunogenicity in biological agents and discusses mechanisms of tolerance and adaptive immune response, including adaptive T-regulatory cell induction and immune response induction. Methods of determining cellular and humoral immune response to biological agents are identified and examined. Assays to detect antidrug antibodies and their isotypes can assist in monitoring immunogenicity and in preventing adverse events. Such strategies also enable resource conservation and may provide regulatory authorities with new insights that can be useful during the process of approving new biological or biosimilar agents.

Control of autoimmune inflammation by celastrol, a natural triterpenoid

Celastrol is a bioactive compound derived from traditional Chinese medicinal herbs of the Celastraceae family. Celastrol is known to possess anti-inflammatory and anti-oxidant activities. Our studies have highlighted the immunomodulatory attributes of celastrol in adjuvant-induced arthritis (AA), an experimental model of human rheumatoid arthritis (RA). RA is an autoimmune disease characterized by chronic inflammation of the synovial lining of the joints, leading eventually to tissue damage and deformities. Identification of the molecular targets of celastrol such as the NF-κB pathway, MAPK pathway, JAK/STAT pathway and RANKL/OPG pathway has unraveled its strategic checkpoints in controlling arthritic inflammation and tissue damage in AA. The pathological events that are targeted and rectified by celastrol include increased production of pro-inflammatory cytokines; an imbalance between pathogenic T helper 17 and regulatory T cells; enhanced production of chemokines coupled with increased migration of immune cells into the joints; and increased release of mediators of osteoclastic bone damage. Accordingly, celastrol is a promising candidate for further testing in the clinic for RA therapy. Furthermore, the results of other preclinical studies suggest that celastrol might also be beneficial for the treatment of a few other autoimmune diseases besides arthritis.

Treatment dilemmas of cetuximab combined with chemotherapy for metastatic colorectal cancer

Although monoclonal antibodies (mAbs) against epidermal growth factor receptor (EGFR) have largely enriched the available therapeutic choices for colorectal cancer (CRC), the understanding and management of their associated clinical toxicities are limited. In addition, the combined strategies of administering EGFR mAbs and traditional cytotoxic agents, such as 5-fluorouracil, oxaliplatin and irinotecan, have resulted in a more complicated management of CRC treatment-related side effects compared with EGFR mAb monotherapy. We believe that a thorough recognition of the toxicities of EGFR mAb drugs is essential for physicians to increase the therapeutic index in the treatment of CRC. This review aims to summarize the existing information regarding the treatment dilemmas of cetuximab combined with chemotherapy in the management of metastatic CRC.

Kinase inhibitors and monoclonal antibodies in oncology: clinical implications

Molecularly targeted cancer therapies, such as small-molecule kinase inhibitors and monoclonal antibodies, constitute a rapidly growing and an important part of the oncology armamentarium. Unlike conventional (cytotoxic) chemotherapeutics, targeted therapies were designed to disrupt cancer cell pathogenesis at specific biological points essential for the development and progression of the tumour. These agents were developed to disrupt specific targets with the aim of minimizing treatment burden compared with conventional chemotherapy. Nevertheless the increasingly common use of targeted therapies has revealed some unanticipated, often clinically significant toxic effects, as well as compromising effective palliative and end-of-life management approaches. Although patients and clinicians welcome improvements in cancer prognosis, these changes can also impact patient quality-of-life. Therefore, as demand for oncology expertise increases, physicians need to apprise themselves of targeted therapies and their clinical implications, including drug-specific side effects, impact on quality of life, and cost issues, especially in relation to end-of-life care. This Review provides a useful summary and guide for professionals treating patients with malignant diseases.

Biological therapy and dentistry: a review paper

In recent years, a new class of drugs has revolutionized the treatment of autoimmune, allergic, infectious, and many more diseases. This new class of drugs is made of 3 groups-cytokines, monoclonal antibodies, and fusion proteins-that may target special damaged cells but not all the cells. These drugs may have side effects such as infection, hypersensitivity, hematologic disorders, cancer, hepatotoxicity, and neurologic disorders. However, there is not enough evidence or long-term studies of the mechanism of action and side effects of these drugs. Patients receiving biological therapies may need special consideration in dentistry. This paper is a review of the classification, mechanism of action, and side effects of these drugs and dental consideration for patients receiving biological therapies.

Predictors for the progression of cervical lesion in rheumatoid arthritis under the treatment of biological agents

STUDY DESIGN

Retrospective cohort analysis.

OBJECTIVE

To clarify the effect of biological agents (BAs) on the development and progression of cervical lesions in patients with rheumatoid arthritis (RA) and to identify biomarkers that accurately predict disease progression.

SUMMARY OF BACKGROUND DATA

The introduction of BAs changed the paradigm of RA treatment. However, their effects on cervical lesions in patients with RA have not been studied.

METHODS

Ninety-one subjects who had received BAs for 2 years or more were enrolled. Mean radiographical interval was 3.9 years. Disease activity was evaluated by disease activity score-C-reactive protein levels, and matrix metalloproteinase-3 levels. Cervical lesions were defined as an atlantodental interval more than 3 mm for atlantoaxial subluxation (AAS), Ranawat value less than 13 mm for vertical subluxation (VS), and anterior or posterior listhesis more than 2 mm for subaxial subluxation. Disease progression was defined radiographically as an increase in the atlantodental interval more than 2 mm for AAS, a decrease in both Ranawat and Redlund-Johnell values more than 2 mm for VS, and an increase in listhesis more than 2 mm for subaxial subluxation. We used multivariate regression techniques to assess predictors of disease progression.

RESULTS

Baseline radiographical evaluation showed no pre-existing cervical lesion in 44 patients, AAS in 29, and VS in 18. Radiological progression occurred in 7% patients without baseline lesions, 79% in the AAS group, and 72% in the VS group. The incidence of progression was significantly lower in patients without lesions at baseline. Multivariate regression analysis demonstrated pre-existing cervical lesions, disease activity score-C-reactive protein levels at baseline and metalloproteinase-3 levels at final visit as good predictors of RA progression.

CONCLUSION

BAs prevented de novo cervical lesions in patients with RA but failed to control progression in patients with pre-existing cervical lesions. Disease activity score-C-reactive protein levels at baseline were related to pre-existing joint destruction, and metalloproteinase-3 levels accurately predicted ongoing bone destruction during BA treatment.

LEVEL OF EVIDENCE

3.

The complexity of adverse side-effects to biological agents

Whereas adverse effects induced by xenobiotics are mainly linked to the pharmacological effect, the adverse side-effects induced by biological agents (BA) are often target-related and linked to the biological consequences of their action. Based on these differences, an original classification of the adverse effects has been proposed. Five types of adverse effects induced by BA are described (α, β, γ, δ, and ε). This classification provides a very useful scheme for a better understanding of these adverse effects. This approach should help to better characterize the pathogenic mechanisms involved and to optimize their management. Healthcare professionals should be aware of the specific risks related to this relatively new class of drugs. Close monitoring of these BA is therefore recommended.

Monoclonal antibodies and fusion proteins and their complications: targeting B cells in autoimmune diseases

The immune system consists of a complex array of immunocompetent cells and inflammatory mediators that exist in complex networks. These components interact through cascades and feedback circuits, maintaining physiologic inflammation and immunosurveillance. In various autoimmune conditions, a foreign or auto-antigen may upset this fine balance, leading to dysregulated immunity, persistent inflammation, and ultimately pathologic sequelae. In recent years, there has been tremendous progress delineating the specific components of the immune system that contribute to normal immunity and specific disease states. With this greater understanding of pathogenesis coupled with advances in biotechnology, many immunomodulatory agents, commonly called biologic agents, have been introduced. The 2 most common classes of biologic agents are monoclonal antibodies and fusion proteins. These agents can inhibit targets with exquisite specificity to optimize outcomes and minimize toxicity. B cells contribute significantly to the initiation and perpetuation of the immune responses. B cells not only can produce potentially pathologic autoantibodies and proinflammatory cytokines but also can present antigens to T cells and provide costimulatory signals essential for T-cell activation, clonal expansion, and effector function. This review focuses on biologic agents targeting B cells in the treatment of rheumatoid arthritis and systemic lupus erythematosus.

Anti-TNF therapies: a comprehensive analysis of adverse effects associated with immunosuppression

Knowledge and understanding about the immunosuppressive properties of anti-TNF therapies and the adverse effects these causes have advanced over the last 10 years since the first of these drugs was approved. These drugs work by inhibiting tumour necrosis factor (TNF) in the body, which plays an essential role in the immune response to invading pathogens. Anti-TNF drugs have therapeutic value because high levels of TNF are thought to be part of the pathophysiology of many chronic inflammatory disorders such as rheumatoid arthritis and Crohn's disease. Anti-TNF drugs are usually well-tolerated, however, there have been reports of many potentially serious adverse effects. This article will comprehensively analyse these adverse effects; the incidence, symptoms and mechanisms will be discussed. In addition, the contraindications of this class of drugs will be explored and the detection and prevention methods that should be put in place by health care professionals who treat patients on these drugs will be described.

Immune-mediated adverse drug reactions

Many adverse drug reactions are mediated by the immune system. This can be because the therapeutic effect of the drug targets the immune system. For example, immunosuppressive drugs increase the risk of infections. It is paradoxical that some immunosuppressive drugs can lead to autoimmune reactions. Another mechanism by which drugs can cause an adverse reaction involves an idiosyncratic response to the drug such as an immune-mediated skin rash. These idiosyncratic drug reactions (IDRs) are difficult to study because of the paucity of valid animal models and their unpredictable nature. Therefore, much of our mechanistic knowledge of IDRs is based on inferences from the clinical characteristics of IDRs rather than on controlled mechanistic studies. In general, IDRs are associated with a delay between starting the drug and the onset of the adverse reaction, and the typical delay is different for different types of IDRs. In contrast, on rechallenge, there is usually a rapid onset of the adverse reaction, which is characteristic of an amnestic immune response. The absence of such a rapid response is usually considered evidence that an IDR is not immune-mediated; yet, there are immune-mediated IDRs that do not have an amnestic response. One possible reason for the lack of an amnestic response is if the IDR has a strong autoimmune component leading to deletion of autoimmune memory cells when the drug is withdrawn. Another interesting characteristic of IDRs is that there are many drugs that can cause different types of IDRs in different patients. A possible explanation is that although the immune response is induced by a drug, it is directed against an autoantigen, and interindividual differences in the immune repertoire determine which autoantigen and target organ are affected. Although testing these hypotheses represents a difficult challenge, the importance of these adverse reactions makes it a high priority.

Evaluation and management of pediatric drug allergic reactions

Drug allergy is a common reason for consulting an allergist. Determining whether a particular drug is involved can be accomplished with a careful history and physical examination, knowledge of the common and idiosyncratic reactions of the drugs in question, and selective skin testing. If a drug reaction is suspected, alternatives exist to allow continued appropriate treatment. A practical approach to the pediatric patient is outlined along with a general discussion of common drug allergic reactions encountered in clinical practice.

Tumor necrosis factor as a therapeutic target of rheumatologic disease

TNF-alpha is a crucial pro-inflammatory and immunoregulatory cytokine that is central to the pathogenesis of various inflammatory and autoimmune conditions. A number of controlled trials have shown effectiveness for TNF-alpha inhibitors in several diseases, in particular rheumatoid arthritis, ankylosing spondylitis, psoriatic arthritis and Crohn's disease. These agents may also be useful in additional autoimmune conditions. The introduction of TNF-alpha inhibitors has revolutionized the therapeutic approach and treatment paradigms especially for patients with rheumatoid arthritis. Despite extensive investigation, the full profile of their mechanisms of action remain incompletely understood. Optimal use of these agents requires consideration of their possible adverse effects. In addition to the presently available TNF-alpha blockers, other agents targeting this key mediator are under study. Recent advances and future directions in anti-TNF-alpha therapy are discussed in this paper.

Rheumatoid arthritis in dermatology

Rheumatoid arthritis (RA) is a chronic progressive disorder characterized by symmetric inflammatory arthritis in association with systemic symptoms. Although considered a "joint disease," RA is associated with involvement in diverse organ systems, including the skin. Common manifestations include Raynaud phenomenon, rheumatoid nodules, and rheumatoid vasculitis. As with other extra-articular manifestations, dermatologic involvement tends to occur in patients with more severe RA. In addition to manifestations related to the disease, there are also sundry dermatologic reactions related to the medications used to treat RA. Understanding the etiology and therapy for cutaneous manifestations of RA will help optimize patient care.

Adverse side-effects to biological agents

Biological agents-like cytokines, monoclonal antibodies and fusion proteins are widely used in anti-inflammatory and tumour therapy. They are highly efficient in certain diseases, but can cause a great variety of adverse side-effects. Based on the peculiar features of biological agents a new classification of these adverse side-effects of biological agents is proposed - related but clearly distinct from the classification of side-effects observed with chemicals and drugs. This classification differentiates five distinct types, namely clinical reactions because of high cytokine levels (type alpha), hypersensitivity because of an immune reaction against the biological agent (beta), immune or cytokine imbalance syndromes (gamma), symptoms because of cross-reactivity (delta) and symptoms not directly affecting the immune system (epsilon). This classification could help to better deal with the clinical features of these side-effects, to identify possible individual and general risk factors and to direct research in this novel area of medicine.