Adrenal insufficiency is a contraindication for omalizumab therapy in mast cell activation disease: risk for serum sickness.

Omalizumab is an effective therapeutic humanized murine IgE antibody in many cases of primary systemic mast cell activation disease (MCAD). The present study should enable the clinician to recognize when treatment of MCAD with omalizumab is contraindicated because of the potential risk of severe serum sickness and to report our successful therapeutic strategy for such adverse event (AE). Our clinical observations, a review of the literature including the event reports in the FDA AE Reporting System, the European Medicines Agency Eudra-Vigilance databases (preferred search terms: omalizumab, Xolair®, and serum sickness) and information from the manufacturer's Novartis database were used. Omalizumab therapy may be more likely to cause serum sickness than previously thought. In patients with regular adrenal function, serum sickness can occur after 3 to 10 days which resolves after the antigen and circulating immune complexes are cleared. If the symptoms do not resolve within a week, injection of 20 to 40 mg of prednisolone on two consecutive days could be given. However, in MCAD patients whose adrenal cortical function is completely suppressed by exogenous glucocorticoid therapy, there is a high risk that serum sickness will be masked by the MCAD and evolve in a severe form with pronounced damage of organs and tissues, potentially leading to death. Therefore, before the application of the first omalizumab dose, it is important to ensure that the function of the adrenal cortex is not significantly limited so that any occurring type III allergy can be self-limiting.

Rituximab-induced serum sickness in a 6-year-old boy with steroid-dependent nephrotic syndrome.

Rituximab (RTX) is a murine-human chimeric monoclonal antibody against CD20 that has been proven effective for preventing relapse in frequently-relapsing or steroid-dependent nephrotic syndrome (NS). Serum sickness, a type-3 hypersensitivity reaction resulting from injection of foreign proteins, has been reported in patients treated with RTX. Herein, we describe a case of RTX-induced serum sickness (RISS) in a 6-year-old boy with steroid-dependent NS. He presented to the hospital with fever and polyarthralgia at 10 days after his fourth dose of RTX. Although he was started on empiric intravenous antibiotics, there was no evidence of septic arthritis and his symptoms resolved over the course of 4 days. He was diagnosed with RISS based on the chronology of RTX administration and the acute-onset self-limiting course of the polyarthritis. His serum human anti-chimeric antibody (HACA) level on day 53 exceeded the limit of quantification (5000 ng/mL). The pathogenesis of RISS and the role of HACAs remain unclear. It is important for clinicians to recognize RISS, because further infusions of RTX may cause more severe reactions in patients with a history of RISS.

Hypersensitivity and immunologic reactions to biologics: opportunities for the allergist.

OBJECTIVE: There has been a great expanse in the use of biological agents during the past decade. However, there are significant differences between biologics and typical pharmaceutical drugs. This review focuses on 3 separate types of adverse reactions to biologics, namely high cytokine reactions, hypersensitivity reactions, and secondary immunodeficiency. DATA SOURCES: A PubMed literature search restricted to the previous 10 years using combinations of search terms, including omalizumab, rituximab, TGN1412, biologic agent, anaphylaxis, hypogammaglobulinemia, desensitization, and cytokine storm, was performed. The results were manually filtered to identify relevant articles with additional references identified from bibliographies. STUDY SELECTION: Reports were selected for TGN1412 cytokine storm, omalizumab anaphylaxis and desensitization, rituximab-induced hypogammaglobulinemia, rituximab anaphylaxis and serum sickness, and monoclonal antibody desensitization. RESULTS: A phase 1 clinical trial using a humanized anti-CD28 monoclonal antibody (TGN1412) caused severe cytokine storm reactions in all 6 subjects, resulting in multiorgan failure. Omalizumab has been reported to cause anaphylaxis in fewer than 0.1% of patients, many with delayed reactions. The mechanism for this anaphylactic reaction is unclear. Rituximab has been associated with hypogammaglobulinemia, serum sickness-like reactions, and anaphylaxis. Rapid drug desensitizations to monoclonal antibodies, including rituximab, suspected of causing immunoglobulin E-mediated reactions have been found to be generally safe and effective. CONCLUSION: Hypersensitivity reactions and immune dysregulation from biologic agents are not rare. The allergist and immunologist should be involved in managing these patients for optimal care.

Serum sickness-like reaction after influenza vaccination.

Serum sickness (SS) and SS-like reaction (SSLR) are rare immune complex-mediated hypersensitivity illnesses characterised by key features of fever, rash, polyarthralgia or polyarthritis. They are self-limiting with an excellent prognosis, settling as the antigen is cleared. We describe a 30-year-old man who presented with fever, rash, polyarthralgia and subcutaneous soft tissue swelling in his hands and feet at day 5 after influenza vaccination. A thorough investigation for infective and autoimmune causes for the presenting symptoms was negative. Given the temporal relationship between the symptoms and influenza vaccination, clinical evidence and biological plausibility of influenza vaccination causing SSLR, a clinical diagnosis of SSLR was made. The patient was treated with anti-histamines, non-steroidal anti-inflammatories and glucocorticoids with gradual resolution of symptoms over 5 weeks.

Rabbit antithymocyte globulin-induced serum sickness disease and human kidney graft survival.

BACKGROUND: Rabbit-generated antithymocyte globulins (ATGs), which target human T cells, are widely used as immunosuppressive agents during treatment of kidney allograft recipients. However, ATGs can induce immune complex diseases, including serum sickness disease (SSD). Rabbit and human IgGs have various antigenic differences, including expression of the sialic acid Neu5Gc and α-1-3-Gal (Gal), which are not synthesized by human beings. Moreover, anti-Neu5Gc antibodies have been shown to preexist and be elicited by immunization in human subjects. This study aimed to assess the effect of SSD on long-term kidney allograft outcome and to compare the immunization status of grafted patients presenting with SSD following ATG induction treatment. METHODS: We analyzed data from a cohort of 889 first kidney graft recipients with ATG induction (86 with SSD [SSD(+)] and 803 without SSD [SSD(-)]) from the Données Informatisées et Validées en Transplantation data bank. Two subgroups of SSD(+) and SSD(-) patients that had received ATG induction treatment were then assessed for total anti-ATG, anti-Neu5Gc, and anti-Gal antibodies using ELISA assays on sera before and after transplantation. RESULTS: SSD was significantly associated with long-term graft loss (>10 years, P = 0.02). Moreover, SSD(+) patients exhibited significantly elevated titers of anti-ATG (P = 0.043) and anti-Neu5Gc (P = 0.007) IgGs in late post-graft samples compared with SSD(-) recipients. CONCLUSION: In conclusion, our data indicate that SSD is a major contributing factor of late graft loss following ATG induction and that anti-Neu5Gc antibodies increase over time in SSD(+) patients. FUNDING: This study was funded by Société d'Accélération du Transfert de Technologies Ouest Valorisation, the European FP7 "Translink" research program, the French National Agency of Research, Labex Transplantex, the Natural Science and Engineering Research Council of Canada, and the Canadian Foundation for Innovation.

Pathogenic mechanisms underlying adverse reactions induced by intravenous administration of snake antivenoms.

Snake antivenoms are formulations of immunoglobulins, or immunoglobulin fragments, purified from the plasma of animals immunized with snake venoms. Their therapeutic success lies in their ability to mitigate the progress of toxic effects induced by snake venom components, when administered intravenously. However, due to diverse factors, such as deficient manufacturing practices, physicochemical characteristics of formulations, or inherent properties of heterologous immunoglobulins, antivenoms can induce undesirable adverse reactions. Based on the time lapse between antivenom administration and the onset of clinical manifestations, the World Health Organization has classified these adverse reactions as: 1 - Early reactions, if they occur within the first hours after antivenom infusion, or 2 - late reactions, when occurring between 5 and 20 days after treatment. While all late reactions are mediated by IgM or IgG antibodies raised in the patient against antivenom proteins, and the consequent formation of immune complexes, several mechanisms may be responsible for the early reactions, such as pyrogenic reactions, IgE-mediated reactions, or non IgE-mediated reactions. This work reviews the hypotheses that have been proposed to explain the mechanisms involved in these adverse reactions to antivenoms. The understanding of these pathogenic mechanisms is necessary for the development of safer products and for the improvement of snakebite envenomation treatment.

Severe serum sickness after H1N1 influenza vaccination.

In this study, the case of a 48-year-old man with severe serum sickness reaction in response to H1N1 influenza immunization is reported. He presented with renal failure and several of the classic signs reported in early descriptions of serum sickness by Clemens von Pirquet and Bela Schick including lymphadenopathy, urticarial skin eruption and facial edema. Serum immunologic studies and tissue histology/immunohistochemistry assisted in firmly establishing the diagnosis in this case. With appropriate therapy, the patient's rash, edema and lymphadenopathy resolved and normal renal function returned. This first reported case of severe serum sickness to H1N1 vaccine is particularly important in light of the Centers for Disease Control and Prevention's recommendation for universal vaccination against influenza, including H1N1, in patients 6 months and older. With increasing numbers of patients receiving this vaccine, even rare adverse reactions may be experienced by numerous individuals. It is imperative that clinicians remain vigilant about possible reactions and quickly institute appropriate therapy.

The C5a receptor has a key role in immune complex glomerulonephritis in complement factor H-deficient mice.

Chronic serum sickness leads to the formation of glomerular immune complexes; however, C57BL/6 mice do not develop glomerulonephritis unless complement factor H (CFH) is absent from the plasma. Here we studied the role for C5a receptor (R) in this setting. The exaggerated humoral immune response in CFH(-/-) mice was normalized in CFH(-/-)C5aR(-/-) double knockout mice, highlighting the C5aR dependence. The CFH knockout mice developed proliferative glomerulonephritis with endocapillary F4/80+ macrophage infiltration, a process reduced in the double knockout mice. There was no interstitial inflammation by histologic criteria or flow cytometry for F4/80+ Ly6C(hi)CCR2(hi) inflammatory macrophages. There were, however, more interstitial CD3+ CD4+ T lymphocytes in CFH knockout mice with chronic serum sickness, while double knockout mice had greater than 5-fold more Ly6C(lo)CCR2(lo) anti-inflammatory macrophages compared to the CFH knockout mice. Mice lacking C5aR were significantly protected from functional renal disease as assessed by blood urea nitrogen levels. Thus, IgG- and iC3b-containing immune complexes are not inflammatory in C57BL/6 mice. Yet when these mice lack CFH, sufficient C3b persists in glomeruli to generate C5a and activate C5aR.

Serum sepsis, not sickness.

Rarely taught in medical schools, clinical reasoning is the ability to discern the important from the unimportant and to arrive at accurate and efficient clinical conclusions. Identifying errors in reasoning is difficult; however, undetected clinical reasoning errors can have exponential consequences. As quality and patient safety come into focus, identifying and preventing clinical reasoning errors have become imperative. The authors present a case of a man sent for admission from a subspecialty clinic diagnosed with infliximab-induced serum sickness. Not countering the expert's diagnosis, initial workup failed to diagnose joint abscess and sepsis. Heuristics are mental shortcuts used to make decision making more efficient but can lead to error. The anchoring heuristic, premature closure, confirmation bias and the blind obedience heuristic are examples. Introspective surveillance and interactive hypothesis testing defend against heuristics. The authors conclude by discussing 4 types of hypersensitivity reactions, serum sickness in particular, and the chimeric nature of infliximab.

Abnormal immune complex processing and spontaneous glomerulonephritis in complement factor H-deficient mice with human complement receptor 1 on erythrocytes.

Complement receptor 1 (CR1) on human erythrocytes (Es) and complement factor H (CFH) on rodent platelets perform immune adherence, which is a function that allows the processing of immune complexes (ICs) bearing C3 by the mononuclear phagocyte system. Similar immune adherence occurs in the glomerular podocyte by CR1 in humans and CFH in rodents. As a model for human IC processing, we studied transgenic mice lacking CFH systemically but with human CR1 on Es. These CR1(hu)Tg/CFH(-/-) mice spontaneously developed proliferative glomerulonephritis, which was accelerated in a chronic serum sickness model by active immunization with heterologous apoferritin. ICs containing Ag, IgG and C3 bound to Es in CR1(hu)Tg/CFH(-/-) mice. In this setting, there was increased IC deposition in glomeruli, attributable to the presence of CR1 on Es, together with the absence of CFH on platelets and podocytes. In the absence of plasma CFH, the accumulated ICs activated complement, which led to spontaneous and chronic serum sickness-induced proliferative glomerulonephritis. These findings illustrate the complexities of complement-dependent IC processing by blood cells and in the glomerulus, and the importance of CFH as a plasma complement regulator.

Serum sickness after treatment with rabbit antithymocyte globulin in kidney transplant recipients with previous rabbit exposure.

Serum sickness after rabbit antithymocyte globulin administration has a reported incidence of 7% to 27% in kidney transplant recipients. We describe 4 patients with previous exposure to rabbits who developed serum sickness after primary rabbit antithymocyte globulin induction. All patients presented with jaw pain. Three of 4 patients treated with plasmapheresis and steroids had prompt recovery, and 1 patient treated with steroids had slower recovery. We performed a telephone interview of 214 patients who contemporaneously underwent transplantation between November 2006 and July 2008 regarding rabbit exposure. More than half the patients had some type of previous rabbit exposure. There was a suggestion that patients with serum sickness were exposed more frequently to rabbits than those without. Jaw pain appears to be a hallmark symptom, and treatment with plasmapheresis and steroids relieves symptoms more rapidly than steroids alone.

Rituximab may form a complex with IgMkappa mixed cryoglobulin and induce severe systemic reactions in patients with hepatitis C virus-induced vasculitis.

OBJECTIVE: To report on 6 cases of hepatitis C virus (HCV)-induced mixed cryoglobulinemia (MC) vasculitis in patients who developed severe systemic reactions after rituximab infusion, and to report the results of the in vitro analysis of the underlying immunologic mechanisms. METHODS: Twenty-two HCV-infected patients with MC vasculitis received rituximab infusions (a low-dose protocol cycle with 375 mg/m2/week for 4 consecutive weeks in 18 patients and a high-dose protocol cycle with 1,000 mg on days 1 and 15 in 4 patients). Systemic drug reactions following rituximab infusion were recorded and analyzed clinically and immunochemically. RESULTS: Six of 22 patients (27.3%) experienced systemic drug reactions after rituximab infusion. Four patients developed a severe flare of MC vasculitis 1 or 2 days after rituximab infusion. Two patients developed serum sickness syndrome 7 and 9 days after the first 1,000 mg rituximab infusion. Compared with patients without drug reactions, those with drug reactions had higher mixed cryoglobulin levels (mean+/-SD 1.4+/-0.82 gm/liter versus 0.71+/-0.77 gm/liter; P=0.0475) and lower C4 levels (mean+/-SD 0.02+/-0.006 gm/liter versus 0.07+/-0.07 gm/liter; P=0.02), and more of them received 1,000 mg high-dose rituximab protocol (50% versus 6.25%; P=0.046). In vitro immunochemical assays showed that rituximab formed a complex with the cryoprecipitating IgMkappa that had rheumatoid factor (RF) activity. Moreover, the in vitro addition of rituximab to serum containing an RF-positive IgMkappa type II mixed cryoglobulin was associated with visibly accelerated cryoprecipitation. CONCLUSION: In HCV-associated MC vasculitis, rituximab may form a complex with RF-positive IgMkappa, leading to accelerated cryoprecipitation and to severe systemic reactions. Rituximab should be administered with caution in MC vasculitis, with use of the 375 mg protocol and plasma exchanges prior to rituximab infusion in patients with high baseline levels of mixed cryoglobulin.

Transfusion-induced serum sickness.

BACKGROUND: Transfusion-induced serum sickness reactions are rarely reported in the literature. The Type III hypersensitivity reaction to heterologous proteins involves deposition of complement and immune complexes in small vessel walls resulting in a leukocytoclastic vasculitis. A case of a multiply transfused patient with several episodes of serum sickness reactions is presented. CASE REPORT: A 61-year-old man with myelodysplastic syndrome type refractory anemia presented with fever, rash, and polyarthralgia 5 days after transfusion of red blood cells (RBCs). By transfusing plasma-free "washed" RBCs, similar serum sickness reactions were avoided. RESULTS: Laboratory investigation showed an increase of serum creatinine, hematuria, and proteinuria. Levels of circulating immune complexes immunoglobulin G and immunoglobulin M were increased. Hypocomplementemia could not be demonstrated. Histopathologic examination of the skin showed leukocytoclastic vasculitis, compatible with serum sickness. CONCLUSION: The importance of early recognition of transfusion-induced serum sickness reactions is emphasized, because this can reduce unnecessary morbidity from this unusual complication of transfusion. To prevent this type of transfusion reaction, patients who experienced serum sickness-like reactions after transfusion should only receive plasma-free washed RBCs.

Delayed allergic reaction to natalizumab associated with early formation of neutralizing antibodies.

BACKGROUND: Natalizumab is a new therapeutic option for relapsing-remitting multiple sclerosis. As with other antibody therapies, hypersensitivity reactions have been observed. In the Natalizumab Safety and Efficacy in Relapsing-Remitting Multiple Sclerosis (AFFIRM) trial, infusion-related hypersensitivity reactions developed in 4% of patients, usually within 2 hours after starting the infusion. OBJECTIVE: To report a significant, delayed, serum sickness-like, type III systemic allergic reaction to natalizumab. DESIGN: Case report describing clinical follow-up and the serial measurement of antinatalizumab antibodies. PATIENT: A 23-year-old man with relapsing-remitting multiple sclerosis developed a fever, arthralgias, urticarial exanthema, and a swollen lower lip during several days after his second infusion of natalizumab. RESULTS: The patient developed a delayed, serum sickness-like, type III systemic allergic reaction to natalizumab. Five weeks after initiation of this therapy, he tested positive for antinatalizumab antibodies and exhibited persistent antibody titers 8 and 12 weeks later. His symptoms completely resolved with a short course of oral glucocorticosteroids. CONCLUSION: Clinicians and patients should be alert not only to immediate but also to significantly delayed substantial allergic reactions to natalizumab.