Hypersensitivity reactions in patients receiving hemodialysis

Pathophysiological changes in patients during hemodialysis and blood reinfusion predict potential development of hemodialysis reactions

Hemodialysis reactions (HDRs) are a type of hypersensitivity reactions (HSRs), such as complement activation-related pseudoallergy (CARPA) observed during nanoparticle infusions. Our study aimed to elucidate the mechanisms of human HDRs by focusing on hemodynamic and clinical chemistry changes of HSR-related or biocompatibility issues during human hemodialysis (HD) and the reinfusion of blood. Based on our recent animal experiments, we hypothesize that increased pulmonary arterial pressure (PAP), and increases in thromboxane B2 (TXB2) and complement 3a (C3a) plasma concentrations will likely manifest in, or at least predict, human HDRs during HD and blood reinfusion. To verify our hypothesis, we measured these parameters during high-flux HD in patients. Since direct PAP measurement was not possible, the plasma concentration of the N-terminal fragment of the brain natriuretic peptide (NT-proBNP) was determined for the noninvasive estimation of PAP. Our results show an increase in NT-proBNP and TXB2 during the reinfusion of extracorporeal blood. The plasma concentration of C3a increased in early HD already and remained elevated up to blood reinfusion. In conclusion, the observed changes in HSR-related parameters or biocompatibility issues in otherwise asymptomatic patients may suggest that a greater activation of these mechanisms could explain the development of human hemodialysis reactions.

CKD-associated pruritus in haemodialysis: a road map for diagnosis and treatment

Of the wide range of symptoms affecting patients with chronic kidney disease (CKD) on haemodialysis, CKD-associated pruritus is one of the most common and burdensome, occurring at moderate-to-severe intensity in 31%-40% of patients, significantly impacting multiple aspects of quality of life, and associated with increased healthcare utilization. Despite the distressing nature of this symptom, clinicians frequently underestimate its prevalence and it is under-reported by patients who may be unaware of the availability of effective treatment options. The identification and management of CKD-associated pruritus should form an essential aspect of patient-centred care; however, patients with CKD may have multiple causes of chronic itch including those of dermatological, systemic, neuropathic and psychogenic origin, and CKD-associated pruritus must be distinguished from these. Together with its highly variable presentation in patients on haemodialysis, the range of potential causes of itch makes differential diagnosis of CKD-associated pruritus challenging. The presence of bilaterally symmetrical and non-dermatomally distributed itching, commonly affecting the back, limbs, chest and head is characteristic of CKD-associated pruritus, although approximately 50% of patients report generalized pruritus. Secondary skin lesions (including excoriation, crusts, impetigo, lichenifications and prurigo also seen in dermatological conditions) may or may not be observed, and xerosis (dry skin) that may exacerbate itching is common. Here, we provide a pragmatic approach to the identification and differential diagnosis of chronic itching in CKD-associated pruritus with the aim of supporting the effective management of this highly distressing symptom in clinical practice.

Low Molecular Weight Heparin-Induced Thrombocytopenia: A Case Series Study of Newly Admitted Hemodialysis Patients

Low molecular weight heparin (LMWH), a common anticoagulant in hemodialysis, can cause the dangerous condition of heparin-induced thrombocytopenia (HIT) in rare cases. The present study reviews five cases of HIT diagnosed in our center, which treats more than 400 maintenance hemodialysis patients annually over a 30-year period. All five cases occurred in incident patients who were being exposed to LMWH for the first time. Treatment involved stopping LMWH and using alternative anticoagulants. Both the 4Ts score and antibody tests were used to confirm the diagnosis of HIT. Following diagnosis, close monitoring was performed for 10-15 days in typical cases or 30 days in severe cases until blood platelet levels recovered to near normal values. Our results suggest that while uncommon, HIT associated with use of LMWH can occur in hemodialysis patients, especially when patients are being exposed to this anticoagulant for the first time.

Characterization of Feline Basophils on the Sysmex XN-1000V and Evaluation of a New WDF Gating Profile

The Sysmex XN-1000V provides a percentage and concentration of basophils from the WNR scattergram, as for human samples, but this method has been shown to be irrelevant in cats. This study aimed to characterize the feline basophil distribution on the WDF channel and to preliminarily evaluate the performance of a new basophil gate on the WDF channel. Cases of feline basophilia were retrospectively retrieved and the scattergram from the WDF and WNR channels were evaluated for any consistent pattern. A new gating setting for the WDF channel was created to include the suspected basophil region. This new gating was applied retrospectively to identified basophilia cases and prospectively to randomly selected feline cases. Manual, WNR, and new WDF methods for basophil identification were compared. Nine cases of feline basophilia were identified. A characteristic WDF scattergram was identified in seven of the nine cases. A new gate was created on the WDF channel and applied to these and 34 additional cases. The comparison study showed that the new method of basophil quantification using the WDF scattergram correlated better with the manual method than the Sysmex XN-1000V method using the WNR scattergram. Basophil concentration in feline peripheral blood can be determined using a new gate on the WDF channel of the Sysmex XN-1000V, which provides better performance than the WNR channel and is comparable to the manual method.

Allergy to the fistula needle: a rare cause of allergy in hemodialysis (a case report)

Anaphylactic reactions are rare but potentially life-threatening events that may occur during medical procedures. This present case highlights a distinct occurrence of an anaphylactic reaction in a patient undergoing hemodialysis, specifically induced by the utilization of a fistula needle along with a review of the literature.

Hemoincompatibility in Hemodialysis-Related Therapies and Their Health Economic Perspectives

Hemobiologic reactions associated with the hemoincompatibility of extracorporeal circuit material are an undesirable and inevitable consequence of all blood-contacting medical devices, typically considered only from a clinical perspective. In hemodialysis (HD), the blood of patients undergoes repetitive (at least thrice weekly for 4 h and lifelong) exposure to different polymeric materials that activate plasmatic pathways and blood cells. There is a general agreement that hemoincompatibility reactions, although unavoidable during extracorporeal therapies, are unphysiological contributors to non-hemodynamic dialysis-induced systemic stress and need to be curtailed. Strategies to lessen the periodic and direct effects of blood interacting with artificial surfaces to stimulate numerous biological pathways have focused mainly on the development of 'more passive' materials to decrease intradialytic morbidity. The indirect implications of this phenomenon, such as its impact on the overall delivery of care, have not been considered in detail. In this article, we explore, for the first time, the potential clinical and economic consequences of hemoincompatibility from a value-based healthcare (VBHC) perspective. As the fundamental tenet of VBHC is achieving the best clinical outcomes at the lowest cost, we examine the equation from the individual perspectives of the three key stakeholders of the dialysis care delivery processes: the patient, the provider, and the payer. For the patient, sub-optimal therapy caused by hemoincompatibility results in poor quality of life and various dialysis-associated conditions involving cost-impacting adjustments to lifestyles. For the provider, the decrease in income is attributed to factors such as an increase in workload and use of resources, dissatisfaction of the patient from the services provided, loss of reimbursement and direct revenue, or an increase in doctor-nurse turnover due to the complexity of managing care (nephrology encounters a chronic workforce shortage). The payer and healthcare system incur additional costs, e.g., increased hospitalization rates, including intensive care unit admissions, and increased medications and diagnostics to counteract adverse events and complications. Thus, hemoincompatibility reactions may be relevant from a socioeconomic perspective and may need to be addressed beyond just its clinical relevance to streamline the delivery of HD in terms of payability, future sustainability, and societal repercussions. Strategies to mitigate the economic impact and address the cost-effectiveness of the hemoincompatibility of extracorporeal kidney replacement therapy are proposed to conclude this comprehensive approach.

Cutaneous adaptive immunity and uraemia: a narrative review

Chronic kidney disease affects 1 in 10 people globally, with a prevalence twenty times that of cancer. A subset of individuals will progress to end-stage renal disease (ESRD) where renal replacement therapy is required to maintain health. Cutaneous disease, including xerosis and pruritus, are endemic amongst patients with ESRD. In the uraemia-associated immune deficiency of ESRD, impaired circulating immune responses contribute to increased infection risk and poorer vaccination response. Clinical manifestations of dysregulated adaptive immunity within the skin have been well-described and have been posited to play a role in cutaneous features of ESRD. However, our understanding of the mechanisms by which adaptive immunity within the skin is affected by uraemia is relatively limited. We provide an overview of how the cutaneous adaptive immune system is impacted both directly and indirectly by uraemia, highlighting that much work has been extrapolated from the circulating immune system and often has not been directly evaluated in the skin compartment. We identify knowledge gaps which may be addressed by future research. Ultimately, greater understanding of these pathways may facilitate novel therapeutic approaches to ameliorate widespread cutaneous symptomatology in ESRD.

Hypersensitive Reactions During Hemodialysis Treatment: What Do We Need to Know?

Kidney replacement therapies (KRTs) including hemodialysis (HD) are one of the treatment options for most of the patients with end-stage kidney disease. Although HD is vital for these patients, it is not hundred percent physiological, and various adverse events including hypersensitivity reactions may occur. Fortunately, these reactions are rare in total and less when compared to previous decades, but it is still very important for at least two reasons: First, the number of patients receiving kidney replacement treatment is increasing globally; and the cumulative number of these reactions may be substantial. Second, although most of these reactions are mild, some of them may be very severe and even lead to mortality. Thus, it is very important to have basic knowledge and skills to diagnose and treat these reactions. Hypersensitivity reactions can occur at any component of dialysis machinery (access, extracorporeal circuit, medications, etc.). The most important preventive measure is to avoid the allergen. However, even with very specific test, sometimes the allergen cannot be found. In mild conditions, HD can be contained with non-specific treatment (topical creams, antihistaminics, corticosteroids). In more severe conditions, treatment must be stopped immediately, blood should not be returned to patient, drugs must be stopped, and rules of general emergency treatment must be followed.

Anaphylaxis secondary to citric acid allergy in End Stage Renal Disease patient

Dialysis reactions are not uncommon in End Stage Renal Disease (ESRD) patients who are undergoing in-center hemodialysis. Here we report the first case of anaphylaxis related to citric acid solutions used for dialysis machine disinfection and descaling. The patient developed repeated episodes of anaphylactic reactions during hemodialysis only in the inpatient setting leading to respiratory failure needing intubation and anaphylactic shock. This had failed to resolve despite using various combinations of different dialysis machines and dialyzer membranes and only resolved after the elimination of citric acid from the dialysis circuit. This case highlights the importance of different allergens in dialysis circuits and emphasizes the importance of looking for alternative reasons for dialyzer reactions.

Complement-mediated dialysis reaction during regular hemodialysis treatment: a case report

BACKGROUND

Hemodialysis reactions (HDRs) are similar to complement activation-related pseudo allergy (CARPA), a hypersensitivity reaction that occurs when administering certain (nano)drugs intravenously. The pathomechanism of CARPA was described based on animal experiments. Typical CARPA-like dialysis reactions, which occur at the start of hemodialysis, have been reported using polysulfone dialyzers. However, to our knowledge, this is the first dialysis reaction that occurred towards the end of hemodialysis treatment.

CASE PRESENTATION

This report describes a 52-year-old Caucasian male patient who had been receiving chronic hemodialysis for 3 years and exhibited a CARPA reaction during his third hour of treatment. Upon activation of the microbubble alarm, the extracorporeal system recirculated for five minutes. Following reconnection, the patient exhibited a drop in systemic blood pressure, chest pain, and dyspnea after five minutes. Symptoms disappeared spontaneously after reducing the speed of the blood pump, placing the patient in a Trendelenburg position, and administering a bolus infusion from the dialysis machine. The remaining dialysis treatment was uneventful.

CONCLUSION

Numerous case reports about reactions occurring with modern high-efficiency polysulfone dialyzers have been published. However, due to changes in the material structure by the manufacturers, we have not encountered such cases lately. The recently reported increase in thromboxane-B2 and pulmonary arterial pressure and complement activation upon re-infusion of extracorporeal blood following dialysis may explain the reaction observed here.

Anaphylaxis From Ethylene Oxide-Sterilized Dialysis Tubing and Needles: A Case Report

Hypersensitivity reactions to ethylene oxide-sterilized dialyzers have been well described. Although ethylene oxide is no longer used to sterilize most dialyzers, it is used on other pieces of dialysis equipment. We present a case of a 78-year-old man who experienced dialysis-related anaphylaxis attributed to an IgE-mediated allergy to dialysis tubing and needles sterilized with ethylene oxide. Shortly after transitioning from a tunneled catheter to an arteriovenous fistula, he developed multiple episodes of intradialytic hypotension and syncope within minutes of starting dialysis. Laboratory evaluation revealed marked leukocytosis, eosinophilia, and elevated anti-ethylene oxide IgE antibody. After pretreatment with corticosteroids and antihistamines, the rinsing of dialysis tubing, and transition of access back to a tunneled catheter, he tolerated subsequent dialysis treatments. Review of his history revealed chronic eosinophilia since the time of hemodialysis initiation. We hypothesize his eosinophilia and mast cell degranulation began upon initial exposure to ethylene oxide and hemodialysis equipment. When use of the arteriovenous fistula was resumed, he was exposed to a higher "dose" of ethylene oxide due to the use of needles. The higher antigenic stimuli triggered a memory immune response, leading to mast cell degranulation and repeated anaphylactic episodes that were overcome by minimization of ethylene oxide-sterilized equipment, corticosteroid pretreatment, and the anti-IgE Fc monoclonal omalizumab.

Immune System Dysfunction and Inflammation in Hemodialysis Patients: Two Sides of the Same Coin

Biocompatibility in hemodialysis (HD) has considerably improved in recent decades, but remains an open issue to be solved, appearing essential to reduce systemic inflammation and enhance patients’ clinical outcomes. Clotting prevention, reduction in complement and leukocyte activation, and improvement of antioxidant effect represent the main goals. This review aims to analyze the different pathways involved in HD patients, leading to immune system dysfunction and inflammation. In particular, we mostly review the evidence about thrombogenicity, which probably represents the most important characteristic of bio-incompatibility. Platelet activation is one of the first steps occurring in HD patients, determining several events causing chronic sub-clinical inflammation and immune dysfunction involvement. Moreover, oxidative stress processes, resulting from a loss of balance between pro-oxidant factors and antioxidant mechanisms, have been described, highlighting the link with inflammation. We updated both innate and acquired immune system dysfunctions and their close link with uremic toxins occurring in HD patients, with several consequences leading to increased mortality. The elucidation of the role of immune dysfunction and inflammation in HD patients would enhance not only the understanding of disease physiopathology, but also has the potential to provide new insights into the development of therapeutic strategies.

Characterization of hypersensitivity reactions to polysulfone hemodialysis membranes

BACKGROUND

In recent years, cases have been reported in which unexpected systemic hypersensitivity reactions occurred in patients dialyzed with polysulfone- or polyethersulfone-biocompatible membranes in the absence of other risk factors. The pathomechanisms involved in these reactions are largely unknown.

OBJECTIVE

To characterize hypersensitivity reactions to polysulfone hemodialysis using clinical and laboratory data and to identify biomarkers suitable for endotype identification and diagnosis.

METHODS

We prospectively collected data from 29 patients with suspected hypersensitivity reactions to polysulfone hemodialysis membranes. Clinical laboratory parameters such as tryptase, blood cell counts, and complement levels were recorded. Acute samples were obtained from 18 cases for the ex vivo assessment of basophil activation by flow cytometry analysis of CD63, CD203, and FcεRI cell membrane expression. Serum cytokines and anaphylatoxin concentrations were evaluated in 16 cases by Luminex and cytometric bead array analysis.

RESULTS

Tryptase was elevated during the acute reaction in 4 cases. Evidence of basophil activation was obtained in 10 patients. Complement activation was found in only 2 cases. However, C5a serum levels tended to increase during the acute reaction in those patients with hypoxemia. Significantly higher serum levels of interleukin-6 were observed during the acute reactions to polysulfone hemodialysis (P = .0103).

CONCLUSION

Based on biomarker analysis, various endotypes were identified, including type I-like (with the involvement of mast cells or basophils), complement, and cytokine (interleukin-6) release-related reactions, with some patients showing mixed reactions. Further research is needed to unravel the exact mechanisms involved in the activation of these cellular and molecular pathways.

Blood-incompatibility in haemodialysis: alleviating inflammation and effects of coagulation

Blood-incompatibility is an inevitability of all blood-contacting device applications and therapies, including haemodialysis (HD). Blood leaving the environment of blood vessels and the protection of the endothelium is confronted with several stimuli of the extracorporeal circuit (ECC), triggering the activation of blood cells and various biochemical pathways of plasma. Prevention of blood coagulation, a major obstacle that needed to be overcome to make HD possible, remains an issue to contend with. While anticoagulation (mainly with heparin) successfully prevents clotting within the ECC to allow removal of uraemic toxins across the dialysis membrane wall, it is far from ideal, triggering heparin-induced thrombocytopenia in some instances. Soluble fibrin can form even in the presence of heparin and depending on the constitution of the patient and activation of platelets, could result in physical clots within the ECC (e.g. bubble trap chamber) and, together with other plasma and coagulation proteins, result in increased adsorption of proteins on the membrane surface. The buildup of this secondary membrane layer impairs the transport properties of the membrane to reduce the clearance of uraemic toxins. Activation of complement system-dependent immune response pathways leads to leukopenia, formation of platelet–neutrophil complexes and expression of tissue factor contributing to thrombotic processes and a procoagulant state, respectively. Complement activation also promotes recruitment and activation of leukocytes resulting in oxidative burst and release of pro-inflammatory cytokines and chemokines, thereby worsening the elevated underlying inflammation and oxidative stress condition of chronic kidney disease patients. Restricting all forms of blood-incompatibility, including potential contamination of dialysis fluid with endotoxins leading to inflammation, during HD therapies is thus still a major target towards more blood-compatible and safer dialysis to improve patient outcomes. We describe the mechanisms of various activation pathways during the interaction between blood and components of the ECC and describe approaches to mitigate the effects of these adverse interactions. The opportunities to develop improved dialysis membranes as well as implementation strategies with less potential for undesired biological reactions are discussed.

Chlorhexidine - a commonly used but often neglected culprit of dialysis associated anaphylactic reactions (case report)

BACKGROUND

Hemodialysis-associated anaphylactic reactions are rare and frequently complex in nature due to the sheer number of possible culprit agents. Unfortunately, dialysis is often unavoidable or strictly essential for life-saving solute clearance or fluid removal in patients with end stage kidney failure and those with severe acute kidney injury. It is of utmost importance that the culprit agent is identified and avoided to allow continuation of dialysis treatment as needed.

CASE PRESENTATION

We present 2 cases of hemodialysis-associated anaphylactic reactions. These patients developed anaphylactic reactions peri-dialysis and were initially suspected to have dialyser reactions. They were investigated in a controlled healthcare setting and possible culprit agents were systemically identified and eliminated. They both underwent allergy testing and were diagnosed with chlorhexidine allergy. Of note, Case 1 was an incident dialysis patient at the time of presentation and Case 2 was a prevalent dialysis patient. This suggests that the time from initial sensitization to reaction may not always be helpful in determining if a particular agent is the culprit of an anaphylactic reaction. In both cases, the patients were dialysed through a tunnelled dialysis catheter. We postulate that the presence of an exit site, which represents a compromise to the integrity of the skin's epidermal barrier, may have a significant role in the development of these reactions. As chlorhexidine is a widely used disinfectant in hemodialysis, it is imperative that we consider it as a possible culprit agent when these reactions arise. To our knowledge, there are no other reported cases of anaphylaxis secondary to chlorhexidine use in dialysis patients other than a previous report in 2017. Our report also highlights the possibility of these reactions occurring more frequently in patients with damaged epidermal barriers and in patients exposed to higher environmental concentrations of chlorhexidine. These are novel concepts that can be explored with further research.

CONCLUSION

Chlorhexidine associated anaphylactic reactions can occur in the peri-dialysis setting and a high index of suspicion is paramount to diagnosis.

A porcine model of hemodialyzer reactions: roles of complement activation and rinsing back of extracorporeal blood

Hemodialysis reactions (HDRs) resemble complement-activation-related pseudoallergy (CARPA) to certain i.v. drugs, for which pigs provide a sensitive model. On this basis, to better understand the mechanism of human HDRs, we subjected pigs to hemodialysis using polysulfone (FX CorDiax 40, Fresenius) or cellulose triacetate (SureFlux-15UX, Nipro) dialyzers, or Dialysis exchange-set without membranes, as control. Experimental endpoints included typical biomarkers of porcine CARPA; pulmonary arterial pressure (PAP), blood cell counts, plasma sC5b-9 and thromboxane-B2 levels. Hemodialysis (60 min) was followed by reinfusion of extracorporeal blood into the circulation, and finally, an intravenous bolus injection of the complement activator zymosan. The data indicated low-extent steady rise of sC5b-9 along with transient leukopenia, secondary leukocytosis and thrombocytopenia in the two dialyzer groups, consistent with moderate complement activation. Surprisingly, small changes in baseline PAP and plasma thromboxane-B2 levels during hemodialysis switched into 30%-70% sharp rises in all three groups resulting in synchronous spikes within minutes after blood reinfusion. These observations suggest limited complement activation by dialyzer membranes, on which a membrane-independent second immune stimulus was superimposed, and caused pathophysiological changes also characteristic of HDRs. Thus, the porcine CARPA model raises the hypothesis that a second "hit" on anaphylatoxin-sensitized immune cells may be a key contributor to HDRs.

Multitargeted interventions to reduce dialysis-induced systemic stress

Hemodialysis (HD) is a life-sustaining therapy as well as an intermittent and repetitive stress condition for the patient. In ridding the blood of unwanted substances and excess fluid from the blood, the extracorporeal procedure simultaneously induces persistent physiological changes that adversely affect several organs. Dialysis patients experience this systemic stress condition usually thrice weekly and sometimes more frequently depending on the treatment schedule. Dialysis-induced systemic stress results from multifactorial components that include treatment schedule (i.e. modality, treatment time), hemodynamic management (i.e. ultrafiltration, weight loss), intensity of solute fluxes, osmotic and electrolytic shifts and interaction of blood with components of the extracorporeal circuit. Intradialytic morbidity (i.e. hypovolemia, intradialytic hypotension, hypoxia) is the clinical expression of this systemic stress that may act as a disease modifier, resulting in multiorgan injury and long-term morbidity. Thus, while lifesaving, HD exposes the patient to several systemic stressors, both hemodynamic and non-hemodynamic in origin. In addition, a combination of cardiocirculatory stress, greatly conditioned by the switch from hypervolemia to hypovolemia, hypoxemia and electrolyte changes may create pro-arrhythmogenic conditions. Moreover, contact of blood with components of the extracorporeal circuit directly activate circulating cells (i.e. macrophages-monocytes or platelets) and protein systems (i.e. coagulation, complement, contact phase kallikrein-kinin system), leading to induction of pro-inflammatory cytokines and resulting in chronic low-grade inflammation, further contributing to poor outcomes. The multifactorial, repetitive HD-induced stress that globally reduces tissue perfusion and oxygenation could have deleterious long-term consequences on the functionality of vital organs such as heart, brain, liver and kidney. In this article, we summarize the multisystemic pathophysiological consequences of the main circulatory stress factors. Strategies to mitigate their effects to provide more cardioprotective and personalized dialytic therapies are proposed to reduce the systemic burden of HD.

A complicated case of Serratia marcescens catheter-related bloodstream infection misdiagnosed as hypersensitivity reactions to bicarbonate dialysate containing acetate

Recurrent fever during/post-dialysis can occur due to infectious or non-infectious causes. We present the case of a 79-year-old patient who had persistent post-dialysis fever after long-term tunneled central venous catheterization with acetate-containing bicarbonate dialysate. Drug-induced lymphocyte stimulation test (DLST) was positive for acetate dialysate, and he was suspected of having acetate dialysate-induced hypersensitivity reaction. However, switching to acetate-free dialysate did not attenuate the fever. Since Serratia marcescens had been isolated twice from the blood, catheter-related bloodstream infection (CRBSI) was suspected. The culture of the catheter tip confirmed CRBSI caused by S. marcescens. Elevation of β-d-glucan levels and appearance of pulmonary nodular shadow on chest computed tomography images indicated complicated fungal infections. Administration of antibiotics and antifungals led to resolution of the pulmonary nodular shadow with attenuation of fever and C-reactive protein levels. DLST for acetate dialysate was negative, and its reuse did not aggravate the symptoms; hence, the first result was considered false-positive. An indwelling catheter is a risk factor for S. marcescens-related CRBSI, which leads to post-dialysis fever. Hypersensitivity reactions to dialysates must be diagnosed considering the clinical course and DLST results.

Hemodialysis-Related Complement and Contact Pathway Activation and Cardiovascular Risk: A Narrative Review

Individuals receiving long-term hemodialysis are at increased risk of developing cardiovascular disease (CVD). Traditional cardiovascular risk factors do not fully explain the high CVD risk in this population. During hemodialysis, blood interacts with the biomaterials of the hemodialysis circuit. This interaction can activate the complement system and the factor XII-driven contact system. FXII activation triggers both the intrinsic pathway of coagulation and the kallikrein-kinin pathway, resulting in thrombin and bradykinin production, respectively. The complement system plays a key role in the innate immune response, but also contributes to the pathogenesis of numerous disease states. Components of the complement pathway, including mannose binding lectin and C3, are associated with CVD risk in people with end-stage kidney disease (ESKD). Both the complement system and the factor XII-driven contact coagulation system mediate proinflammatory and procoagulant responses that could contribute to or accelerate CVD in hemodialysis recipents. This review summarizes what is already known about hemodialysis-mediated activation of the complement system and in particular the coagulation contact system, emphasizing the potential role these systems play in the identification of new biomarkers for CVD risk stratification and the development of potential therapeutic targets or innovative therapies that decrease CVD risk in ESKD patients.

Reporte de un caso con reacción a la polisulfona durante hemodiálisis. Clínica Reynadial, Guayaquil, 2020

El tratamiento de hemodiálisis (HD) presupone un cierto riesgo de reacciones adversas de hipersensibilidad, se han descrito casos de hipersensibilidad con membranas biocompatibles, como la polisulfona. En este artículo describimos el caso de un paciente que se realiza tratamiento de HD usando dializador de polisulfona, aproximadamente a los 10 minutos de iniciar presenta manifestaciones digestivas, caracterizada por diarreas liquidas, no relacionadas con evento alimenticio, sin flemas, ni contenido hemático, sin pujos ni tenesmo, presenta dolor abdominal difuso, vómitos e hipotensión arterial. Estas reacciones fueron consideradas como hipersensibilidad relacionada con el proceso de hemodiálisis, el cuadro clínico no reapareció en observaciones sucesivas cuando las sesiones se llevaron a cabo utilizando una membrana de celulosa.

A new immune-toxicological test for polysulfone hypersensitivity in hemodialysis patients

Incompatibility of dialysis procedure due to hypersensitivity against dialyzer material, currently mainly based on polysulfone and derivatives, cannot be assessed by routine laboratory tests. Although the frequency of such symptoms is suspected to be lower than 2%, it resembles an important clinical problem because dialysis procedures are frequently accompanied by symptoms of non-tolerability with reasons not being entirely clear. To enlighten the role of polysulfone hypersensitivity, we adapted known standardized material immune-toxicological tests (lymphocyte transformation test, basophil degranulation test) to the specific conditions of dialysis and polysulfone material sensitivity. We developed a method of polysulfone micronisation and measured humoral immune response of isolated patient's lymphocytes when incubated with polysulfone dispersion. Thirty-nine samples from 103 patients with suspected polysulfone hypersensitivity within the dialysis population of a nation-wide dialysis provider (n = 15.761 patients) showed positive results for type 1 (n = 19), type 4 (n = 18) or both type (n = 2) reactions. This is the first methodological report showing plausible in-vitro results of patients' samples concerning polysulfone intolerance. Further clinical and laboratory research is needed to define true polysulfone hypersensitivity and to enlighten the field of hypothetic subclinical material incompatibility in patients with impaired dialysis tolerability.

Molecular Mechanisms of Premature Aging in Hemodialysis: The Complex Interplay Between Innate and Adaptive Immune Dysfunction

Hemodialysis (HD) patient are known to be susceptible to a wide range of early and long-term complication such as chronic inflammation, infections, malnutrition, and cardiovascular disease that significantly affect the incidence of mortality. A large gap between the number of people with end-stage kidney disease (ESKD) and patients who received kidney transplantation has been identified. Therefore, there is a huge need to explore the underlying pathophysiology of HD complications in order to provide treatment guidelines. The immunological dysregulation, involving both the innate and adaptive response, plays a crucial role during the HD sessions and in chronic, maintenance treatments. Innate immune system mediators include the dysfunction of neutrophils, monocytes, and natural killer (NK) cells with signaling mediated by NOD-like receptor P3 (NLRP3) and Toll-like receptor 4 (TLR4); in addition, there is a significant activation of the complement system that is mediated by dialysis membrane-surfaces. These effectors induce a persistent, systemic, pro-inflammatory, and pro-coagulant milieu that has been described as inflammaging. The adaptive response, the imbalance in the CD4+/CD8+ T cell ratio, and the reduction of Th2 and regulatory T cells, together with an altered interaction with B lymphocyte by CD40/CD40L, have been mainly implicated in immune system dysfunction. Altogether, these observations suggest that intervention targeting the immune system in HD patients could improve morbidity and mortality. The purpose of this review is to expand our understanding on the role of immune dysfunction in both innate and adaptive response in patients undergoing hemodialysis treatment.

Hypersensitivity reactions to bicarbonate dialysate containing acetate: a case report with literature review

Although hemodialysis-hypersensitivity reactions have various causes, only a few cases of hypersensitivity to acetate dialysate accompanied by fever have been reported. We present the case of a 69-year-old hemodialysis patient who was admitted due to fever after dialysis. He had undergone online hemodiafiltration using acetate-free citrate-containing dialysate. After admission, we switched to acetate-containing bicarbonate dialysate. He was diagnosed with pneumonia and treated with ceftriaxone. However, fever that occurred post dialysis persisted, displaying a gradual elevation in CRP level and eosinophils (up to 9.7 mg/dL and 3774 cells/μL, respectively). After a series of negative workups for infection and dialysis membrane allergy, we suspected that acetate-containing bicarbonate dialysate to be the cause of the allergic reaction and switched to acetate-free bicarbonate dialysate. Consequently, eosinophil count decreased and the fever abated. The drug-induced lymphocyte stimulation test finding (for acetate dialysate) was positive, and he was diagnosed with acetate dialysate-induced hypersensitivity reactions. The condition was not detected earlier due to the complications associated with pneumonia.

Reactions to Synthetic Membranes Dialyzers: Is there an Increase in Incidence?

Background: Reactions to dialyzers used in dialysis have been reported more frequently in recent years. Evidence, however, shows that the reaction rate has remained stable for years. Summary: One explanation for the apparent increase in publication frequency could be the lack of knowledge that dialyzer reactions may well occur with biocompatible membranes. Studies showed that the cause of these reactions is very diverse and varied, involving multiple materials. However, polyvinylpyrrolidone continues to be the main suspect, but without conclusive results. There are no differences between the different fibers, and although polysulfone is the most described, it is also the most used. Key Messages: The change to cellulose triacetate continues to be the most appropriate form of treatment. The classification of these reactions into type A and B complicates the diagnosis, and its true usefulness is in doubt.

NUC041, a Prodrug of the DNA Methytransferase Inhibitor 5-aza-2',2'-Difluorodeoxycytidine (NUC013), Leads to Tumor Regression in a Model of Non-Small Cell Lung Cancer

5-aza-2′,2′-difluorodeoxycytidine (NUC013) has been shown to be significantly safer and more effective than decitabine in xenograft models of human leukemia and colon cancer. However, it suffers from a similar short half-life as other DNA methyltransferase inhibitors with a 5-azacytosine base, which is problematic for nucleosides that primarily target tumor cells in S phase. Because of the relative instability of 5-azanucleosides, a prodrug approach was developed to improve the pharmacology of NUC013. NUC013 was conjugated with trimethylsilanol (TMS) at the 3′ and 5′ position of the sugar, rendering the molecule hydrophobic and producing 3′,5′-di-trimethylsilyl-2′,2′-difluoro-5-azadeoxycytidine (NUC041). NUC041 was designed to be formulated in a hydrophobic vehicle, protecting it from deamination and hydrolysis. In contact with blood, the TMS moieties are readily hydrolyzed to release NUC013. The half-life of NUC013 administered intravenously in mice is 20.1 min, while that of NUC013 derived from intramuscular NUC041 formulated in a pegylated-phospholipid depot is 3.4 h. In a NCI-H460 xenograft of non-small cell lung cancer, NUC013 was shown to significantly inhibit tumor growth and improve survival. Treatment with NUC041 also led to significant tumor growth inhibition. However, NUC041-treated mice had significantly more tumors ulcerate than either NUC013 treated mice or saline control mice, and such ulceration occurred at significantly lower tumor volumes. In these nude mice, tumor regression was likely mediated by the derepression of the tumor suppressor gene p53 and resultant activation of natural killer (NK) cells.