Effects of retinoids on in vitro and in vivo IgE production

Modulación de la respuesta alérgica por los carotenoides de la dieta

<p>Los carotenoides son pigmentos isoprenoides que están presentes de manera natural y en altas concentraciones en la mayoría de alimentos vegetales —entre ellos, aguacate, papaya, tomate y zanahoria—, pero también encontrados como aditivos y colorantes en diversos productos cárnicos, aceites vegetales, salsas, aderezos, harinas, entre otros. En los últimos años, algunos estudios han descrito que los carotenoides de la dieta participan en varios procesos fisiopatológicos, incluyendo la respuesta inmune de tipo alérgico. Las tasas de prevalencia para este tipo de enfermedades han incrementado de manera alarmante durante las últimas cinco décadas en todo el mundo, a la vez que varios factores e hipótesis se han planteado tratando de explicar este fenómeno: uno de ellos es la hipótesis de la dieta, la cual plantea que la composición de varios micro y macronutrientes de la alimentación, así como los cambios en los patrones dietarios, influirían en tal problemática. Evidencia epidemiológica y básica experimental emergente señala que los carotenoides de la dieta participan en la regulación de la inflamación alérgica, y por ello se postulan como coadyuvantes en la terapia de tales padecimientos. En el presente artículo se revisará el estado del arte en relación a los efectos de los carotenoides de la dieta sobre la patología alérgica.</p>

The impact of diet on asthma and allergic diseases

The incidence of allergic diseases is increasing, both in developed and developing countries, concomitantly with the rise in living standards and the adoption of a 'western lifestyle'. For two decades, the hygiene hypothesis - which proposes that the lack of early childhood exposure to infectious agents increases susceptibility to allergic diseases in later life - provided the conceptual framework for unravelling the mechanisms that could account for the increased incidence of allergic diseases. In this Review, we discuss recent evidence that highlights the role of diet as a key factor influencing immune homeostasis and the development of allergic diseases through a complex interplay between nutrients, their metabolites and immune cell populations. Although further investigations are still required to understand these complex relationships, recent data have established a possible connection between metabolic homeostasis and allergic diseases.

Localized Th1-, Th2-, T regulatory cell-, and inflammation-associated hepatic and pulmonary immune responses in Ascaris suum-infected swine are increased by retinoic acid

Pigs infected with Ascaris suum or controls were given 100 microg (low-dose) or 1,000 microg (high-dose) all-trans retinoic acid (ATRA)/kg body weight in corn oil or corn oil alone per os on days after inoculation (DAI) -1, +1, and +3 with infective eggs. Treatment with ATRA increased interleukin 4 (IL4) and IL12p70 in plasma of infected pigs at 7 DAI and augmented bronchoalveolar lavage (BAL) eosinophilia observed at 7 and 14 DAI. To explore potential molecular mechanisms underlying these observations, a quantitative real-time reverse transcription (RT)-PCR array was used to examine mRNA expression in tissue. Ascaris-infected pigs had increased levels of liver mRNA for T-helper-2 (Th2)-associated cytokines, mast cell markers, and T regulatory (Treg) cells, while infected pigs given ATRA had higher IL4, IL13, CCL11, CCL26, CCL17, CCL22, and TPSB1 expression. Gene expression for Th1-associated markers (IFNG, IL12B, and TBX21), the CXCR3 ligand (CXCL9), IL1B, and the putative Treg marker TNFRSF18 was also increased. Expression of IL4, IL13, IL1B, IL6, CCL11, and CCL26 was increased in the lungs of infected pigs treated with ATRA. To determine a putative cellular source of eosinophil chemoattractants, alveolar macrophages were treated with IL4 and/or ATRA in vitro. IL4 induced CCL11, CCL17, CCL22, and CCL26 mRNA, and ATRA increased the basal and IL4-stimulated expression of CCL17 and CCL22. Thus, ATRA augments a diverse Th1-, Th2-, Treg-, and inflammation-associated response in swine infected with A. suum, and the increased BAL eosinophilia may be related to enhanced induction of eosinophil chemokine activity by alveolar macrophages.

Augmentation of antibody responses by retinoic acid and costimulatory molecules

Antibody production is crucial for a successful vaccine response. Beyond the ability of vitamin A (VA) and its active metabolite, all-trans-retinoic acid (RA) to restore growth in VA-deficient animals, supplementation with VA and/or treatment with RA can augment antibody responses in both VA-deficient and VA-adequate animals. RA alone, and in combination with stimuli that are ligands for the Toll-like receptor family, can augment the adaptive immune response leading to a heightened primary antibody response, and a stronger recall response upon restimulation. Mechanisms may include regulation of cell populations, type 1/type 2 cytokines, and B cell-related transcription factors, leading to accelerated B cell maturation.

Role of retinoic acid in the imprinting of gut-homing IgA-secreting cells

Antibody-secreting cells (ASCs) lodging in the mucosa of the small intestine are derived from activated B cells that are thought to arise in gut-associated lymphoid tissues (GALT). Upon leaving the GALT, B cells return to the blood where they must express the gut-homing receptors alpha4beta7 and CCR9 in order to emigrate into the small bowel. Recent evidence indicates that gut-associated dendritic cells (DCs) in GALT induce gut-homing receptors on B cells via a mechanism that depends on the vitamin A metabolite retinoic acid (RA). In addition, although ASC associated with other mucosal tissues secrete IgA in an RA-independent fashion, the presence of high levels of RA in intestine and GALT can promote B cell class switching to IgA and thus, boost the production of IgA in the intestinal mucosa. Here, we discuss the role of RA in the imprinting of gut-homing ASC and the evidence linking RA with the generation of intestinal IgA-ASCs.

Fatty acid composition of serum lipid classes in mice following allergic sensitisation with or without dietary docosahexaenoic acid-enriched fish oil substitution

Dietary fatty acids have been shown to influence allergic sensitisation. Bothn-3 andn-6 PUFA are involved in targeted mediation of inflammatory responses during allergic sensitisation and manifestation of atopic diseases. In the present experiments we investigated whether supplementation of DHA-enriched fish oil partly substituting dietary sunflower-seed oil, in comparison with sunflower-seed oil, supplemented to mice influences fatty acid composition of serum lipid classes. The effects of the two different diets were also investigated depending on allergic sensitisation. Supplementation of DHA and EPA in doses of 2 and 0·12 % (w/w) to non-sensitised and sensitised mice resulted in significantly increased percentile contributions of DHA to all lipid classes. In contrast, serum values of then-6 PUFA arachidonic acid (AA) were significantly lower, both in non-sensitised and sensitised mice fed the DHA-enriched diet. The fatty acid composition of serum lipids also reflected allergic sensitisation: the EPA:AA ratio in TAG, cholesteryl esters and phospholipids in non-supplemented animals fell to 23, 29 and 29 % respectively of the original value after allergic sensitisation, whereas it decreased to 70, 80 and 76 % respectively only in the animals supplemented with DHA. In summary, allergic sensitisation alone decreased significantly the EPA:AA ratios in serum TAG, while concomitant supplementation of DHA-enriched fish oil ameliorated this decrease. We postulate from the present results that the amelioration of the severity of allergic sensitisation after DHA supplementation may be linked to altered ratios of the eicosanoid precursors EPA and AA as well as DHA needed for further metabolic activation to pro- or anti-inflammatory bioactive lipids.

Retinoic acid promotes mouse splenic B cell surface IgG expression and maturation stimulated by CD40 and IL-4

Retinoic acid (RA) increases antibody production in vivo but its role in B-cell activation is unclear. In a model of purified mouse splenic B cells stimulated by CD40 coreceptor (as a surrogate of T cell co-stimulation), IL-4, a principal Th-2 cytokine, and ligation of the B-cell antigen receptor, CD40 engagement or IL-4 alone induced B-cell activation indicated by increased Ig gamma1 germline transcripts, cell proliferation, and surface (s)IgG1 expression, while triple stimulation with the combination of anti-CD40/IL-4/anti-mu synergized to heighten B-cell activation. Although RA was growth inhibitory for anti-CD40-activated B cells, RA increased the proportion of B cells that had more differentiated phenotypes, such as expression of higher level of activation-induced deaminase, Blimp-1, CD138/syndecan-1 and sIgG1. Overall, RA can promote B-cell maturation at the population level by increasing the number of sIgG1 and CD138 expressing cells, which may be related to the potentiation of humoral immunity in vivo.

Role of vitamin A elimination or supplementation diets during postnatal development on the allergic sensitisation in mice

Vitamin A (VA) and its derivatives, the retinoids, are important factors for the development of the immune system. It has been shown in adult animals that proliferation of lymphocyte populations and antibody secretion are retinoid dependent, while little is known about the effects of retinoids during postnatal development. The aim of this study was to investigate the role of VA on allergic sensitisation during lactation and after weaning using an in vivo system for postnatal allergic sensitisation in mice. Different VA diets (basal/VA elimination/VA (as retinyl palmitate) supplemented) were fed to the dams throughout lactation and directly to the pups after weaning. Allergic sensitisation was induced with a single peritoneal ovalbumin (OVA) injection at day 28 after weaning. The phenotype of lymphocytes was analysed by flow cytometry and functional data were obtained by analysis of (IL-4/IFN-gamma) cytokine production and antibody production (OVA-specific IgG1 and IgE) in the offspring. VA/retinyl palmitate supplementation during lactation and after weaning decreased CD3+, CD4+, CD8+ and B220+ populations in splenic lymphocytes but also significantly enhanced IL-4 production and OVA-specific IgE after sensitisation. In contrast, mice fed VA-elimination diet displayed no significant alteration of lymphocyte numbers and a slightly increased IL-4 production. Our results showed that a single allergen injection during postnatal development induces allergic sensitisation whose degree is modified by the VA content of the maternal diet during lactation and the diet of the pups after weaning, indicating an important role of VA on the severity of the allergic sensitisation.

Effects of dietary retinoids and carotenoids on immune development

Carotenoids and retinoids are groups of nutritionally-relevant compounds present in many foods of plant origin (carotenoids) and animal origin (mainly retinoids). Their levels in human subjects vary depending on the diversity and amount of the individual's nutrient intake. Some carotenoids and retinoids have been investigated for their effects on the immune system bothin vitroandin vivo. It has been shown that retinoids have the potential to mediate or induce proliferative and differentiating effects on several immune-competent cells, and various carotenoids are known to be inducers of immune function. The immune-modulating effects of retinoids have been well documented, while the effects of carotenoids on the immune system have not been investigated as extensively, because little is known about their molecular mechanism of action. The present review will mainly focus on the molecular mechanism of action of retinoids and particularly carotenoids, their nutritional origin and intake, their transfer from the maternal diet to the child and their effects or potential effects on the developing immune system.

Evaluation of diet and growth in children with and without atopic eczema: follow-up study from birth to 4 years

Current research into dietary factors contributing to the development of allergic diseases is directed towards new active approaches instead of passive elimination diets. The present study aimed to investigate the explanatory role of the diet in a probiotic intervention study on the appearance of atopic eczema (AE) in childhood and the safety of perinatal supplementation with probiotics (Lactobacillus rhamnosus strain GG; ATCC 53 103). A prospective follow-up study from birth to 48 months of children (n 159) with a family history of allergic disease was carried out. Outcome measures included growth, dietary intake assessed with 4 d food diaries and their association with AE by logistic regression models. Increased intakes of retinol, Ca and Zn, with perinatal administration of probiotics, reduced the risk of AE, whilst an increase in intake of ascorbic acid increased the likelihood of AE. Perinatal administration of probiotics was safe, as it did not influence the height (mean difference 0·04 (95 % CI −0·33, 0·40) sd scores, P=0·852) or the weight-for-height (mean difference −3·35 (95 % CI −7·07, 0·37)%, P=0·077) of the children at 48 months with and without perinatal administration of probiotics. Up to 48 months, AE did not affect height (mean difference −0·05 (95 % CI −0·42, 0·33) sd scores, P=0·815), but mean weight-for-height in children with AE was −5·1 % (95 % CI −8·9, −1·2 %) lower compared with children without (P=0·010). The joint effects of nutrients and probiotics need to be considered in active prevention and management schemes for allergic diseases.

Retinol concentrations after birth are inversely associated with atopic manifestations in children and young adults

BACKGROUND

Vitamin A has anti-inflammatory and immunomodulatory effects, and its deficiency results in impaired specific and innate immunity. Vitamin A is essential for inducing the gut-homing specificity on T cells.

OBJECTIVE

As an impaired gut immune response in early infancy may contribute to the development of atopic sensitization, we looked for an association of plasma retinol concentrations and the subsequent development of allergic symptoms in healthy infants.

METHODS

A cohort of 200 unselected, full-term newborns were followed up from birth to age 20 years. The plasma retinol concentration was determined in cord blood (n=97), at ages of 2, 4 and 12 months (n=95), and at ages 5 years (n=155) and 11 years (n=151). The subjects were re-examined at the ages of 5, 11 and 20 years with assessment of the occurrence of allergic symptoms during the preceding year, skin prick testing and measurement of serum total IgE.

RESULTS

subjects with allergic symptoms or a positive skin prick test (SPT) in childhood or adolescence had lower retinol concentrations in infancy and childhood than symptom-free subjects. The difference was most pronounced at age 2 months. Retinol concentration at 2 months correlated inversely with positive SPT at ages of 5 and 20 years, and with allergic symptoms at age 20 years.

CONCLUSION

Retinol concentration in young infants is inversely associated with the subsequent development of allergic symptoms. We propose that an inborn regulation of retinol may play a role in atopic sensitization, possibly through regulating the intestinal T cell responses.

Cytokine and Ig-production by CG-containing sequences with phosphorodiester backbone and dumbbell-shape

BACKGROUND

Immunostimulatory oligodeoxynucleotides (CpG-ODN) usually contain phosphorothioate (PS) backbones for nucleotide protection, which may result in some nonspecific side-effects like prolongation of coagulation time.

OBJECTIVE

The aim of the present study was to investigate the immunomodulatory potential of DNA molecules without PS backbones. Thus, we designed phosphorodiester (PO) molecules with a dumbbell-like covalently-closed structure (dSLIM-30L1).

METHODS

We analyzed their effects on peripheral blood mononuclear cells (PBMC) from spontaneous high and low immunoglobulin (Ig)E producer (allergic and nonallergic donors) in comparison with linear CpG-ODN (lin-30L1) with PS backbones, using enzyme-linked immunosorbent assay and flow cytometry.

RESULTS

We observed a decrease of spontaneous IgE levels in PBMC from high IgE producer of approximately 27% with both dSLIM-30L1 and lin-30L1. In addition, both molecules enhanced the production of IgA, IgM and IgG1/IgG2, but with a slightly different pattern. Both molecules stimulated the secretion of the T(H)1-like cytokines interleukin (IL)-2, interferon-gamma and IL-12p40 and the pro-inflammatory cytokine IL-6. The immunomodulatory potential of dSLIM-30L1 and lin-30L1 was also effective in PBMC from nonallergic donors, as was confirmed for IL-2, IL-12p40, IgG1/IgG2 and IgM.

CONCLUSION

Our data show an inhibition of IgE production but also enhancement of the inflammatory cytokine response in PBMC from allergic and nonallergic donors by covalently-closed PO-based dSLIM-30L1 with a pattern similar to that of linear PS-based lin-30L1, while avoiding PS-modifications and thus PS-mediated side-effects. Whether such molecules are useful for the treatment of allergic diseases will need further clarification by appropriate in vivo studies.

Management of food allergy: vitamins, fatty acids or probiotics?

The dietary approach to allergic disease in infancy is evolving from passive allergen avoidance to active stimulation of the immature immune system, the aim of which is to support the establishment of tolerance. This may include probiotics providing maturational signals for the gut-associated lymphoid tissue and by balancing the generation of pro and anti-inflammatory cytokines in addition to their capacity to reduce the dietary antigen load by degrading and modifying macromolecules. Probiotics have also been shown to reverse the increased intestinal permeability characteristic of children with food allergy and to enhance specific IgA responses frequently defective in children with food allergy. The promotion of gut barrier functions by probiotics also includes the normalization of the gut microecology, alterations in which have been demonstrated in allergic individuals. Dietary lipids, especially long-chain polyunsaturated fatty acids, regulate immune function and may modify the adherence of microbes in the mucosa thereby contributing to host-microbe interactions. The properties of specific dietary compounds in optimal combinations and the joint effects of nutrients can be exploited in the development of specific prophylactic and therapeutic interventions. To meet these targets, rigorous scientific effort is required to elucidate how the food matrix and the dietary content impacts on the complex cascade of interrelated immunological mechanisms in food allergy.

Non-acne dermatologic indications for systemic isotretinoin

Systemic isotretinoin has been used to treat severe acne vulgaris for 20 years. However, isotretinoin also represents a potentially useful choice of drugs in many dermatologic diseases other than acne vulgaris. Diseases such as psoriasis, pityriasis rubra pilaris, condylomata acuminata, skin cancers, rosacea, hidradenitis suppurativa, granuloma annulare, lupus erythematosus and lichen planus have been shown to respond to the immunomodulatory, anti-inflammatory and antitumor activities of the drug. Isotretinoin also helps prevent skin cancers such as basal cell carcinoma or squamous cell carcinoma. A combination of systemic isotretinoin and interferon-alpha-2a may provide a more potent effect than isotretinoin alone in the prevention and treatment of skin cancers.Systemic isotretinoin may be considered as an alternative drug in some dermatologic diseases unresponsive to conventional treatment modalities. However, randomized clinical trials aimed at determining the role of systemic isotretinoin therapy in dermatologic diseases other than acne vulgaris are required.

Inhibition of immunoglobulin E production in allergic model mice by supplementation with vitamin E and beta-carotene

A diet containing different amounts of vitamin E (alpha-tocopherol; 0.5 mg, 5 mg, 10 mg or 50 mg per 100 g diet) was supplemented to BALB/c mice for 6 weeks. These mice were subcutaneously immunized twice with ovalbumin (OVA). A passive cutaneous anaphylaxis (PCA) analysis demonstrated that the mice fed on the diet containing 5 mg of vitamin E produced the highest level of the OVA-specific immunoglobulin E (IgE) antibody. A lower level of serum IgE was found in the mice supplemented with 0.5 mg, 10 mg and 50 mg of vitamin E. A sandwich ELISA analysis showed that the pattern of the total IgE antibody level among these four groups was the same as that of the allergen-specific IgE. In a separate experiment, 5 mg of vitamin E and/or 50 mg of beta-carotene was supplemented to the basal diet containing vitamin E as alpha-tocopherol acetate (5 mg) in order to evaluate the effect of their combination on OVA-specific and total IgE production in the mice. The supplementation with beta-carotene alone had no effect on OVA-specific or total IgE production. In contrast, supplementation with vitamin E plus beta-carotene effectively suppressed both the antigen-specific and total IgE antibodies. The serum vitamin E and beta-carotene levels were increased by supplementation with the respective compounds. These results strongly suggest that the combination of dietary vitamin E and beta-carotene suppressed IgE production and would therefore help to prevent the type-I allergic reaction.

Antioxidant activity, lipid peroxidation and skin diseases. What's new

Due to its interface function between the body and the environment, the skin is chronically exposed to both endogenous and environmental pro-oxidant agents, leading to the harmful generation of reactive oxygen species (ROS). There is compelling evidence that oxidative stress is involved in the damage of cellular constituents, such as DNA, cell membrane lipids or proteins. To protect the skin against the over-load of oxidant species, it contains a well-organised system of both chemical and enzymatic antioxidant which are able to work in a synergistic manner. Skin antioxidant network protects cells against oxidative injury and prevent the production of oxidation products, such as 4-hydroxy-2-nonenal or malonaldehyde, which are able to induce protein damage, apoptosis or release of pro-inflammatory mediators, such as cytokines. When oxidative stress overwhelms the skin antioxidant capacity the subsequent modification of cellular redox apparatus leads to an alteration of cell homeostasis and a generation of degenerative processes. Topical application or oral administration of antioxidants has been recently suggested as preventive therapy for skin photoaging and UV-induced cancer. The recognition that ROS can act as second messengers in the induction of several biological responses, such as the activation of NF-kB or AP-1, the generation of cytokines, the modulation of signalling pathways, etc., has led many researchers to focus on the possible effects of antioxidants in many pathological processes. The recent demonstration that the peroxisome proliferators-activated receptors, whose natural ligands are polyunsaturated fatty acids and theirs oxidation products, have a central role in the induction of some skin diseases, such as psoriasis or acne, has indicated new links between free radicals and skin inflammation. Based on these findings, the review summarises the possible correlations between antioxidant imbalance, lipid oxidative breakage and skin diseases, from both a pathological and therapeutic points of view.

Inhibition of IgE-Production by Peroxisome Proliferator-Activated Receptor Ligands

In this study we analyzed the effect of peroxisome proliferator-activated receptor-alpha and -gamma ligands on immunoglobulin synthesis and cytokine production in non-allergic and atopic dermatitis donors in vitro, but also in vivo ovalbumin-sensitized mice. A significant inhibition in CD40+ interleukin-4-mediated, but also basal IgE synthesis from peripheral blood mononuclear cells of atopic dermatitis donors was observed in the presence of the peroxisome proliferator-activated receptor-alpha ligand (up to 47+/-12%) and peroxisome proliferator-activated receptor-gamma ligand (69+/-5%). By contrast, the production of other isotypes such as IgA, IgG, and IgM was only modest inhibited. Analysis of cytokine production from the peripheral blood mononuclear cells shows inhibition of several cytokines by both peroxisome proliferator-activated receptor ligands. The most inhibitory effect on cytokine production was observed by the peroxisome proliferator-activated receptor-gamma ligand in peripheral blood mononuclear cells from atopic dermatitis donors with high IgE baseline production. Coculture experiments show that the decrease of IgE production by ciglitazone was monocyte dependent (up to 63+/-7%). Finally, in vivo experiments from ovalbumin-sensitized mice confirmed the in vitro findings showing that the interleukin-4-mediated immune response was inhibited in ciglitazone-treated mice.

Modulation of the Th1/Th2 bias by an immunoglobulin histamine complex in the ovalbumin allergy mouse model

Vaccination with the antiallergic drug Histaglobin is used to treat a broad range of human allergic diseases including bronchial asthma, allergic rhinitis, and atopic dermatitis. In order to further elucidate its functional activity, Histaglobin was investigated in an in vivo mouse allergy model. Mice were sensitized with ovalbumin either prior to or after Histaglobin treatment, and its antiallergic potential was evaluated. Ovalbumin-sensitized mice exhibited increased serum levels of IL-4, tumor necrosis factor alpha (TNF-alpha), and an increase of total and ovalbumin-specific IgE; total and ovalbumin-specific IgG levels were also elevated. Subsequent administration (therapeutic treatment) of Histaglobin resulted in a decrease of total and specific serum IgE levels; total and specific IgG1 serum levels were reduced by more than 50% and 45%, respectively; the mice displayed a down-regulation of IL-4 and TNF-alpha serum levels and showed increased levels of IFN-gamma and IgG2a. Mice pretreated with Histaglobin, prior to ovalbumin sensitization (prophylactic treatment), were found to be widely unresponsive to ovalbumin. They exhibited higher serum levels of IFN-gamma and IgG2a (total and specific) compared to saline-treated control mice. The inhibitory effects were still observed 1 month post-immunization. Our data, indicating a Histaglobin-induced modulation of the Th1/Th2 balance in favour of Th1, correspond with the well-known antiallergic activity of Histaglobin observed in patients.

Expression of nuclear retinoic acid receptor in peripheral blood mononuclear cells (PBMC) of healthy subjects

In vertebrates, both nuclear all-trans and 9-cis retinoic acid receptors (RAR and RXR) belonging to the steroid/thyroid/retinoid nuclear receptor superfamily play a crucial role in the vitamin A action. Qualitative analysis of all known RAR or RXR subtypes in both pooled and non-pooled peripheral blood mononuclear cells (PBMC) from healthy human subjects has been performed by reverse transcription and polymerase chain reaction (RT-PCR). Our data, based on qualitative RT-PCR analysis has shown that human PBMC are capable to express RAR alpha, RAR gamma, RXR alpha, and RXR beta.

Safety issues in isotretinoin therapy

Isotretinoin (Accutane, Roche Laboratories Inc, Nutley, NJ) is an important drug, not only for the treatment of severe acne, but also for other diagnoses and in chemoprevention settings. Because the use of isotretinoin is increasing, it is important for physicians to be aware of the adverse events, toxicities, and management issues related to its use. The most important issue is that of congenital defects, which has resulted in new pregnancy prevention policies and programs implemented by the manufacturer. A relatively new concern is that of depression associated with isotretinoin use, also resulting in new policies placed by the manufacturer and the FDA. The most common adverse effects observed during treatment are mucocutaneous and ocular in nature, but laboratory abnormalities and effects in the nervous, musculoskeletal, gastrointestinal, pulmonary, hematologic, and other systems are also described. Additionally, potential drug interactions, follow-up, and toxicity prevention measures are discussed.