Characterization of "peak E," a novel amino acid associated with eosinophilia-myalgia syndrome

On-line HPLC-tandem mass spectrometry analysis of contaminants of L-tryptophan associated with the onset of the eosinophilia-myalgia syndrome

The structural characterization of a number of contaminants of L-tryptophan (Trp) associated with eosinophilia myalgia syndrome has been performed for the first time by the powerful structural elucidation technique of tandem mass spectrometry coupled with on-line HPLC (LC-ESI-MS/MS). The identity of the contaminants: peaks UV-5, 3-(phenylamino)alanine, (PAA); E 1,1'-ethylidenebis(tryptophan); 200, 2-(3-indolylmethyl)-L-tryptophan; (all identified as case related) and peaks 1, 3-carboxy-1,2,3,4-tetrahydro-beta-carboline; 2, 3-carboxy-1-methyl-1,2,3,4-tetrahydro-beta-carboline; 100, 2-(2,3 dihydroxy-1-[3-indolyl]propyl)-L-tryptophan; and 300 and 400, diastereomers of 3-carboxy-1-[3-indolyl-methyl]-1,2,3,4-tetrahydro-beta-carboline, have been confirmed by this technique. By comparison of tandem MS (MS/MS) data from these compounds with the MS/MS data of several other impurities, we have structurally characterized peaks CC, KK and OO, as well as two previously unreported components labeled as peak P18 and peak P31. Peak P18 was unresolved from the large Trp peak and has been characterized as indole-3-ethylamine. Peak P31 was previously unresolved from peak 200, a case related compound and therefore its structure is of extreme importance. This compound has been tentatively identified as 2-(3-indolyl)-L-tryptophan.

Presence of tetrahydro-beta-carboline-3-carboxylic acids in foods by gas chromatography-mass spectrometry as their N-methoxycarbonyl methyl ester derivatives

Various tetrahydro-beta-carboline-3-carboxylic acids (TH beta C-3-COOH) are identified in commercial foods and drinks by GC-MS. Positive identification of 1-methyl-1,2,3,4-tetrahydro-beta-carboline-3-carboxylic acid (MTCA) is demonstrated in soy and tabasco sauces, wine, beer, wine vinegar, cider, orange juice, toasted bread, blue cheese and yoghurt. 1,2,3,4-Tetrahydro-beta-carboline-3-carboxylic acid (THCA) occurs in toasted bread, beer, cider, wine vinegar, soy and tabasco sauce, orange juice and blue cheese. MTCA and THCA are reported for the first time in several of these products. MTCA appears as a mixture of two diastereoisomers with the same mass spectra. MTCA is the major TH beta C-3-COOH in foodstuffs except for toasted bread that contains more THCA. GC-MS analysis of N-methoxycarbonyl methyl ester derivatives of TH beta C-3-COOHs was used for chemical identification. Those derivatives were synthesized in a qualitatively using methyl chloroformate or methyl chloroformate and diazomethane reagents. Electron impact mass spectra of N-methoxycarbonyl-TH beta C-3-COOH methyl esters are reported and fragmentation assigned and discussed. These results prove the presence of TH beta C-3-COOHs in commercial foodstuffs suggesting their uptake during the daily consumption of foods.

Mouse strain and source of L-tryptophan affects hepatic nuclear tryptophan binding

This study describes that the affinity for specific L-tryptophan binding to hepatic nuclei in vitro is markedly decreased in NZBWF1 mice in comparison to that in Swiss mice. Also, the hepatic nuclei of NZBWF1 mice have a significantly decreased binding response in vitro to Showa Denko L-tryptophan (implicated in the eosinophilia-myalgia syndrome) or to its contaminants, 1,1'-ethylidenebis(tryptophan) or 3-phenylamino-L-alanine, when each is added to control, non-implicated L-tryptophan compared with hepatic nuclei of Swiss mice. Enhanced hepatic protein synthesis induced by tube-feeding control L-tryptophan is much less in NZBWF1 mice than in Swiss mice. Tube-feeding of Showa Denko L-tryptophan induced less stimulation of hepatic protein synthesis than did control L-tryptophan in Swiss mice but essentially none in NZBWF1 mice. NZBWF1 mice have a genetically altered response to L-tryptophan which may prove to be useful is studying the role of L-tryptophan in health and in disease.

[Environmental factors and iatrogenic elements in systemic scleroderma and related syndromes. Review of the literature]

The etiology of scleroderma remains unknown. Although a genetic susceptibility seems to play a role, some environmental and iatrogenic factors have been suggested to trigger the disease. Contact for many months or years with natural or synthetic "toxic" products (by inhalation, cutaneous contact, injection, swallowing or surgical implant) could be implicated in the development of typical scleroderma or pseudo-scleroderma. These products are either occupational or non occupational like those used at home in daily life. We will sum up the knowledges about this subject.

Contaminants in biotechnologically manufactured L-tryptophan

The epidemic outbreak of a new disease, the eosinophilia-myalgia syndrome (EMS), was traced back to the intake of L-tryptophan (Trp) of certain lots from a single manufacturer. Since some trace contaminants were related to EMS, it appeared to be necessary to identify and find the origin of most trace contaminants in the EMS related Trp in order to apply this knowledge to a prospective manufacturing practice. Seventeen contaminants were determined in an implicated Trp lot by a single reversed-phase high-performance liquid chromatography run using UV and fluorescence detection. Most of these contaminants were classified as Trp metabolites, non-physiological oxidation or carbonyl condensation compounds of Trp. The amount and the pattern of contaminants were compared with recently manufactured Trp and Trp-containing preparations.

Cognitive deficits in a murine model of the eosinophilia-myalgia syndrome: a preliminary report

The described study was to determine the effects of chronic exposure to 1,1'-ethylidenebis[L-tryptophan] (EBT), a tryptophan contaminant, on cognitive behavior of female C57BL/6 (C57) mice. EBT (also designated as "peak E" or "peak 97") is one of several compounds that are suspect in the eosinophilia-myalgia syndrome (EMS). Groups of female C57 mice (12/group) were injected IP with saline (SAL), tryptophan (TRY), EBT, or an EBT + tryptophan combination (EBT + TRY) over a 6-week period. Previous experiments established that the dosing conditions produce several characteristics of EMS, including dermal inflammation and fibrosis, increased dermal mast cells, and increased levels of quinolinic acid. The mice exposed to EBT + TRY were abnormal during the solution of a Morris water maze problem. First, they had a shorter latency to locate the submerged platform goal during the initial day of training compared to SAL or TRY mice; secondly, they did not show the systematic reduction in latency to locate the platform goal across days of training noted for SAL or TRY mice. These abnormalities occurred in the absence of altered body weight or gross motor activity during the treatment procedure, or in the animal's swim speeds at the time of testing, 3 days after termination of treatment. The results suggest that prolonged exposure to EBT + TRY can alter the reaction to a stressful environment and can alter cognitive behavior.

Dot-like focal contacts in adherent eosinophils, their redistribution into peripheral belts, and correlated effects on cell migration and protected zone formation

We have examined the organization of F-actin and focal contacts in eosinophils and the functional consequences correlated with their predistribution. In activated eosinophils adherent to laminin, F-actin is localized in large, uniformly distributed, dot-like structures. Co-localized with the F-actin are a variety of typical components of focal contacts including: the alpha 6 and beta 1 integrins subunits (which mediate eosinophil adhesion to laminin), vinculin, talin, pp125FAK, paxillin, and tyrosine phosphorylated proteins, but not the beta 2 integrin subunit which is not involved in eosinophil adhesion to laminin. In unactivated eosinophils on laminin (which do not adhere well) and in activated eosinophils on non-adhesive surfaces (human serum albumin, tenascin, or a mixture of tenascin and laminin), dot-like accumulations of F-actin do not form. When activated eosinophils are incubated on laminin in the presence of low concentrations of 1,1′-ethylidenebis(L-tryptophan), a remarkable rearrangement occurs. Both conventional and confocal microscopy suggest that the dot-like structures rearrange from a uniform distribution into thick, peripheral belts surrounding each cell with few dot-like structures internal to the belt. Functional consequences occur as a result of this rearrangement of focal contacts and the cytoskeleton. The belt of focal contacts acts as a size-dependent permeability barrier; fluorescent 8 kDa polyethylene glycol does not label the substrate underneath the cells whereas 3.5 kDa polyethylene glycol labels the substrate uniformly. The formation of belts of focal contacts also blocks the ability of eosinophils to migrate on laminin in response to a chemotactic gradient. While the mechanism of 1,1′-ethylidenebis(L-tryptophan) action remains to be determined, experiments indicate that the function of 1,1′-ethylidenebis(L-tryptophan) is distinct from the function of drugs that alter tyrosine kinase and serine/threonine kinase activities. Our observations reveal a novel mechanism for regulating cell behavior in invasive cells in which the rearrangement of focal contacts and the associated cytoskeleton may control cell migration and the sequestration of secreted cytotoxic and degradatory molecules. We propose that 1,1′-ethylidenebis(L-tryptophan) may mimic the function of an endogenous regulator of eosinophil morphology and behavior.

EBT, a tryptophan contaminant associated with eosinophilia myalgia syndrome, is incorporated into proteins during translation as an amino acid analog

The tryptophan dimer 1,1'-ethylidenebis[L-tryptophan] was identified as a contaminant of tryptophan preparations associated with Eosinophilia-Myalgia Syndrome. In this paper, we describe experiments examining the hypothesis that 1,1'-ethylidenebis[L-tryptophan] acts as an amino acid analog replacing L-tryptophan during the synthesis of proteins. We propose further that proteins containing 1,1'-ethylidenebis[L-tryptophan] are rejected in an autoimmune process identified clinically as Eosinophilia-Myalgia Syndrome. Rabbit reticulocyte lysates containing an estimated 1 microM L-tryptophan were used to assay the ability of 1,1'-ethylidenebis[L-tryptophan] to compete with 3H-L-tryptophan for incorporation into proteins translated from BMV RNA. 1,1'-Ethylidenebis[L-tryptophan] in concentrations of 40, 80 and 110 microM reduced lysate 3H-L-tryptophan incorporation to 81%, 76% and 75% of control incorporation obtained in the absence of 1,1'-ethylidenebis[L-tryptophan]. In the presence of 20 microM L-tryptophan, 110 microM 1,1'-ethylidenebis[L-tryptophan] reduced 3H-L-tryptophan incorporation to 56% of control incorporation. In contrast, ethyl-L-tryptophan did not significantly reduce 3H-L-tryptophan incorporation. In the presence of 110 microM 1,1'-ethylidenebis[L-tryptophan] and 20 microM L-tryptophan, 3H-L-leucine incorporation was not significantly reduced compared to incorporation in the absence of 1,1'-ethylidenebis[L-tryptophan], demonstrating that proteins were translated to full length during elongation. These findings suggest that 1,1'-ethylidenebis[L-tryptophan], but not ethyl-L-tryptophan, reduced 3H-L-tryptophan incorporation into proteins by substituting for L-tryptophan rather than by causing premature termination or significant slowing of nascent protein chains.

Enhanced collagen synthesis and transcription by peak E, a contaminant of L-tryptophan preparations associated with the eosinophilia myalgia syndrome epidemic

The pathogenesis of the eosinophilia myalgia syndrome (EMS) remains unclear. Several abnormal constituents have been found in the L-tryptophan lots responsible for the illness, particularly, 1,1-ethylidenebis[L-tryptophan], also called peak E or EBT, and 3-phenylamino-alanine or peak 5. However, the role of these contaminants in the pathogenesis of EMS and in the development of fibrosis is unknown. We now report that peak E, a dimer of L-tryptophan, is a potent stimulus for human dermal fibroblast DNA and collagen synthesis. Peak E (0.1-1.0 microM) increased DNA synthesis up to four-fold (P = 0.0001) in a dose-dependent manner (r = 0.987). When added to monolayer cultures for 2 to 24 h, peak E (0.5 to 100 microM) caused a progressive, more than threefold increase in alpha 1(I) procollagen mRNA levels and collagenous protein. No increase in procollagen mRNA levels was found after the addition of another major L-tryptophan contaminant, peak 5, or with L-tryptophan itself. Transient transfection with a 2.5-kb alpha 1(I) procollagen promoter-luciferase construct showed that peak E causes a twofold upregulation of promoter activity (P = 0.022). Contraction of collagen gels, consisting of human dermal fibroblasts incorporated into a type I collagen lattice, was enhanced two-fold by exposure to peak E (P = 0.001). We conclude that a major constituent of contaminated batches of L-tryptophan, peak E, is a potent stimulus for fibroblast activation and collagen synthesis. This stimulatory action of peak E may provide a direct mechanism for the development of fibrosis in EMS.

Classification of morphea (localized scleroderma)

OBJECTIVE

To classify and describe morphea (localized scleroderma).

DESIGN

A review of morphea and its subtypes is presented.

RESULTS

The current classification of morphea is incomplete and confusing. As knowledge of the spectrum of disease continues to evolve, the controversy and confusing nature of its multiple subtypes present a challenge for the physician who encounters a patient with this condition. Thus, we propose that morphea be classified into the following five groups: plaque, generalized, bullous, linear, and deep. This classification, based on clinical morphologic findings, will simplify the diagnostic and therapeutic approach.

CONCLUSION

Morphea represents a wide variety of clinical entities that seen to be on the opposite end of the scleroderma spectrum from systemic sclerosis. The cutaneous lesions eventually evolve from a sclerotic stage to a nonindurated stage, and residual hypopigmentation or hyperpigmentation follows. The histologic pattern in patients with morphea is similar to that in patients with progressive systemic sclerosis. Although treatment is nonstandardized, hydroxychloroquine sulfate may be beneficial.

Subchronic toxicity of 3-phenylamino alanine, an impurity in L-tryptophan reported to be associated with eosinophilia-myalgia syndrome

Consumption of certain product lots of L-tryptophan (LT) has been reported to be epidemiologically associated with an outbreak of eosinophilia-myalgia syndrome (EMS) in the United States. Since the production lots were found to contain 3-phenylamino alanine (PAA) as an impurity, its effects were studied by administering the substance orally by gavage to 5-week-old Sprague-Dawley rats. Groups of animals were given PAA for 13 consecutive weeks at dose levels of 1, 10 and 100 mg/kg per day. The animals were killed at 4 or 8 weeks. Hematological and blood biochemical tests were performed and detailed histopathological observations were made. No significant abnormalities were observed in the test animals and in particular no EMS-like conditions. A brief summary of other animal studies using several species of rats and mice performed in our laboratory since 1989 on various LT related substances is also presented. No EMS-like effects were observed in these studies.

Eosinophil-active cytokine from mononuclear cells cultured with L-tryptophan products: an unexpected consequence of endotoxin contamination

BACKGROUND

The eosinophilia-myalgia syndrome, caused by a contaminant or contaminants in epidemiologically implicated L-tryptophan products, is characterized by eosinophilia and eosinophil degranulation. We hypothesized that immune cells are stimulated by implicated L-tryptophan and produce eosinophil-active cytokines.

OBJECTIVES

This study was designed to identify substances in L-tryptophan causing the eosinophilia-myalgia syndrome.

METHODS

Peripheral blood mononuclear cells were cultured with L-tryptophan products, and supernatants were tested for their ability to enhance eosinophil degranulation and survival in vitro and for their cytokine content. Subsequently, 46 different L-tryptophan lots were analyzed for their in vitro biologic activities.

RESULTS

After peripheral blood mononuclear cells were cultured with implicated L-tryptophan, their supernatants enhanced eosinophil degranulation and survival. These activities were blocked by anti-granulocyte-macrophage colony-stimulating factor (GM-CSF) antibody; immunoreactive GM-CSF was measurable in the supernatants. Monocytes, but not T lymphocytes, were the responding cells. However, no correlation was observed between the in vitro biologic activity and lots of epidemiologically implicated L-tryptophan products. This biologic activity in the L-tryptophan products was characterized as endotoxin.

CONCLUSION

Although L-tryptophan products stimulate peripheral blood mononuclear cells to produce GM-CSF, this response is caused by endotoxin contamination of the L-tryptophan products and not by a specific L-tryptophan contaminant. Endotoxin contamination must be considered as a possible cause of eosinophil-active cytokine production by peripheral blood mononuclear cells.

Accumulation of 3-(phenylamino)alanine, a constituent in L-tryptophan products implicated in eosinophilia-myalgia syndrome, in blood and organs of the Lewis rats

3-(Phenylamino)alanine (PAA), a newly discovered impurity in case-associated L-tryptophan tablets, has been investigated as a possible contributing factor in the etiology of eosinophilia-myalgia syndrome (EMS). We have studied distribution and elimination of PAA in rats which were administered a single 5 mg/kg dose of PAA by gastric gavage. PAA concentrations in blood, brain, kidney and liver were measured by high-performance liquid chromatography (HPLC) with electrochemical detection. The concentration of PAA in each tissue reached a maximum at 5 h, and then gradually declined. A high level of PAA still remained at 24 h, indicating gradual elimination. The concentration of PAA in brain at 5 h was 2139 ng/g tissue, demonstrating passage through the blood-brain barrier. Consecutive administration of PAA (5 mg/kg) for 4 days resulted in approximately double the concentration in all tissues. Chronic treatment using PAA incorporated into food pellets for 6 weeks resulted in similar accumulations in each tissue, and following 12 days on a PAA free diet, levels of this drug were still detectable in all tissues.

Eosinophilic hepatitis: a new feature of the clinical spectrum of the eosinophilia-myalgia syndrome

The eosinophilia-myalgia syndrome associated with L-tryptophan-containing products is highlighted by eosinophilia, incapacitating myalgias, and diverse multisystemic manifestations. In addition to involvement of the skin, skeletal muscle, and peripheral nerves, visceral damage has been quite prominent, particularly affecting the lungs, the heart, and the liver. Hepatic involvement has been manifested by altered liver tests but is clinically silent. We report the unique case of a woman with this syndrome who developed abdominal pain, a clinical picture of hepatitis and chronically abnormal liver tests. Histologic examination of the liver disclosed eosinophilic hepatitis with piecemeal necrosis. The occurrence of clinically overt hepatic involvement has not been reported previously. Potential mechanisms of liver damage in eosinophilia-myalgia syndromes are discussed.

Eosinophilia-myalgia syndrome and tryptophan production: a cautionary tale

An epidemic of a new disease, termed eosinophilia-myalgia syndrome, occurred in the USA in 1989. This syndrome was linked to the consumption of L-tryptophan manufactured by a single company utilizing a fermentation process. All the findings indicate that the illness was probably triggered by an impurity formed when the manufacturing conditions were modified. This outbreak highlights the need for close monitoring of the chemical purity of biotechnology-derived products, and for rigorous testing of such products following any significant changes to the manufacturing process.

Identification of four metabolites of 3-(phenylamino)alanine, a constituent in L-tryptophan products implicated in eosinophilia-myalgia syndrome, in rats

3-(Phenylamino)alanine (PAA), a contaminant found in L-tryptophan tablets, has been discussed as a possible cause of eosinophilia-myalgia syndrome (EMS). We administered PAA (100 mg/kg) by gastric gavage to Wistar rats to determine its distribution and metabolism. We developed a purification procedure, using Bond Elut SCX cartridges followed by high performance liquid chromatography (HPLC) in order to determine levels of PAA. The level of PAA in blood was 4.22 micrograms/ml at 5 h and urinary excretion was 21.7 micrograms for 5 h and 84.6 micrograms between 5 and 24 h. The amount of PAA in the contents of the large intestine at 5 h was 0.76 microgram, indicating poor transfer of PAA to the large intestine. However, the highest concentration of PAA was 12.3 micrograms/g in the brain, indicating the passage of PAA through the blood-brain barrier. In addition to detecting PAA in the blood and organs, we also detected four metabolites of PAA in urine. We used gas chromatography mass spectrometry to identify PAA in rat liver, as well as N-(hydroxyphenyl)glycine, N-phenylglycine, 3-(pheylamino)lactic acid, and 3-(hydroxyphenylamino)-lactic acid in rat urine. These results suggest that the degradation pathway of PAA is similar to that of phenylalanine.

Eosinophilia-myalgia syndrome in Germany: an epidemiologic review

OBJECTIVE

To review the epidemiologic features of eosinophilia-myalgia syndrome (EMS) in Germany.

DESIGN

We determined the incidence of EMS in Germany through May 1992 and analyzed the dose of L-tryptophan used, the duration of intake, and the concurrent medications.

MATERIAL AND METHODS

All patients receiving L-tryptophan preparations in Germany were already under medical supervision before the onset of the disease; thus, information on patient history and other potential risk factors was readily available. Because of the drug status of L-tryptophan preparations, brands could be accurately traced back to suppliers of raw materials. Statistical differences in age and gender of patients, dose of L-tryptophan, eosinophil count, and skin involvement were sought between patients with and those without concurrent medications.

RESULTS

On the basis of guidelines established by the Centers for Disease Control and Prevention, 105 patients fulfilled the criteria for EMS. No apparent correlation was found between the incidence of EMS and the dose of L-tryptophan or the duration of intake before onset of EMS. Assessment of the study group showed that 45% were taking various other medications, whereas 55% were taking L-tryptophan only. Analysis by type of pharmaceutical agent showed no preponderance of a specific concurrent drug (in particular, psychotropic drugs). Thus, concurrently used medications did not seem to be an important variable. All cases of EMS were associated with L-tryptophan from formulators that had used raw materials from the previously implicated source.

CONCLUSION

This study supports the pathophysiologic role of a contaminant in L-tryptophan in the occurrence of cases of EMS in Germany.

Chronic fatigue: a peculiar evolution of eosinophilia myalgia syndrome following treatment with L-tryptophan in four Italian adolescents

We describe four Italian adolescents in whom a persistent, debilitating fatigue appeared after therapeutic ingestion of products containing L-tryptophan and subsequent to the development of a transient rise in eosinophil count and severe myalgia (Eosinophilia Myalgia Syndrome-EMS). Their clinical picture was indistinguishable from that of the so-called Chronic Fatigue Syndrome. A chronic fatigue may occur after diverse triggering agents and its represents the peculiar clinical evolution of these four paediatric cases of EMS.

High-performance liquid chromatographic determination of 1,1'-ethylidenebis(L-tryptophan) in L-tryptophan preparations

In studies to determine the cause or causes of the eosinophilia myalgic syndrome (EMS) and to monitor the purity of L-tryptophan preparations, an HPLC method has been developed for determining 1,1'-ethylidenebis(L-tryptophan) (EBT) in L-tryptophan (W) preparations. The W preparations are extracted with 0.1% trifluoroacetic acid (TFA) and filtered, and the EBT is purified by passage through a Sep-Pak C18 cartridge. The cartridge is washed with water and 6% acetonitrile in water, and EBT is eluted with methanol. The water-diluted eluate is then chromatographed on a silica-based, reversed-phase HPLC column with a gradient of water and 80% acetonitrile, both solvents containing 0.1% TFA. EBT absorbance is measured at 280 nm. The average recovery of EBT from L-tryptophan powder, spiked over the range 1.2-4.8 micrograms/g, was 91%. The limit of determination was approximately 0.6 micrograms/g. Sixteen test samples of W products manufactured by the company to which most of the cases of EMS have been traced contained > 70 micrograms of EBT/g. Three nonpatient-related test samples either did not contain EBT or contained < 2 micrograms of EBT/g.

A murine model of the eosinophilia-myalgia syndrome induced by 1,1'-ethylidenebis (L-tryptophan)

The eosinophilia-myalgia syndrome (EMS) is a recently described disease that has been associated with the ingestion of L-tryptophan containing trace amounts of several impurities. The first such contaminant to be identified and linked epidemiologically to the EMS epidemic was 1,1'-ethylidenebis(L-tryptophan) (EBT), but its role in the etiology and pathogenesis of the syndrome has been controversial. We report the development of inflammation and fibrosis affecting the dermis and subcutis, including the fascia and perimyseal tissues, after the daily intraperitoneal administration of EBT to female C57BL/6 mice. Such changes are accompanied by increased numbers of mast cells, many of which appear to be degranulating. Plasma levels of quinolinic acid, a metabolic product of L-tryptophan via the kynurenine pathway, are reduced initially, and then become elevated when inflammation and fibrosis are more pronounced. The nature and location of the inflammatory cell infiltrate and fibrosis, as well as the presence of mast cells and alterations of L-tryptophan metabolism, are consistent with findings reported in patients with EMS. This murine model suggests that EBT may have been one of the mediators of EMS and should facilitate studies of the pathogenesis of EMS.

1,1'-Ethylidenebis(tryptophan) (Peak E) induces functional activation of human eosinophils and interleukin 5 production from T lymphocytes: association of eosinophilia-myalgia syndrome with a L-tryptophan contaminant

This study was designed to clarify the important association between eosinophilia-myalgia syndrome (EMS) and the L-tryptophan contaminant, "Peak E." To determine the functional activation of eosinophils induced by Peak E, eosinophil cationic protein (ECP) release was examined. Peak E augumented the release of ECP from peripheral blood normodense eosinophils by degranulation. Proliferative analysis using the human eosinophilic leukemia cell line EoL-3 showed prominent cellular replication in the presence of Peak E. Moreover, Peak E upregulated interleukin 5 (IL-5) receptor levels on normodense eosinophils. Of particular interest, Peak E-stimulated human splenic T cells produced bioactive and immunoreactive IL-5. Marked induction of IL-5 mRNA in Peak E-stimulated T cells was also shown by reverse-transcriptase polymerase chain reaction (RT-PCR). In contrast, L-tryptophan without the contaminant showed none of these effects. Thus, these data suggest that Peak E might be involved in the pathogenesis of EMS through bimodal mechanism including IL-5 generation by T cells and potentiation of eosinophil functional activation.

L-tryptophan-induced eosinophilia-myalgia syndrome associated with primary cutaneous malignant fibrous histiocytoma and extraabdominal desmoid tumor

A 57-year-old woman with L-tryptophan-induced eosinophilia-myalgia syndrome, 23 months after the onset of symptoms, experienced development of a parasternal malignant fibrous histiocytoma on previously scleroderma-like skin areas and, almost concurrently, an extraabdominal desmoid tumor of the left arm muscle fascia. The malignant fibrous histiocytoma was treated by surgical excision without sign of recurrence or metastasis 19 months later. Radiation therapy was performed on the extraabdominal desmoid tumor. We suspect that these two connective tissue tumors in this patient were related to the exposure to contaminated L-tryptophan, which interfered with connective tissue metabolism.

Chronic immune activation in the eosinophilia-myalgia syndrome

Eosinophilia-myalgia syndrome (EMS) is a multisystem illness of uncertain pathogenesis that occurred in an epidemic related to the ingestion of contaminated L-tryptophan. To investigate the role of immune dysfunction in EMS we prospectively measured a serologic index of T-cell activation, the soluble interleukin-2 receptor (sIL-2R), in 7 patients followed into the late stages of the illness. As a group, EMS patients had significantly elevated sIL-2R levels throughout the study. Five patients suffered chronic symptoms of myalgia, arthralgia, muscle cramps, fatigue, or subjective memory impairment and all had persistently elevated sIL-2R levels. Two patients had near-resolution of EMS and normal sIL-2R levels. We conclude that chronic symptoms are common in EMS and are associated with persistent T-cell activation as measured by serum sIL-2R levels. These findings suggest that immunosuppressive treatment may be beneficial in EMS.

Immune-mediated mechanisms and immune activation of fibroblasts in the pathogenesis of eosinophilia-myalgia syndrome induced by L-tryptophan

To determine the immunopathogenesis of the persistent symptoms of patients with eosinophilia-myalgia syndrome (EMS) induced by L-tryptophan, we performed immunocytochemical studies on 10 muscle and fascia biopsy specimens obtained during the acute disease and the chronic persistent connective tissue sclerosis. A series of monoclonal antibodies was used in a single- or double-immunostaining technique to detect and quantify T-cell subsets, macrophages, major histocompatibility complex antigens, eosinophilic basic protein-positive cells, and resting fibroblasts expressing Thy-I antigen or activated fibroblasts expressing the activation marker F-19. We found inflammatory cells consisting of CD8+ cells (45% +/- 8.9%), T4 cells (36% +/- 10.1%), and macrophages (19% +/- 12%), scattered or perivascularly in the fascia, the perimysium, and the endomysial septae. Only rare granulated or degranulating eosinophils were noted. Many muscle fibers around fascicles or near blood vessels expressed major histocompatibility complex-I antigens. The mean number of fibroblasts in the fascia, the perimysial connective tissue, and the spindle capsule was increased in the EMS patients' specimens compared with the endomysial cells seen in six disease-control muscle biopsy specimens from patients with chronic inflammatory myopathies or dystrophies (P < .01). Up to 70% of the fibroblasts in EMS were activated and up to 30% of them expressed HLA-DR antigen. In the disease controls up to 29% of the fibroblasts were activated but none expressed DR. Repeat muscle biopsy a year later in a patient whose symptoms persisted showed reduced inflammation but an increased number of activated fibroblasts and enhanced DR expression. We conclude that in EMS there is a T-cell-mediated process against components of the extracellular matrix, including fibroblasts, in the fascia and the perimysium that persists even years after the drug is discontinued. Because the fibroblasts are activated and aberrantly express DR antigen, they may be the target cells playing a role in the continuing clinical and histologic signs of tissue sclerosis.

Contaminants in L-tryptophan associated with eosinophilia myalgia syndrome

In late 1989, an epidemic of eosinophilia-myalgia syndrome (EMS) that resulted in several thousand cases of the syndrome and 36 deaths was recognized in the United States. Physicians in New Mexico linked the epidemic to the ingestion of L-tryptophan (LT). Results of studies indicated that one or more trace contaminants in LT were likely causes of the EMS epidemic. Investigators traced the LT that was taken by most patients with EMS to a single manufacturer, Showa Denko K.K. of Japan. We now report results of high performance liquid chromatographic analysis of LT samples from this manufacturer. Three sets of blind-coded samples were analyzed: the priority case lot set, which included 54 case-associated LT lots and 50 noncase-associated LT lots that were taken by case and control subjects who used only one brand of LT; the single lot case set, which included 73 case-associated LT lots and 25 noncase associated LT lots taken by case and control subjects who used only a single lot of LT; and the South Carolina tablet set, which included LT tablets taken by case subjects (n = 26) and by control subjects (n = 52). We statistically compared the concentration of each contaminant in case-associated, noncase-associated, and control samples of each sample set. The analyses showed that there were more than 60 minor contaminants in the LT from Showa Denko K.K., and that six of these contaminants were associated with EMS. The structures of three contaminants are known, but the identities of the other three contaminants are currently unknown.(ABSTRACT TRUNCATED AT 250 WORDS)

Metabolism and distribution in the rat of peak E substance, a constituent in L-tryptophan product implicated in eosinophilia-myalgia syndrome

Peak E substance, 1,1'-ethylidenebis[tryptophan], a contaminant found in L-tryptophan tablets, has been suggested as a causative agent for eosinophilia-myalgia syndrome (EMS). Peak E substance (50 mg/kg) was administered perorally to Wistar rats to determine its metabolism and distribution. A purification procedure using Bond Elut C8 cartridges followed by HPLC was developed for the determination of peak E substance. The plasma concentration of peak E substance was 136 ng/ml at 1 h, and urinary excretion was 717 ng at 5 h and 10342 ng for 5-24 h, showing slow excretion of peak E substance into urine. The amount of peak E substance in the contents of the large intestine at 5 h, however, was 3136 micrograms, much greater than urinary excretion for 24 h, indicating considerable transfer of peak E substance to large intestine without decomposition by gastric fluid in the stomach. We have detected for the first time not only the occurrence of peak E substance in plasma and urine, but also 1-methyl-tetrahydro-beta-carboline-3-carboxylic acid (MTCA) in blood and organs of rats treated with peak E substance, thereby suggesting MTCA as one of the the metabolites of peak E substance. The amount of MTCA in the contents of the large intestine as well as in urine of rats treated with peak E substance was significantly greater than in L-tryptophan-treated rats (50 mg/kg p.o.), demonstrating that MTCA was more readily produced from peak E substance than from L-tryptophan. Finally, we propose acetaldehyde-induced production of MTCA from peak E substance.

Accumulation of 1-methyl-tetrahydro-beta-carboline-3-carboxylic acid in blood and organs of rat. A possible causative substance of eosinophilia-myalgia syndrome associated with ingestion of L-tryptophan

1-Methyl-tetrahydro-beta-carboline-3-carboxylic acid (MTCA) may cause eosinophilia-myalgia syndrome (EMS) associated with ingestion of L-tryptophan. The distribution and excretion of MTCA were studied in rats which had received perorally a single 1.6 mg/kg dose of MTCA. MTCA concentrations in blood, kidney, liver, brain, heart, spleen, lung and gastrocnemius muscle were measured by HPLC combined with fluorometric detection. The concentration of MTCA in each organ reached a maximum at 1 h and then gradually declined. However, a significant level of MTCA still remained at 5 h, when 52% of ingested MTCA remained in the contents of the large intestine. Twenty-nine percent of the ingested MTCA was excreted in urine over the course of 24 h. A higher dose (10 mg/kg) of MTCA resulted in significant elevations in the concentrations and amounts of MTCA in the various organs. In addition, chronic treatment with a 10 mg/kg dose of MTCA for 6 weeks further increased the concentrations and amounts of MTCA in each organ. However, no histological changes were observed in any of the organs after chronic treatment. This is the first report which demonstrates accumulation of MTCA in the blood and various organs, including muscle, of rats.

Pathological and immunological effects of ingesting L-tryptophan and 1,1'-ethylidenebis (L-tryptophan) in Lewis rats

The eosinophilia-myalgia syndrome (EMS) has been associated with ingestion of L-tryptophan (L-TRP) produced by a single manufacturer. Epidemiological data implicated 1,1'-ethylidenebis (L-tryptophan) (EBT) (peak 97 or peak E) as a possible etiologic agent. We showed previously that Lewis rats treated with the L-TRP implicated in EMS develop fasciitis and perimyositis similar to those seen in human EMS. We now report the pathology associated with the treatment of Lewis rats with synthetic EBT and/or L-TRP. All animals treated for 6 wk with case-associated L-TRP or EBT developed significant myofascial thickening, compared with animals in the vehicle control and control L-TRP groups. However, even those animals receiving the control L-TRP showed a mild but significant increase in the thickness of the myofascia, compared with vehicle-treated control animals. All animals except vehicle controls also exhibited significant pancreatic pathology, including fibrosis and acinar changes. Only animals treated with case-associated L-TRP for 6 wk showed evidence of immune activation with increased frequency of CD8, Ia, and IL-2 receptor-positive cells in the peripheral blood. Animals receiving L-TRP or EBT for < 6 wk did not show significant differences in myofascial thickness, although these animals did show pancreatic acinar changes. Although these results demonstrate for the first time the pathological effects of EBT, they do not rule out the possibility that other impurities in the EMS-case-associated L-TRP may also contribute to some of the features of EMS.

Acetaldehyde-induced formation of 1-methyl-1,2,3,4-tetrahydro-beta-carboline-3-carboxylic acid in rats

1-Methyl-1,2,3,4-tetrahydro-beta-carboline-3-carboxylic acid (MTCA) is one of the metabolites of peak E substance, which, based on epidemiological studies, has been thought to be a possible causative agent of the tryptophan-induced eosinophilia-myalgia syndrome. Acute ethanol and L-tryptophan administration in rats pretreated with cyanamide resulted in the formation of MTCA. Concentrations of MTCA were estimated at 27 ng/g in blood and 33 ng/g in kidneys. Chronic treatment with a liquid diet containing ethanol as 36% of the total calories for 6 weeks increased these levels. MTCA was barely observed in rats that had received acute or chronic ethanol in the absence of cyanamide, or in the cyanamide-tryptophan controls. Cyanamide facilitation of ethanol-dependent MTCA biosynthesis may be due to a potentiation of the blood level of acetaldehyde derived from ethanol. The blood acetaldehyde level in rats that had been acutely treated with cyanamide, ethanol and L-tryptophan was 348 microM, and averaged 503 microM in rats that received the same treatment after chronic consumption of ethanol. In contrast to the above findings, L-tryptophan intake promoted the formation of 1,2,3,4-tetrahydro-beta-carboline-3-carboxylic acid (TCCA) in rats. This is the first report of MTCA in mammalian tissue during tryptophan and ethanol metabolism.

Separation and isolation of trace impurities in L-tryptophan by high-performance liquid chromatography

A high-performance liquid chromatographic (HPLC) profiling method was developed to separate trace impurities in L-tryptophan products associated with the eosinophilia-myalgia syndrome (EMS) epidemic. The test portion was dissolved in water, and the solution was filtered and chromatographed on a silica-based C18 reversed-phase HPLC column by using linear gradient elution with water and acetonitrile-water (80:20); both solvents contained 0.1% trifluoroacetic acid for ion-pairing. The method was used to profile 200 test samples from six manufacturers of L-tryptophan. The method was modified to include the use of a C18 disposable cartridge to retain the 1,1'-ethylidene-bis(L-tryptophan) (peak E, peak 97 or EBT), the impurity most strongly associated with EMS, and to remove the L-tryptophan before HPLC separation and quantitation. Recoveries of EBT added to test portions (2 micrograms/g and above) averaged 80%.

Lung disease in systemic sclerosis (scleroderma)

Scleroderma (SSc) is a disease characterized by skin fibrosis but it is the end-organ effect of microvascular injury and fibrosis that is important prognostically. Pulmonary involvement in SSc patients, either of parenchymal fibrosis and/or pulmonary hypertension, is a major cause of morbidity and mortality. Interstitial lung disease occurs more commonly in patients with diffuse SSc and is associated with a loss of lung volume, as well as a defect of gas exchange. Parenchymal fibrosis may also cause pulmonary hypertension. Isolated pulmonary hypertension occurs exclusively in patients with limited SSc and is detectable by a reduced DCO. The early identification of either manifestation is difficult. Patients may have minimal symptoms, unremarkable physical findings, normal chest radiographs and/or minimally abnormal pulmonary function tests at a time when significant lung pathology is present. It is essential to attempt to identify pulmonary disease early, at a potentially reversible stage. Multiple therapeutic endeavours have yielded only short-term or minimal benefits in symptoms and pulmonary function, and thus a major alteration in SSc pulmonary prognosis has not been achieved. Further study of the pathogenesis of this disease manifestation will be helpful in its earlier identification and intervention.

Eosinophilia-myalgia syndrome: lessons for public health researchers

OBJECTIVE

To review epidemiological investigations into the epidemic of eosinophilia-myalgia syndrome which occurred predominantly in the United States of America in mid to late 1989, and examine the implications for similar urgent public health research in Australia.

DATA SOURCES

Published data from epidemiological research, and relevant regulatory statements.

OUTCOME

Intensive epidemiological investigations established that eosinophilia-myalgia syndrome was strongly associated with ingestion of L-tryptophan produced by a single manufacturer. It is likely that an identified contaminant has a role in pathogenesis, although the mechanism of action remains unclear.

CONCLUSIONS

Rapid epidemiological investigation led to early containment measures and prevention of further public exposure to the causative agent. The episode highlighted the importance of preparedness amongst public health organisations to promptly initiate investigations of disease outbreaks, and demonstrated the benefits of a nation-wide ability to coordinate these studies. There may be encumbrances to urgent public health research in the form of inadequate mechanisms of data linkage. It is recommended that attention be given to such barriers now rather than in a time of crisis.

L-tryptophan and the eosinophilia-myalgia syndrome: current understanding of the etiology and pathogenesis

The eosinophilia-myalgia syndrome (EMS) is a newly recognized illness that occurred in an epidemic form during the summer of 1989. The illness was characterized in the acute phase by myalgia and eosinophilia, followed in many patients by chronic cutaneous lesions, progressive neuropathy, and myopathy. EMS was associated with ingestion of L-tryptophan, an essential amino acid marketed as a nutritional supplement but widely used as a therapeutic agent. Evidence of abnormal L-tryptophan metabolism has been described in patients with EMS, and most likely reflects increased activity of indoleamine 2,3-dioxygenase, the rate-limiting enzyme of tryptophan metabolism. A contaminant identified in EMS-associated L-tryptophan preparations has been isolated and characterized, but its biologic effects and role as the etiologic agent in EMS remain to be established. Pathologic observations and experimental studies indicate that eosinophils, mononuclear inflammatory cells, and fibroblasts are potential effector cells, and interleukin-5 and transforming growth factor-beta are important mediators in the pathogenesis of the syndrome. Although few new cases of EMS occurred following the withdrawal of L-tryptophan, affected patients continue to manifest late sequelae of the disease, including dermal fibrotic conditions. This tragic outbreak of a newly recognized illness has focused interest on the role of chemical and environmental agents in the pathogenesis of various idiopathic illness characterized by tissue inflammation and fibrosis.

3-(Phenylamino)alanine, a novel aniline-derived amino acid associated with the eosinophilia-myalgia syndrome: a link to the toxic oil syndrome?

The eosinophilia-myalgia syndrome (EMS) is an inflammatory disease that occurred in epidemic proportions in the United States during 1989. Cases of EMS were also reported in Europe and elsewhere. Clinically, EMS resembles the Spanish toxic oil syndrome. EMS has been associated with ingestion of manufactured L-tryptophan and, more specifically, with lots of tryptophan that contained the trace contaminant 1,1'-ethylidenebis(tryptophan) (EBT). Another trace contaminant ("peak UV-5") has been reported, but the strength of its association with EMS has not been demonstrated. Herein we report independently that peak UV-5 is 3-(phenylamino)alanine (PAA). Patients with EMS ingested significantly greater amounts of both PAA and EBT than did control tryptophan users. PAA is chemically similar to 3-phenylamino-1,2-propanediol, an aniline derivative isolated from samples of oil that were consumed by persons in whom the toxic oil syndrome developed. The discovery of an aniline-derived contaminant in tryptophan raises the possibility that EMS and toxic oil syndrome may have a common etiologic trigger.