Defects of monocyte interleukin 12 production and humoral immunity in Whipple's disease

Decreased levels of interleukin-12p40 in the serum of patients with Whipple's disease

BACKGROUND

An impaired production of interleukin (IL)-12 and T cell interferon-gamma (IFN-gamma) of in vitro stimulated monocytes has been discussed as a pathogenic factor in Whipple's disease (WD). It is unclear whether this defect of cellular immunity is translated to the humoral immune system and to serum correlates.

METHODS

We analyzed the serum of 40 patients with Whipple's disease in various degrees of disease activity by sandwich enzyme-linked immunosorbent assay for differences in cytokine and cell adhesion molecule concentrations compared with age- and sex-matched controls.

RESULTS

We observed a highly significant reduction of IL-12p40 levels (patients, 0.18+/-0.05 ng/ml (mean+/-SEM); controls, 3.19+/-0.39 ng/ml; p<0.01) in all stages of disease activity, whereas the concentration of IL-12p70 was comparable with controls. Furthermore, we observed a slight decrease in tumour necrosis factor alpha (TNF-alpha) concentrations in the serum of patients (patients, 6.36+/-0.90 pg/ml; controls, 10.5+/-1.23 pg/ml; p<0,05). The levels of other cytokines such as IFN-gamma, IL-2, IL-13 and transforming growth factor beta, as well as soluble cell adhesion molecules lymphocyte function-associated antigen 3 and intercellular adhesion molecule 1, were not significantly different compared with controls. Levels of immunoglobulin G2 (IgG2) measured in the serum of WD patients were below normal in 24 of 29 patients and were even below the 95% confidence interval in 10 patients.

CONCLUSION

Our data demonstrate a persistent defect of the cellular immune response with decreased serum concentrations of IL-12p40 and TNF-alpha and decreased IgG2 levels in a large group of WD patients. These data support as in vivo finding the results obtained in previous investigations with stimulated monocytes/lymphocytes. The isolated decrease in IL-12p40 may hint at possible defects in the IL-12/IFN-gamma promoter system.

IL-16 Is Critical forTropheryma whippleiReplication in Whipple’s Disease

Whipple's disease (WD) is a rare systemic disease caused by Tropheryma whipplei. We showed that T. whipplei was eliminated by human monocytes but replicated in monocyte-derived macrophages (Mphi) by inducing an original activation program. Two different host molecules were found to be key elements for this specific pattern. Thioredoxin, through its overexpression in infected monocytes, was involved in bacterial killing because adding thioredoxin to infected Mphi inhibited bacterial replication. IL-16, which was up-regulated in Mphi, enabled T. whipplei to replicate in monocytes and increased bacterial replication in Mphi. In addition, anti-IL-16 Abs abolished T. whipplei replication in Mphi. IL-16 down-modulated the expression of thioredoxin and up-regulated that of IL-16 and proapoptotic genes. In patients with WD, T. whipplei replication was higher than in healthy subjects and was related to high levels of circulating IL-16. Both events were corrected in patients who successfully responded to antibiotics treatment. This role of IL-16 was not reported previously and gives an insight into the understanding of WD pathophysiology.

Immunosuppressive therapy in Whipple's disease patients is associated with the appearance of gastrointestinal manifestations

OBJECTIVES

Whipple's disease is a rare chronic disorder, which is caused by systemic infection with Tropheryma whipplei. The first symptom of Whipple's disease usually is a nondestructive polyarthritis resembling in many aspects seronegative rheumatoid arthritis. This polyarticular inflammatory arthropathy preceding the diagnosis of Whipple's disease for several years frequently is treated with nonsteroidal antiinflammatory drugs (NSAIDs) and with immunosuppressive therapy. There is evidence that altered immune functions play a role in the manifestation of the disease and that Whipple's disease is associated with opportunistic infections. We therefore asked whether immunosuppressive treatment for arthropathy may alter the course of Whipple's disease.

PATIENTS AND METHODS

In a series of 27 patients with Whipple's disease clinical data were documented and the patients were followed for 3-4 yr. The patients were classified into three groups according to their medication: (i) patients with immunosuppressive therapy preceding the diagnosis, (ii) patients with NSAIDs before diagnosis, and (iii) patients without such therapies.

RESULTS

Arthropathies occurred in the mean 8 yr before diagnosis and were the first symptom in 63% of the patients. Gastrointestinal involvement usually became evident later on and frequently led to the diagnosis of Whipple's disease. In patients with immunosuppressive treatment, diarrhea occurred in the median 4 months after the initiation of such therapy and diagnosis of Whipple's disease was made after another 2 months. In contrast, other medical treatments were not closely followed by the onset of diarrhea.

CONCLUSIONS

These results indicate an association between immunosuppressive therapy and the onset of diarrhea in Whipple's disease and thus support the concept that immunologic factors play a role in disease pathogenesis. Further investigation on the interaction of the immune system and Tropheryma whipplei infection are required to understand the factors contributing to the clinical manifestation of this rare disorder and possibly to introduce preventive interventions.

Whipple's disease presenting with symmetrical panniculitis

Specific cutaneous involvement in Whipple's disease is extremely rare. The condition usually runs a chronic course, with symptoms preceding diagnosis by years or even decades. We report a 44-year-old man who presented with a rapid onset of progressive, extensive, symmetrical plaques of panniculitis affecting the inner thighs and forearms. He had accompanying large joint arthritis and was profoundly anaemic. Biopsy of the subcutis revealed a florid septal panniculitis with infiltration of the septa by foamy macrophages containing intracellular granules that stained strongly with periodic acid-Schiff reagent. A similar but more intense infiltrate was seen in the small bowel lamina propria, and a diagnosis of Whipple's disease was made. Symmetrical panniculitis has not previously been reported as a manifestation of Whipple's disease.

Whipple disease

Whipple disease is a rare disease caused by infection with the bacterium Tropheryma whippelii. Humans are the only known host for the infection. The signs of systemic infection include gastrointestinal problems, weight loss, and arthritis. Signs of central nervous system infection include cognitive changes, supranuclear gaze palsy, altered level of consciousness, and movement disorders. The diagnosis is based on clinical findings as well as microscopic examination of biopsy specimens and, more recently, polymerase chain reaction (PCR) analysis, which has high sensitivity and specificity. Although the organism historically has been difficult to culture, several recent attempts have been successful. Antibiotic treatment is recommended for 1 year while monitoring the clinical signs and cerebrospinal fluid PCR results.

Whipple's disease

Whipple's disease is an infectious disease caused by a gram-positive bacterium, Tropheryma whipplei. The first case was reported in 1907 by GH Whipple. Its classic symptoms are diarrhea and arthralgias, but symptoms can be various. Cardiac or central nervous system involvement, not always associated with digestive symptoms, may also be observed. For a long time, diagnosis has been based on duodenal biopsy, which is positive using periodic acid-Schiff staining. However, for patients without digestive symptoms, results can be negative, leading to a delay in diagnosis. For 10 years, a tool based on polymerase chain reaction targeting the 16S rDNA sequence has been used. In vitro culture of the bacterium, achieved 3 years ago, has allowed new perspectives for diagnosis and treatment. The natural evolution of the disease without treatment is always fatal. Current treatment is based on administration of trimethoprim-sulfamethoxazole for at least 1 year.

Mucosal immune response to Tropheryma whipplei

Whipple's disease is a rare infectious disease caused by the ubiquitously occurring Tropheryma whipplei in predisposed persons. Genetic or acquired defects in the mucosal and peripheral immune system become apparent as diminished Th1 immune functions with decreased production of IL-12 and IFN-gamma accompanied by an increased secretion of IL-4. These defects may enable T. whipplei to survive and replicate. The recently established cultivation of the bacterium in HEL cells and the isolation from infected intestinal biopsies enable a multitude of experimental possibilities which may lead to an improved diagnosis as well as understanding of the etiology and pathogenesis of Whipple's disease.

Whipple's disease

Whipple's disease, or intestinal lipodystrophy, is a systemic infectious disorder affecting mostly middle-aged white men. Patients present with weight loss, arthralgia, diarrhoea, and abdominal pain. The disease is commonly diagnosed by small-bowel biopsy; the appearance of the sample is characterised by inclusions in the lamina propria staining with periodic-acid-Schiff, which represent the causative bacteria. Tropheryma whipplei has been classified as an actinomycete and has been propagated in vitro, which allows the possibility of improving diagnostic strategies, for example through antibody-based detection of the bacillus on duodenal tissue or in circulating monocytes. Cell-mediated immunity in active and inactive Whipple's disease has subtle defects that might predispose some individuals to symptomatic infection with this bacillus, which probably occurs ubiquitously. Although most patients respond well to empirical antibiotic treatment, some with relapsing disease have a poor outlook. The recent findings and concerted research might allow development of new strategies for diagnosis, treatment, and monitoring of patients with Whipple's disease.

Dysregulated peripheral and mucosal Th1/Th2 response in Whipple's disease

BACKGROUND & AIMS

An impaired monocyte function and impaired interferon (IFN)-gamma production has been suggested as a possible pathogenetic factor in Whipple's disease (WD) and as a cause for the delayed elimination of Tropheryma whipplei in some patients.

METHODS

We studied, in a series of 20 WD patients with various degrees of disease activity, cellular immune functions.

RESULTS

We found an increased in vitro production of interleukin (IL)-4 by peripheral mononuclear blood cells as determined by enzyme-linked immunosorbent assay, but reduced secretion of IFN-gamma and IL-2 as compared with age- and sex-matched controls. In addition, we observed a significantly reduced monocyte IL-12 production in response to various stimuli in WD patients whereas other cytokines were comparable with controls; these immunologic alterations were not significantly different in patients with various disease activities. At the mucosal level, we found decreased CD4 T-cell percentage and a significantly impaired IFN-gamma secretion.

CONCLUSIONS

Our data define a defective cellular immune response in a large series of WD patients and point to an important pathogenetic role of impaired Th1 responses. The decreased monocyte IL-12 levels may result in reduced peripheral and mucosal IFN-gamma production and lead to an increased susceptibility to T. whipplei infection in certain hosts.

Neurologic presentation of Whipple disease: report of 12 cases and review of the literature

We report 12 cases of Whipple disease in patients with prominent neurologic symptoms, along with 122 cases of Whipple disease with nervous system involvement reported in the literature. We analyzed the clinical signs and results of additional examinations in 2 groups: the first group included patients with predominantly but not exclusively neurologic signs, and the second included patients with clinically isolated neurologic presentation of the disease. Whipple disease is a multisystemic infectious disease due to Tropheryma whippelii that may present with prominent or isolated symptoms of either the central or the peripheral nervous system. Recent reports stress the importance of polymerase chain reaction (PCR) analysis of cerebrospinal fluid, magnetic resonance imaging (MRI) during follow-up, and prolonged antibiotic therapy with drugs able to cross the blood-brain barrier. Cerebrospinal fluid should be analyzed repeatedly during follow-up, and treatment should be discontinued only when the results of PCR assay performed on cerebrospinal fluid are negative. Other examinations to be done include searching for gastrointestinal tract involvement with multiple duodenal biopsies and searching for systemic involvement with lymph node biopsies, which should be analyzed with light microscopy, electron microscopy, and PCR. When all examinations are negative, if Whipple disease is suspected and a lesion is found on brain MRI, a stereotactic cerebral biopsy should be performed. Treating Whipple disease with long-term trimethoprim-sulfamethoxazole is usually effective, but the use of third-generation cephalosporins in case of incomplete response deserves further attention.

Whipple's disease: a granulomatous masquerader

Whipple's disease is a multisystemic infection that affects middle-aged white men. It typically presents with fever, polyarthritis, diarrhea, steatorrhea, and weight loss. Many other systems can be involved, however, including the central nervous system, heart, lymphatics, lungs, bone marrow, and skin. Recent work has demonstrated the causative organism to be a complex bacteria, Tropheryma whipplei. The diagnosis is established most securely by periodic acid-Schiff staining of foamy monocyte-macrophages in biopsy tissue and body fluids, by electron microscopy, which reveals bacilli within membrane-bound vesicles, and by molecular amplification techniques using polymerase chain reaction of tissues and body fluids. The differential diagnosis includes chronic multisystemic infections and granulomatous disorders, because Whipple's disease is a fascinating blend of both. The condition can resemble sarcoidosis and mycobacterial disease and fungal, protozoal, and bacillary infections. Earlier diagnosis leads to earlier treatment and hopefully the prevention of chronic disabling complications and needless mortality from this once uniformly fatal condition.

The diagnosis and treatment of Whipple's disease

Whipple's disease is a rare, chronic, and systemic infectious disease caused by the ubiquitously occurring bacterium Tropheryma whippelii. For two reasons, the disease represents a good example for documenting the input of modern molecular-based techniques into pathogenetic, diagnostic, and therapeutic concepts in clinical medicine. First, the unidentified and uncultivable causative organism has been characterized by novel molecular-genetic techniques. Second, in contrast to other chronic inflammatory disorders, clinical manifestations of T. whippelii infection seem to be based on reduced T-cell helper type 1 (TH1) activity. These findings have led to an improved pathophysiologic understanding of the disease and to new aspects in treatment strategies that are discussed in this paper.

Iron loading: a risk factor for Whipple's disease?

Because of impairment of microbial iron acquisition ability, some potential pathogens can cause disease only in iron loaded hosts. Tropheryma whippelii, the etiologic agent of Whipple's disease, is a possible example. Whipple's disease is non-contagious, occurs mainly in middle-aged white males, and displays many, but not all, of the complications of hereditary haemochromatosis. Tropheryma whippelii is a gastrointestinal commensal that causes disease in persons who have a Th1-Th2 imbalance. Host susceptibility may be exacerbated by iron loading. Consideration should be given to have patients evaluated for levels of interferon-gamma and interleukin-4 as well as for serum ferritin and transferrin iron saturation.

Whipple's disease and "Tropheryma whippelii"

Whipple's disease is a rare bacterial infection that may involve any organ system in the body. It occurs primarily in Caucasian males older than 40 years. The gastrointestinal tract is the most frequently involved organ, with manifestations such as abdominal pain, malabsorption syndrome with diarrhea, and weight loss. Other signs include low-grade fever, lymphadenopathy, skin hyperpigmentation, endocarditis, pleuritis, seronegative arthritis, uveitis, spondylodiscitis, and neurological manifestations, and these signs may occur in the absence of gastrointestinal manifestations. Due to the wide variability of manifestations, clinical diagnosis is very difficult and is often made only years or even decades after the initial symptoms have appeared. Trimethoprim-sulfamethoxazole for at least 1 year is usually considered adequate to eradicate the infection. The microbiological diagnosis of this insidious disease is rendered difficult by the virtual lack of culture and serodiagnostic methods. It is usually based on the demonstration of periodic acid-Schiff-positive particles in infected tissues and/or the presence of bacteria with an unusual trilaminar cell wall ultrastructure by electron microscopy. Recently, the Whipple bacteria have been characterized at the molecular level by amplification of their 16S rRNA gene(s). Phylogenetic analysis of these sequences revealed a new bacterial species related to the actinomycete branch which was named "Tropheryma whippelli." Based on its unique 16S ribosomal DNA (rDNA) sequence, species-specific primers were selected for the detection of the organism in clinical specimens by PCR. This technique is currently used as one of the standard methods for establishing the diagnosis of Whipple's disease. Specific and broad-spectrum PCR amplifications mainly but not exclusively from extraintestinal specimens have significantly improved diagnosis, being more sensitive than histopathologic analysis. However, "T. whippelii" DNA has also been found in persons without clinical and histological evidence of Whipple's disease. It is unclear whether these patients are true asymptomatic carriers or whether differences in virulence exist among strains of "T. whippelii" that might account for the variable clinical manifestations. So far, six different "T. whippelii" subtypes have been found by analysis of their 16S-23S rDNA spacer region. Further studies of the pathogen "T. whippelii" as well as the host immune response are needed to fully understand this fascinating disease. The recent cultivation of the organisms is a promising major step in this direction.

Whipple's disease and Tropheryma whippelii: secrets slowly revealed

Whipple's disease was described in 1907 and was designated "intestinal lipodystrophy," despite the detection of bacteria in 1 specimen. This finding was later substantiated by the success of antibiotic therapy, which resulted in dramatic clinical responses, and by use of electron microscopy, which detected monomorphic bacilli in affected tissues. Many attempts at culture failed, and these bacteria were characterized as actinomycetes for the first time by means of broad-range 16S rDNA amplification and molecular phylogenetic methods. The name "Tropheryma whippelii" was proposed for this bacterium. Whipple's disease is a systemic disease that affects many organ systems, producing protean manifestations. This article summarizes recent developments with regard to this topic as well as unanswered questions regarding the pathogenesis and acquisition of infection, the biology and ecology of the organism, the clinical spectrum of disease, diagnosis of the disease, and therapy.

Whipple's disease

Whipple's disease is a systemic bacterial infection and the common though not invariable manifestations are diarrhoea, weight loss, abdominal pain, and arthralgia. Arthritis or arthralgia may be the only presenting symptom, predating other manifestations by years. Virtually all organs in the body may be affected, with protean clinical manifestations. Various immunological abnormalities, some of which may be epiphenomena, are described. The causative organism is Tropheryma whippelii. The disease is uncommon though lethal if not treated. Recent data suggest the disease occurs in an older age group than previously described. The characteristic histopathological features are found most often in the small intestine. These are variable villous atrophy and distension of the normal villous architecture by an infiltrate of foamy macrophages with a coarsely granular cytoplasm, which stain a brilliant magenta colour with PAS. These pathognomonic PAS positive macrophages may also be present in the peripheral and mesenteric lymph nodes and various other organs. The histological differential diagnoses include histoplasmosis and Mycobacterium avium-intercellulare complex. The clinical diagnosis of Whipple's disease may be elusive, especially if gastrointestinal symptoms are not present. A unique sign of CNS involvement, if present, is oculofacial-skeletal myorhythmia or oculomasticatory myorhythmia, both diagnostic of Whipple's disease. A small bowel biopsy is often diagnostic, though in about 30% of patients no abnormality is present. In patients with only CNS involvement, a stereotactic brain biopsy can be done under local anaesthetic. A recent important diagnostic test is polymerase chain reaction of the 16S ribosomal RNA of Tropheryma whippelii. Whipple's disease is potentially fatal but responds dramatically to antibiotic treatment. In this review the current recommended treatments are presented. The response to treatment should be monitored closely, as relapses are common. CNS involvement requires more vigorous treatment because there is a high rate of recurrence after apparently successful treatment.

Whipple's disease revisited

Whipple's disease has traditionally been considered to be a rare multisystem disorder dominated by malabsorption. The recent identification of the Whipple's disease bacillus has, using polymerase chain reaction based assays, fueled advances in the investigation, diagnosis, and management of this disease. This leader reviews the aetiology, clinical manifestations, investigation, and treatment of Whipple's disease in the light of this new information.

Toward a new understanding of Whipple's disease

Since the first successful antibiotic treatment of Whipple's disease in 1952, many breakthroughs have occurred in the diagnosis and treatment of this disease that was once thought fatal. This article provides a historic overview and highlights recent encouraging discoveries regarding this underdiagnosed disease, including the use of polymerase chain reaction techniques and the recent cultivation of the Tropheryma whippelii bacterium.

Macrophagic myofasciitis

A most unusual inflammatory myopathy, called macrophagic myofasciitis, first described by the Groupe d'Etudes et Recherche sur les Maladies Musculaires Acquises et Dysimmunitaires (GERMMAD), a specific branch of the Association Française contre les Myopathies was recorded with an increasing frequency from 1993 in the main French myopathologic centers. In October 1999, 65 macrophagic myofasciitis cases were recorded since our first description. We described the characteristics of the first 22 patients. The 22 patients (sex-ratio M/F, 1:3) were referred with the presumptive diagnosis of polymyositis (11), polymyalgia rheumatica (five), mitochondrial cytopathy (four), and congenital myopathy or muscle dystrophy (one each). Symptoms included myalgias (91%), arthralgias (68%), marked asthenia (55%), muscle weakness (45%), and fever (32%). Abnormal laboratory findings included elevated CK levels (50%), markedly increased ESR (37%), and myopathic EMG (35%). Muscle biopsy showed a unique myopathologic pattern characterized by 1) centripetal infiltration of epimysium, perimysium, and perifascicular endomysium by sheets of large cells of the monocyte/macrophage lineage (CD68+, CD1a-, S100-), with a PAS-positive content; 2) absence of necrosis, of both epithelioid and giant cells, and of mitotic figures; 3) presence of occasional CD8+ T-cells; 3) inconspicuous muscle fibre damage. The picture was easily distinguishable from sarcoid myopathy and fasciitis-panniculitis syndromes. The infectious diseases could not be documented in our patients. Patients improved under steroid therapy, associated or not with nonspecific antibiotic therapy. The authors discuss the main etiologic hypothesis of the macrophagic myofasciitis.

[Macrophagic myofasciitis: description and etiopathogenic hypotheses. Study and Research Group on Acquired and Dysimmunity-related Muscular Diseases (GERMMAD) of the French Association against Myopathies (AFM)]

PURPOSE

A new type of inflammatory myopathy of unknown etiology has recently been described in France. The myopathy, called macrophagic myofasciitis, had never been described in the literature.

METHODS

In December 1998, 35 cases of macrophagic myofasciitis were reported, showing an increase in its incidence since the description of the first case in 1993. The first 22 cases are described.

RESULTS

The 22 patients were each referred with a presumptive diagnosis of either polymyositis (11 patients), polymyalgia rheumatica (5 patients), mitochondrial cytopathy (4 patients), or congenital myopathy or muscle dystrophy (1 patient for each). Clinical symptoms included myalgias (91%), arthralgias (68%), marked asthenia (55%), muscle weakness (45%), and fever (32%). Laboratory findings included elevated CK levels (50%) and a marked increased in the erythrocyte sedimentation rate (37%). Electromyographic recordings showed the existence of myopathy (35%). Muscle biopsy showed a unique pattern characterized by: (i) centripetal infiltration of the epimysium, perimysium and perifascicular endomysium by non epitheloid, cells of the monocyte/macrophage lineage (CD68+, CD1a-, S100-) with both large cytoplasm and PAS-positive content; (ii) absence of necrosis, of both epithelioid and giant cells, and of mitotic figures; (iii) occasional CD8+ T-cells; and, (iiii) minimal myocyte suffering. The disease symptoms were easily distinguishable from those of sarcoid myopathy and fasciitis-panniculitis syndromes. Infectious diseases known to be associated with reactive histiocytosis, including Whipple's disease, Mycobacterium avium intracellulare infection and malakoplakia, could not be documented. Patients' condition improved under corticosteroid therapy, associated or not with non-specific antibiotic therapy.

CONCLUSION

A new inflammatory muscle disorder of unknown etiology, characterized by a distinctive pathological pattern of macrophagic myofasciitis, is emerging in France. Diagnosis is based on muscular biopsy. Numerous clinical, epidemiological and etiopathologic studies initiated by the GERMMAD (Groupe d'études et de recherche sur les maladies musculaires acquises) are in progress.

Whipple's disease

Whipple's disease is a chronic, multisystem disease that is caused by Tropheryma whippelii infection. More information is now known about this unusual infectious process, which was once considered uniformly fatal. Immunologic, diagnostic, and therapeutic advancements are reviewed in this article. Hopefully, future advances in the basic and clinical sciences will lead to a more rapid diagnosis, more complete understanding of the effects of infection, improved therapy, and better clinical outcome.

Macrophagic myofasciitis: an emerging entity. Groupe d'Etudes et Recherche sur les Maladies Musculaires Acquises et Dysimmunitaires (GERMMAD) de l'Association Française contre les Myopathies (AFM)

BACKGROUND

An unusual inflammatory myopathy characterised by an infiltration of non-epithelioid histiocytic cells has been recorded with increasing frequency in the past 5 years in France. We reassessed some of these cases.

METHODS

We did a retrospective analysis of 18 such cases seen in five myopathology centres between May, 1993, and December, 1997. The myopathological changes were reassessed at a clinopathology seminar.

FINDINGS

Detailed clinical information was available for 14 patients. The main presumptive diagnoses were polymyositis and polymyalgia rheumatica. Symptoms included myalgias in 12 patients, arthralgias in nine, muscle weakness in six, pronounced asthenia in five, and fever in four. Abnormal laboratory findings were occasionally observed, and included raised creatine kinase concentrations, increased erythrocyte sedimentation rate, and myopathic electromyography. Muscle biopsy showed infiltration of the subcutaneous tissue, epimysium, perimysium, and perifascicular endomysium by sheets of large macrophages, with a finely granular PAS-positive content. Also present were occasional CD8 T cells, and inconspicuous muscle-fibre damage. Epithelioid and giant cells, necrosis, and mitotic figures were not seen. The images were easily distinguishable from sarcoid myopathy and fasciitis-panniculitis syndromes. Whipple's disease, Mycobacterium avium intracellulare infection, and malakoplakia could not be confirmed. Ten patients were treated with various combinations of steroids and antibiotics; symptoms improved in eight patients, and stabilised in two.

INTERPRETATION

A new inflammatory muscle disorder of unknown cause, characterised by a distinctive pathological pattern of macrophagic myofasciitis, is emerging in France.

Environmental occurrence of the Whipple's disease bacterium (Tropheryma whippelii)

Whipple's disease is a systemic disorder in which a gram-positive rod-shaped bacterium is constantly present in infected tissues. After numerous unsuccessful attempts to culture this bacterium, it was eventually characterized by 16S rRNA gene analysis to be a member of the actinomycetes. The name Tropheryma whippelii was proposed. Until now, the bacterium has only been found in infected human tissues, but there is no evidence for human-to-human transmission. Here we report the detection of DNA specific for the Whipple's disease bacterium in 25 of 38 wastewater samples from five different sewage treatment plants in the area of Heidelberg, Germany. These findings provide the first evidence that T. whippelii occurs in the environment, within a polymicrobial community. This is in accordance with the phylogenetic relationship of this bacterium as well as with known epidemiological aspects of Whipple's disease. Our data argue for an environmental source for infection with the Whipple's disease bacterium.