Whipple's disease: new aspects of pathogenesis and treatment

Whipple's disease: rare disorder and late diagnosis

Whipple's disease is a rare systemic infectious disorder caused by the bacterium Tropheryma whipplei. We report the case of a 61-year-old male patient who presented to emergency room complaining of asthenia, arthralgia, anorexia, articular complaints intermittent diarrhea, and a 10-kg weight loss in one year. Laboratory tests showed the following results: Hb = 7.5 g/dL, albumin = 2.5 mg/dL, weight = 50.3 kg (BMI 17.4 kg/m²). Upper gastrointestinal endoscopy revealed areas of focal enanthema in the duodenum. An endoscopic biopsy was suggestive of Whipple's disease. Diagnosis was confirmed based on a positive serum polymerase chain reaction. Treatment was initiated with intravenous ceftriaxone followed by oral trimethoprim-sulfamethoxazole. After one year of treatment, the patient was asymptomatic, with Hb = 13.5 g/dL, serum albumin = 5.3 mg/dL, and weight = 70 kg (BMI 24.2 kg/m²). Whipple's disease should be considered a differential diagnosis in patients with prolonged constitutional and/or gastrointestinal symptoms. Appropriate antibiotic treatment improves the quality of life of patients.

[Whipple disease revealed by anti-TNFα therapy]

INTRODUCTION

Whipple disease is a rare infectious disease with protean clinical manifestations. This infection may mimic chronic inflammatory rheumatisms such as rheumatoid arthritis or spondylarthritis. In this context, introduction of a biotherapy after a diagnostic hesitation does not always lead to early complications. Sometimes, the clinical degradation follows an initial improvement, encouraging continuation of the immunosuppressive treatment and leading consequently to a greater diagnostic delay.

CASE REPORTS

We report two cases of Whipple disease diagnosed in the context of an inflammatory disease with anti-TNFα failure. The first patient was a 53-year-old man who presented with an axial and peripheral spondylarthritis who was treated with etanercept and adalimumab. The second was a 42-year-old man who received adalimumab and then etanercept for a peripheral spondylarthritis.

CONCLUSION

Whipple disease should be suspected in all patients who present with a chronic inflammatory rheumatism that is partially or not controlled with anti-TNFα therapy and who had persisting elevated acute phase reactants.

Isolated CNS Whipple disease with normal brain MRI and false-positive CSF 14-3-3 protein: a case report and review of the literature

Whipple disease (WD) is usually a systemic infectious disease that can have central nervous system (CNS) involvement. WD confined to the CNS is extremely rare and difficult to diagnose, but can be fatal if not treated in a timely fashion. We present the case of a 42-year-old man with a subacute dementia accompanied by a movement disorder consisting of progressive supranuclear gaze palsy, myoclonus, and ataxia. Our patient lacked the typical magnetic resonance imaging (MRI) findings reported with isolated CNS WD and had a false-positive cerebrospinal fluid (CSF) 14-3-3 protein. The patient expired, and definitive diagnosis of isolated CNS WD was made by autopsy with characteristic macrophage accumulations found in the brain but not in the gastrointestinal tract. We examine the literature on isolated CNS WD and discuss how these previously unreported findings make a rare diagnosis even more challenging. The reported patient is the first in the literature with tissue diagnosis of isolated CNS WD in the setting of normal brain MRI and positive CSF 14-3-3 protein. Isolated CNS WD should be added to the list of considerations for a false-positive CSF 14-3-3 protein. Even in the absence of typical MRI lesions, a patient with subacute progressive dementia, supranuclear gaze palsy, and other various neurologic abnormalities should have the diagnosis of isolated CNS WD considered.

Tropheryma whipplei aortic valve endocarditis, cured without surgical treatment

Background

Culture-negative endocarditis due to Tropheryma whipplei is a rare disease. Mostly the diagnosis is made by histologic examination of resected heart valve tissue.

Case presentation

In this case report, we described a patient with a classical Whipple’s disease. Transesophageal echocardiography (TEE) showed a vegetation on noncoronary cusp of the aortic valve. Whipple’s disease was confirmed by positive Tropheryma whipplei polymerase chain reaction (PCR) in EDTA blood and a duodenal biopsy with positive periodic acid-Schiff stain (PAS) macrophages.

Conclusion

Due to timely diagnosis, our patient was treated with antibiotics without valve replacement.

Whipple's disease

Whipple's disease is a chronic multisystemic infection, due to Tropheryma whipplei, a bacterium ubiquitously present in the environment. Although it is very rare, its clinical features are non-specific and can affect several different districts. Whipple's disease is therefore a condition that should always be kept in mind by doctors working in several branches of medicine, such as internal medicine, gastroenterology, rheumatology, neurology, and cardiology. The condition is fatal if not promptly recognized and treated, but the best treatment is still not completely defined, especially in relapsing disease, neurological manifestations, and in cases of immunoreconstitution after initiation of antibiotic treatment.

Previous immunosuppressive therapy is a risk factor for immune reconstitution inflammatory syndrome in Whipple's disease

INTRODUCTION

Whipple's disease is a rare chronic infection caused by Tropheryma whipplei. Although most patients respond to antibiotics, in some of them the start of the treatment is followed by recurrence of inflammation. Since polymerase chain reaction is negative for Tropheryma whipplei, this reinflammation cannot be a relapse of Whipple's disease itself. Very recently, it has been recognised as a complication of Whipple's disease and defined immune reconstitution inflammatory syndrome (IRIS). Our aim is to study the prevalence and the clinical features of IRIS in Italian patients with Whipple's disease.

METHODS

Evidence of IRIS was retrospectively revaluated in the clinical notes of 22 patients with Whipple's disease. Patients with no evidence of IRIS served as controls for the clinical findings.

RESULTS

Recurrence of arthralgia and/or fever allowed a diagnosis of IRIS in 5/22 patients. One patient died. Previous immunosuppressive therapy was found in all patients with IRIS but only in 7/17 controls (Fisher test, p=0.039). Age at diagnosis and diagnostic delay were higher in patients with IRIS compared to controls. However, statistical significance was not reached.

CONCLUSIONS

IRIS is a frequent complication of Whipple's disease and it can be fatal. The risk of IRIS is greatly increased in patients previously treated with immunosuppressive therapy.

Intrafamilial circulation of Tropheryma whipplei, France

Tropheryma whipplei, which causes Whipple disease, has been detected in 4% of fecal samples from the general adult population of France. To identify T. whipplei within families, we conducted serologic and molecular studies, including genotyping, on saliva, feces, and serum from 74 relatives of 13 patients with classic Whipple disease, 5 with localized chronic T. whipplei infection, and 3 carriers. Seroprevalence was determined by Western blot and compared with 300 persons from the general population. We detected T. whipplei in 24 (38%) of 64 fecal samples and 7 (10%) of 70 saliva samples from relatives but found no difference between persons related by genetics and marriage. The same circulating genotype occurred significantly more often in families than in other persons. Seroprevalence was higher among relatives (23 [77%] of 30) than in the general population (143 [48%] of 300). The high prevalence of T. whipplei within families suggests intrafamilial circulation.

Whipple's disease presenting with neurological symptoms in an immunosuppressed patient

We report an unusual case of Whipple's disease, which remained undiagnosed for several years in a patient being treated with immunosuppressive therapy for many years. The patient presented with a purpuric rash, neurological symptoms, lymphadenopathy and gastrointestinal symptoms. The diagnosis was made by endoscopic biopsy of the duodenum with periodic acid Schiff staining, as well as PCR testing on blood and cerebrospinal fluid. The patient was successfully treated with intravenous ceftriaxone, followed by oral co-trimoxazole for 1 year.

Macrophage-related diseases of the gut: a pathologist's perspective

The resident macrophages of the gastrointestinal tract represent the largest population of macrophages in the human body and are usually located in the subepithelial lamina propria. This strategic location guarantees a first-line defense to the huge numbers of potentially harmful bacteria and antigenic stimuli that are present in the intestinal lumen. In non-inflamed mucosa, macrophages phagocytose and kill microbes in the absence of an inflammatory response. However, in the event of an epithelial breach and/or microbial invasion, new circulating monocytes and lymphocytes will be recruited to the damaged area of the gut, which will result in the secretion of proinflammatory mediators and engage a protective inflammatory response. Although macrophages are usually not conspicuous in normal mucosal samples of the gut, they can easily be detected when they accumulate exogenous particulate material or endogenous substances or when they become very numerous. These events will mostly occur in pathologic conditions, and this review presents an overview of the diseases which are either mediated by or affecting the resident macrophages of the gut.

Disseminated sarcoidosis presenting as granulomatous gastritis: a clinical review of the gastrointestinal and hepatic manifestations of sarcoidosis

Commonly considered a pulmonary disease, sarcoidosis is actually a multisystemic granulomatous disorder of unclear etiology. There is a wide range of organ system involvement, with gastrointestinal being among the rarest. We describe the diagnostic challenge of a patient presenting with gastritis without pulmonary complaints who was later found to have extrathoracic disseminated sarcoidosis. This case highlighted both the variability in the presentation of the disease and difficulties in its diagnosis. We performed a literature review to identify studies published on gastrointestinal and hepatic sarcoidosis to better understand the characteristics of this disease and help in the differentiation between other commonly encountered disorders that may be mimicked in presentation. We have also created a diagnostic approach that can be applied when endoscopic or hepatic biopsies reveal granulomas. We anticipate that this review may be useful for clinicians who face these diagnostic dilemmas and management decisions for this complex and variable condition.

Tropheryma whipplei: a common bacterium in rural Senegal

BACKGROUND

Tropheryma whipplei is known as the cause of Whipple's disease, but it is also an emerging pathogen, detected in stool, that causes various chronic localized infections without histological digestive involvement and is associated with acute infections, including gastroenteritis and bacteremia.

METHODS/PRINCIPAL FINDINGS

We conducted a study in 2008 and 2009 using 497 non-diarrheic and diarrheic stool samples, 370 saliva samples, 454 sera samples and 105 samples obtained from water samples in two rural Sine-Saloum villages (Dielmo and Ndiop) in Senegal. The presence of T. whipplei was investigated by using specific quantitative PCR. Genotyping was performed on positive samples. A serological analysis by western blotting was performed to determine the seroprevalence and to detect seroconversion. Overall, T. whipplei was identified in 31.2% of the stool samples (139/446) and 3.5% of the saliva samples (13/370) obtained from healthy subjects. The carriage in the stool specimens was significantly (p<10(-3)) higher in children who were between 0 and 4 years old (60/80, 75%) compared to samples obtained from individuals who were between 5 to 10 years old (36/119, 30.2%) or between 11 and 99 years old (43/247, 17.4%). The carriage in the stool was also significantly more common (p = 0.015) in subjects with diarrhea (25/51, 49%). We identified 22 genotypes, 16 of which were new. Only one genotype (#53) was common to both villages. Among the specific genotypes, one (#52) was epidemic in Dielmo (15/28, 53.4%, p<10(-3)) and another (#49) in Ndiop (27.6%, p = 0.002). The overall seroprevalence was estimated at 72.8% (291/400). Seroconversion was detected in 66.7% (18/27) of children for whom PCR became positive in stools between 2008 and 2009.

CONCLUSIONS/SIGNIFICANCE

T. whipplei is a common bacterium in the Sine-Saloum area of rural Senegal that is contracted early in childhood. Epidemic genotypes suggest a human transmission of the bacterium.

Diagnosis of fulminant pneumonia caused by Legionella pneumophila serogroup 8 with the sequence analysis of the 16S rRNA gene

Pneumonia is the fourth leading cause of death in Japan. Accurate and rapid detection of the causative pathogen(s) is necessary and important for appropriate antimicrobial treatment, especially in patients with rapidly progressive pneumonia or immunocompromised patients. Conventional methods, such as cultivations, detection of urinary antigens or PCR amplification of specific genes, inevitably require the precise presumption of potential pathogens in each case, and pneumonia caused by unanticipated microorganisms might lead to inadequate antimicrobial treatments and unfortunate consequences. We herein report an immunocompromised female patient (69 years old) with fulminant pneumonia caused by Legionella (L.) pneumophila serogroup 8. Ordinary cultivation methods and urinary antigen detection failed to identify the causative organisms. Accordingly, DNA was extracted from the bronchoalveolar lavage fluid and used for the PCR-based cloning of the bacterial 16S rRNA gene. Sequencing analysis of the isolated clones revealed the predominance of L. pneumophila. Based on this information, the patient received an appropriate and successful antimicrobial treatment. In addition, L. pneumophila serogroup 8 was identified with culturing the bronchoalveolar lavage fluid and serotyping with L. pneumophila antisera. The 16S rRNA gene sequencing analysis can reveal the potential pathogens without any presumption about the organism, and can evaluate the kinds and ratio of bacterial species in each specimen. In conclusion, this cultivation-independent method is a potential diagnostic modality for pneumonia, especially in patients with rapidly progressive pneumonia or those who are immunocompromised.

High frequency of Tropheryma whipplei in culture-negative endocarditis

"Classical" Whipple's disease (cWD) is caused by Tropheryma whipplei and is characterized by arthropathy, weight loss, and diarrhea. T. whipplei infectious endocarditis (TWIE) is rarely reported, either in the context of cWD or as isolated TWIE without signs of systemic infection. The frequency of TWIE is unknown, and systematic studies are lacking. Here, we performed an observational cohort study on the incidence of T. whipplei infection in explanted heart valves in two German university centers. Cardiac valves from 1,135 patients were analyzed for bacterial infection using conventional culture techniques, PCR amplification of the bacterial 16S rRNA gene, and subsequent sequencing. T. whipplei-positive heart valves were confirmed by specific PCR, fluorescence in situ hybridization, immunohistochemistry, histological examination, and culture for T. whipplei. Bacterial endocarditis was diagnosed in 255 patients, with streptococci, staphylococci, and enterococci being the main pathogens. T. whipplei was the fourth most frequent pathogen, found in 16 (6.3%) cases, and clearly outnumbered Bartonella quintana, Coxiella burnetii, and members of the HACEK group (Haemophilus species, Actinobacillus actinomycetemcomitans, Cardiobacterium hominis, Eikenella corrodens, and Kingella kingae). In this cohort, T. whipplei was the most commonly found pathogen associated with culture-negative infective endocarditis.

Regulatory T cells in patients with Whipple's disease

Classical Whipple's disease (CWD) is caused by chronic infection with Tropheryma whipplei that seems to be associated with an underlying immune defect. The pathognomonic hallmark of CWD is a massive infiltration of the duodenal mucosa with T. whipplei-infected macrophages that disperse systemically to many other organ systems. An alleviated inflammatory reaction and the absence of T. whipplei-specific Th1 reactivity support persistence and systemic spread of the pathogen. In this article, we hypothesized that regulatory T cells (T(reg)) are involved in immunomodulation in CWD, and we asked for the distribution, activation, and regulatory capacity of T(reg) in CWD patients. Whereas in the lamina propria of CWD patients before treatment numbers of T(reg) were increased, percentages in the peripheral blood were similar in CWD patients and healthy controls. However, peripheral T(reg) of CWD patients were more activated than those of controls. Elevated secretion of IL-10 and TGF-β in the duodenal mucosa of CWD patients indicated locally enhanced T(reg) activity. Enhanced CD95 expression on peripheral memory CD4(+) T cells combined with reduced expression of IFN-γ and IL-17A upon polyclonal stimulation by CD4(+) cells from untreated CWD patients further hinted to T(reg) activity-related exhaustion of effector CD4(+) T cells. In conclusion, increased numbers of T(reg) can be detected within the duodenal mucosa in untreated CWD, where huge numbers of T. whipplei-infected macrophages are present. Thus, T(reg) might contribute to the chronic infection and systemic spread of T. whipplei in CWD but in contrast prevent mucosal barrier defect by reducing local inflammation.

Tropheryma whipplei aortic valve endocarditis without systemic Whipple's disease

Culture-negative endocarditis is most often the result of prior antimicrobial therapy. Tropheryma whipplei is the etiologic agent of Whipple's disease, which is typically characterized by diarrhea, weight loss, and intra-abdominal lymphadenopathy. We present the case of a 48-year-old male with Whipple's endocarditis of the aortic valve who did not develop signs of systemic Whipple's disease. Our patient was treated with a regimen that included ceftriaxone for 6 weeks prior to his cardiac surgery, yet valve pathology demonstrated abundant T. whipplei, suggesting that a prolonged antibiotic course is necessary for the treatment of Whipple's endocarditis.

Granulomatous colitis of boxer dogs

Granulomatous colitis (GC) is a rare, breed-specific inflammatory bowel disease of young Boxer dogs. GC has been refractory to treatment and associated with high mortality rates, but culture-independent molecular analysis has transformed therapy and prognosis by uncovering a correlation between GC and Escherichia coli invasion within colonic mucosal macrophages. GC-associated invasive E coli are similar to a newly identified E coli pathotype, "adherent and invasive E coli," that are increasingly associated with Crohn's disease in humans. Successful treatment of GC requires antimicrobials that are effective against E coli and penetrate intracellularly. Enrofloxacin is widely regarded as the antibiotic of choice.

Defining causality in emerging agents of acute bacterial diarrheas: a step beyond the Koch’s postulates

Diarrheal illnesses account for significant morbidity and mortality worldwide. Most cases of diarrhea are caused by bacteria, viruses or parasites. Advances in molecular biology and epidemiology have allowed the identification of emerging pathogens that may cause or, at least, may be associated with diarrhea. However, the same advances have also revealed the complexity of the gut microbiome, suggesting that a potential agent of diarrhea may also been found in healthy individuals. In addition, most of the newly identified emerging agents of diarrhea are ubiquitous and have not yet fulfilled Koch’s postulates. Research investigations should address appropriate matched controls and integrate findings from medical microbiology, epidemiology and molecular biology. This integrative approach should provide insights to our knowledge regarding exposition to common source or risk factors. Here, we aim to review some of these emerging bacterial agents of diarrheas and propose guidelines or prescriptions that may help in defining causality.

IL-16 promotes T. whipplei replication by inhibiting phagosome conversion and modulating macrophage activation

The replication of Tropheryma whipplei (the agent of Whipple's disease) within human macrophages is associated with the expression of IL-16, a cytokine known for its chemotactic and inflammatory properties. In this study, we asked whether IL-16 acts on T. whipplei replication by interfering with the endocytic pathway. We observed that in macrophages, T. whipplei was located within late phagosomes that were unable to fuse with lysosomes; in monocytes, T. whipplei was eliminated in phagolysosomes. Moreover, adding IL-16 to monocytes induced bacterial replication and inhibited phagolysosome formation. On the other hand, blocking IL-16 activity, either with anti-IL-16 antibodies in human macrophages or by using murine IL-16(-/-) bone marrow-derived macrophages, inhibited T. whipplei replication and rescued phagolysosome biogenesis. Furthermore, we propose that IL-16-mediated interference with the endocytic pathway is likely related to macrophage activation. First, IFNγ induced T. whipplei elimination and phagolysosome formation and inhibited IL-16 production by macrophages. Second, the full transcriptional response of murine macrophages to T. whipplei showed that T. whipplei specifically modulated the expression of 231 probes in IL-16(-/-) macrophages. Gene Ontology analysis revealed that 10 of 13 over-represented terms were linked to immune responses, including proinflammatory transcriptional factors of the NF-κB family. Our results demonstrated a previously unreported function for IL-16 in promoting bacterial replication through inhibited phagolysosome biogenesis and modulated macrophage activation program.

Should we systematically perform central nervous system imaging in patients with Whipple's endocarditis?

BACKGROUND

Whipple's endocarditis is an uncommon disease, with approximately 100 cases reported to date. Case series suggest that Whipple's endocarditis usually presents without extracardiac manifestations of Whipple's disease.

METHODS

We report 4 consecutive cases of Whipple's endocarditis associated with brain lesions. All patients fulfilled Duke Criteria for definite endocarditis. Whipple's disease was diagnosed through 16S rRNA polymerase chain reaction assays on valves excised from patients with culture-negative endocarditis (n=3) or through polymerase chain reaction and periodic acid staining-positive foamy macrophages on duodenal biopsy (n=1).

RESULTS

All patients were male, aged 56 to 72 years. They presented with mitral (n=1), aortic (n=1), mitral and aortic (n=1), and tricuspid (n=1) endocarditis. Brain magnetic resonance imaging was performed because of mild-to-moderate cognitive disorders (n=3) or ataxia (n=1) and revealed multiple (n=3) or solitary (n=1) contrast-enhancing lesions. Cerebrospinal fluid studies revealed meningitis in 1 case. Polymerase chain reaction assays on cerebrospinal fluid were negative for all patients. All patients received intravenous ceftriaxone (2-4 weeks) associated with gentamicin (2 weeks), followed by 1 year of oral trimethoprim-sulfamethoxazole, with favorable outcomes.

CONCLUSION

Whipple's associated central nervous system disease may be common but frequently undiagnosed, in patients with Whipple's endocarditis. Because treatment is different when neurologic disease is present (ie, trimethoprim-sulfamethoxazole vs doxycycline/hydroxychloroquine), clinicians should consider brain imaging in patients diagnosed with Whipple's endocarditis.

Systemic Tropheryma whipplei: clinical presentation of 142 patients with infections diagnosed or confirmed in a reference center

Culture of Tropheryma whipplei, the agent of Whipple disease (WD), was achieved in our laboratory in 2000, allowing new perspectives for the diagnosis of this disease and for the description of other potential clinical manifestations caused by this microorganism. Since 2000, we have developed new tools in our center in Marseille, France, to optimize the diagnosis of T whipplei infections. Classic WD was characterized by positive periodic acid-Schiff performed on duodenal biopsy. In the absence of duodenal histologic involvement, localized infections were defined by specific positive T whipplei polymerase chain reaction (PCR) results obtained using samples of other tissues and body fluids. The physicians in charge of patients were asked to complete a questionnaire. A total of 215 diagnoses were performed or confirmed and, among these, 142 patients with sufficient clinical data were included.Herein, we report epidemiologic data, clinical manifestations, and diagnostic tools of T whipplei infections. In the 113 patients with classic WD, the main symptom was arthralgia (88/113, 78%), which explains the many cases misdiagnosed as inflammatory rheumatoid disease (56/113, 50%). Frequently immunosuppressive treatments, more recently including tumor necrosis factor inhibitor, had been previously prescribed (50%) and were often responsible for more rapid clinical progression (43%). Sometimes a short course of antibiotics improved the clinical status.Endocarditis was the second most frequent manifestation of T whipplei, with 16 cases. The clinical picture of this entity corresponds to cardiovascular involvement with acute heart failure (50%) occurring without fever (75%) or previous valvular disease (69%). Neurologic symptoms were the third major manifestation. Other localized infections such as adenopathy, uveitis, pulmonary involvement, or joint involvement were sporadic. Infection with T whipplei resulted in multifaceted conditions. Some localized infections due to this agent have recently been reported and may correspond to emerging entities. Patients with inflammatory rheumatoid disease must be systematically interviewed to determine the efficacy of previous immunosuppressive and antibiotic therapies.

Specific and nonspecific B-cell function in the small intestines of patients with Whipple's disease

Whipple's disease is a chronic multisystemic infection caused by Tropheryma whipplei that is characterized by arthritis, weight loss, and diarrhea. The immunological defects in the duodenal mucosa, the site of major replication of the agent underlying the pathogenesis of Whipple's disease, are poorly understood. Mucosal immunoglobulins are essential for the defense against intestinal pathogens; therefore, we analyzed the B-cell response in duodenal specimens and sera of Whipple's disease patients. Whereas systemic immunoglobulin production was affected only marginally, duodenal biopsy specimens of Whipple's disease patients contained reduced numbers of immunoglobulin-positive plasma cells and secreted less immunoglobulin compared to healthy controls but showed a weak secretory IgA response toward T. whipplei. This T. whipplei-specific intestinal immune response was not observed in controls. Thus, we were able to demonstrate that general mucosal immunoglobulin production in Whipple's disease patients is impaired. However, this deficiency does not completely abolish T. whipplei-specific secretory IgA production that nonetheless does not protect from chronic infection.

IS-pro: high-throughput molecular fingerprinting of the intestinal microbiota

The human intestinal microbiota is known to play an important role in human health and disease, and with the advent of novel molecular techniques, disease-specific variations in its composition have been found. However, analysis of the intestinal microbiota has not yet been applicable in large-scale clinical research or routine diagnostics because of the complex and expensive nature of the techniques needed. Here, we describe a new PCR-based profiling technique for high-throughput analysis of the human intestinal microbiota, which we have termed IS-pro. This technique combines bacterial species differentiation by the length of the 16S-23S rDNA interspace region with instant taxonomic classification by phylum-specific fluorescent labeling of PCR primers. We validated IS-pro in silico, in vitro, and in vivo, on human colonic biopsies and feces, and introduced a standardized protocol for data analysis. IS-pro is easy to implement in general clinical microbiological laboratories with access to capillary gel electrophoresis, and the high-throughput nature of the test makes analysis of large numbers of samples feasible. This combination renders IS-pro ideally suited for use in clinical research and routine diagnostics.

Failure and relapse after treatment with trimethoprim/sulfamethoxazole in classic Whipple's disease

OBJECTIVES

Classic Whipple's disease is a chronic disease caused by Tropheryma whipplei. A recent study reported that intravenous treatment with ceftriaxone or meropenem followed by a 1 year treatment with trimethoprim/sulfamethoxazole cured all patients. However, we have previously reported that T. whipplei is poorly susceptible to beta-lactams and resistant to trimethoprim. Herein, we want to evaluate these antibiotic regimens.

PATIENTS AND METHODS

Since the organism was first cultured in Unité des Rickettsies, Marseille (France), we received samples for the diagnosis of T. whipplei infections. Among the 37 patients referred to us for management, 24 patients presented classic Whipple's disease. Among them, 14 patients treated with trimethoprim/sulfamethoxazole were followed up for >3 years.

RESULTS

None of the 14 patients was cured. One patient presented with an adverse side effect necessitating treatment cessation. Two patients developed an immune reconstitution inflammatory syndrome. One patient died 4 weeks after initiation of the treatment. Five patients developed clinical resistance; four of these having mutations on the target gene of sulfamethoxazole (folP). Five patients developed a relapse after cessation of trimethoprim/sulfamethoxazole after an average of 30 months. The high relapse rate may be linked to our recruitment. However, discrepancies with other centres could be due to the heterogeneity of diagnosis and cure criteria, different follow-up methods or infections due to T. whipplei strains with better susceptibility to antibiotics.

CONCLUSIONS

We confirmed, as predicted from prior testing of T. whipplei susceptibility, that trimethoprim/sulfamethoxazole is not optimal for classic Whipple's disease. In addition, 1 year treatment may be followed by relapses.

Tropheryma whipplei in patients with pneumonia

This bacterium may be an etiologic agent of pneumonia.

Tropheryma whipplei is the etiologic pathogenic agent of Whipple disease (WD), characterized by various clinical signs, such as diarrhea, weight loss, lymphadenopathy, and polyarthritis. PCR-based methods for diagnosis of WD have been developed. T. whipplei has been identified in saliva and stool samples from patients with WD and from healthy persons. T. whipplei DNA has also been found in bronchoalveolar lavage (BAL) samples of a child with pneumonia. We detected DNA of T. whipplei in 6 (3%) of 210 BAL samples collected in intensive care units by using 16S rDNA and specific quantitative PCR. We identified 4 novel genotypes of T. whipplei. In 1 case, T. whipplei was the only bacterium; in 4 others, it was associated with buccal flora. We suggest that T. whipplei should be investigated as an etiologic agent of pneumonia.

Tropheryma whipplei, the Whipple's disease bacillus, induces macrophage apoptosis through the extrinsic pathway

Tropheryma whipplei, the etiological agent of Whipple's disease, is an intracellular bacterium that infects macrophages. We previously showed that infection of macrophages results in M2 polarization associated with induction of apoptosis and interleukin (IL)-16 secretion. In patients with Whipple's disease, circulating levels of apoptotic markers and IL-16 are increased and correlate with the activity of the disease. To gain insight into the understanding of the pathophysiology of this rare disease, we examined the molecular pathways involved in T. whipplei-induced apoptosis of human macrophages. Our data showed that apoptosis induction depended on bacterial viability and inhibition of bacterial protein synthesis reduced the apoptotic program elicited by T. whipplei. Induction of apoptosis was also associated with a massive degradation of both pro- and anti-apoptotic mediators. Caspase-specific inhibition experiments revealed that initiator caspases 8 and 10 were required for apoptosis, in contrast to caspases 2 and 9, in spite of cytochrome-c release from mitochondria. Finally, the effector caspases 3 and 6 were mandatory for apoptosis induction. Collectively, these data suggest that T. whipplei induces apoptosis through the extrinsic pathway and that, beside M2 polarization of macrophages, apoptosis induction contributes to bacterial replication and represents a virulence trait of this intracellular pathogen.

Whipple disease

Whipple disease (WD) is a rare disease caused by Tropheryma whipplei. The classic profile of the patient is that of a middle-aged man presenting with fever, chronic diarrhea, and arthralgias. Extragastrointestinal manifestations are not rare. A high degree of clinical suspicion for the disease is needed in atypical cases. Trimethoprim-sulfamethoxazole is the treatment of choice. We present two patients with WD. The first presented with melena and generalized hyperpigmentation. The second had depression for two years before the typical symptoms. Both hyperpigmentation and long-lasting depression without the typical manifestations of the disease are rare. Histologic examination of tissue biopsies was diagnostic for WD. Both patients were treated successfully with trimethoprim-sulfamethoxazole.

Review of microarray studies for host-intracellular pathogen interactions

Obligate intracellular bacteria are privileged soldiers on the battlefield that represent host-pathogen interactions. Microarrays are a powerful technology that can increase our knowledge about how bacteria respond to and interact with their hosts. This review summarizes the limitations inherent to host-pathogen interaction studies and essential strategies to improve microarray investigations of intracellular bacteria. We have compiled the comparative genomic and gene expression analyses of obligate intracellular bacteria currently available from microarrays. In this review we explore ways in which microarrays can be used to identify polymorphisms in different obligate intracellular bacteria such as Coxiella burnetii, Chlamydia trachomatis, Ehrlichia chaffeensis, Rickettsia prowazekii and Tropheryma whipplei. These microarray studies reveal that, while genomic content is highly conserved in obligate intracellular bacteria, genetic polymorphisms can potentially occur to increase bacterial pathogenesis. Additionally, changes in the gene expression of C. trachomatis throughout its life cycle, as well as changes in the gene expression profile of the pathogens R. prowazekii, Rickettsia rickettsii, Rickettsia typhi, T. whipplei and C. trachomatis following environmental changes, are discussed. Finally, an in vivo model of Rickettsia conorii within the skin is discussed. The gene expression analyses highlight the capacity of obligate intracellular bacteria to adapt to environmental changes and potentially to thwart the host response.