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

Whipple's disease: A rare disease that can be spotted by many doctors

Whipple's disease, an extremely rare, chronic infection caused by Tropheryma whipplei, an actinobacterium ubiquitously present in the environment, is a multisystemic condition that can affect several organs. Therefore, Whipple's disease should always be considered by physicians working across various branches of medicine, including internal medicine, rheumatology, infectious diseases, gastroenterology, haematology, and neurology. Initially, Whipple's disease is challenging to diagnose due to both its rarity and non-specific clinical features, almost indistinguishable from rheumatological conditions. A few years later, the onset of gastrointestinal symptoms increases the specificity of its clinical picture and helps in reaching the correct diagnosis. Diagnosis is typically made by finding PAS-positive macrophages in the lamina propria at duodenal biopsy. PCR for Tropheryma whipplei is nowadays also increasingly available, and represents an undeniable help in diagnosing this condition. However, it may also be misleading as false positives can occur. If not promptly recognized and treated, central nervous system involvement may develop, which can be fatal. The therapeutic gold standard has not yet been fully established, particularly in cases of recurrent disease, neurological involvement, and an immune reconstitution inflammatory syndrome that may arise following the initiation of antibiotic therapy.

A Case of Whipple's Disease With Concomitant Esophageal Candidiasis

Whipple's Disease (WD) is a rare disease caused by the infection of Tropheryma whipplei. It can lead to immunosuppression and a multitude of effects on different organ systems, resulting in a constellation of seemingly unrelated findings. Although treatment may appear straightforward, T. whipplei can be difficult to eradicate. We present the case of a 36-year-old male with months of progressively worsening watery diarrhea, migratory arthralgias, and weight loss. He had undergone an extensive evaluation for rheumatologic, oncologic, and infectious disorders without positive findings. Esophagogastroduodenoscopy and colonoscopy revealed esophageal candidiasis, Helicobacter pylori infection, and foamy macrophages in the lamina propria of the duodenum and ileum with positive polymerase chain reaction for T. whipplei. There were no other risk factors for esophageal candidiasis. He received treatment for his esophageal candidiasis and H. pylori infection and was treated for WD with ceftriaxone for 2 weeks, followed by hydroxychloroquine and doxycycline for 1 year. Symptoms resolved after 3 months of therapy. One year later, repeat bidirectional endoscopy was performed. Biopsies were negative for T. whipplei, although there were persistent foamy macrophages. There have been previously reported cases of patients with WD with concomitant esophageal candidiasis, and this association implies a likely state of relative immunosuppression associated with WD, which is thought to be the result of impaired T helper cell 1 activity. This impairment likely contributes to the high rate of relapse. Having a low threshold for repeat evaluation is advisable for recurrent symptoms, but long-term surveillance strategies are not clearly defined.

Use of bevacizumab in a patient with Whipple's disease: managing diagnostic uncertainty

A man in his 30s with intellectual disability presented with 1 month of diarrhoea, weight loss and dyspnoea. Investigations were hampered due to significant anxiety. Laboratory tests detected microcytic anaemia and hypoalbuminaemia. CT demonstrated a fat-containing infiltrate in the mediastinum, mesentery and axillae, and pulmonary ground-glass infiltrates. Biopsy of the axilla showed cystic lymphatic malformations involving adipose tissue and lymph nodes, leading to a provisional diagnosis of generalised lymphatic anomaly. Over the subsequent 4 months, the patient's respiratory status deteriorated, leading to type 1 respiratory failure necessitating intubation. After multidisciplinary discussion, a decision was made to trial bevacizumab, an anti-VEGF agent, with subsequent improvement in respiratory status. While intubated, gastroscopy was performed; duodenal biopsies revealed pathognomonic changes of Whipple's disease, confirmed on PCR of duodenal and axillae biopsies. This was deemed the most likely unifying diagnosis; antibiotic treatment was commenced, bevacizumab was ceased, and the patient has remained well after 18 months.

Current knowledge of the immune reconstitution inflammatory syndrome in Whipple disease: a review

Immune reconstitution inflammatory syndrome (IRIS) is characterized by exaggerated and dysregulated inflammatory responses that occur as a result of reconstitution of adaptive or innate immunity. A wide range of microorganisms have been found to be associated with IRIS, such as human immunodeficiency virus (HIV), Mycobacterium and actinobacteria. Whipple disease (WD) is an infectious disorder caused by the Gram-positive bacterium Tropheryma whipplei (T. whipplei) and IRIS also serves as a complication during its treament. Although many of these pathological mechanisms are shared with related inflammatory disorders, IRIS in WD exhibits distinct features and is poorly described in the medical literature. Novel investigations of the intestinal mucosal immune system have provided new insights into the pathogenesis of IRIS, elucidating the interplay between systemic and local immune responses. These insights may be used to identify monitoring tools for disease prevention and to develop treatment strategies. Therefore, this review synthesizes these new concepts in WD IRIS to approach the feasibility of manipulating host immunity and immune reconstitution of inflammatory syndromes from a newer, more comprehensive perspective and study hypothetical options for the management of WD IRIS.

Patients with Whipple's disease have a high prevalence of Helicobacter pylori infection

INTRODUCTION

Whipple's disease is a rare systemic infection due to an impaired immunological response against T. whipplei in genetically predisposed individuals. Since we previously noted development of H. pylori related complications in some patients with Whipple's disease, our aim was to study the prevalence of H. pylori infection and H. pylori related disorders in Whipple's disease.

METHODS

Whipple's disease patients diagnosed from Jan-2002 to Dec-2021 and two controls per patient, matched for age, gender, ethnicity and year of H. pylori testing were enrolled.

RESULTS

34 patients with Whipple's disease and 68 controls were enrolled. H. pylori infection (13/34 vs 8/68, p<0.01), H. pylori-related gastritis (p<0.01) and gastric atrophy (p = 0.01) were significantly more common in patients with Whipple's disease than controls. H. pylori infection and Whipple's disease were diagnosed synchronously in 6/13 patients, and during follow-up in the remaining 7. Interestingly, these last 7 patients were all on trimethoprim-sulfamethoxazole long-term therapy. Two patients developed H. pylori-related gastric malignancies during follow-up. No patients on doxycycline developed H. pylori infection.

CONCLUSIONS

H. pylori infection and related disorders are common in patients with Whipple's disease and should always be excluded both at time of diagnosis and during follow-up. These findings should be taken into account when selecting antibiotics for Whipple's disease long-term prophylaxis.

Humoral immunogenicity of COVID-19 vaccines in patients with coeliac disease and other noncoeliac enteropathies compared to healthy controls

OBJECTIVES

Data are lacking on the immunogenicity of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines in patients affected by coeliac disease, Whipple's disease and other noncoeliac enteropathies (NCE), characterised by primary or drug-related immunosuppression. We aimed to assess humoral response to SARS-CoV-2 vaccination in these patients compared to controls.

METHODS

Between December 2021 and January 2022, IgG anti-SARS-CoV-2 spike protein antibodies were measured in serum samples of coeliac disease, Whipple's disease and NCE patients attending our gastroenterology outpatient clinic for follow-up, who had received their first SARS-CoV-2 vaccination dose 3-6-9 (±1) months prior. Humoral response was compared with healthy controls (vaccinated healthcare workers undergoing serological screening), matched for gender, age, and time from first vaccine dose at sample collection.

RESULTS

A total of 120 patients [107 coeliac disease; 10 Whipple's disease; 2 common-variable immunodeficiency (CVID); 1 idiopathic villous atrophy; 77 F, 42 ± 16 years] and 240 matched controls (154 F, 43 ± 14 years) were enrolled. At 3, 6 and 9 months, humoral response in coeliac patients was not impaired compared to controls. Inadequate humoral response to vaccination was significantly more common among Whipple's disease patients than controls ( P  < 0.001). Patients on immunosuppressive therapy had markedly lower IgG anti-SARS-CoV-2 antibody titres (median 14 vs. 520 BAU/mL, P  < 0.001). As expected, patients with CVID showed no humoral response to vaccination.

CONCLUSIONS

Humoral immunogenicity of SARS-CoV-2 vaccines was not reduced in coeliac disease patients compared to controls, although it was in Whipple's disease and CVID patients. Post-vaccination humoral response should be monitored in patients with Whipple's disease and chronic enteropathies on immunosuppressive therapy in order to schedule vaccine booster doses.

Rapidly progressive dementia and intractable diarrhea: a teaching case report and a systematic review of cognitive impairment in Whipple’s disease

Objective

Methods

Results

Conclusions

Supplementary Information

Human galectin-1 and galectin-3 promote Tropheryma whipplei infection

Tropheryma whipplei, is an actinobacterium that causes different infections in humans, including Whipple's disease. The bacterium infects and replicates in macrophages, leading to a Th2-biased immune response. Previous studies have shown that T. whipplei harbors complex surface glycoproteins with evidence of sialylation. However, the exact contribution of these glycoproteins for infection and survival remains obscure. To address this, we characterized the bacterial glycoprofile and evaluated the involvement of human β-galactoside-binding lectins, Galectin-1 (Gal-1) and Galectin-3 (Gal-3) which are highly expressed by macrophages as receptors for bacterial glycans. Tropheryma whipplei glycoproteins harbor different sugars including glucose, mannose, fucose, β-galactose and sialic acid. Mass spectrometry identification revealed that these glycoproteins were membrane- and virulence-associated glycoproteins. Most of these glycoproteins are highly sialylated and N-glycosylated while some of them are rich in poly-N-acetyllactosamine (Poly-LAcNAc) and bind Gal-1 and Gal-3. In vitro, T. whipplei modulates the expression and cellular distribution of Gal-1 and Gal-3. Although both galectins promote T. whipplei infection by enhancing bacterial cell entry, only Gal-3 is required for optimal bacterial uptake. Finally, we found that serum levels of Gal-1 and Gal-3 were altered in patients with T. whipplei infections as compared to healthy individuals, suggesting that galectins are also involved in vivo. Among T. whipplei membrane-associated proteins, poly-LacNAc rich-glycoproteins promote infection through interaction with galectins. T. whipplei modulates the expression of Gal-1 and Gal-3 both in vitro and in vivo. Drugs interfering with galectin-glycan interactions may provide new avenues for the treatment and diagnosis of T. whipplei infections.

Tumor Necrosis Factor Inhibitors Exacerbate Whipple's Disease by Reprogramming Macrophage and Inducing Apoptosis

Tropheryma whipplei is the agent of Whipple’s disease, a rare systemic disease characterized by macrophage infiltration of the intestinal mucosa. The disease first manifests as arthralgia and/or arthropathy that usually precede the diagnosis by years, and which may push clinicians to prescribe Tumor necrosis factor inhibitors (TNFI) to treat unexplained arthralgia. However, such therapies have been associated with exacerbation of subclinical undiagnosed Whipple’s disease. The objective of this study was to delineate the biological basis of disease exacerbation. We found that etanercept, adalimumab or certolizumab treatment of monocyte-derived macrophages from healthy subjects significantly increased bacterial replication in vitro without affecting uptake. Interestingly, this effect was associated with macrophage repolarization and increased rate of apoptosis. Further analysis revealed that in patients for whom Whipple’s disease diagnosis was made while under TNFI therapy, apoptosis was increased in duodenal tissue specimens as compared with control Whipple’s disease patients who never received TNFI prior diagnosis. In addition, IFN-γ expression was increased in duodenal biopsy specimen and circulating levels of IFN-γ were higher in patients for whom Whipple’s disease diagnosis was made while under TNFI therapy. Taken together, our findings establish that TNFI aggravate/exacerbate latent or subclinical undiagnosed Whipple’s disease by promoting a strong inflammatory response and apoptosis and confirm that patients may be screened for T. whipplei prior to introduction of TNFI therapy.

Refractory Effusions, Crumbly Bones, Mystifying Cachexia and an Absent Mind: An Unusual Presentation of Whipple's Disease with Review of Literature

Whipple's disease is a bacterial infection caused by Tropheryma whipplei and is known to cause perplexing clinical presentations, making its diagnosis challenging. The beginning by the involvement of the gastrointestinal tract, Whipple's disease can slowly progress to affect almost any organ system and lead to chronic multi-system inflammatory disease. Hereby, we present a middle age man who initially manifested with shortness of breath and chronic weight loss. He subsequently developed pleuro-pericardial effusion, ascites, mesenteric lymphadenopathy, possible myocarditis, and severe osteopenia with multiple vertebral fractures during his illness. Esophagogastroduodenoscopy with the biopsy and subsequent molecular confirmation of disease led to the confirmation of WD. Therapeutic management included two separate antibiotic regimens in an attempt to address the refractory course of WD in this patient.

Long-term morbidity and mortality in Whipple's disease: a single-center experience over 20 years

Background: Little is known about long-term morbidity and mortality in Whipple's disease (WD). Aim: To describe morbidity and mortality in patients with WD on a long-term follow-up. Materials & methods: Comorbidities, mortality and causes of death were retrospectively registered. Results: A total of 35 patients with WD (9F, 54 ± 11 years) were followed-up for a median of 104 months. Nine patients developed ten complications; three patients died. A total of 31 severe comorbidities apparently unrelated to WD were found in 20 patients: preneoplastic/neoplastic disorders in seven, thromboembolic and cardiovascular events in seven, pneumonia in four, candidiasis in ten patients. Conclusion: WD is frequently complicated by potentially life-threatening infectious, neoplastic and thromboembolic disorders, thus highlighting the need for a life-long multidisciplinary follow-up.

Epidemiology of Whipple's Disease in the USA Between 2012 and 2017: A Population-Based National Study

OBJECTIVE

Prior studies on the epidemiology of Whipple's disease are limited by small sample size and case series design. We sought to characterize the epidemiology of Whipple's disease in the USA utilizing a large population-based database.

METHODS

We queried a commercial database (Explorys Inc, Cleveland, OH), an aggregate of electronic health record data from 26 major integrated healthcare systems in the USA. We identified a cohort of patients with a diagnosis of Whipple's disease based on systemized nomenclature of medical terminology (SNOMED CT) codes. We calculated the overall and age-, race-, ethnicity, and gender-based prevalence of Whipple's disease and prevalence of associated diagnoses using univariate analysis.

RESULTS

A total of 35,838,070 individuals were active in the database between November 2012 and November 2017. Of these, 350 individuals had a SNOMED CT diagnosis of Whipple's disease, with an overall prevalence of 9.8 cases per 1 million. There was no difference in prevalence based on sex. However, prevalence of Whipple's disease was higher in Caucasians, non-Hispanics, and individuals > 65 years old. Individuals with a diagnosis of Whipple's disease were more likely to have associated diagnoses/findings of arthritis, CNS disease, endocarditis, diabetes, malignancy, dementia, vitamin D deficiency, iron deficiency, chemotherapy, weight loss, abdominal pain, and lymphadenopathy.

CONCLUSIONS

To our knowledge, this is the largest study to date examining the epidemiology of Whipple's disease. In this large population-based study, the overall prevalence of Whipple's disease in the USA is 9.8 cases per 1 million people. It affects men and women at similar rates and is more common in Caucasians, non-Hispanics, and people > 65 years old.

Peripheral-blood b-cell subset disturbances in inflammatory joint diseases induced by Tropheryma whipplei

Objective

To look for abnormalities in circulating B-cell subsets in patients with rheumatic symptoms of Whipple’s disease (WD).

Method

Consecutive patients seen between 2010 and 2016 for suspected inflammatory joint disease were identified retrospectively. Results of standardized immunological and serological tests and of peripheral-blood B-cell and T-cell subset analysis by flow cytometry were collected. Patients with criteria suggesting WD underwent PCR testing for Tropheryma whipplei, and those with diagnosis of WD (cases) were compared to those without diagnosis (controls). We used ROC curve analysis to evaluate the diagnostic value of flow cytometry findings for WD.

Results

Among 2917 patients seen for suspected inflammatory joint disease, 121 had suspected WD, including 9 (9/121, 7.4%) confirmed WD. Proportions of T cells and NK cells were similar between suspected and confirmed WD, whereas cases had a lower proportion of circulating memory B cells (IgD^-CD38^low, 18.0%±9.7% vs. 26.0%±14.2%, P = 0.041) and higher ratio of activated B cells over memory B cells (4.4±2.0 vs. 2.9±2.2, P = 0.023). Among peripheral-blood B-cells, the proportion of IgD+CD27- naive B cells was higher (66.2%±18.2% vs. 54.6%±18.4%, P = 0.047) and that of IgD-CD27+ switched memory B cells lower (13.3%±5.7% vs. 21.4%±11.9%, P = 0.023), in cases vs. controls. The criterion with the best diagnostic performance was a proportion of IgD+CD27- naive B cells above 70.5%, which had 73% sensitivity and 80% specificity.

Conclusion

Our study provides data on peripheral-blood B-cell disturbances that may have implications for the diagnosis and pathogenetic understanding of WD.

[The rich diversity of Whipple's disease]

Whipple's disease (WD) is a rare, chronic multiorgan disease which can caused by Tropheryma whipplei, a ubiquitous gram positive bacterium. Detection of T. whipplei is mostly performed histologically using periodic acid-Schiff (PAS) staining in affected tissues to visualize characteristic PAS-positive macrophages and by the polymerase chain reaction (PCR). Clinically, WD is often characterized by gastrointestinal symptoms (diarrhea, colic-like abdominal pain and weight loss). Arthritis is a common presentation of WS, often leading to a misdiagnosis of seronegative rheumatoid arthritis and as a consequence to immunosuppressive therapy. The clinical presentation of WD is highly polymorphic affecting different organ systems (e. g. cardiac or neurological manifestation) and making an appropriate clinical diagnosis and even the diagnostic process itself difficult. This article reports on three cases presenting with completely different leading symptoms (initially misdiagnosed as seronegative rheumatoid arthritis, spondyloarthritis and adult onset of Still's disease, respectively) that illustrate the rich diversity of WD. The cases were chosen to draw attention to the fact that although WD is mainly associated with the field of gastroenterology and gastrointestinal (GI) involvement is common, it may appear without GI symptoms. In cases of a clinical suspicion of WD, diagnostic efforts should be made to detect the bacterium in the affected organ. The German S2k guidelines on GI infections and WD published in January 2015 summarized the current state of the art for WD. The currently recommended primary treatment is antibiotics that can infiltrate the cerebrospinal fluid, e. g. ceftriaxone, followed by cotrimoxazole, which should be maintained over several months.

Tropheryma whipplei Increases Expression of Human Leukocyte Antigen-G on Monocytes to Reduce Tumor Necrosis Factor and Promote Bacterial Replication

BACKGROUND & AIMS

Infection with Tropheryma whipplei has a range of effects-some patients can be chronic carriers without developing any symptoms, whereas others can develop systemic Whipple disease, characterized by a lack a protective inflammatory immune response. Alterations in HLA-G function have been associated with several diseases. We investigated the role of HLA-G during T whipplei infection.

METHODS

Sera, total RNA, and genomic DNA were collected from peripheral blood from 22 patients with classic Whipple's disease, 19 patients with localized T whipplei infections, and 21 asymptomatic carriers. Levels of soluble HLA-G in sera were measured by enzyme-linked immuosorbent assay, and expressions of HLA-G and its isoforms were monitored by real-time polymerase chain reaction. HLA-G alleles were identified and compared with a population of voluntary bone marrow donors. Additionally, monocytes from healthy subjects were stimulated with T whipplei, and HLA-G expression was monitored by real-time polymerase chain reaction and flow cytometry. Bacterial replication was assessed by polymerase chain reaction in the presence of HLA-G or inhibitor of tumor necrosis factor (TNF) (etanercept).

RESULTS

HLA-G mRNAs and levels of soluble HLA-G were significantly increased in sera from patients with chronic T whipplei infection compared with sera from asymptomatic carriers and control individuals. No specific HLA-G haplotypes were associated with disease or T whipplei infection. However, T whipplei infection of monocytes induced expression of HLA-G, which was associated with reduced secretion of TNF compared with noninfected monocytes. A neutralizing antibody against HLA-G increased TNF secretion by monocytes in response to T whipplei, and a TNF inhibitor promoted bacteria replication.

CONCLUSIONS

Levels of HLA-G are increased in sera from patients with T whipplei tissue infections, associated with reduced production of TNF by monocytes. This might promote bacteria colonization in patients.

Non-neoplastic histiocytic and dendritic cell disorders in lymph nodes

Benign and malignant proliferations of histiocytes and dendritic cells may be encountered in lymph nodes. Reactive histiocytic and dendritic cell infiltrates occur in response to diverse stimuli and in addition to causing lymphadenopathy, may be present unexpectedly in lymph nodes excised for other indications. This review summarizes the pathogenesis and histopathological features of the various non-neoplastic histiocytic and dendritic cell infiltrates that can occur in lymph nodes.

Architectural and functional alterations of the small intestinal mucosa in classical Whipple's disease

Classical Whipple's disease (CWD) affects the gastrointestinal tract and rather elicits regulatory than inflammatory immune reactions. Mechanisms of malabsorption, diarrhea, and systemic immune activation are unknown. We here analyzed mucosal architecture, barrier function, and immune activation as potential diarrheal trigger in specimens from 52 CWD patients. Our data demonstrate villus atrophy and crypt hyperplasia associated with epithelial apoptosis and reduced alkaline phosphatase expression in the duodenum of CWD patients. Electrophysiological and flux experiments revealed increased duodenal permeability to small solutes and macromolecules. Duodenal architecture and permeability ameliorated upon antibiotic treatment. Structural correlates for these alterations were concordant changes of membranous claudin-1, claudin-2, claudin-3, and tricellulin expression. Tumor necrosis factor-α and interleukin-13 were identified as probable mediators of epithelial apoptosis, and altered tight junction expression. Increased serum markers of microbial translocation and their decline following treatment corroborated the biological significance of the mucosal barrier defect. Hence, mucosal immune responses in CWD elicit barrier dysfunction. Diarrhea is caused by loss of absorptive capacity and leak flux of ions and water. Downregulation of tricellulin causes increased permeability to macromolecules and subsequent microbial translocation contributes to systemic inflammation. Thus, therapeutic strategies to reconstitute the mucosal barrier and control inflammation could assist symptomatic control of CWD.

Clinical Manifestations, Treatment, and Diagnosis of Tropheryma whipplei Infections

Whipple's disease is a rare infectious disease that can be fatal if left untreated. The disease is caused by infection with Tropheryma whipplei, a bacterium that may be more common than was initially assumed. Most patients present with nonspecific symptoms, and as routine cultivation of the bacterium is not feasible, it is difficult to diagnose this infection. On the other hand, due to the generic symptoms, infection with this bacterium is actually quite often in the differential diagnosis. The gold standard for diagnosis used to be periodic acid-Schiff (PAS) staining of duodenal biopsy specimens, but PAS staining has a poor specificity and sensitivity. The development of molecular techniques has resulted in more convenient methods for detecting T. whipplei infections, and this has greatly improved the diagnosis of this often missed infection. In addition, the molecular detection of T. whipplei has resulted in an increase in knowledge about its pathogenicity, and this review gives an overview of the new insights in epidemiology, pathogenesis, clinical manifestations, diagnosis, and treatment of Tropheryma whipplei infections.

Whipple's disease

In recent years, it has become apparent that Tropheryma whipplei not only causes a chronic multisystemic infection which is often preceded by arthropathies for many years, well known as 'classical' Whipple's disease, but also clinically becomes manifest with localized organ affections and acute (transient) infections in children. T. whipplei is found ubiquitously in the environment and colonizes in some healthy carriers. In this review, we highlight new aspects of this enigmatic infectious disorder.

Tropheryma whipplei infection and Whipple's disease

Recent advances in medical microbiology, epidemiology, cellular biology, and the availability of an expanded set of diagnostic methods such as histopathology, immunohistochemistry, PCR, and bacterial culture have improved our understanding of the clinical range and natural course of Tropheryma whipplei infection and Whipple's disease. Interdisciplinary and transnational research activities have contributed to the clarification of the pathogenesis of the disorder and have enabled controlled trials of different treatment strategies. We summarise the current knowledge and new findings relating to T whipplei infection and Whipple's disease.

From past sailors' eras to the present day: scurvy as a surprising manifestation of an uncommon gastrointestinal disease

A 45-year-old man presented with follicular exanthema in his lower limbs, alternating bowel habits and significant weight loss. His medical history included seronegative arthritis, bipolar disease and an inconclusive diagnostic laparoscopy. Diagnostic work up revealed microcytic anaemia and multivitamin deficiency. Skin biopsy of the exanthema suggested scurvy. Owing to these signs of malabsorption, upper endoscopy with duodenal biopsies was performed, exhibiting villous atrophy and extensive periodic acid-Schiff-positive material in the lamina propria, therefore diagnosing Whipple's disease (WD). After starting treatment with ceftriaxone and co-trimoxazole, an impressive recovery was noted, as the wide spectrum of malabsorption signs quickly disappeared. After a year of antibiotics, articular and cutaneous manifestations improved, allowing the patient to stop taking corticosteroids and antidepressants. This truly unusual presentation reflects the multisystemic nature of WD, often leading to misdiagnosis of other entities. Scurvy is a rare finding in developed countries, but its presence should raise suspicion for small bowel disease.

Arthralgia and blood culture-negative endocarditis in middle Age Men suggest tropheryma whipplei infection: report of two cases and review of the literature

Background

Whipple’s disease is a rare, often multisystemic chronic infectious disease caused by the rod-shaped bacterium Tropheryma whipplei. Very rarely the heart is involved in the process of the disease, leading to culture-negative infective endocarditis. Up to 20 % of all infective endocarditis are blood culture-negative and therefore a diagnostic challenge. We present two unusual cases of culture-negative infective endocarditis encountered in two different patients with prior history of arthralgia. A history of rheumatic arthritis or even a transient arthralgia should put Tropheryma whipplei on the top of differentials in patients of this age group presenting with culture-negative infective endocarditis, especially in cases of therapy resistance to antirheumatic agents.

Case presentation

The first patient was a 55 year-old Caucasian male with culture-negative Whipple-related adhesive pericarditis and endocarditis of the aortic valve. Importantly, the patient reported a 15-year history of therapy resistant sero-negative migratory polyarthritis. Aortic valve endocarditis developed during treatment with tocilizumab. The second patient was a 65-year-old male patient with no prior history of the classic Whipple’s disease who presented with a culture-negative aortic valve endocarditis. His past medical history revealed episodes of transient arthralgia, which he was not treated for however, due to the self-limiting nature of the symptoms. Both patients underwent aortic valve replacement surgery. During surgery, pericardectomy was necessary in the first patient due to adhesive pericarditis. Post surgery both patients were started on long-term treatment with trimetoprim-sulfamethoxazol. At 1-year follow-up of both patients, echocardiographic and clinical assessment revealed no signs of persistent infection. Both men reported negative history of arthralgia during the one year period post surgery.

Conclusion

Tropheryma whipplei culture negative-infective endocarditis is an emerging clinical entity, predominantly found in middle-aged and older men with a history of arthralgia. These data highlight the need for ruling out Whipple’s disease in patients with a history of arthralgia prior to initiation of biological agents in treatment of rheumatoid arthritis. There is also a need to assess for Tropheryma whipplei in all patients with culture- negative infective endocarditis.

Systematic review: Whipple's disease (Tropheryma whipplei infection) and its unmasking by tumour necrosis factor inhibitors

BACKGROUND

The classical form of Whipple's disease (WD), clinically characterised by arthropathy, diarrhoea and weight loss, is rare. Recently, other more frequent forms of Tropheryma whipplei infection have been recognised. The clinical spectrum includes an acute, self-limiting disease in children, localised forms affecting cardiac valves or the central nervous system without intestinal symptoms, and asymptomatic carriage of T. whipplei which is found in around 4% of Europeans. Genomic analysis has shown that T. whipplei represents a host-dependent or opportunistic bacterium. It has been reported that the clinical course of T. whipplei infection may be influenced by medical immunosuppression.

AIM

To identify associations between immunomodulatory treatment and the clinical course of T. whipplei infection.

METHODS

A PubMed literature search was performed and 19 studies reporting on immunosuppression, particularly therapy with tumour necrosis factor inhibitors (TNFI) prior to the diagnosis in 41 patients with Whipple?s disease, were evaluated.

RESULTS

As arthritis may precede the diagnosis of WD by many years, a relevant percentage (up to 50% in some reports) of patients are treated with immunomodulatory drugs or with TNFI. Many publications report on a complicated Whipple?s disease course or T. whipplei endocarditis following medical immunosuppression, particularly after TNFI. Standard diagnostic tests such as periodic acid-Schiff stain used to diagnose Whipple?s disease often fail in patients who are pre-treated by TNFI.

CONCLUSIONS

In cases of doubt, Whipple?s disease should be excluded before therapy with TNFI. The fact that immunosuppressive therapy contributes to the progression of T. whipplei infection expands our pathogenetic view of this clinical entity.

Role of dendritic cells in the pathogenesis of Whipple's disease

Accumulation of Tropheryma whipplei-stuffed macrophages in the duodenum, impaired T. whipplei-specific Th1 responses, and weak secretion of interleukin-12 (IL-12) are hallmarks of classical Whipple's disease (CWD). This study addresses dendritic cell (DC) functionality during CWD. We documented composition, distribution, and functionality of DC ex vivo or after in vitro maturation by fluorescence-activated cell sorting (FACS) and by immunohistochemistry in situ. A decrease in peripheral DC of untreated CWD patients compared to healthy donors was due to reduced CD11c(high) myeloid DC (M-DC). Decreased maturation markers CD83, CD86, and CCR7, as well as low IL-12 production in response to stimulation, disclosed an immature M-DC phenotype. In vitro-generated monocyte-derived DC from CWD patients showed normal maturation and T cell-stimulatory capacity under proinflammatory conditions but produced less IL-12 and failed to activate T. whipplei-specific Th1 cells. In duodenal and lymphoid tissues, T. whipplei was found within immature DC-SIGN(+) DC. DC and proliferating lymphocytes were reduced in lymph nodes of CWD patients compared to levels in controls. Our results indicate that dysfunctional IL-12 production by DC provides suboptimal conditions for priming of T. whipplei-specific T cells during CWD and that immature DC carrying T. whipplei contribute to the dissemination of the bacterium.

A tetravalent alphavirus-vector based dengue vaccine provides effective immunity in an early life mouse model

Dengue viruses (DENV1-4) cause 390 million clinical infections every year, several hundred thousand of which progress to severe hemorrhagic and shock syndromes. Preexisting immunity resulting from a previous DENV infection is the major risk factor for severe dengue during secondary heterologous infections. During primary infections in infants, maternal antibodies pose an analogous risk. At the same time, maternal antibodies are likely to prevent induction of endogenous anti-DENV antibodies in response to current live, attenuated virus (LAV) vaccine candidates. Any effective early life dengue vaccine has to overcome maternal antibody interference (leading to ineffective vaccination) and poor induction of antibody responses (increasing the risk of severe dengue disease upon primary infection). In a previous study, we demonstrated that a non-propagating Venezuelan equine encephalitis virus replicon expression vector (VRP), expressing the ectodomain of DENV E protein (E85), overcomes maternal interference in a BALB/c mouse model. We report here that a single immunization with a tetravalent VRP vaccine induced NAb and T-cell responses to each serotype at a level equivalent to the monovalent vaccine components, suggesting that this vaccine modality can overcome serotype interference. Furthermore, neonatal immunization was durable and could be boosted later in life to further increase NAb and T-cell responses. Although the neonatal immune response was lower in magnitude than responses in adult BALB/c mice, we demonstrate that VRP vaccines generated protective immunity from a lethal challenge after a single neonatal immunization. In summary, VRP vaccines expressing DENV antigens were immunogenic and protective in neonates, and hence are promising candidates for safe and effective vaccination in early life.

Relationship between previous treatments and onset of symptoms in patients with Whipple's disease

The clinical features of Whipple's disease (WD) consist of arthropathy that precedes the involvement of other organs, such as the gastrointestinal tract, nervous system and heart. It has been shown that gastrointestinal manifestations can be precipitated by immunosuppressive therapy used to control the arthropathy. In the present study, we investigated the clinical features of the Italian population of patients affected by WD. The clinical histories of 22 patients with WD were reviewed. Relationship between previous treatments and onset of symptoms was analysed. 20/22 patients suffered from arthropathy that had started before gastrointestinal complaints; gastrointestinal symptoms were present in 18 patients and neurological involvement was found in 5. WD must always be taken into account in male patients with long-standing ill-defined arthropathy, and it should be ruled out before starting immunosuppressive or antibiotic treatment that can make correct diagnosis and management very difficult.

Widespread colonization of the lung by Tropheryma whipplei in HIV infection

RATIONALE

Lung infections caused by opportunistic or virulent pathogens are a principal cause of morbidity and mortality in HIV infection. It is unknown whether HIV infection leads to changes in basal lung microflora, which may contribute to chronic pulmonary complications that increasingly are being recognized in individuals infected with HIV.

OBJECTIVES

To determine whether the immunodeficiency associated with HIV infection resulted in alteration of the lung microbiota.

METHODS

We used 16S ribosomal RNA targeted pyrosequencing and shotgun metagenomic sequencing to analyze bacterial gene sequences in bronchoalveolar lavage (BAL) and mouths of 82 HIV-positive and 77 HIV-negative subjects.

MEASUREMENTS AND MAIN RESULTS

Sequences representing Tropheryma whipplei, the etiologic agent of Whipple's disease, were significantly more frequent in BAL of HIV-positive compared with HIV-negative individuals. T. whipplei dominated the community (>50% of sequence reads) in 11 HIV-positive subjects, but only 1 HIV-negative individual (13.4 versus 1.3%; P = 0.0018). In 30 HIV-positive individuals sampled longitudinally, antiretroviral therapy resulted in a significantly reduced relative abundance of T. whipplei in the lung. Shotgun metagenomic sequencing was performed on eight BAL samples dominated by T. whipplei 16S ribosomal RNA. Whole genome assembly of pooled reads showed that uncultured lung-derived T. whipplei had similar gene content to two isolates obtained from subjects with Whipple's disease.

CONCLUSIONS

Asymptomatic subjects with HIV infection have unexpected colonization of the lung by T. whipplei, which is reduced by effective antiretroviral therapy and merits further study for a potential pathogenic role in chronic pulmonary complications of HIV infection.

Whipple's Disease: Our Own Experience and Review of the Literature

Whipple's disease is a chronic infectious systemic disease caused by the bacterium Tropheryma whipplei. Nondeforming arthritis is frequently an initial complaint. Gastrointestinal and general symptoms include marked diarrhoea (with serious malabsorption), abdominal pain, prominent weight loss, and low-grade fever. Possible neurologic symptoms (up to 20%) might be associated with worse prognosis. Diagnosis is based on the clinical picture and small intestinal histology revealing foamy macrophages containing periodic-acid-Schiff- (PAS-) positive material. Long-term (up to one year) antibiotic therapy provides a favourable outcome in the vast majority of cases. This paper provides review of the literature and an analysis of our 5 patients recorded within a 20-year period at a tertiary gastroenterology centre. Patients were treated using i.v. penicillin G or amoxicillin-clavulanic acid + i.v. gentamicin for two weeks, followed by p.o. doxycycline (100 mg per day) plus p.o. salazopyrine (3 g per day) for 1 year. Full remission was achieved in all our 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.

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.

Infectious causes of chronic diarrhoea

Infections are an uncommon cause of chronic diarrhoea. Parasites are most likely, including protozoa like giardia, cryptosporidia and cyclospora. Bacteria are unlikely to cause chronic diarrhoea in immunocompetent individuals with the possible exception of Yersinia, Plesiomonas and Aeromonas. Infectious diarrhoea can trigger other causes of chronic diarrhoea, including inflammatory bowel disease, irritable bowel syndrome and "Brainerd-type" diarrhoea. A thorough evaluation should detect most infections causing chronic diarrhoea.

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.

Renal transplantation in AA amyloidosis associated with Whipple's disease

Whipple's disease (WD) is a chronic infection caused by Thropheryma whipplei that usually manifests with intestinal, articular, pulmonary, neurological and cardiac abnormalities. Rarely, WD has been associated with renal AA amyloidosis.We report a 50 year-old male with nephrotic syndrome and renal failure whose renal biopsy revealed extensive AA amyloidosis. Amyloid was not found in other organs, namely in gastrointestinal tract and bone marrow. There was no evidence of chronic inflammatory disease, and despite detailed investigation, the diagnosis of the underlying disease remained obscure. Eight months after referral he started peritoneal dialysis. Three years later he developed anorexia, weight loss, anemia, and recurrent attacks of non-bloody diarrhea. A biopsy of the small intestine showed typical histological findings of WD and PCR was positive for T. whipplei. He was treated with ceftriaxone followed by co-trimoxazole, with remission of complaints and histological features. Three years later the patient underwent successful cadaveric kidney transplantation. In this case, AA amyloidosis preceded the manifestations of WD. To the best of our knowledge, this is the first report of kidney transplantation in a patient with amyloidosis due to WD. Recurrence of amyloidosis in renal graft is not expected.

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.

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.

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.