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

Fever and Increased Gastrointestinal Uptake on Positron Emission Tomography after Anti-Tumour Necrosis Factor Therapy: A Case Report of Whipple's Disease

Introduction

Whipple's disease is a rare condition that can present with atypical and non-specific features requiring a high index of suspicion for diagnosis.

Case Presentation

We present a case of a man in his 40s with peripheral arthritis and bilateral sacro-ileitis for 4-5 years that was treated with an anti-tumour necrosis factor therapy, which led to worsening of his symptoms, elevation of the inflammatory markers, and the development of fever, night sweats, anorexia, and a significant weight loss. The patient had no abdominal pain, diarrhoea, or other gastrointestinal symptoms. An FDG-PET scan showed increased uptake in the stomach and caecum. Endoscopic examination showed inflammatory changes in the stomach and normal mucosa of the duodenum, jejunum, terminal ileum, caecum, and colon. Histopathology was inconclusive, but the diagnosis was confirmed with Tropheryma whipplei PCR testing. He had no neurological symptoms, but cerebrospinal fluid Tropheryma whipplei PCR was positive. He was treated with intravenous ceftriaxone 2 g daily for 4 weeks, followed by trimethoprim/sulfamethoxazole 160/800 mg twice daily for 1 year with close monitoring and follow-up.

Conclusion

This case presents an atypical and challenging presentation of Whipple's disease and the importance of proactive testing for neurological involvement.

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.

Peripheral T-Cell Reactivity to Heat Shock Protein 70 and Its Cofactor GrpE from Tropheryma whipplei Is Reduced in Patients with Classical Whipple's Disease

Classical Whipple's disease (CWD) is characterized by the lack of specific Th1 response toward Tropheryma whipplei in genetically predisposed individuals. The cofactor GrpE of heat shock protein 70 (Hsp70) from T. whipplei was previously identified as a B-cell antigen. We tested the capacity of Hsp70 and GrpE to elicit specific proinflammatory T-cell responses. Peripheral mononuclear cells from CWD patients and healthy donors were stimulated with T. whipplei lysate or recombinant GrpE or Hsp70 before levels of CD40L, CD69, perforin, granzyme B, CD107a, and gamma interferon (IFN-γ) were determined in T cells by flow cytometry. Upon stimulation with total bacterial lysate or recombinant GrpE or Hsp70 of T. whipplei, the proportions of activated effector CD4⁺ T cells, determined as CD40L⁺ IFN-γ⁺, were significantly lower in patients with CWD than in healthy controls; CD8⁺ T cells of untreated CWD patients revealed an enhanced activation toward unspecific stimulation and T. whipplei-specific degranulation, although CD69⁺ IFN-γ⁺ CD8⁺ T cells were reduced upon stimulation with T. whipplei lysate and recombinant T. whipplei-derived proteins. Hsp70 and its cofactor GrpE are immunogenic in healthy individuals, eliciting effective responses against T. whipplei to control bacterial spreading. The lack of specific T-cell responses against these T. whipplei-derived proteins may contribute to the pathogenesis of CWD.

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.

Causal inference regarding infectious aetiology of chronic conditions: a systematic review

BACKGROUND

The global burden of disease has shifted from communicable diseases in children to chronic diseases in adults. This epidemiologic shift varies greatly by region, but in Europe, chronic conditions account for 86% of all deaths, 77% of the disease burden, and up to 80% of health care expenditures. A number of risk factors have been implicated in chronic diseases, such as exposure to infectious agents. A number of associations have been well established while others remain uncertain.

METHODS AND FINDINGS

We assessed the body of evidence regarding the infectious aetiology of chronic diseases in the peer-reviewed literature over the last decade. Causality was assessed with three different criteria: First, the total number of associations documented in the literature between each infectious agent and chronic condition; second, the epidemiologic study design (quality of the study); third, evidence for the number of Hill's criteria and Koch's postulates that linked the pathogen with the chronic condition. We identified 3136 publications, of which 148 were included in the analysis. There were a total of 75 different infectious agents and 122 chronic conditions. The evidence was strong for five pathogens, based on study type, strength and number of associations; they accounted for 60% of the associations documented in the literature. They were human immunodeficiency virus, hepatitis C virus, Helicobacter pylori, hepatitis B virus, and Chlamydia pneumoniae and were collectively implicated in the aetiology of 37 different chronic conditions. Other pathogens examined were only associated with very few chronic conditions (≤ 3) and when applying the three different criteria of evidence the strength of the causality was weak.

CONCLUSIONS

Prevention and treatment of these five pathogens lend themselves as effective public health intervention entry points. By concentrating research efforts on these promising areas, the human, economic, and societal burden arising from chronic conditions can be reduced.