Renal amyloidosis in Whipple disease: a case report

Infections and AA amyloidosis: An overview

BACKGROUND

Amyloidoses are a heterogeneous group of systemic diseases characterised by extracellular accumulation of insoluble amyloid fibrils derived from unfolded proteins. Inflammatory (AA) amyloidosis can complicate various inflammatory disorders that are associated with a sustained acute phase response and serum amyloid A (SAA) protein overproduction. Chronic infections were the first recognised cause of amyloidoses. However, with the better management of underlying diseases, the frequency of AA amyloidosis is decreasing.

PURPOSE

The aim of this overview was to discuss the several infections associated with AA amyloidosis and the relative frequency of infections as aetiological factors.

METHODS

A search of the literature was performed using the PubMed database using the MeSH terms "Amyloidosis" and "Infections," from inception to December 31st, 2019. Articles written in other languages than English or French were excluded.

RESULTS

The frequency of AA amyloidosis secondary to infections decreased from more than 50% to less than 20% after the 2000s, with a parallel increase in the frequency of AA amyloidosis secondary to inflammatory diseases and to an unknown cause.

CONCLUSION

Whereas new antibiotics have been developed and sanitary conditions are better, infections still represent 5%-30% of the causes of AA amyloidosis, including in developed countries. These data argue for better screening of chronic infections to prevent AA amyloidosis and the development of new strategies to manage recurrent infections.

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.

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.