Genotypes at SAA1 locus correlate with the clinical severity of AA-amyloidosis

A case with rheumatoid arthritis and systemic reactive AA amyloidosis showing rapid regression of amyloid deposition on gastroduodenal mucosa after a combined therapy of corticosteroid and etanercept

Systemic reactive amyloid A (AA) amyloidosis is one of the critical complications associated with rheumatoid arthritis (RA). Recently, there are several useful reports of anti-tumor necrosis factor therapy for RA-related systemic reactive AA amyloidosis patients. However, the time-kinetic transition between effective anti-inflammatory therapies and regression of AA amyloid deposits remains uncertain. Here, we report a RA patient with systemic reactive AA amyloidosis who was successfully treated with prednisolone and etanercept, showing marked regression of gastroduodenal mucosal amyloid deposits within only 4 months. This is the first case report of RA-related systemic reactive AA amyloidosis histopathologically demonstrating rapid regression of amyloid deposits on gastroduodenal mucosa after adequate suppression of the underlying inflammatory condition.

[Amyloidoses in the Berlin Museum of Medical History of the Charité]

The Berliner Medizinhistorische Museum (Berlin Museum of Medical History) of the Charité is located in its own separate building and was officially opened in 1899. It currently houses 10,000 specimens, of which 23 were labelled with the diagnosis "amyloid" or "amyloidosis". In this retrospective study we aimed to histologically verify the diagnosis, classify the amyloid deposits immunohistochemically and correlate the type of amyloid with clinico-pathological data. The specimens were obtained between 1866 and 1987 and included 17 kidneys, five spleens and one liver. The diagnosis could be confirmed histologically using Congo red staining and polarization microscopy in 22 specimens. However, the diagnosis could not be confirmed in the oldest specimen, which had been labelled by Rudolf Virchow himself. Immunohistochemically amyloid was classified as either AA amyloidosis (19 cases) or AL amyloidosis (two cases). Tuberculosis was the most common cause of AA amyloidosis. This study shows that a surgical pathological re-evaluation of historical specimens can verify the original diagnosis. This is historically fascinating and also offers a valuable addition to student teaching.

SAA1 gene polymorphisms and the risk of AA amyloidosis in Japanese patients with rheumatoid arthritis

To investigate the precise modality of association between SAA1 gene polymorphisms and the development of AA amyloidosis in patients with rheumatoid arthritis (RA), Japanese patients with RA (n=153), among whom 29 were histologically diagnosed as having amyloidosis, were genotyped for three single nucleotide polymorphisms (SNPs), C-13T, C2995T, and C3010T, in the SAA gene. Pairwise linkage disequilibrium coefficients between each pair of SNPs were calculated and estimated haplotype frequencies were compared between patients with and without amyloidosis. Possible associations between these SNPs and amyloidosis were analyzed by a case-control study and by the Kaplan-Meier method, in which the endpoint was defined as the time of diagnosis of AA amyloidosis. The -13T and 2995C alleles, which were in a tight linkage disequilibrium, were more frequent in the patients with amyloidosis, and the groups with the -13TT and 2995CC genotype had worse survival curves than patients without these genotypes, whereas C3010T was not associated with amyloidosis. Moreover, the haplotype containing -13C and 2995T was found to be protective. Both C-13T and C2995T were associated with the development of amyloidosis. Examining both polymorphisms may be more useful than examining only one of them for estimating the risk of the development of amyloidosis.

Relative transcriptional activities of SAA1 promoters polymorphic at position -13(T/C): potential association between increased transcription and amyloidosis

The risk associated with the serum amyloid A (SAA) 1 gene and developing AA-amyloidosis is still controversial. In familial Mediterranean fever or Caucasoid rheumatoid arthritis (RA), the SAA1.1 allele is a risk factor for the development of AA-amyloidosis. However, individuals with the SAA1.3 allele are susceptible to AA-amyloidosis in the Japanese RA population, but those with the SAA1.1 are not. Previous reports have indicated that the -13T/C single nucleotide polymorphism (SNP) at the 5'-flanking region of SAA1 appears to be a better marker of AA-amyloidosis than the exon-3 based haplotype, i.e., SAA1.1 or SAA1.3, in both Japanese and American Caucasian populations. So far, it is unknown why the -13T SNP increases the amyloidogenicity of the patients. In the present study, a luciferase reporter gene assay showed that the transcriptional activity of the SAA1 having the -13T-containing promoter was significantly higher than activities of those with -13C-containing promoters (Fisher's protected least significance difference test). We suggest that having the -13T SNP in the SAA1 promoter correlates with the amyloidogenicity in part as a result of this increased transcriptional activity.