PTAA and B10: new approaches to amyloid detection in tissue—evaluation of amyloid detection in tissue with a conjugated polyelectrolyte and a fibril-specific antibody fragment

Abstract

Aims: We analysed the suitability of two little known substances for the detection of amyloid in surgical pathology specimens, that is the conjugated polyelectrolyte polythiophene acetic acid (PTAA) and the camelid antibody domain B10.

Methods: We compared the amyloid detection of PTAA and B10 to Congo red in 106 amyloid-containing tissue biopsies of diverse anatomical and precursor origin by evaluating the accordance in four grades (grade 0: no staining, grade 1: staining of <33% of the amyloid deposits, grade 2: 33–66% and grade 3: >66%).

Results: PTAA showed grade 2–3 staining in 57 (54%) cases, while B10 presented this accordance in only 25 (24%) tissue biopsies. Grade 1 staining was found in 11 (10%) samples with PTAA and in 62 (58%) cases with B10. No staining at all (grade 0) occurred in 38 (36%) biopsies when using PTAA and in 19 (18%) cases when using B10.

Conclusion: Although conformation-sensitive detection seemed promising, PTAA and B10 stain only a fraction of the examined amyloid samples when using routine surgical pathology settings. This study emphasises the necessity of having optimised pre-analytical protocols for recovery, storage and handling of samples if these novel amyloid ligands are to be used in routine diagnosis of amyloid.

Keywords:

• amyloid
• PTAA
• camelid antibody

Abbreviations
PTAA	=	polythiophene acetic acid

Abbreviations
PTAA	=	polythiophene acetic acid

Acknowledgements

The authors thank K. Peter R. Nilsson (Department of Chemistry, Linköping University, Linköping, Sweden) for providing us with PTAA and the very fruitful discussion of the data and manuscript. This study was supported by grants of the Swedish research foundation (G.W.), grants of the European Union (EU FP6 EURAMY; C.R., G.W.), the DFG (SFB 610; M.F.) and the BMBF (BioFuture; M.F.).

Declaration of interest:

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the article.