Mass Spectrometry Amyloid Typing Is Reproducible across Multiple Organ Sites

Figure 1

Immunohistochemical typing of amyloid in myocardial tissue by a basic panel of antibodies. The confirmation of amyloid deposition was done via Congo red and Sirius red staining, the amyloid typing via IHC analysis (right panels). The tissue sample of case 1 failed during IHC staining with AL κ, AL λ, SAA, and TTR antibodies. The examined tissues of cases 2 and 3 had a false positive reaction with SAA and/or TTR antibodies, weak and/or negative reaction with AL κ antibody, respectively. In cases 4, 7, 10, and 11 examined tissue had a positive reaction with more than one antibody which is classified as no immunospecific staining (NS). Amyloid fibril protein (AL κ) was typed correctly in case 5. Amyloid fibril protein (AL λ) was typed correctly in cases 6, 8, and 9. IHC staining intensity was classified as negative (-), weak (+), moderate (++), and strong (+++). The amyloid subtype was determined based on the strongest IHC reaction.

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