Diagnosis and classification of amyloidosis by an immuno-histological method

Following the recent classification of amyloidosis by the amyloid proteins involved, we decided to approach its tissue diagnosis and chemical classification by an immunohistological method. Post-mortem tissue specimens from various organs of patients with primary and secondary amyloidosis were examined by the immunoperoxidase technique with specific antibodies against proteins AL and AA which respectively characterize primary and secondary amyloidosis. The major advantage of this technique is that it can be applied to formalin fixed, paraffin embedded tissues. The immunoperoxidase technique proved to be extremely sensitive for the detection of amyloid deposits. Moreover, the deposited proteins could be clearly characterized as AL or AA by the specific anti-sera. We therefore believe that the immunooperoxidase technique is extremely useful for the early tissue diagnosis and chemical classification of amyloidosis.