Amyloid fibril protein AA in Papua New Guinean amyloidosis

The protein composition of amyloid fibrils isolated from 8 patients representative of the spectrum of amyloidosis found in Papua New Guinea was investigated. All fibril preparations, including 3 from patients with amyloidosis secondary to lepromatous leprosy and one from an unusual juvenile case of primary amyloidosis, contained the non immunoglobulin amyloid protein, protein AA. However, only 44% of 36 amyloid patients had detectable levels of the protein AA related serum component, protein SAA. Alkali degraded material from each of the fibril preparations failed to react in double immunodiffusion tests with antiserum to the amyloid related light chain VλV, but evidence was found for this immunoglobulin light chain specificity in the serum of one patient.