Biomarkers of axonal damage to favor early diagnosis in variant transthyretin amyloidosis (A-ATTRv).

Early identification of ATTRv amyloidosis disease onset is still often delayed due to the lack of validated biomarkers of this disease. Light chain neurofilament (NfL) have shown promising results in early diagnosis in this disease, but data is still needed, including with alternative measuring methods. Our aim was to study the levels of NfL measured by ELISA. Furthermore, interstitial matrix metalloproteinase type 1 (MMP-1) serum levels were measured as a potential new biomarker in ATTRv. Serum NfL and MMP-1 were measured using ELISA assays in 90 participants (29 ATTR-V30M patients, 31 asymptomatic V30M-TTR variant carriers and 30 healthy controls). Median NfL levels among ATTRv amyloidosis patients were significantly higher (116 pg/mL vs 0 pg/mL in both comparison groups). The AUC comparing ATTRv amyloidosis patients and asymptomatic carriers was 0.90 and the NfL concentration of 93.55 pg/mL yielded a sensitivity of 79% and a specificity of 87%. NfL levels had a significant positive correlation with NIS values among patients. We found a negative significant correlation between eGFR and NfL levels. Finally, MMP1 levels were not different between groups. Evidence of NfL use for early diagnosis of ATTR-PN amyloidosis is growing. ELISA seems a reliable and available technique for it quantification. Decreased GFR could influence NfL plasma levels.

Inotersen and severe thrombocytopenia: 2 case reports and review.

Hereditary transthyretin amyloidosis (hATTR) is an ultra-rare illness. Inotersen is a 2'-O-methoxyethyl (2'MOE)-modified antisense oligonucleotides (ASO) approved in 2018 as a polyneuropathy treatment for adults with hereditary transthyretin amyloidosis stages 1 or 2. Inotersen can produce grade 4 thrombocytopenia as a severe adverse reaction that can lead to potentially fatal hemorrhage complications. We describe our experience in the management of severe thrombocytopenia with inotersen. The onset of the thrombocytopenia and the incidences described in the cases in our hospital are different from that described in the literature. Also, recovery of platelet levels was faster in our patient who was administered human immunoglobulin G, which suggests that there is an immunological component.