Classification of patients with non-alcoholic fatty liver disease using rapid immunoassay of serum type IV collagen compared with liver histology and other fibrosis markers

Aim Non-alcoholic fatty liver disease (NAFLD) can progress to non-alcoholic fatty liver (NAFL) or non-alcoholic steatohepatitis (NASH). We investigated the association among serum type IV collagen level, liver histology, and other fibrosis markers in NAFLD progression. Methods We evaluated 184 patients diagnosed with NAFLD following biopsy, including 89 males and 95 females with an average age of 52.6 and 62.6 years, respectively. Non-alcoholic fatty liver disease was classified as NAFL or NASH using Matteoni's classification, and the grade and stage of NASH were assessed using Brunt's classification. Serum type IV collagen was measured by a rapid and sensitive latex particle-enhanced turbidimetric immunoassay. Results Forty-two patients with NAFL and 142 patients with NASH were included in this study. Compared with patients with NAFL, patients with NASH showed more significant liver function disorder and increased expression of fibrosis markers including type IV collagen, collagen 7S, Mac2-binding protein (M2BP), and hyaluronic acid (HA). Expression of type IV collagen and collagen 7S, but not M2BP and HA, was more significantly elevated in patients with stage 1 NASH than in patients with NAFL, indicating that type IV collagen and collagen 7S may be better discriminators of NASH and NAFL than M2BP and HA at an early stage of fibrosis. When patients were stratified by NAFLD activity score, type IV collagen and collagen 7S were significantly elevated as NAFLD activity score progressed, whereas M2BP and HA expression were not significantly elevated. Conclusion Type IV collagen may be a useful measure of NASH severity as latex particle-enhanced turbidimetric immunoassay-based rapid type IV collagen assay can be carried out routinely.