Cirrhosis of liver: Interference of serpins in quantification of SERPINA4 – A preliminary study

Abstract

Background: Cirrhosis of liver is a pathological condition, wherein functions of liver are impaired by chronic liver exploitations. Due to decrease in synthetic capacity, expressions of plasma proteins tend to decrease in blood stream. Serpins (Serine protease inhibitors) are class of plasma proteins expressed from liver with structural similarities and diverse functions. SERPINA4 (Kallistatin) is a multifunctional serpin clade A protein expressed from liver and concentration in serum is the reflection of extent of liver dysfunction. Objective: To identify interference of other serpins by immunological cross reactivity with SERPINA4 in cirrhotic liver and healthy subjects. Materials and methods: Blood samples were collected from 20 subjects (10 cirrhotic liver, 10 healthy) from R.L. Jalappa Hospital and Research Centre, Kolar, Karnataka, India. Separation of proteins was carried out by SDS-PAGE. Cross reactivity study was analyzed using western blot. Results: Proteins present in cirrhotic liver and healthy subject's serum were separated by SDS PAGE. There was no band detection on both (cirrhotic liver and healthy) PVDF (polyvinylidene diflouride) membranes. However, a significant band was observed with recombinant kallistatin. Conclusion: Structurally similar serpins with minor amino acid sequence similarities did not show any immunological cross reactivity with SERPINA4 due to non identical epitope in cirrhotic liver and healthy subjects. Present study revealed that there is no interference of serpins for immunological reactions in quantitative estimation of kallistatin which needs further validation.