Galactose-deficient IgA1 (Gd-IgA1) attracts a lot of attention as a critical effector molecule in the pathogenesis and progression of IgA nephropathy (IgAN) in recent studies. It has been suggested that several O-link glycan-modified regions exist in the heavy chain hinge region of human IgA1 molecule and that Gd-IgA1 circulates in the blood of patients with pathological condition of IgAN. The measuring system using snail (helix aspersa; HAA) lectin, that is extracted from snails, has been used in numerous studies in the past and it was revealed that serum levels of Gd-IgA1 in patients with IgAN are significantly elevated compared to the levels of healthy subjects or patients with renal diseases other than IgAN. Thus, the importance and purpose of measuring serum Gd-IgA1 level have been gradually recognized from such studies. 

However, since the measuring system using HAA lectin is not suitable for measuring multiple and massive samples in large scale studies due to its instability of glycan-recognizing activity, the development of an alternative measuring system that can quantitatively measure human Gd-IgA1 in serum with stable and reliable data has been considered as an essential and urgent matter. This IBL ELISA kit using a monoclonal antibody that specifically recognizes the galactose-deficient hinge sequence of human Gd-IgA1 is a non-lectin-dependent measuring system that can quantitatively measure Gd-IgA1 in human serum,which is also suitable for large scale studies because of its stability."