Quantitative immunoassay for the detection of autoantibodies to nephrin

A kit, comprising:

• (c) a first polypeptide comprising an epitope from the extracellular domain of a mammalian nephrin, and a second polypeptide comprising an epitope from the extracellular domain of a mammalian nephrin,
• wherein
• (i) the first polypeptide is immobilized on a solid carrier, or
• (ii) configured for immobilization on a solid carrier, or
• (iii) the kit comprises a solid carrier configured for immobilization of the first polypeptide and the second polypeptide is labeled or configured for labeling with a detectable label,
• wherein the kit comprises a solid carrier if the first polypeptide is configured for immobilization on a solid carrier,
• and wherein the kit comprises a detectable label if the second polypeptide is configured for labeling with a detectable label,
• or
• (d) a first polypeptide comprising an epitope from the extracellular domain of a mammalian nephrin and a second polypeptide comprising an epitope from the extracellular domain of a mammalian nephrin,
• wherein
• the first polypeptide is labeled or configured for labeling with a first detectable label and the second polypeptide is labeled or configured for labeling with a second detectable label,
• wherein the kit comprises a first detectable label if the first polypeptide is configured for labeling with a first detectable label,
• and wherein the kit comprises a second detectable label if the second polypeptide is configured for labeling with a second detectable label.