Methods for performing ex vivo diagnostic tests for the presence of a proliferation-inducing ligand (APRIL) in a sample

A method for performing an ex vivo diagnostic test for the presence of A Proliferation-Inducing Ligand (APRIL) in a sample, comprising:

• a) contacting the sample with an APRIL-binding antibody comprising:
• i) a VH domain comprising an amino acid sequence having complementarity determining region (CDR) sequences set forth in SEQ ID NOs:
• 25-27, and a VL domain comprising an amino acid sequence comprising CDR sequences set forth in SEQ ID NOs:
• 28-30,
• ii) a VH domain comprising an amino acid sequence having complementarity determining region (CDR) sequences set forth in SEQ ID NOs:
• 5-7 and a VL domain comprising an amino acid sequence comprising CDR sequences set forth in SEQ ID NOs:
• 8-10,
• iii) a VH domain comprising an amino acid sequence having complementarity determining region (CDR) sequences set forth in SEQ ID NOs:
• 15-17 and a VL domain comprising an amino acid sequence comprising CDR sequences set forth in SEQ ID NOs:
• 18-20,
• iv) a VH domain comprising an amino acid sequence having complementarity determining region (CDR) sequences set forth in SEQ ID NOs:
• 35-37 and a VL domain comprising an amino acid sequence comprising CDR sequences set forth in SEQ ID NOs:
• 38-40, or
• v) a VH domain comprising an amino acid sequence having complementarity determining region (CDR) sequences set forth in SEQ ID NOs:
• 45-47 and a VL domain comprising an amino acid sequence comprising CDR sequences set forth in SEQ ID NOs:
• 48-50;
• and
• b) detecting binding between APRIL in the human sample and the APRIL-binding antibody.