A historical essay on detection of anti-neutrophil cytoplasmic antibodies.

In this essay we describe a number of the known and not so known experiences of the early anti-neutrophil cytoplasmic antibodies (ANCAs) days, explaining why and how we reached consensus on the standard indirect immunofluorescence (IIF) techniques, the naming of the two principal C- and P-ANCA patterns, why we chose to use IIF as the standard technique, how the solid phase assays have developed and where we stand today, the use of ANCA for diagnosis and the importance of using several techniques for that purpose, how ANCA titres are related to disease activity and the clinical impact of this, and finally the implications of ANCA being a natural, polyclonal antibody response against various epitopes in relation to diagnostics and disease patterns.