There is provided an immunoassay by which the amount of human medullasin
present inside granulocytes, which are one leukocyte component in blood,
can be determined with high accuracy and with good reproducibility. Also
provided is an immunoassay of medullasin, wherein when measuring the
medullasin in blood using an anti-human medullasin antibody, the
determination of the amount of human medullasin in a blood sample using
said anti-human medullasin antibody is carried out after treating the
blood sample with an aqueous liquid having a specific osmotic pressure
different to the osmotic pressure of blood to completely break up the
leukocytes. Also provided is a method of diagnosing multiple sclerosis
characterized in that the human medullasin content of a blood sample is
measured using an immunoassay, and the onset of multiple sclerosis and
the extent of the disease is diagnosed according to the size of, or
changes in, this measured value.
