C1q microtiter plate ELISA system for detecting circulating immune complexes and its application of testing the sera...

We have developed a C1q microtiter plate ELISA system for detecting circulating immune complexes. The sensitivity of our system ranges between 0.5 and 32 micrograms equivalents of aggregated human IgG per ml. We have applied this system to 21 normal healthy controls and 80 neurological patients. Average level of circulating immune complexes in normal healthy controls is 4.67 +/- 2.67 micrograms per ml. We choose the upper limit of normality as 10.01 micrograms per ml (M + 2SD) and define the cases above this limit as positive cases. We have found high percentages of positivity in multiple sclerosis and amyotrophic lateral sclerosis.