Complement and circulating immune complexes in children with mumps meningitis.

Haemolytic activity of complement (CH50) and occurrence of circulating immune, complexes (CIC) were studied in serum samples from children with mumps meningitis taken at regular intervals. The decrease of CH50 was observed in 46 out of 77 samples (60%) in the Ist examination, between 1-6th day from the appearance of symptoms, in 43/67 samples (64%) in the IInd examination, between 12--16th day of disease, and in 7/22 samples (32%) in the IIIrd examination, between 12--14th month of observation since the appearance of symptoms. Typical changes of complement level during the disease were of such profile that the most pronounced decrease was in the Ist and IInd examination with the normalization in the IIIrd examination. The presence of CIC was found in 21%, 15% and 14% of samples in the Ist, IInd, and IIIrd examination respectively. Serum sample form the child on 5th day of disease, with high concentration of CIC (482 micrograms/ml), was subjected to sepharose 6B gel filtration on the calibrated column. The molecular weight of thus analyzed immune complexes was as follows: 2.5 X 10(6) and 5.0 X 10(5) daltons. CIC contained anti-mumps antibodies, determined by Elisa, in IgG, IgA and IgM classes.