Serum C3 and C4 levels were measured in 23 healthy subjects and 105 patients with bronchial asthma, by an immunodiffusion method using M-Partigen Plates. The serum levels of C4 were significantly increased in patients over 60 years old compared to the healthy subjects.
The levels of C3 were significantly higher in male cases than in female cases with bronchial asthma. The serum levels of C3 and C4 in asthma patients with infectious type, in severe cases and in cases with steroid therapy were within the normal limits during non-attack periods, but significantly increased during attack periods.
In asthmatic patients with mixed and infectious type, and in mild and severe cases, a significant correlation was observed between the serum levels of C3 and C4 during their non-attack periods.