Serum levels of the third component of complement (C3) were significantly lower in patients with perennial asthma and also in patients with the longer duration of the disease. No change in C3-proactivator (C3PA) and CH50 levels was observed in asthma patients. Significantly raised C4 levels were observed in the patients with late onset asthma.
Raised serum IgE levels were found in all the three groups of asthma patients studied (depending on age of onset, duration and periodicity of the disease) above the control group. Within a group no difference was found with the duration or periodicity of the disease. However, low IgE levels were observed in patients with late onset asthma as compared to early onset asthma patients but this difference was not statistically significant.