Complement activation in bronchial asthma evaluated by the C3d/C3 index.
In order to demonstrate a suspected complement activation in bronchial asthma, we measured the C3d (split product of C3) and the C3d/C3 ratio in 73 adults. Both are considered to be a sensitive index of complement activation. Compared with the value obtained in 47 normal subjects, the C3d level and the C3d/C3 ratio level were found significantly higher in asthmatic subjects. Fourteen asthmatics presented an increased C3d/C3 above the calculated limit of normality. These 14 subjects differed from the other asthmatics by a significantly lower C4 plasmatic level, suggesting an activation of the classical pathway of the complement system. Nevertheless, the clinical significance of these observations remains difficult to interpret in view of the absence of significant differences of clinical, allergologic and respiratory functional parameters between asthmatics with low or high C3d/C3 index.
D000293:Adolescent; D000328:Adult; D000368:Aged; D000936:Antigen-Antibody Complex / Q000032:analysis; D001249:Asthma / Q000276:immunology*; D003167:Complement Activation; D003176:Complement C3 / Q000032:analysis; D015933:Complement C3d; D005260:Female; D006801:Humans; D007073:Immunoglobulin E / Q000032:analysis; D008297:Male; D008875:Middle Aged; D011852:Radioallergosorbent Test
D000936:Antigen-Antibody Complex; D003176:Complement C3; D007073:Immunoglobulin E; D015933:Complement C3d