Association of Serum Complement Components (C3 and C4) with Disease Activity in Yemeni Bronchial Asthmatic Patients

Objective: To assess the role of the complement components (C3 and C4) in the pathogenesis and severity of bronchial asthma (BA) among Yemeni patients. Methods: This cross-sectional, clinic-based study was conducted in Sana’a city, Yemen in the period from March to June 2012. It included 100 BA patients, where demographic and clinical data were collected using a pre-designed, structured questionnaire. Blood samples then collected by venipuncture, and sera were then separated and tested for the levels of C3 and C4 by immunoturbidimetry assay. Data were analyzed using suitable statistical tests using IBM SPSS Statistics, version Results: Of 100 patients, 53% were males and 29% were older than 40 years. The mean age of patients was 34.7± 17.5 years (range: 6–80). The majority of patients had active asthma (81.0%) and experienced asthma for more than two years (66.0%). Dyspnea (81.0%) and cough (65.0%) were the most frequent clinical features, while edema (11.0%) was the least frequent clinical feature among asthmatic patients. The mean level of serum C3 among BA patients was elevated (127.9 ± 21.3 mg/dL) and was significantly higher among females, patients aged 40 years or older and those with active BA, but there was no statistically significant difference with respect to the duration of asthma. In contrast, the mean level of serum C4 was normal (27.6 ± 8.8 mg/dL) but was significantly higher among patients aged 40 years or older and those having asthma for more than two years. Wheezing was significantly associated with the mean level of serum C3 among BA patients. Similarly, the mean level of serum C4 was significantly higher among patients having cough. Conclusions: The majority of Yemeni patients with BA have elevated levels of serum C3, which can be significantly higher in females, patients older than 40 years and those with active asthma. On the other hand, the levels of serum C4 are normal among the majority of Yemeni patients with BA, but these can be elevated among those with severe clinical features or long-term asthma. Keywords: Active asthma, Bronchial asthma, Complement, C3, C4, Yemen