Seventy-five CIU patients and twenty-five healthy control subjects were included in the study. Blood was taken from all subjects to measureplasma levels of the histamine and DAO.
RESULTS:
Mean plasmahistamine levels were significantly higher in CIU patients (11.59+/-10.98 nM) than in the control subjects (8.75+/-2.55 nM) (p=0.04). Mean DAO activities were lower in patients of CIU (80.86+/-26.81 histamine degrading unit [HDU]/ml) than in the controls (81.60+/-9.67 HDU/ml), but without significant difference. In 15 CIU patients with gastrointestinal symptoms, the mean histamine concentration was higher (12.43+/-7.97 nM) and DAO activity was lower (77.93+/-27.53 HDU/ml) than in the remaining 60 CIU patients without gastrointestinal symptoms (11.38+/-11.67 nM and 81.58+/-26.82 HDU/ml), without significant difference. The relationship between DAO activity and plasmahistamine concentrations showed a significant negative linear value (p=0.001). There were no significant relationships between plasmahistamine concentrations and symptom severity score.
CONCLUSION:
In CIU patients, a high plasmahistamine concentration may not be explained by DAO activity. CIU patients with gastrointestinal (GI) symptoms showed no significantly lower DAO activity. Larger group studies are required to elucidate the relationship between plasmahistamine concentrations and DAO activity, especially of CIU patients with GI symptomsto understand the difference in CIU patients with and without GI symptoms.