Arylsulfatase activity of asthmatic children

Human eosinophil arylsulfatase (AS) is known to inactivate a slow reacting substance of anaphylaxis (SRS-A). Arylsulfatase A (AS-A) and arylsulfatase B (AS-B) activity was assayed by a modification of the method of Inoue using chromatography, and peripheral eosinophil cell counts were obtained to observe the circadian rhythm of 6 healthy controls and 7 children with asthma. There was no significant diurnal variation in AS between the two groups. Eosinophil counts of both groups were lower in the morning and higher at night. Theophylline and beta 2 stimulants did not affect these activities significantly. Forty asthmatic children were selected to evaluate AS activity and eosinophil counts during and after attacks. AS-B activity was significantly higher in children during attacks than at other times, 5.70 +/- 2.00 vs. 3.74 +/- 0.66 4 MUnmol/ml/2hr (p less than 0.05). This result was more evident within 24 hours of the attack (p less than 0.01). Eosinophil counts were significantly lower during attack, and there was a negative correlation between the eosinophil counts and AS-B activity. AS-B activity in mild asthmatic children was greater than in severe cases. A significant rise in AS-B was seen in EIB negative asthmatics (p less than 0.01), but no remarkable change was seen in either AS-A or AS-B in the EIB positive group. The data suggest that higher AS-B activity during asthma attacks could inactivate SRS-A and modulate allergic inflammatory reaction.