Urinary sIgA in Children With Urinary Tract infection

Abstract

Urinary secretory lgA (sigA) was measured using a specific ELISA with insolubilized anti-lgA and enzyme-linked antisecretory component. This fest was applied to unprocessed urine from healthy children and from children with urinary tract infection. Normal range was a function of age. In 175 healthy children the excretion rate of sigA was low in infants younger than 6 months but was constant between ages 6 months to 15 years (median 0.69 mg/gm creatinine, range 0.15 to 3.4 mg/gm creatinine), whereas sigA concentration (milligrams per liter of urine) increased continuously with age. No sex difference was noted. There were no significant circadian changes or day-to-day variability. Thirty giris, age 1 to 16 years, were examined; they had a history of recurrent symptomatic episodes of urinary tract infection but had anatomically normal tracts and no symptoms, and no bacteriuria at the time of study. sigA excretion rate was significantly lower (0.45 mg/gm, creatinine, 0.08 to 0.75 mg/gm creatinine) than in controls. In contrast, 11 giris examined at the time of symptomatic urinary tract infections, and who had normal urinary tracts, had significantly (P