Antibody-secreting cells in acute urinary tract infection as indicators of local immune response

Mucosal immune mechanisms are believed to be important in host defense against urinary tract infection. To study the human immune response in the urinary tract, peripheral blood antibody-secreting cells (ASC), believed to originate from the mucosal surfaces, were investigated with the enzyme-linked immunospot assay. Pathogen-specific ASC were found in 17 (89%) of 19 patients with pyelonephritis and in 12 (70%) of 17 with LUTI (lower urinary tract infection); for infections caused by Escherichia coli, the respective figures were 17 (100%) and 10 (71%). The responses in pyelonephritis were stronger (P < .001) and lasted longer than those in LUTI: 15 patients with pyelonephritis (74%) but only 1 with LUTI (6%) had > 100 ASC/10(6) cells. A similar difference was seen in the number of all immunoglobulin-secreting cells. The ASC assay offers a new means for assessing the human immune response in urinary tract infection and may be useful in localizing the infection. It might prove valuable in predicting harmful postinfection processes.