Serological response to Escherichia coli pili in pyelonephritis.

The serological response to Escherichia coli pili was studied in 4 adult male patients with pyelonephritis and in 11 uninfected controls. Antibody to the specific pilus antigen of the infecting strain of each patient was measured with indirect immune electron microscopy. Antibody to a cross-reacting antigen of the type 1 pili of heterologous E. coli 346 was quantitated with an enzyme-linked immunosorbent assay. Few antipilus antibodies were found in the serum of control patients with either technique. All pyelonephrine patients developed an increase in specific antipilus antibodies belonging to the immunoglobulins classes G, A, and M. Antibodies to the cross-reacting type 1 pilus antigen were found in the serum of three of the four patients and were predominantly immunoglobulin G. Few or no antipilus antibodies were present in the urine of infected or control patients. These results suggest that a serological response to the pill of infecting organisms develops after pyelonephritis.