Immunoglobulin classes of urinary and serum antibodies in mycoplasmal pyelonephritis

During 9 attacks of M. hominis pyelonephritis in 8 patients, the presence of IgA, IgG and IgM antibodies in urine and serum was studied by an indirect immunofluorescence technique. Antibodies were present in the urine for a period of 12 days. One to 4 days after the onset of the attack, IgA was in all cases demonstrable in urine, followed later by IgG. IgM was present in the urine of one patient only during the first 4 days of illness. In serum, IgG appeared as early as 1-4 days after the attack, followed later by IgA and IgM, IgA disappearing after one to two weeks.