Serum immunoglobulin response in uncomplicated gonorrhoea.

Sera from 225 men and 140 women were examined by an indirect immunofluorescent antibody technique for antibody reactive with Neisseria gonorrhoeae. Antigonococcal IgM was demonstrated at a titre of greater than or equal to 16 in about 45% of infected, but in only 3% of non-infected, patients. Most of this antibody occurred in sera of patients who had been infected for less than 14 days. Antibody of the IgA class was found at a titre of greater than or equal to 16 in over half the infected, but in none of the non-infected, patients. IgG antibody reactive with the gonococcus was found in each infected patient at a titre of greater than or equal to 16 but in only 8% of controls. The mean log titre of this antibody was significantly higher in patients who had been infected for more than seven days than in those whose infection was of shorter duration.