DIAGNOSTIC-VALUE OF THE INDIRECT IMMUNOFLUORESCENCE ASSAY IN CAT-SCRATCH DISEASE WITH BARTONELLA-HENSELAE AND AFIPIA-FELIS ANTIGENS

Serum samples from 35 cat scratch disease (CSD) patients, 180 control patients (123 without lymph node enlargement and 57 with lymph node en largement not evoking CSD), and 102 nonpatient subjects (35 with cat c ontact and 67 without cat contact) were tested by semiquantitative ind irect immunofluorescence assay for the presence of antibodies directed to Afipia felis (ATCC 53690(T)) or Bartonella henselae (ATCC 49882(T) ), The CSD group had statistically higher antibody titers against B. h enselae than the control groups (P < 10(-5)), whereas no difference in A. felis antibody titers was evidenced among all groups tested, Among the 317 serum samples studied, the three with high A. felis antibody titers (greater than or equal to 64) also had high antibody titers aga inst other alpha-2 proteobacteria. The value of the indirect immunoflu orescence assay with B. henselae antigen for the diagnosis of CSD was as follows: for a cutoff of 32, sensitivity was 0.80, specificity was 0.85, and the likelihood ratio was 5.1; for a cutoff of 64, the likeli hood ratio was 12.1, In summary, in France, CSD is associated with hig h antibody titers against B. henselae, as preciously described in the United States, However, the causes for B. henselae seronegativity in C SD patients and those for high antibody titers outside the typical nos ological frame of CSD still have to be identified.