Value of antigen detection using an enzyme immunoassay in the diagnosis and prediction of invasive aspergillosis in two adult and pediatric hematology units during a 4-year prospective study.
BACKGROUND
Invasive aspergillosis (IA) is a well recognized, life-threatening infection in neutropenic patients and stem cell transplantation recipients. Early diagnosis is important to achieve the best outcome for these patients; however, definite proof often is difficult to obtain due to counterindicated invasive procedures.


METHODS
This study evaluated the specificity and sensitivity of the detection of galactomannan (GM) for the diagnostic and prediction of IA in 347 children from the Pediatric Hematology Service and 450 patients from the Bone Marrow Transplantation Unit at the Hôpital Saint-Louis in Paris. Serial screening of Aspergillus GM circulating antigen was evaluated using a double sandwich ELISA assay (Platelia Aspergillus) on 6209 sera. Among the patients studied, 53 presented with confirmed IA (n = 27 patients) or probable IA (n = 26 patients).


RESULTS
Antigen was detected on at least two sequential sera in 48 of 53 patients, with a sensitivity of 90.6%. GM antigenemia was detected before the onset of radiologic signs in 31 of 48 patients (64.6%), with a mean of -8.4 days, and before clinical symptoms in 18 of 48 patients (39.6%), with a mean of -6.9 days. In patients without IA, 44 of 744 had positive antigenemia, resulting in a specificity of 94%. False positive results could not be related to the presence of a concurrent mucositis.


CONCLUSIONS
This large, prospective study allowed the authors to define better the conditions for the use of GM immunocapture ELISA in surveying patients who are at high risk for IA. The presence of antigen has a good diagnostic value mainly when there is an increase in the titer on two consecutive sera samples. A repeated negative result is a strong argument against the diagnosis of IA; however, an awareness of the possibility of unexplained false negative results is important.
Sulahian
A
A
Laboratoire de Parasitologie-Mycologie, Hôpital Saint-Louis, Paris, France. asulahian@bhdc.jussieu.fr
Boutboul
F
F
Ribaud
P
P
Leblanc
T
T
Lacroix
C
C
Derouin
F
F
D000293:Adolescent; D000328:Adult; D000946:Antigens, Fungal / Q000032:analysis*; D001228:Aspergillosis / Q000175:diagnosis* / Q000276:immunology; D001230:Aspergillus / Q000276:immunology*; D016026:Bone Marrow Transplantation; D002648:Child; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005690:Galactose / Q000031:analogs & derivatives; D006801:Humans; D016867:Immunocompromised Host; D008297:Male; D008351:Mannans / Q000032:analysis*; D008875:Middle Aged; D011446:Prospective Studies; D012680:Sensitivity and Specificity
D000946:Antigens, Fungal; D008351:Mannans; C012990:galactomannan; D005690:Galactose