Aspergillus antigen and PCR assays in bone marrow transplanted children.

Screening for Aspergillus antigen and DNA has been introduced for the early diagnosis of invasive aspergillosis (IA) in adults, but data in children at risk are scarce. Seventeen 1-108 month-old children were screened for Aspergillus antigenaemia by a commercial assay before and after bone marrow transplantation (BMT). Seventy-one serum samples were examined retrospectively by a novel nested PCR assay. Results of both assays were correlated with clinical, radiological and microbiological findings used for the definition of invasive aspergillosis by the European Organisation for Research and Treatment of Cancer (EORTC). Three cases of probable or possible IA were defined, and in 14 children invasive aspergillosis was ruled out. In 10 children, Aspergillus antigen was detected in at least two consecutive serum samples, a microbiological EORTC criteria of IA. Specific DNA was detected in 8 antigen-positive and 2 antigen-negative sera. A positive predictive value of 20% was calculated for both assays. Hence, a high rate of positive results of antigen Elisa and PCR assays in BMT children are due to transient antigenaemia and fungaemia without clinical relevance. According to our data, prospective studies in well defined pediatric patients are urgently needed to determine the value of serial Aspergillus PCR assays for the early diagnosis of invasive aspergillosis in children at risk.