[The significance of immunological analysis for the detection of residual neuroblasts in bone marrow].

Immunological analysis is complementary to morphological investigation to detect bone marrow (BM) metastases in neuroblastoma patients. It is essential at time of BM harvest for an autograft, since it is the only examination which allows a precise evaluation of the graft contamination by malignant cells. Simple indirect immunofluorescence staining with anti-neuroblastoma monoclonal antibodies (UJ13A and HSAN 1-2) allows a final detection of about 1% malignant cells in the BM, and 1% when cells are gathered in clumps. The use of an immunocytochemical method (alkaline phosphatase) together with double immunofluorescence staining permits to detect as few as one residual neuroblastoma cell in 10(4) normal ones. These two methods used together have allowed to assess the neuroblastoma nature of rare isolated cells with pseudo-lymphocytic aspect.