USEFULNESS OF MAC AND MACISH TECHNIQUES I N THE STUDY OF HEMATOLOGICAL MALIGNANCIES

BACKGROUND: Banding techniques are essential in the chromosomal analys is for the cytogenetic diagnosis. Even that, conventional cytogenetic techniques destroy the cytoplasmic membrane and the lineage involvemen t of the karyotyped cells is unknown. In this work the usefulness of a method that keeps the cell intact and allows the sequential applicati on of immunological, cytochemical, morphological and cytogenetic techn iques in the same cell is shown. This technique is called MAC for morp hology, antibodies and chromosomes. The combination of MAC and in situ hybridization techniques (MACISH method) allows the detection of a ch romosome abnormality in all the cells even when no mitosis are present . PATIENTS AND METHODS: The MAC method was applied in 51 patients and the MACISH method in 9 patients in order to identify the cells which k aryotype is analyzed. We have studied 47 patients with normal karyotyp e (37 chronic lymphocytic leukaemia [CLL] and 10 essential trombocytha emias [ET] and 4 patients with different diseases and abnormal karyoty pe. RESULTS: Among 37 patients with CLL and normal karyotype, in 9 cas es only normal T-cells were in mitoses and in 28 cases the normal kary otype belonged to neoplastic B cells. Trisomy 12 has been confined exc lussively to the leukaemic B cells with the MACISH technique in 3 of t hese CLL cases. In 10 patients with FT and normal karyotype the MAC me thod showed that in any case the mitosis analyzed belonged to the mega karyocyte lineage. In 4 patients with different chromosomal abnormalit ies the haematological cell lines involved in the neoplasia were known with the MAC method. CONCLUSION: In this work is shown the usefulness of the combination of the MAC and MACISH techniques with conventional cytogenetics in order to complet the chromosomic study of the haemato logical neoplasms is confirmed. These methods are specially usefull wh en different cell lineages are involved in the neoplasia, reactive pro liferations are suspected, or to discard false aneuploidies.