BONE-MARROW HISTOLOGY AND CD34 IMMUNOSTAINING IN THE PROGNOSTIC EVALUATION OF PRIMARY MYELODYSPLASTIC SYNDROMES

The prognostic impact of bone marrow biopsy (BMB) histology and CD34 i mmunoreactivity was compared with that of the more conventional parame ters (the FAB diagnosis, peripheral blood values, percentage of BM bla sts and some common prognostic scores) in 100 MDS patients. Statistica l correlations among the cytological, haematological, histological and immunohistochemical parameters and their relationship with clinical o utcome were searched for. At univariate analysis, FAB classification ( P < 0.001), pattern of blastic infiltration at BMB (P < 0.005), presen ce of CD34(+) aggregates (P < 0.0005), percentage of blasts in BM aspi rate (P < 0.0001) and percentage of CD34 positivity (P < 0.0001) prove d to be linked to leukaemic transformation and, except for FAB classif ication, retained a high degree of prognostic significance in terms of survival. Leukaemic transformation occurred in 16/18 patients simulta neously presenting 'large' blastic infiltrates at BMB and CD34(+) aggr egates (P < 0.00001); 9/17 evaluable patients died within 12 months of diagnosis (P < 0.001). Discriminant functions for leukaemic transform ation and survival did not offer any advantage over univariate analysi s in the prognostic work-up. The results indicate that the size of bla stic aggregates and CD34 positivity allowed patients with a worse prog nosis to be identified irrespective of their FAB subtype, but the prog nostic impact is considerably greater when both parameters are simulta neously taken into account, as testified by the restricted and homogen ous subgroup of patients with both 'large' and CD34-positive aggregate s.