Persistent changes in the immune system 4-10 years after ABMT

The aim of the present study was to investigate whether the early changes i n the immune system observed after ABMT would persist over years, Eighty-fi ve patients with malignant lymphoma were treated with ABMT in Norway from 1 987 until 1993, Of the 46 patients in CR by 1997, 36 were enrolled in our s tudy. Median time from ABMT was 5 years (4-10 years). Immunophenotyping sho wed an increase in the median number of B cells (0.35 x 10(9)/l in patients vs 0.28 x 10(9)/l in controls), and a decrease in T cells (1.08 vs 1.35 x 10(9)/l). Furthermore, a lower median count of CD4(+) T cells (0.54 x 10(9) /l in patients vs 0.87 x 10(9)/l in controls) resulted in reduced CD4/CD8 r atios (0.8(-) in patients vs 1.6 in controls), The subgroup of CD4+ T cells expressing the 'naive' phenotype CD45RA was 19.5% in patients vs 38% in co ntrols. In contrast, the fraction expressing the 'memory' phenotype CD45RO was higher in the ABMT group (76% vs 54%), When stimulated, larger fraction s of CD3(+)CD4(+) cells in patients produced IFN-gamma (32% vs 16%) or IL-4 (7% vs 1%) compared to controls; thus a differentiation into the functiona lly separate subgroups Th1 and Th2, with a dominant Th2 response. Our data further suggest that the decrease in CD4+ T cell counts and the imbalance b etween CD45RA(+) and CD45RO(+) subsets persists 4-10 years after ABMT.