In vitro tests in severe aplastic anaemia (SAA): a prospective study in 46 patients treated with immunosuppression.

Forty-six patients with severe aplastic anaemia (SAA) were studied for CFU-c growth on admission and 1 month post-treatment with immunosuppression (IS). Twenty-three patients became transfusion independent after IS, and were considered responders, and 23 did not. CFU-c growth from unfractionated bone marrow cells was comparable in both groups on admission and 1 month post-treatment. CFU-c growth from E rosette depleted BM cells (E-BM) was also comparable on admission. However, 1 month post-treatment, responders showed a significantly higher CFU-c growth (P = 0.02) from E-BM cells compared to non-responders. At the same time 7/8 responders studied showed T cell mediated suppression of autologous CFU-c growth. T cell depletion experiments do not give predictive information on the outcome of IS therapy on admission. They may, however, be helpful to identify responders early post-treatment.