[Study on the pathogenesis of acquired pure amegakaryocytic thrombocytopenic purpura].

OBJECTIVE

To investigate the possible pathogenesis of acquired pure amegakaryocytic thrombocytopenic purpura(APATP).

METHODS

Twenty eight patients with APATP were studied. Bone marrow mononuclear cells(MNCs) from these patients were plated into methyl cellulose cultures for CFU-GM, CFU-E and CFU-MK assay. The influence of depleting T cells or adherent cells from patients' marrow cells on CFU-MK growth was observed. The humoral inhibitory effect on CFU-MK was determined by co-incubation of patients' sera or IgG with normal or autologous MNCs prior to cultures. The serum MK-CSA was also assessed.

RESULTS

Fifteen cases (53.6%) of APATP was resulted from intrinsic defect of CFU-MK. The megakaryocyte colony formation was augmented significantly in 3 T lymphocytes-depleted and 2 mono-macrophages depleted patients. Sera from 6 patients(21.4%) were inhibitor to CFU-MK. The inhibitor originated from IgG and selectively directed against the megakaryocyte. In the remaining 2 cases, the pathogenesis was not ascertained.

CONCLUSION

The intrinsic defect of megakaryocyte progenitor cell is considered to be a primary pathogenesis of APATP. In some patients the disease can result from abnormal immune mechanisms. The decompensation of MK-CSA production could also be an important cause for APATP.