[Preliminary assessment of immune reconstitution after autologous peripheral hematopoietic stem cell transplantation (AHSCT)].

BACKGROUND & OBJECTIVES: Though high dose chemo-therapy combined with autologous hematopoietic stem cell transplantation (AHSCT) has made great progress on the treatment of chemo-sensitive malignant tumors, the relapse rate remains high. Successful immune reconstitution after AHSCT may reduce recurrence; therefore this study was to explore the characteristics of immune reconstitution after AHSCT and assess its feasibility in clinical use.

METHODS: Twenty four cases after AHSCT were enrolled in our study. There were 19 Non-hodgkin Lymphoma (NHL), 3 Hodgkin Lymphoma (HD) and 2 rhabdomyosarcoma. Nineteen cases had achieved complete remission (CR) while 5 partial remission (PR) before AHSCT. All cases were administered Interleukin (IL)-2 and Interferon (IFN)-alpha after AHSCT. Some patients were given thymus factor and/or CIK infusion. Phenotypes of peripheral blood T, B, NK subsets and immunological profile of TH1/TH2 by intracellular staining of cytokines after PMA/ionomycin stimulation were evaluated.

RESULTS: 75% of the cases achieved CR while 4.17% were progression of disease (PD) and 16.67% were relapsed during the median follow-up time of 12 (2-60) months. The changes of immune parameters after AHSCT were as followed: (1) CD4+T cells (normal control 33.5+/-6.9%) started to decrease dramatically one month after AHSCT, which was 2.5-13% (median rate 5.6%)in the 2nd month; and then slowly increased to 10-20% in the 7th month, but did not return back to normal even after one year in all patients. In addition, reversed ratio of CD4/CD8 lasted for a long period of time. B cells also began to decrease 1 month after AHSCT, and recovered to normal in the 4th month. But B cells remained 0% in the 6th month and 1% in 12th month in patients treated by rituximab before receiving AHSCT. The ratio of NK cells was 10-20% (higher than normal controls) in the 2nd month, then returned to normal thereafter. (2) The cytokine secretion by T cell: there were 48.79% patients whose TH1 was lower than normal controls or at the lower limit of normal range. All the patients with normal TH1 were treated by IFN-alpha or CIK cell infusion. TH2 was much higher than normal level among 68.29% cases and this abnormality lasted at least for 1 year in some cases. TH2 at normal range was only observed in cases receiving IFN-alpha treatment. Furthermore, IFN-alpha could significantly decrease TH2 level. (3) Increasing tendency of CD4+CD25+/CD4+, CD4+CD69+/CD4+ ratio was observed in patients received additional thymus factor treatment compared to those did not.

CONCLUSIONS: Administration of CIK cells, thymus factor, IL-2 and IFN-alpha after AHSCT could improve the immunologic function of patients, and TH1/TH2 ratio may virtually reflect the immune status of patients. However more information is required to make prognostic assessments of immune reconstruction and the long-term survival rate.