OBJECTIVE To retrospectively analyze the clinical features and prognostic factors of patients with angioimmunoblastic T-cell lymphoma (AITL). METHODS The clinicopathological and follow-up data of 18 AITL patients undergoing integrated treatment from Feb. 1998 to April 2009 in our department were retrospectively analyzed. All of the patients received CHOP-like regimens as initial chemotherapy, including 4 once treated with radiotherapy and 1 with high dose therapy followed by autologous stem cell transplantation (HDT-ASCT) as upfront consolidation therapy. B-cell, T-cell and NK-cell subgroup proportions in the peripheral blood were tested by flow cytometry in 6 patients. RESULTS The median age of the 18 patients was 55 years, male and female ratio was 2.6:1. Seventy-two percent of the patients were in an advanced stage. 72% of them had B symptoms, 69% hypergammaglobulinemia, 60% elevated LDH and 47% anemia. Forty-four percent achieved CR after initial treatment with CHOP-like regimens. With the median follow-up of 26 months, the overall 2-year survival and disease free survival (DFS) rates were 62.2% and 44.4%, respectively. In the univariate analysis, only age > 30 years and primary refractory disease adversely affected overall survival (OS); age > 30 years, advanced stage, B symptoms and splenomegaly adversely affected DFS. Four patients suffered from severe pneumonia during treatment, 2 of them died of respiratory failure. Flow cytometry of peripheral blood lymphocytes showed that 5 of the 6 tested cases had decreasing proportion of CD3(+)CD4(+) T cells, B cells and NK cells but elevated CD3(+)CD8(+) T cells. Two heavily treated patients achieved partial and complete response by thalidomide therapy, with a progression free survival (PFS) of 2 and 6+ months, respectively. CONCLUSIONS AITL patients do not response well to CHOP-like regimens chemotherapy. Age < 30 years and sensitive to initial chemotherapy are associated with prolonged OS. Effectiveness of thalidomide in the treatment of AITL deserves further investigation. Peripheral blood lymphocytes test indicates that AITL patients suffered from both natural and acquired immune defects.