[Effects of concentration of cyclosporine A on the early response to immunosuppressive therapy in severe aplastic anemia].

OBJECTIVE: To evaluate the effects of cyclosporine A (CsA) whole-blood concentration on the early response to immunosuppressive therapy (IST) in severe and very severe aplastic anemia (SAA/VSAA). METHODS: Ninety SAA/VSAA patients treated with rabbit antithymocyte globulin (ATG) plus CsA as first line therapy in our hospital were retrospectively analysed. CsA levels between the response group and non-response group, and response rates of patients with variant CsA levels were compared respectively. RESULTS: (1) There was no significant difference in the beginning unmodified CsA blood concentration between IST responded and non-responded SAA/VSAA patients. The beginning unmodified C(0) 133.91 ug/L in IST 2-month responders was higher than that of 49.9 ug/L in non-responded SAA patients (P = 0.009); (2) The mean CsA C(0) and C(2) levels during the third month following IST were significantly different in responders and non-responders(197.52 µg/L vs 161.49 µg/L, P = 0.024, and 738.76 µg/L vs 615.46 µg/L, P = 0.009), and no significant difference in other periods of IST (P > 0.05); (3) The response rate (87.5%) was significantly higher in patients with CsA C(0) ≥ 200µg/L the third month following IST than those of 55.6% in patients with CsA C(0) 150 - 200 µg/L (P = 0.023) and 59.3% in patients with CsA C(0) < 150 µg/L (P = 0.046), respectively. The response rate was significantly higher of C(2) ≥ 700 µg/L group than that of C(2) < 700 µg/L group (80.5%vs 55.3%, P = 0.012). CONCLUSIONS: The CsA concentration related to the early IST response. The third month CsA concentrations was the most important for the response and maintaining CsA levels with C(0) ≥ 200 µg/L and C(2) ≥ 700 µg/L may improve the response to IST in SAA/VSAA.