Efficacy of low-dose OKT3 as cytolytic induction therapy in heart transplantation

The need for prophylactic cytolytic treatment in heart transplantation is a controversial issue. Its use, however, might prevent the onset of cellular rejection in the immediate postoperative period, facilitating patient management. It has recently been suggested that the administration of these products at low doses might have the same immunologic impact and would reduce secondary effects and the cost of treatment.

In a nonrandomized retrospective study, we assessed 45 consecutive patients who underwent orthotopic heart transplantation in 1992 and 1993. Six patients who died before receiving the complete OKT3 dose were excluded. Twenty-three patients were treated with 5mg/day doses of OKT3 for 7 consecutive days. Another 16 patients received 2.5 mg of OKT3 for 7 consecutive days.

There were no significant differences between the two groups with respect to CD3 counts on days 2 (0.1% +/- 0.3% versus 0.04% +/- 0.25%; p > 0.05) and 6 (0.2% +/- 0.45% versus 0.1% +/- 0.3%; p > 0.05), number of rejection episodes (1.45% +/- 0.8% per year of follow-up versus 1.7% +/- 1.2%, p = 0.66), number of infectious complications (8 versus 3, p > 0.05), total methylprednisolone dose used to treat rejection crises (3900 +/- 2765 versus 3600 +/- 1963 mg; p = 0.71), adverse effects attributed to OKT3 (two versus none), or length of the postoperative hospital stay (36.8 +/- 19 versus 30.2 +/- 20.9 days).

As cytolytic induction therapy in heart transplantation, a daily regimen of 2.5 mg of OKT3 for 7 days achieves the same clinical and immunologic effect as the conventional 5 mg/day dose. In addition, it results in a considerable reduction in the cost of treatment.