PILOT-STUDY OF LOW-DOSE AZATHIOPRINE IN PRESENSITIZED PATIENTS AWAITING HEART OR LUNG TRANSPLANTATION

In an effort to reduce the level of presensitization in patients on ou r heart and lung transplant waiting list, ten patients with random pan el reactivity persistently above 10% on monthly screening for duration s of 2 to 59 months were given low-dose azathioprine (25 to 75 mg/day) for 1 to 22 months. All patients had positive T-cell panel reactivity (10% to 70%) against specific (n = 6), multispecific (n = 1), or unde fined (n = 3) HLA loci, and four additional patients had positive B-ce ll panel reactivity (5% to 40%). No effect of azathioprine on panel re activity was seen in four of ten patients (40%), whereas a significant and sustained reduction in panel reactivity occurred in six patients (60%), all within 2 months of commencing azathioprine. All nonresponde rs had antibodies with class I (A locus) specificity, whereas all six responders had multispecific or undefined antibody specificities. A fo rmal trial of low-dose azathioprine in presensitized recipients is war ranted.