Double-blind, placebo-controlled trial of human lymphoblastoid interferon prophylaxis of cytomegalovirus infection in renal transplant recipients

We have conducted a double-blind, placebo-controlled trial of human lymphoblastoid interferon prophylaxis of cytomegalovirus (CMV) infection in 74 renal transplant recipients. Interferon (3 x 10(6) units was given thrice weekly for the first 6 weeks, then twice weekly for a further 8 weeks.During the period of interferon therapy, the incidence of CMV excretion was lower in the interferon group (28% versus 50%, P = 0.065), mainly due to a significant reduction of CMV reactivation (9% versus 56%, P = 0.02). However, for the whole study period (including the follow-up period after interferon therapy), there was no difference in the incidence of CMV excretion (44% versus 53%). The onset of CMV excretion was delayed (8.2 +/- 0.8 to 20.9 +/- 5.5 weeks, P = 0.04). The duration of CMV excretion was also reduced (11.1 +/- 3.1 to 29.4 +/- 5.7 weeks, P = 0.008). The number of positive CMV isolates from urine and saliva was significantly less in the interferon group. There was no difference in the site of CMV excretion. Of the patients in the treatment group who excreted CMV, 43% developed disease as compared to 63% in the control group (difference not significant). There was also no significant difference in the severity of the CMV infection between the two groups. Benefit appears to be restricted to seropositive recipients of seronegative kidneys.The interferon regime used in this study was well tolerated, with mild fever being the only reported side-effect. No patient had to stop therapy because of toxicity. The incidence of rejection and graft loss was not different between the two groups.