Immunosuppression Modifications Based on an Immune Response Assay: Results of a Randomized, Controlled Trial.

BACKGROUND: An immune function assay shows promise for identifying solid organ recipients at risk for infection or rejection. The following randomized prospective study was designed to assess the clinical benefits of adjusting immunosuppressive therapy in liver recipients based on immune function assay results.

METHODS: Adult liver recipients were randomized to standard practice (control group; n = 102) or serial immune function testing (interventional group; n = 100) performed with a commercially available in vitro diagnostic assay (ImmuKnow; Viracor-IBT Laboratories, Lee's Summit, MO) before transplantation, immediately after surgery and at day 1, weeks 1 to 4, 6, and 8, and months 3 to 6, 9, and 12. The assay was repeated within 7 days of suspected/confirmed rejection/infection and within 1 week after event resolution.

RESULTS: Based on immune function values, tacrolimus doses were reduced 25% when values were less than 130 ng/mL adenosine triphosphate (low immune cell response) and increased 25% when values were greater than 450 ng/mL adenosine triphosphate (strong immune cell response). The 1-year patient survival was significantly higher in the interventional arm (95% vs 82%; P < 0.01) and the incidence of infections longer than 14 days after transplantation was significantly lower among patients in the interventional arm (42.0% vs. 54.9%, P < 0.05). The difference in infection rates was because of lower bacterial (32% vs 46%; P < 0.05) and fungal infection (2% vs 11%; P < 0.05). Among recipients without adverse events, the study group had lower tacrolimus dosages and blood levels.

CONCLUSIONS: Immune function testing provided additional data which helped optimize immunosuppression and improve patient outcomes.