Increased production of beta2-microglobulin after heart transplantation.

Serum beta2-microglobulin (beta2m) levels were measured to evaluate the state of immunoactivation in stable heart transplant recipients. Serum beta2m and renal function of 29 heart transplant recipients were compared with 16 control subjects, who were age and sex matched, and 11 patients with chronic kidney failure. Serum creatinine and 24-hour urine collection for albuminuria were used as markers of renal impairment. Heart transplant recipients with normal renal function (n = 7) had significantly elevated beta2m levels compared with control subjects: 2.6 +/- 0.9 vs 1.66 +/- 0.32 microg/ml, p < or = 0.05. Heart transplant recipients with impaired renal function (n = 22) had significantly elevated beta2m compared with the chronic kidney failure group: 4.42 +/- 1.3 vs 3.49 +/- 0.66 microg/ml (p < or = 0.05); although there was no significant difference in serum creatinine levels. Albuminuria excretion was significantly elevated in the chronic kidney failure group compared with the heart transplant recipients with impaired renal function (p < or = 0.05). Elevated serum beta2m in heart transplant recipients suggests increased beta2m production, reflecting increased immunoactivation. This observation could be useful in monitoring long-term immunosuppressive therapy.