Reliability and usefulness of immunofluorescence in heart transplantation

To study the reliability and usefulness of immunofluorescence on heart biopsy specimens for routine monitoring of heart transplant recipients for rejection, frozen sections of 72 consecutive endomyocardial biopsy specimens from 18 heart transplant recipients during the first 6 weeks after transplantation (and later) and from 11 control specimens from donor hearts and other nontransplantation patients were studied. Fifteen patients received OKT3 induction. The diagnosis of vascular (humoral) rejection pattern as defined by Hammond was based on the microvascular deposition of immunoglobulin and C3 or C1q. Echocardiographic data and right-sided heart catheterization were obtained simultaneously.

The results showed that immunofluorescence was positive for a vascular rejection pattern in 60% (43 of 72) overall, in heart transplant recipients it was positive in 59% (36 of 61), and in control subjects it was positive in 63% (7 of 11). Most of the patients who had positive immunofluorescence had no hemodynamic compromise. Humoral rejection was not predicted by positive immunofluorescence in our study. We also found no correlation with either positive or negative immunofluorescence for the short-term or long-term outcome during the first 6 weeks after transplantation.

The usefulness of routine immunofluorescence in all surveillance heart biopsies is questionable as determined by this study.