IMMUNOADSORPTION WITH PROTEIN-A IN HUMORAL REJECTION OF KIDNEY-TRANSPLANTS

The presence of alloantibodies may play a role in accelerated or acute humoral rejection. Different therapeutic strategies based on a remova l of anti donor antibodies and prevention of their resynthesis have be en used in the management of transplant rejection episodes. Immunoadso rption with staphylococcal protein A, a method to selectively remove i mmunoglobulin G, may represent a new treatment to reverse humoral reje ction in kidney transplantation. From 1991 to January 1996, such a met hod was used in 23 patients in whom an acute humoral rejection develop ed over a mean period of 14.1 +/- 9.5 days after operation. Twenty-two patients had been transplanted from living donors and one from a cada veric donor. The ages ranged from 23 to 58 years (mean, 34 +/- 10 year s). All transplants were performed according to a negative direct cros smatch. Basic immunosuppression included cyclosporine, steroids, azath ioprine, and antilymphocyte globulin or monoclonal antibodies (OKT3). Rejection was diagnosed on the basis of hematochemical tests, Doppler ultrasonography, and kidney biopsy. Only steroid and monoclonal and po lyclonal antibody resistant rejections with >165% positive direct cros smatches against the donor were treated with Protein A immunoabsorptio n. The procedure used is based on the treatment of 2-3 plasma volumes for the first 2 days and then every other day until a negative crossma tch is obtained, together with improvement in clinical status (mean tr eatments, 7.3 +/- 4.5 [range, 4-23]; mean duration of treatment, 12.3 +/- 10.2 days [range, 3-44]). From the start of treatment, azathioprin e is replaced by cyclophosphamide at a dose of 1-2 mg/kg/day. During t reatment, a remarkable fall in immunoglobulin G levels is achieved on the first day, whereas immunoglobulin M titers remain constant, with a slight decrease in serum albumin. Immediately after treatment, a nega tive crossmatch was found in 22 (95.6%) of 23 patients. In six patient s (26%), graft function did not recover, and one patient (4.3%) died. Preliminary results show that immunoabsorption with staphylococcal pro tein A may be an effective support in the treatment of humoral acute r ejection, particularly when it is performed as soon as an early diagno sis of humoral rejection is made. In fact, such treatment has a highly selective adsorption, allows treatment of large volumes of plasma, an d can achieve a rapid decrease in the titer of circulating immunoglobu lins.