Mismatch-specific anti-HLA antibody production following aorta transplants

Donor-specific anti-HLA antibodies after bone-graft transplantation. Impact on a subsequent renal transplantation: a case report

Immunological evaluation by panel-reactive antibody (PRA) and determination of anti-HLA specificity are important phases in the evaluation of patients awaiting kidney transplantation. The main causes of immunization are previous solid organ transplantation, hemotransfusion, and pregnancy. It is also possible that immunogenicity can be triggered by vascularized tissue grafts. Immune induction by cryopreserved bone prostheses is not yet understood. A 19-year-old patient with osteosarcoma had undergone resection of the left proximal tibia with reconstruction using human bone in 1997. The donor HLA typing was as follows: A3, A29 (19); B44 (12), Bw4; DR13 (6), DR7, DR52, DR53. The patient was subsequently enrolled onto the waiting list for cadaveric donor kidney transplantation due to chronic kidney failure caused by cisplatin toxicity. Pretransplantation immunological screening using the complement-dependent cytotoxicity (CDC) technique revealed a PRA of 63%. IgG antibody specificities were detected against class I and class II donor antigens, specifically anti-A3, B44, DR7 antibodies, using flow cytometry (Tepnel Luminex). Further immunological studies using single HLA specificity analysis (LSA Class I degrees -II degrees , Tepnel-Luminex) showed direct antibodies against all donor antigen specificities. This case showed immune induction after the implantation of bone prosthesis in a kidney transplant candidate, underlining the importance of the availability of HLA typing data of donors of a human prosthesis.

Vascular Tissue Banking: State of the Art

INTRODUCTION

The cardiovascular homograft banks in Italy were set up in 1994 in Milan (Lombardia) and Treviso (Veneto) and in 2001 in Bologna, Emilia Romagna. In this study we briefly summarize the data from Emilia Romagna Cardiovascular Tissue Bank.

MATERIAL AND METHODS

In Emilia Romagna, vascular homografts were harvested from brain-dead multiorgan donors (aged 15-55 years) by a dedicated vascular surgery team. All donors were virologically screened for human immunodeficiency virus (HIV), hepatitis B and C, Treponema pallidum, cytomegalovirus (CMV), and Toxoplasma. After transferring the vascular homografts to Emilia Romagna Cardiovascular Tissue Bank facilities, the arteries were prepared, classified (class III to I), and transferred to an antibiotic-containing solution under a laminar flow cabinet. After the decontamination, all homografts were cryopreserved and stored in the vapour phase of liquid nitrogen. Microbiological tests were performed in all phases of preparation. Samples were routinely taken from 1 vessel and formalin fixed for the histology. Bags with cryopreserved homografts were sent in dry ice to the hospitals when required and thawing protocol of the Bank was included.

RESULTS AND CONCLUSIONS

From January 2002 to October 2004, 543 homografts from 125 heart-beating donors were harvested and transferred to Emilia Romagna Cardiovascular Tissue Bank. After preparation, 459 of 543 (85%) were cryopreserved and stored. Vascular homografts classified class I were discarded. Other criteria of rejection were: (1) positive serology, and (2) persistent positive microbiology after decontamination. From March 2002, 333 cryopreserved homografts were assigned to several vascular surgery departments in Italy. The assessment of 3-year activity of Emilia Romagna Cardiovascular Tissue Bank might be used as an indicator of the efficiency of selecting, cryopreserving, and allocating quality-controlled vascular homografts.

Immune response following fresh arterial homograft replacement for aortoiliac graft infection

INTRODUCTION

this prospective study defines the immune response to fresh arterial homograft replacement for graft infection.

MATERIALS AND METHODS

ten patients who underwent ABO-compatible homograft transplantation were studied for anti-HLA antibody production, and CD3-CD4-CD8-positive lymphocytes subset. Immunological studies were performed preoperatively, and at early (1, 3, 7 days) and late (1, 3, 6, 12, 18, 24 months) follow-up. All patients received immunosuppressive treatment with cyclosporine (1-3 mg/kg/day). Abdominal CT scans were performed postoperatively at the 1, 6, 12, 18, 24 months follow-up.

RESULTS

preoperatively, antibodies could not be detected. Postoperatively, as from 1st month post-transplant, a progressive increase in % PRA was observed in all patients, up to the 12th month of follow-up. Subsequently, at 18 and 36 months, a progressive decrease in % PRA was detected. Data showed that the recipient antibodies were directed against donor-specific antigens. During the immediate postoperative period (1, 3, 7 days) CD3- and CD4-positive T lymphocytes slightly increased, whereas CD8 simultaneously decreased. Later, CD3 and CD4 progressively decreased and CD8 increased. Clinically, all patients were cured of infection at late follow-up. CT scans showed thickening of the aortic wall (range: 2.5-4.5 mm), with no signs of aneurysmal degeneration.

CONCLUSIONS

fresh arterial homografts are immunogenic. Implanted homografts induce a strong anti-HLA antibody response, similar to chronic rejection, in spite of immunosuppressive treatment.