ENDOMYOCARDIAL BIOPSY FINDINGS AFTER PHOTOPHERESIS TREATMENT OF CARDIAC TRANSPLANT REJECTION

Photopheresis is a potential therapy for allograft rejection in which reinfusion of mononuclear cells exposed to ultraviolet-A irradiation a fter pretreatment with 8-methoxypsoralen may initiate immunosuppressiv e responses. Endomyocardial biopsies (EMBs) of cardiac transplant reci pients with moderate acute rejection (IHSLT grades 2 and 3) treated wi th photopheresis (7 patients/9 treatments) and followed for six months or more were evaluated and compared with biopsies of patients treated with corticosteroids (7 patients/8 treatments) and followed for a sim ilar time period. The first posttreatment EMB showed improvement in 10 0% of corticosteroid-treated patients, compared with 56% of photophere sis-treated patients (p < 0.005). Interstitial infiltrates of >90% T-l ymphocytes were present in a greater percentage of photopheresis-treat ed patients than in corticosteroid-treated patients on the first five posttreatment EMBs (p < 0.005) as follows: EMB 1, 90% vs. 25%; EMB 2, 90% vs. 25%; EMB 3, 78% vs. 0%; EMB 4, 56% vs. 0%, EMB 5, 56% vs. 0%. Postphotopheresis EMBs also showed giant cell reaction in 1 patient an d extensive band-like infiltrates in 3 patients. Our results suggest t hat interstitial T-cell infiltrates are more prevalent and persist lon ger after photopheresis than after corticosteroid treatment of heart a llograft rejection. Whether these T-lymphocytes are alloreactive or me diate immunosuppressive signals is unknown. The use of new immunosuppr essive therapies may modify endomyocardial biopsy findings, requiring adjustment of the diagnostic criteria for assessing and grading allogr aft rejection.