Mixed Rejection Is a Low Frequency Event and Not Just Cellular Rejection and C4d Deposition in the Cardiac Allograft

s S113 2012. H&E, C4d and CD68 of paraffin embedded sections were analyzed. We scored C4d and CD68 according to ISHLT 2011 classification and Acute cellular Rejction (ACR) according to ISHLT 1990 and 2005 . C4d EMBs positive were 182, with a prevalence of 6.4% in our population study. We calculated the rejection score and severe rejection score in all patients included in the study. Results: Results. In C4d positive EMBs ACR 0 was 71/136 (52%), 1A 40/136 (29%), 1B 13/136 (10%) grade 2 1/136 (1%), 3A 8/136 (6%), 3B 3/136 (2%). In C4d negative group ACR 0 was 1070/1767 (61%), 1A 477/1767 (27%), 1B 41/1767 (2%), 2 42/1767 (2,3%), 3A 130/1767 (7,3%), 3B 7/1767 (0,4%). The severe rejection score was higher in C4d positive patients 0,49±0,50 vs C4d negative patients0,27±0,26 (p= 0,04) . In patients with recurrent C4d positivity severe rejection score was higher 0,68±0,20 than in C4d negative patients 0,24±0,43 (p= 0,015). Conclusion: Conclusions. ACR and AMR coexist in HTx patients and are strictly related. In C4d positive EMBs a diffuse pattern of ACR (1B and 3B) was more frequently observed compared to C4d negative EMBs. Higher severe rejection score in AMR patients indicates that the two types of rejection interact and represent a new distinct pathological entity.