Introduction & Aim: We were curious about the relationship between recurrent antibody-mediated rejection of cardiac transplants and the proportion of total IgG-positive plasma cells in the inflammatory infiltrate and IgG4 subtype, and we planned a preliminary study.

Patients and Methods: 14 endomyocardial biopsy specimens from 12 patients whose clinical course with recurrent suspected or overt AMR and/or acute cellular rejection (ACR) attacks, performed at Başkent University were examined. Some biopsies from these patients, histopathologically diagnosed with acute rejection were selected, and immunoglobulin-G (IgG) and IgG4 stained immunohistochemical. And the frequency, ratio, and profile of plasma cells were evaluated in 1 high magnification area where the most concentrated inflammation area. PRA screening and DSA detection was performed by LUMİNEX method (One lambda. Inc., Canoga Park, CA, USA) and MFI 1.000 ≥ was considered positive.

Results: The proportion of IgG positive plasma cells exceeded 10% of the inflammatory infiltrate, for all cases. Although all biopsy sites were screened, no positive plasma cells were detected in the controlled IgG4 immunostaining. We noticed that there was an interesting positive correlation between IgG positive plasma cell count/HPF and anti HLA antibodies mean flouresance intensity (MFI) values (Table1).

Discussion: These findings brought to mind the newly defined 'plasma cell-rich acute rejection (PCRAR),' which has been associated with poor allograft prognosis in renal transplants. Plasma cell ratios in allograft hearts may be associated with a chronic insidious clinical course. For this reason, it may be possible to determine a meaningful threshold value for plasma cell count with controlled studies in larger case series.