Objective: This study evaluated the impact of bridge-to-transplant ventricular assist device support on development of acute cellular (ACR) and antibody-mediated rejection (AMR) with due consideration of seasonal behaviour in cardiac allografts. Method: We studied 263 consecutive right ventricular endomyocardial biopsies (EMB) between 01/2011 and 03/2012 prospectively. Paraffin-embedded sections were evaluated for acute cellular rejection, endothelial cell swelling and capillary deposition of C4d, C3d and IgA/M/G. The effects of VAD (n= 101) on ACR and AMR, classified according to the ISHLT, were studied for seasonal effects and compared to results of EMB harvested from patients without VAD support (n=162). Results: Our results did not reveal significant differences between the two groups in any given parameter. A positive correlation was found for endothelial cell swelling and capillary C4d deposition; the data failed to show a correlation between C4d and C3d deposition or C3d deposition and endothelial swelling. Complement and immunoglobulin depositions seemed to be more pronounced but without statistical significance in autumn and winter. Conclusion: Our results demonstrate only statistically insignificantly more pronounced capillary complement deposition in autumn and winter. The use of VAD did not predict development of AMR or ACR. The C3d staining does not add to the pathological diagnosis of AMR.