Kidney Transplantation/immunology; Liver Transplantation/immunology; Neutrophils/metabolism; Opportunistic Infections/immunology; Pancreas Transplantation/immunology; Postoperative Complications/diagnosis; Postoperative Complications/immunology; Receptors, IgG/blood; Adult; Aged; Biomarkers/blood; Flow Cytometry; Germany; Graft Rejection/physiopathology; Graft Rejection/prevention & control; HLA-DR Antigens/blood; HLA-DR Antigens/immunology; Humans; Kidney Transplantation/pathology; Liver Transplantation/pathology; Lymphocyte Count; Middle Aged; Monocytes/immunology; Monocytes/metabolism; Neutrophils/immunology; Opportunistic Infections/blood; Opportunistic Infections/microbiology; Opportunistic Infections/physiopathology; Pancreas Transplantation/pathology; Postoperative Complications/blood; Postoperative Complications/microbiology; Postoperative Complications/physiopathology; Prognosis; Receptors, IgG/immunology; Sensitivity and Specificity