In kidney transplant recipients, the expression of monocyte HLA-DR showed a significant decrease two weeks after transplantation compared with that before transplantation [24]

In kidney transplant recipients, the expression of monocyte HLA-DR showed a significant decrease two weeks after transplantation compared with that before transplantation [24]. cells, CD19+ B cells and natural killer (NK) cells, and median fluorescence intensity (MFI) of FKBP4 human being leukocyte antigen (HLA)-DR on monocytes and TMS CD64 on neutrophils. The machine learning models including support vector machine (SVM), logistic regression (LR), multi-layer perceptron (MLP) and random forest (RF) were applied for analysis. Results The pneumonia and stable groups showed significant difference in cell counts of each subpopulation and MFI of monocyte HLA-DR and neutrophil CD64. The SVM model by monocyte HLA-DR (MFI), neutrophil CD64 (MFI), CD8+ T cells (cells/l), NK TMS cells (cell/l) and TBNK (T cells, B cells and NK cells, cells/l) experienced the best TMS overall performance with the average area under the curve (AUC) of 0.940. The RF model best predicted the individuals who would progress into severe pneumonia, with the average AUC of 0.760. All the models had good overall performance validated by external data. Conclusions The immune monitoring panel was tightly associated with pneumonia in kidney transplant recipients. The models developed by machine learning techniques identified patients at risk and predicted the prognosis. Based on the results of immune monitoring, better individualized therapy might be achieved. kidney transplant, blood routine, procalcitonin, computed tomography 46 eligible pneumonia patients underwent the immune monitoring test during the first week after admission to hospital. The average time from admission to test was 2.20??2.08?days (2 patients received the test 7?days after admission and most cases received the first test within 3?days). Because they received the test when diagnosed with pneumonia, the average time from transplantation to receiving the test was the same as the time from transplantation to developing pneumonia, namely 14.67??15.24?months. Among them, 29 cases (63.0%) were between 3 and 12?months post transplantation, and 17 (37.0%) cases developed into severe pneumonia. As control, 100 eligible stable kidney transplant TMS recipients with the data of 100 assessments were randomly selected. The average time from transplantation to receiving the test was 10.33??8.47?months. The clinical characteristics of the pneumonia group and the stable group showed no significant difference in age, gender, donor source, time since transplant and CNI regimen. Obviously, the stable group had a better allograft function than the pneumonia group. Because 16 patients in the pneumonia group received transplants in other hospitals, the induction treatment was not available. As a result, the induction treatment showed significant difference in these two groups. The details were shown in Table ?Table11. Table 1 Clinical characteristics of the patients standard deviation, donation after citizens’ death, anti-thymocyte globulin, not available, calcineurin inhibitor, cyclosporine A *?Tested by Fishers exact test; #?Tested by MannCWhitney U test Similarly, patients receiving the immune monitoring test from January 1st, 2020 to March 31st, 2020 were collected as external data for validation. 110 patients received 174 assessments, but after exclusion, 10 pneumonia patients and 32 stable patients were enrolled. The characteristics of these patients were shown in Additional file 1: Table S2. Immune status characterized by the panel Compared with the stable group, the pneumonia group showed poor immune status, which was characterized by significantly lower cell counts of total T cells (CD3+ T cells), T cell subsets (CD4+ T cells and CD8+ T cells), B cells and NK cells (Table ?(Table2).2). Even though percentages of total T cells and NK cells showed statistical difference, they were not clinically significant (pneumonia vs stable, 76.79??11.71vs 73.35??10.28 for total T cells, human leukocyte antigen-DR, median fluorescence intensity, standard deviation, T, B and NK cells, natural.