A New Routine Immunity Score (RIS2020) to Predict Severe Infection in Solid-Organ Transplant Recipients

BACKGROUND Infection is a cause of morbidity and mortality in solid-organ transplantation (SOT). We evaluated a new score that is applied during the first month after transplantation. The score comprises biomarkers of innate and acquired immunity to predict infections in SOT. MATERIAL AND METHODS Prospectively collected blood samples from 377 heart, liver, or kidney recipients were analyzed at 2 centers in Madrid (Spain) and Lima (Peru). Biomarkers were tested before transplantation and at days 7 and 30 after transplantation. During the first 6 months after transplantation, 183 (48.5%) patients developed severe infections (bacterial infections and/or CMV disease). Risk for severe infection was assessed using logistic regression analysis. We designed a score, the routine immunity score (RIS2020), which is based on the sum of the hazard ratios (HRs) of each biomarker. RESULTS The risk factors for severe infection were as follows: Moderate IgG hypogammaglobulinemia (IgG <600 mg/dL at days 7 or 30, HR 2.07, 95% CI 1.37-3.12, p=0.0005, 2 points), CD4 <400 cells/uL at day 30 (HR 1.76, 95% CI 1.03-3.04, p=0.039, 2 points), C3 <80 mg/dL at day 30 (HR 2.18, 95%CI 1.16-4.06, p=0.014, 2 points), and CRP >3 mg/dL at day 30 (HR 2.11, 95% CI 1.12-3.97, p=0.02, 2 points). In patients with ≥4 points, the HR for infection was 5.18 (95% CI 3.06-8.75; p<0.001). RIS2020 was an independent predictor of severe infection in multivariate models. CONCLUSIONS An immunological score combining moderate IgG hypogammaglobulinemia and other parameters of innate and acquired immunity could better identify the risk for severe infection in SOT.