Hypocomplementemia in Kidney Transplant Recipients: Impact on the Risk of Infectious Complications

Abstract

The usefulness of monitoring of complement levels in predicting the occurrence of infection in kidney transplant (KT) recipients remains largely unknown. We prospectively assessed serum complement levels (C3 and C4) at baseline and at months 1 and 6 in 270 patients undergoing KT. Adjusted hazard ratios (aHRs) for infection in each posttransplant period were estimated by Cox regression. The prevalence of C3 hypocomplementemia progressively decreased from 21.5% at baseline to 11.6% at month 6 (p = 0.017), whereas the prevalence of C4 hypocomplementemia rose from 3.7% at baseline to 9.2% at month 1 (p = 0.004). Patients with C3 hypocomplementemia at month 1 had higher incidences of overall (p = 0.002), bacterial (p = 0.004) and fungal infection (p = 0.019) in the intermediate period (months 1-6). On multivariate analysis C3 hypocomplementemia at month 1 emerged as a risk factor for overall (aHR 1.911; p = 0.009) and bacterial infection (aHR 2.130; p = 0.014) during the intermediate period, whereas C3 hypocomplementemia at month 6 predicted the occurrence of bacterial infection (aHR 3.347; p = 0.039) in the late period (>6 month). A simple monitoring strategy of serum C3 levels predicts the risk of posttransplant infectious complications in KT recipients.

Clinical immune‐monitoring strategies for predicting infection risk in solid organ transplantation

“…The utility of this strategy has been shown in a prospective study of 270 kidney transplant recipients, in which the presence of C3 hypocomplementemia (serum levels <83.0 mg dl −1 ) at month 1 was as an independent risk factor for the subsequent occurrence of overall and bacterial infection (hazard ratios of 1.9 and 2.1, respectively). 35 Comparable findings have been reported for liver 36 and heart transplant recipients. 37 Unfortunately, the only intervention that seems feasible in a patient with low complement levels consists of decreasing immunosuppression, which in turn could increase the risk of graft rejection.…”

Management of immunosuppressive therapy in liver transplant recipients who develop bloodstream infection

“…Finally, we did not collect any parameter to define the “net state of immunosuppression” such as peripheral lymphocyte subpopulations, serum immunoglobulins, and serum complement that could have influenced predisposition to and outcome of the infectious complications in our patients.…”

Clinical, cellular, microscopic, and ultrastructural studies of a case of fibrogenesis imperfecta ossium

“…Increased susceptibility to both Gram-positive and Gram-negative bacterial infection have been described with C3 deficiency. 27,28 Osteoblasts can be stimulated to produce C3 by 1,25-dihydroxyvitamin D. 29 In culture experiments when anti-C3 antibody was used, osteoclast formation was greatly inhibited. 30 There has been no evidence for cleavage of C3 in either osteoblasts or osteoclasts.…”