Immunologic Predictors of Liver Transplantation Outcomes in HIV-HCV Co-Infected Persons

Efficient T-Cell Compartment in HIV-Positive Patients Receiving Orthotopic Liver Transplant and Immunosuppressive Therapy

BACKGROUND

In patients undergoing orthotopic liver transplant (OLT), immunosuppressive treatment is mandatory and infections are leading causes of morbidity/mortality. Thus, it is essential to understand the functionality of cell-mediated immunity after OLT. The aim of the study was to identify changes in T-cell phenotype and polyfunctionality in human immunodeficiency virus-positive (HIV+) and -negative (HIV-) patients undergoing immunosuppressive treatment after OLT.

METHODS

We studied peripheral blood mononuclear cells from 108 subjects divided into 4 groups of 27: HIV+ transplanted patients, HIV- transplanted patients, HIV+ nontransplanted patients, and healthy subjects. T-cell activation, differentiation, and cytokine production were analyzed by flow cytometry.

RESULTS

Median age was 55 years (interquartile range, 52-59 years); the median CD4 count in HIV+ patients was 567 cells/mL, and all had undetectable viral load. CD4+ and CD8+ T-cell subpopulations showed different distributions between HIV+ and HIV- OLT patients. A cluster representing effector cells expressing PD1 was abundant in HIV- transplanted patients and they were characterized by higher levels of CD4+ T cells able to produce interferon-γ and tumor necrosis factor-α.

CONCLUSIONS

HIV- transplanted patients have more exhausted or inflammatory T cells compared to HIV+ transplanted patients, suggesting that patients who have already experienced a form of immunosuppression due to HIV infection respond differently to anti-rejection therapy.

Immunological profiles of HIV-positive recipients of liver transplant

BACKGROUND

Scarce data are available about immune cell frequencies in HIV-positive recipients of liver transplant. Alterations in immune subsets can lead to persistent immune activation and disease progression or reduced HIV-specific responses. In liver transplantation, impaired immune tolerance can lead to organ rejection.

METHODS

HIV-positive subjects with undetectable HIVRNA and CD4 > 100/mm3 were included. Control groups were non-transplanted HIV-positive patients with similar immunovirological parameters and healthy subjects. B cells (memory, transitional, and mature subsets), T cells (effector TH1, nonclassic TH1, TH17, TH1/17; T regulatory naïve and effector subsets and CD8+ T regulatory cells), and NK cells (CD56dim and CD56bright subsets) were analyzed by flow cytometry.

RESULTS

A total of 56 patients, including 14 HIV-positive transplant recipients (HIV-LT), 14 HIV-positive controls, and 28 healthy controls were included. Median age of HIV-LT patients was 54.9 years with median time from transplant of 7.6 years. Eleven (79%) were HIV/HCV coinfected. Compared to nontransplanted patients, HIV-LT displayed significantly increased frequency of T CD8+ cells, lower percentage of T CD4+ cell, and lower number of nonclassic TH1, TH1/17 cells and naïve T CD4+ regulatory cells (Tregs). Healthy controls showed increased numbers of B cell subsets and decreased percentage of T effector subpopulations compared to HIV-LT. Compared to HIV-positive patients, healthy controls had higher B cells, NK cells, CD4+ T cells, naïve CD4+ Tregs but lower CD8+ T cells, effector Tregs, CD8+ Tregs, and all T effector cell subsets.

CONCLUSIONS

Immune cell subpopulations potentially associated with HIV progression and organ rejection were detected in HIV-positive transplant recipients. We confirmed altered frequencies of B, T, and NK cell populations in HIV-positive liver transplant recipients compared to healthy controls. The imbalance among immune cell subsets deserves further studies to identify markers of transplant outcome and potential therapeutic targets.

End-Stage Renal Disease-Associated Gut Bacterial Translocation: Evolution and Impact on Chronic Inflammation and Acute Rejection After Renal Transplantation

Chronic inflammation in end-stage renal disease (ESRD) is partly attributed to gut bacterial translocation (GBT) due to loss of intestinal epithelium integrity. Increased levels of circulating lipopolysaccharide (LPS) –a surrogate marker of GBT– contribute to maintain a chronic inflammatory state. However, circulating LPS can be neutralized by lipoproteins and transported to the liver for elimination. While ESRD-associated GBT has been widely described, less is known about its changes and impact on clinical outcome after kidney transplantation (KT). One hundred and forty-six renal transplant recipients with serum samples obtained immediately before and 1 year after transplantation (1-Year post KT) were included. Intestinal epithelium integrity (iFABP), total LPS (by measuring 3-hydroxymyristate), LPS activity (biologically active LPS measured by the LAL assay), inflammatory biomarkers (sCD14 and cytokines), lipoproteins and LPS-binding proteins (LBP and phospholipid transfer protein [PLTP] activity) were simultaneously measured. At 1-Year post KT, iFABP decreased but remained higher than in normal volunteers. Total LPS concentration remained stable while LPS activity decreased. Inflammation biomarkers decreased 1-Year post KT. We concomitantly observed an increase in lipoproteins. Higher sCD14 levels before transplantation was associated with lower incidence of acute rejection. Although GBT remained stable after KT, the contemporary increase in lipoproteins could bind circulating LPS and contribute concomitantly to neutralization of LPS activity, as well as improvement in ESRD-associated chronic inflammation. Chronic exposure to LPS in ESRD could promote endotoxin tolerance and explain why patients with higher pre-transplant sCD14 are less prompt to develop acute rejection after transplantation.

Macrophage activation marker, soluble CD163, is an independent predictor of short-term mortality in patients with cirrhosis and bacterial infection

BACKGROUND & AIMS

Innate immune system dysfunction is common in advanced cirrhosis, with a central role of the monocyte/macrophage system. Monocytes and macrophages express the scavenger receptor CD163, which is regulated by inflammatory mediators. Cleavage of the receptor leads to the formation of soluble (s)CD163 that represents an anti-inflammatory response. We aimed to study the clinical importance of sCD163 in cirrhosis.

METHODS

Sera of 378 patients were assayed for sCD163 by ELISA [193 outpatients and 185 patients with acute decompensation (AD)]. A 5-year follow-up observational study was conducted to assess the possible association between sCD163 level and poor disease outcomes.

RESULTS

sCD163 level was associated with disease severity, but not with the presence of varices or prior variceal bleeding. In outpatients, sCD163 level did not predict the development of disease-specific complications or the long-term mortality. In patients with AD episode, sCD163 level was significantly higher compared to outpatients but only in the presence of bacterial infection (INF) (AD-INF:4586, AD-NON-INF:3792 and outpatients: 3538 ng/ml, P < 0.015 and P = 0.001, respectively). sCD163 level gradually increased according to severity of infection. During bacterial infections, high sCD163 level (>7000 ng/ml) was associated with increased mortality rate (42% vs. 17%, P < 0.001) and was identified as an independent predictor of 28-day mortality (hazard ratio:2.96, 95% confidence intervals:1.27-6.95) in multivariate Cox-regression model comprising aetiology, co-morbidity, model for end-stage liver disease score and leucocyte count as covariates.

CONCLUSIONS

High sCD163 level is useful to identify patients with high-risk of death during an AD episode complicated by bacterial infection. This finding serves as an additional hint towards the significance of anti-inflammatory response during bacterial infection.