Limits...
Altered functionality of anti-bacterial antibodies in patients with chronic hepatitis C virus infection.

Lamontagne A, Long RE, Comunale MA, Hafner J, Rodemich-Betesh L, Wang M, Marrero J, Di Bisceglie AM, Block T, Mehta A - PLoS ONE (2013)

Bottom Line: Since the alpha gal epitope is found on gut enterobacteria, it has been hypothesized that anti-gal antibodies are generated as a result of increased bacterial exposure in patients with liver disease.In addition, markers of microbial exposure were determined.In an analysis of serum from more than 100 patients with liver disease, we have shown that those with increased levels of this modified anti-gal antibody had increased levels of markers of bacterial exposure.

View Article: PubMed Central - PubMed

Affiliation: Drexel University College of Medicine, and Department of Microbiology and Immunology and Drexel Institute for Biotechnology and Virology, Doylestown, Pennsylvania, USA. anne.lamontagne@drexelmed.edu

ABSTRACT

Background: Using comparative glycoproteomics, we have previously identified a glycoprotein that is altered in both amount and glycosylation as a function of liver cirrhosis. The altered glycoprotein is an agalactosylated (G0) immunoglobulin G molecule (IgG) that recognizes the heterophilic alpha-gal epitope. Since the alpha gal epitope is found on gut enterobacteria, it has been hypothesized that anti-gal antibodies are generated as a result of increased bacterial exposure in patients with liver disease.

Methods: The N-linked glycosylation of anti-gal IgG molecules from patients with fibrosis and cirrhosis was determined and the effector function of anti-bacterial antibodies from over 100 patients examined. In addition, markers of microbial exposure were determined.

Results: Surprisingly, the subset of agalactosylated anti-gal antibodies described here, was impaired in their ability to mediate complement mediated lysis and inhibited the complement-mediated destruction of common gut bacteria. In an analysis of serum from more than 100 patients with liver disease, we have shown that those with increased levels of this modified anti-gal antibody had increased levels of markers of bacterial exposure.

Conclusions: Anti-gal antibodies in patients with liver cirrhosis were reduced in their ability to mediate complement mediated lysis of target cells. As bacterial infection is a major complication in patients with cirrhosis and bacterial products such as LPS are thought to play a major role in the development and progression of liver fibrosis, this finding has many clinical implications in the etiology, prognosis and treatment of liver disease.

Show MeSH

Related in: MedlinePlus

Peripheral markers of LPS exposure in patients with liver fibrosis correlate with the level of LRAGG.A) There is a statistically significant increase in the level of LPS Binding Protein (LBP) detected in the sera of patients with mild liver fibrosis (P = 0.0002) and also as a function of liver cirrhosis (P = 0.0013). B) A similar increase is seen in soluble CD14 (sCD14) with the progression of liver fibrosis to liver cirrhosis (P = 0.0020). C) There is a direct correlation between LBP and LRAGG (rS = 0.4168, P<0.0001) and between sCD14 and LRAGG (rS = 0.5287, P<0.0001) (D). rS denotes the Spearman’s correlation coefficient. For panels A & B, samples size is Normal, n = 20; Stage 1–2, n = 21; and Stage 5–6 (Cirrhosis), n = 39.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC3672197&req=5

pone-0064992-g004: Peripheral markers of LPS exposure in patients with liver fibrosis correlate with the level of LRAGG.A) There is a statistically significant increase in the level of LPS Binding Protein (LBP) detected in the sera of patients with mild liver fibrosis (P = 0.0002) and also as a function of liver cirrhosis (P = 0.0013). B) A similar increase is seen in soluble CD14 (sCD14) with the progression of liver fibrosis to liver cirrhosis (P = 0.0020). C) There is a direct correlation between LBP and LRAGG (rS = 0.4168, P<0.0001) and between sCD14 and LRAGG (rS = 0.5287, P<0.0001) (D). rS denotes the Spearman’s correlation coefficient. For panels A & B, samples size is Normal, n = 20; Stage 1–2, n = 21; and Stage 5–6 (Cirrhosis), n = 39.

Mentions: Since we have observed that patients with more advanced fibrosis show a reduced killing of alpha-gal containing target cells (Figure 3A) and actually inhibited complement mediated killing of bacteria (Figure 3B–C), it was of interest to see if these same people also had evidence of bacterial exposure in their circulation. We have done this through the measurements of markers of endotoxin exposure such as soluble CD14 (sCD14) and LPS binding protein (LBP) in patients with varying levels of liver fibrosis. Both of these proteins are upregulated in the presence of LPS and have been used by us and by others as markers of bacterial exposure [21]. Briefly, the levels of LBP and sCD14 were determined in patients with varying levels of liver fibrosis through the use of a commercially available anti-sCD14 and LBP ELISA kits. As Figure 4A shows, while all patients have basal levels of LBP (panel A) or sCD14 (panel B), patients with increasing levels of liver fibrosis have much greater levels of circulating sCD14 and LBP, suggesting that these patients may have increasing levels of LPS in their circulation. That is, normal patients (n = 21) have a mean of 8289 ng/ml (±702) of peripheral LBP, patients with limited fibrosis (n = 21) have 9836 ng/mL (±1382) and patients with advanced fibrosis/cirrhosis (n = 39) have 11877 ng/mL (±3471). A similar increase is observed with sCD14, where normal patients have a mean of 5843 ng/ml (±1394) of peripheral sCD14, patients with limited fibrosis have 6744 ng/mL (±1577) and patients with advanced fibrosis have 8599 ng/mL (±2913). For both LBP and sCD14, there was a statistically significant difference between the fibrosis groups (p<0.05; see figure 3). These data suggest that HCV patients, like HIV/HCV co-infected patients, may have increased levels of LPS exposure early in their liver fibrosis. Figures 4C–D show the relationship between the level of these peripheral markers of endotoxin exposure and the level of LRAGG. As this figure shows, there is a direct correlation between the level of LRAGG and the peripheral markers of endotoxin exposure. LRAGG was correlated both to LBP with a Spearman's correlation coefficient of 0.4168 (P<0.0001) and sCD14 with a Spearman's correlation coefficient of 0.5287 (P<0.0001). LPB and sCD14 also correlated with each other with a Spearman's correlation coefficient of 0.4665 (P<0.0001).


Altered functionality of anti-bacterial antibodies in patients with chronic hepatitis C virus infection.

Lamontagne A, Long RE, Comunale MA, Hafner J, Rodemich-Betesh L, Wang M, Marrero J, Di Bisceglie AM, Block T, Mehta A - PLoS ONE (2013)

Peripheral markers of LPS exposure in patients with liver fibrosis correlate with the level of LRAGG.A) There is a statistically significant increase in the level of LPS Binding Protein (LBP) detected in the sera of patients with mild liver fibrosis (P = 0.0002) and also as a function of liver cirrhosis (P = 0.0013). B) A similar increase is seen in soluble CD14 (sCD14) with the progression of liver fibrosis to liver cirrhosis (P = 0.0020). C) There is a direct correlation between LBP and LRAGG (rS = 0.4168, P<0.0001) and between sCD14 and LRAGG (rS = 0.5287, P<0.0001) (D). rS denotes the Spearman’s correlation coefficient. For panels A & B, samples size is Normal, n = 20; Stage 1–2, n = 21; and Stage 5–6 (Cirrhosis), n = 39.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3672197&req=5

pone-0064992-g004: Peripheral markers of LPS exposure in patients with liver fibrosis correlate with the level of LRAGG.A) There is a statistically significant increase in the level of LPS Binding Protein (LBP) detected in the sera of patients with mild liver fibrosis (P = 0.0002) and also as a function of liver cirrhosis (P = 0.0013). B) A similar increase is seen in soluble CD14 (sCD14) with the progression of liver fibrosis to liver cirrhosis (P = 0.0020). C) There is a direct correlation between LBP and LRAGG (rS = 0.4168, P<0.0001) and between sCD14 and LRAGG (rS = 0.5287, P<0.0001) (D). rS denotes the Spearman’s correlation coefficient. For panels A & B, samples size is Normal, n = 20; Stage 1–2, n = 21; and Stage 5–6 (Cirrhosis), n = 39.
Mentions: Since we have observed that patients with more advanced fibrosis show a reduced killing of alpha-gal containing target cells (Figure 3A) and actually inhibited complement mediated killing of bacteria (Figure 3B–C), it was of interest to see if these same people also had evidence of bacterial exposure in their circulation. We have done this through the measurements of markers of endotoxin exposure such as soluble CD14 (sCD14) and LPS binding protein (LBP) in patients with varying levels of liver fibrosis. Both of these proteins are upregulated in the presence of LPS and have been used by us and by others as markers of bacterial exposure [21]. Briefly, the levels of LBP and sCD14 were determined in patients with varying levels of liver fibrosis through the use of a commercially available anti-sCD14 and LBP ELISA kits. As Figure 4A shows, while all patients have basal levels of LBP (panel A) or sCD14 (panel B), patients with increasing levels of liver fibrosis have much greater levels of circulating sCD14 and LBP, suggesting that these patients may have increasing levels of LPS in their circulation. That is, normal patients (n = 21) have a mean of 8289 ng/ml (±702) of peripheral LBP, patients with limited fibrosis (n = 21) have 9836 ng/mL (±1382) and patients with advanced fibrosis/cirrhosis (n = 39) have 11877 ng/mL (±3471). A similar increase is observed with sCD14, where normal patients have a mean of 5843 ng/ml (±1394) of peripheral sCD14, patients with limited fibrosis have 6744 ng/mL (±1577) and patients with advanced fibrosis have 8599 ng/mL (±2913). For both LBP and sCD14, there was a statistically significant difference between the fibrosis groups (p<0.05; see figure 3). These data suggest that HCV patients, like HIV/HCV co-infected patients, may have increased levels of LPS exposure early in their liver fibrosis. Figures 4C–D show the relationship between the level of these peripheral markers of endotoxin exposure and the level of LRAGG. As this figure shows, there is a direct correlation between the level of LRAGG and the peripheral markers of endotoxin exposure. LRAGG was correlated both to LBP with a Spearman's correlation coefficient of 0.4168 (P<0.0001) and sCD14 with a Spearman's correlation coefficient of 0.5287 (P<0.0001). LPB and sCD14 also correlated with each other with a Spearman's correlation coefficient of 0.4665 (P<0.0001).

Bottom Line: Since the alpha gal epitope is found on gut enterobacteria, it has been hypothesized that anti-gal antibodies are generated as a result of increased bacterial exposure in patients with liver disease.In addition, markers of microbial exposure were determined.In an analysis of serum from more than 100 patients with liver disease, we have shown that those with increased levels of this modified anti-gal antibody had increased levels of markers of bacterial exposure.

View Article: PubMed Central - PubMed

Affiliation: Drexel University College of Medicine, and Department of Microbiology and Immunology and Drexel Institute for Biotechnology and Virology, Doylestown, Pennsylvania, USA. anne.lamontagne@drexelmed.edu

ABSTRACT

Background: Using comparative glycoproteomics, we have previously identified a glycoprotein that is altered in both amount and glycosylation as a function of liver cirrhosis. The altered glycoprotein is an agalactosylated (G0) immunoglobulin G molecule (IgG) that recognizes the heterophilic alpha-gal epitope. Since the alpha gal epitope is found on gut enterobacteria, it has been hypothesized that anti-gal antibodies are generated as a result of increased bacterial exposure in patients with liver disease.

Methods: The N-linked glycosylation of anti-gal IgG molecules from patients with fibrosis and cirrhosis was determined and the effector function of anti-bacterial antibodies from over 100 patients examined. In addition, markers of microbial exposure were determined.

Results: Surprisingly, the subset of agalactosylated anti-gal antibodies described here, was impaired in their ability to mediate complement mediated lysis and inhibited the complement-mediated destruction of common gut bacteria. In an analysis of serum from more than 100 patients with liver disease, we have shown that those with increased levels of this modified anti-gal antibody had increased levels of markers of bacterial exposure.

Conclusions: Anti-gal antibodies in patients with liver cirrhosis were reduced in their ability to mediate complement mediated lysis of target cells. As bacterial infection is a major complication in patients with cirrhosis and bacterial products such as LPS are thought to play a major role in the development and progression of liver fibrosis, this finding has many clinical implications in the etiology, prognosis and treatment of liver disease.

Show MeSH
Related in: MedlinePlus