A Promoter Polymorphism in the CD59 Complement Regulatory Protein Gene in Donor Lungs Correlates With a Higher Risk for Chronic Rejection After Lung Transplantation.

Complement activation leads primarily to membrane attack complex formation and subsequent target cell lysis. Protection against self-damage is regulated by complement regulatory proteins, including CD46, CD55, and CD59. Within their promoter regions, single-nucleotide polymorphisms (SNPs) are present that could influence transcription. We analyzed these SNPs and investigated their influence on protein expression levels. A single SNP configuration in the promoter region of CD59 was found correlating with lower CD59 expression on lung endothelial cells (p = 0.016) and monocytes (p = 0.013). Lung endothelial cells with this SNP configuration secreted more profibrotic cytokine IL-6 (p = 0.047) and fibroblast growth factor ß (p = 0.036) on exposure to sublytic complement activation than cells with the opposing configuration, whereas monocytes were more susceptible to antibody-mediated complement lysis (p < 0.0001). Analysis of 137 lung transplant donors indicated that this CD59 SNP configuration correlates with impaired long-term survival (p = 0.094) and a significantly higher incidence of bronchiolitis obliterans syndrome (p = 0.046) in the recipient. These findings support a role for complement in the pathogenesis of this posttransplant complication and are the first to show a deleterious association of a donor CD59 promoter polymorphism in lung transplantation.

Anti-ETAR and anti-AT1R autoantibodies are elevated in patients with endstage cystic fibrosis.

Autoantibodies against endothelin-1 type A receptor (ETAR) are present in systemic sclerosis complicated by lung fibrosis and pulmonary hypertension. As increased serum levels and local overproduction of endothelin-1 in the airways are reported in cystic fibrosis (CF) patients, we reasoned that anti-ETAR antibodies could be prevalent in endstage CF patients prior to lung transplantation (LTx). Also, ETAR autoantibodies are frequently associated with autoantibodies against the angiotensin II type 1 receptor (AT1R). We analyzed the presence of anti-ETAR and anti-AT1R autoantibodies in 43 LTx patients (chronic obstructive pulmonary disease (COPD), n=20; CF, n=13; interstitial lung disease (ILD), n=1). We observed overall higher anti-ETAR and anti-AT1R autoantibody titers in sera taken prior to LTx in the CF patient group as compared to COPD. No difference was found in autoantibody levels between patients with CF versus ILD. In sera taken post-LTx we found the same difference in anti-ETAR and anti-AT1R autoantibody titers between patients with CF versus COPD. No difference was found in antibody titers between sera taken prior to or 6 months after LTx. There was no association between autoantibody levels and other relevant demographic parameters, and we found no association between autoantibody titers and the development of the bronchiolitis obliterans syndrome. Both autoantibody titers were strongly correlated. We hypothesize that due to prolonged exposure to bacterial infection, increased levels of AT1R and ETAR result in a deregulated immune response causing autoantibody formation. Further research is expedient to elucidate the occurrence of autoantibodies against ETAR and AT1R and their role in disease progression.

Anti-BPIFA1/SPLUNC1: a new autoantibody prevalent in patients with endstage cystic fibrosis.

BACKGROUND: Bactericidal/permeability increasing protein fold containing family A (BPIFA) 1, is a secreted protein of the upper airways that shares structural homology with BPI and exhibits comparable antimicrobial capacities. We hypothesized that CF patients have circulating IgG or IgA anti-BPIFA1 autoantibodies, similarly as reported for BPI autoantibodies. METHODS: We analyzed pre- and post-transplantation sera from 67 endstage lung disease patients who underwent lung transplantation (LTx) because of COPD (n=27), CF (n=25), and ILD (n=15). RESULTS: Anti-BPIFA1 (48%) and anti-BPI (92%) were elevated in CF patients compared to healthy controls, with anti-BPIFA1 IgG isotype being most prevalent, whereas anti-BPI is of the IgA isotype. Levels of anti-BPI autoantibodies significantly declined post-LTx, whereas anti-BPIFA1 did not. No relation was found between autoantibodies against BPIFA1 and BPI. CONCLUSION: Our results indicate that BPIFA1 is a novel target for autoantibodies in CF. The function of these autoantibodies needed to be investigated in future studies.

Lung transplantation affects expression of the chemokine receptor type 4 on specific T cell subsets.

Alloreactive T cells that infiltrate the graft after lung transplantation (LTx) play a role in chronic rejection. Chemokines such as thymus and activation-regulated chemokine (TARC), macrophage-derived chemokine (MDC) and monocyte chemotactic protein-1 (MCP-1) are produced locally in the lung and attract T cells via chemokine receptor 4 (CCR4). In a TARC gradient, cells expressing CCR4(++) migrate more efficiently than CCR4(+) -expressing cells. In this study, we compared the CCR4 expression of T cells in blood from 20 lung transplant recipients to healthy controls. We then examined whether CCR4 expression is associated with the occurrence of chronic rejection. The CCR4(++) expression was decreased on CD4 T cells from LTx patients (P < 0·0001) when compared to healthy controls. The analysis of CD4 T cell subsets showed that this decrease was present on central memory, effector memory and terminally differentiated T cells (P = 0·0007, P < 0·0001 and P = 0·05, respectively), while a trend was found for naive CD4 T cells (P = 0·06). Also, the expression of CCR4(+) on regulatory T cells (T(regs) ) was decreased in LTx patients when compared to healthy controls (P = 0·02). Interestingly, the CCR4(++) expression on CD4 effector memory T cells was decreased in patients developing chronic rejection sometimes more than a year before the clinical diagnosis when compared to patients who did not (P = 0·04). The analysis of CD8 T cell subsets only showed the CCR4(+) expression to be increased significantly on effector memory and terminally differentiated CD8 T cells (P = 0·02, P = 0·03, respectively) in LTx patients, but no relation was found in chronic rejection. In conclusion, the expression of CCR4 on T cell subsets was altered after LTx and appears to be related to chronic rejection.