The source matters: no impact of the CCL2/MCP-1-1-2518G polymorphism of the donor on renal allograft outcome during the first year after transplantation

The protective effect of MCP-1 -2518 A>G promoter polymorphism in Turkish chronic renal failure patients requiring long-term hemodialysis

OBJECTIVE

Monocyte chemoattractant protein-1 (MCP-1) plays a major role in the pathogenesis and progression of different types of human renal disease. Therefore, in this study, we aimed to investigate the effect of MCP-1 gene -2518 A>G promoter polymorphism in chronic renal failure (CRF) patients requiring long-term hemodialysis.

METHODS

The study population consisted of 201 adult CRF patients requiring long-term hemodialysis and 194 healthy controls. The polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique was used for genotyping of MCP-1 -2518 A>G polymorphism in the CRF patients and healthy controls.

RESULTS

There were statistically significant differences in terms of genotypic (χ (2) = 12.69, p = 0.02) and allelic (χ (2) = 5.72, p = 0.02) frequencies of MCP-1 -2518 A>G between CRF patients and control subjects. According to our results, in the patient group MCP-1 -2518 AA genotype frequency was significantly higher than that of control group. On the other hand, heterozygous AG genotype frequency in the control group was significantly higher than that of the study group. Three different main disease subgroups of CRF (hypertension, diabetes mellitus, and atherosclerosis) patients were also evaluated, and significant associations were found between hypertension (genotype: χ (2) = 9.28, p = 0.01; allele: χ (2) = 6.00, p = 0.01), atherosclerosis (genotype: χ (2) = 5.37, p = 0.02; allele: χ (2) = 4.13, p = 0.04), and distributions of MCP-1 -2518 A>G genotypes and alleles. However, no significant association was found between diabetes mellitus and distributions of MCP-1 -2518 A>G genotype and allele frequencies (genotype: χ (2) = 2.37, p = 0.3; allele: χ (2) = 1.88, p = 0.17).

CONCLUSION

Current data show that MCP-1 -2518 AA genotype may cause susceptibility to CRF, while G allele may have a protective effect against development of CRF. In addition, MCP-1 -2518 AA genotype seems to associate with CRF originated from hypertension and atherosclerosis in our study population.

Role of C-C motif ligand 2 and C-C motif receptor 2 in murine pulmonary graft-versus-host disease after lipopolysaccharide inhalations

Environmental exposures are a potential trigger of chronic pulmonary graft-versus-host disease (pGVHD) after successful recovery from hematopoietic cell transplant (HCT). We hypothesized that inhalations of LPS, a prototypic environmental stimulus, trigger pGVHD via increased pulmonary recruitment of donor-derived antigen-presenting cells (APCs) through the C-C motif ligand 2 (CCL2)-C-C motif receptor 2 (CCR2) chemokine axis. B10.BR(H2(k)) and C57BL/6(H2(b)) mice underwent allogeneic (Allo) or syngeneic (Syn) HCT with wild-type (WT) C57BL/6, CCL2(-/-), or CCR2(-/-) donors. After 4 weeks, recipient mice received daily inhaled LPS for 5 days and were killed at multiple time points. Allo mice exposed to repeated inhaled LPS developed prominent lymphocytic bronchiolitis, similar to human pGVHD. The increase in pulmonary T cells in Allo mice after LPS exposures was accompanied by increased CCL2, CCR2, and Type-1 T-helper cytokines as well as by monocytes and monocyte-derived dendritic cells (moDCs) compared with Syn and nontransplanted controls. Using CCL2(-/-) donors leads to a significant decrease in lung DCs but to only mildly reduced CD4 T cells. Using CCR2(-/-) donors significantly reduces lung DCs and moDCs but does not change T cells. CCL2 or CCR2 deficiency does not alter pGVHD pathology but increases airway hyperreactivity and IL-5 or IL-13 cytokines. Our results show that hematopoietic donor-derived CCL2 and CCR2 regulate recruitment of APCs to the Allo lung after LPS exposure. Although they do not alter pathologic pGVHD, their absence is associated with increased airway hyperreactivity and IL-5 and IL-13 cytokines. These results suggest that the APC changes that result from CCL2-CCR2 blockade may have unexpected effects on T cell differentiation and physiologic outcomes in HCT.

Early urinary CCL2 is associated with the later development of interstitial fibrosis and tubular atrophy in renal allografts

BACKGROUND

Chronic renal allograft injury resulting in progressive interstitial fibrosis and tubular atrophy (IFTA) is a leading cause of graft loss. The goal of this study was to identify early urinary predictors for the subsequent development of IFTA in a prospective cohort of patients (n=111) who underwent serial protocol biopsies at 0, 6, and 24 months.

METHODS

The urinary proteins evaluated were CCL2, CXCL9, CXCL10, and alpha1-microglobulin (alpha1M) using ELISA and immunonephelometry.

RESULTS

We first evaluated urines obtained at 1 to 3 months and found that alpha1M and CXCL10 were associated with IFTA at 6 months but not at 24 months. Next, we evaluated urines at 6 months and found that CCL2 was associated with both IFTA and graft dysfunction at 24 months. On univariate analysis, 6-month urinary CCL2 was a risk factor for developing 24-month IFTA, defined as ci+ct score more than 0 (odds ratio 1.045, 95% confidence interval: 1.005-1.084, P=0.028). Furthermore, CCL2 remained an independent predictor of IFTA on multivariate analysis (odds ratio 1.049, 95% confidence interval: 1.006-1.094, P=0.024) when adjusted for donor age, delayed graft function, deceased donation, and angiotensin-converting enzyme inhibitor/angiotensin receptor blocker exposure. In comparison, alpha1M, CXCL9, and CXCL10 were not associated with late graft outcomes.

CONCLUSION

This study demonstrates that early urinary CCL2 is an independent predictor for the subsequent development of IFTA at 24 months.