CD86 molecule is the ligand for both costimulatory (CD28) and coinhibitory (CTLA-4) molecules, and it regulates immune response after allogeneic hematopoietic stem cell transplantation (alloHSCT). Therefore, we postulate that
Allogeneic hematopoietic stem cell transplantation (alloHSCT) has been established as an effective treatment for patients with hematological malignancies. With the aim of reducing the level of transplantation failure, several studies achieved to elucidate the immunological mechanism involved in this process. Graft-versus-host disease (GvHD) caused by donor-derived T-cells is one of the most common causes of morbidity and mortality after allogeneic HSCT [
Altogether, 295 adult patients (pts) undergoing related donor- (RD-) matched HSCT (105 pts) and unrelated donor- (URD-) matched HSCT (190 pts) at the Department of Hematology and Bone Marrow Transplantation, Medical University of Silesia, Katowice, between 2006 and 2010 were included in this study. This study was the continuation of the previous work published in immunogenetics [
Primary diagnoses for HSCT patients were as follows: acute myeloid leukemia—147, acute lymphoblastic leukemia—66, chronic myeloid leukemia—18, myelodysplastic syndrome—19, severe aplastic anemia—17, paroxysmal nocturnal hemoglobinuria—11, and other cases—17.
Bone marrow (BM) was the source of hematopoietic stem cells in 124 transplants, and peripheral blood progenitor cells (PBPC) were the source in 163 cases. For 8 recipients, a second transplantation was needed (second transplantation was from RD in 1 case and URD in 7 cases), and for double transplantation, the first source of hematopoietic cells was BM and the second was PBPC.
Myeloablative conditioning (MAC) regimens were based on cyclophosphamide with either busulfan or total body irradiation (TBI) or on melphalan, fludarabine, and alemtuzumab. Reduced-toxicity myeloablative conditioning (RTMAC) was based on treosulfan and fludarabine or cyclophosphamide. Reduced-intensity conditioning (RIC) consisted of fludarabine and busulfan. Antithymocyte globulin (ATG) was used in all recipients of HSCT from unrelated donors. SAA patients received cyclophosphamide and ATG.
The Local Ethics Committee approved this study, and all patients and controls gave their informed consent for the study procedures.
Genomic DNA was isolated from donors’ and recipients’ frozen whole blood using a QIAamp Blood mini kit (Hilden, Germany). The rs1129055 (named also as CD86+1057G>A or CD86A304T), rs9831894, and rs2715267 (named also as −3479T>G) SNPs were genotyped in recipient samples using the following TaqMan® SNP Genotyping Assays, respectively: C___7504226_10, C_____56422_10, and C__26193522_10 (Applied Biosystems, Foster City, USA). The rs1129055 was genotyped also in donors. Genotyping for SNPs was validated using direct sequencing.
Model coefficients and their 95% confidence intervals (95% CI) were estimated based on
To control type I error in the case of many tests for differences between cases’ and controls’ SNPs, genotypes adjusted for significance level were estimated. Because of correlation between SNPs, estimation of
Differences were considered to be statistically significant if the
No polymorphism data from donors and recipients demonstrated deviation from Hardy-Weinberg equilibrium.
We observed no linkage disequilibrium between all investigated
Linkage disequilibrium between
|
rs9831894 | rs2715267 |
---|---|---|
rs1129055 | 0.064 | 0.016 |
rs9831894 | — | 0.142 |
Haplotype analysis showed that the G-C-T haplotype (30.8%) was the most frequently observed in alloHSCT patients. Similar frequency was found for haplotype G-A-G (28%). For A-A-T and G-A-T haplotypes, the frequencies were 16.2% and 14.2%, respectively, and for the other, the frequencies were below 3.5% (Table
The frequencies of haplotypes in recipients for
Haplotypes (rs1129055, rs9831894, and rs2715267) | Number | Frequency |
---|---|---|
G-C-T | 165.24 | 0.308 |
G-A-G | 149.96 | 0.28 |
A-A-T | 87.09 | 0.162 |
G-A-T | 76.32 | 0.142 |
A-C-G | 18.92 | 0.035 |
A-A-G | 16.64 | 0.031 |
A-C-T | 12.35 | 0.023 |
G-C-G | 9.49 | 0.018 |
In univariate analysis, we found that none of the investigated
The distribution of genotypes in groups of patients with and without aGvHD in relation to
Recipients | aGvHD present | aGvHD absent | OR | 95% CI | aGvHD present versus aGvHD absent | |||
---|---|---|---|---|---|---|---|---|
|
% |
|
% | |||||
rs1129055 | GG | 77 |
|
76 |
|
1 |
— |
|
AG | 62 |
|
45 |
|
1.36 | 0.83–2.23 | ||
AA | 14 |
|
7 |
|
1.91 | 0.75–4.87 | ||
Σ | 153 |
|
128 |
|
— | |||
Hardy-Weinberg equilibrium | ||||||||
|
|
|||||||
|
||||||||
rs9831894 | AA | 57 |
|
47 |
|
1 |
— |
|
AC | 63 |
|
64 |
|
0.81 | 0.48–1.36 | ||
CC | 24 |
|
19 |
|
1.04 | 0.51–2.11 | ||
Σ | 144 |
|
130 |
|
— | |||
Hardy-Weinberg equilibrium | ||||||||
|
|
|||||||
|
||||||||
rs2715267 | TT | 69 |
|
52 |
|
1 |
— |
|
GT | 64 |
|
63 |
|
0.77 | 0.47–1.26 | ||
GG | 21 |
|
15 |
|
1.05 | 0.50–2.21 | ||
Σ | 154 |
|
130 |
|
— | |||
Hardy-Weinberg equilibrium | ||||||||
|
|
Donors | aGvHD present | aGvHD absent | OR | 95% CI | aGvHD present versus aGvHD absent | |||
---|---|---|---|---|---|---|---|---|
|
% |
|
% | |||||
rs1129055 | GG | 80 |
|
54 |
|
1 |
— |
|
AG | 55 |
|
46 |
|
0.81 | 0.48–1.36 | ||
AA | 11 |
|
13 |
|
0.58 | 0.24–1.36 | ||
Σ | 146 |
|
113 |
|
— | |||
Hardy-Weinberg equilibrium | ||||||||
|
|
Logistic regression analysis including recipient
The relapse incidences occurred in 32 patients. Twenty-six of them died due to this complication. None of the recipients’
Median follow-up was 24 months (range: 0.5–67.5). In the present cohort of patients, 198 recipients were alive and 97 died during the observation period. For the living patients, the median OS was 34.23 months (Q1 = 23.36, Q3 = 50.38), while for the dead recipients, the median OS was 5.53 months (Q1 = 2.77, Q3 = 13.48).
The Cox regression analysis showed that the recipients with the rs2715267GG genotype have increased risk of death (HR = 1.93; 95% CI: 1.14–3.08,
The presentation of overall survival times in relation to the
Proportion of survivors | 95% | 90% | 85% | 75% |
---|---|---|---|---|
rs2715267 | Time (months) | |||
TT | 2 | 3.83 | 5.53 | 18.38 |
TG | 2.33 | 3.73 | 5.47 | 11.77 |
GG | 1.43 | 2.3 | 3.5 | 5.07 |
The presence of the rs2715267GG genotype resulted in worse OS during 24-month observation than did the presence of the TT and GT genotypes, for which the OS was similar (48.4% versus 68.2% and 72.4%, log-rank
Overall survival in recipients of allogeneic HSCT in relation to rs2715267 polymorphism in the
In univariate analysis, we found no associations between
Based on the results described above and our previous data [
An analysis of the associations between two genetic factors and risk of aGvHD using the Svejgaard and Ryder method [
Factor A (carriers of A alleles for
aGvHD present | aGvHD absent | ||||
A+B+ | 35 | 13 | |||
A−B+ | 32 | 25 | |||
A+B− | 29 | 36 | |||
A−B− | 39 | 51 | |||
|
|||||
Test | OR |
|
95% CI | Comparison | Individual association |
(1) A | 1.58 | 0.07 | 0.97–2.58 | ||
(2) B |
|
|
|
||
(3) ++ versus −+ | 2.10 | 0.08 | 0.92–4.80 | A in B-positive | A association |
(4) +− versus −− | 1.05 | 0.87 | 0.55–2.00 | A in B-negative | |
(5) ++ versus +− |
|
|
|
B in A-positive | B association |
(6) −+ versus −− | 1.67 | 0.13 | 0.86–3.27 | B in A-negative | |
(7) +− versus −+ | 0.63 | 0.21 | 0.31–1.29 | Differences between A and B association | |
(8) ++ versus −− |
|
|
|
Combined association |
Factor A (carriers for the
aGvHD present | aGvHD absent | ||||
A+B+ | 36 | 14 | |||
A+B− | 32 | 41 | |||
A−B+ | 26 | 21 | |||
A−B− | 33 | 35 | |||
|
|||||
Test | OR |
|
95% CI | Comparison | Individual association |
(1) A | 1.l7 | 0.54 | 0.70–1.95 | ||
(2) B |
|
|
|
||
(3) ++ versus −+ | 2.08 | 0.09 | 0.89–4.83 | A in B-positive | A association |
(4) +− versus −− | 0.83 | 0.58 | 0.43–1.61 | A in B-negative | |
(5) ++ versus +− |
|
|
|
B in A-positive | B association |
(6) −+ versus −− | 1.31 | 0.47 | 0.62–2.77 | B in A-negative | |
(7) +− versus −+ | 0.63 | 0.22 | 0.30–1.32 | Differences between A and B association | |
(8) ++ versus −− |
|
|
|
Combined association |
Also, based on current and previous results, we used the Svejgaard and Ryder method to assess the influence of a recipient’s CT60GG genotype and a donor’s rs1129055GG genotype on the risk of aGvHD.
Possession of two susceptible factors: factor A (rs1129055GG genotype in donors) and factor B (CT60GG in recipients), increased the risk of aGvHD 2.73 times (OR 2.73, 95% CI: 1.25–5.95,
Posttransplant T-cell activation plays the key role in alloimmune reactivity that can lead to the recognition of non-self-antigens and cause GvHD or contribute to the elimination of leukemic cells (GVL) and to the prevention of an infection. The balance between alloreactivity and immunotolerance for recipient cells is of great importance. This balance is dependent on the strengths of the costimulatory and coinhibitory signals. In both situations, ligands for costimulatory (CD28) and coinhibitory (CTLA-4) molecules are CD80 and CD86. The role of
We focused our attention on associations of the three SNPs (rs1129055, rs9831894, and rs2715267) with aGvHD, relapse rate, and overall survival. The selection of SNPs was made on the basis of literature data, in silico analysis, and our previous study.
The results of a
The rs2715267T>G SNP was previously described by Abdallah et al. [
Moreover, in another immune tolerance-related disease, like asthma [
In our work on multiple sclerosis, we found that the presence of G allele (GT or GG genotype) in this SNP was associated with higher risk of this T-cell-dependent disease [
On the basis of literature data, we speculate that G allele confers susceptibility to autoimmune disease, which is associated with overstimulation of immune response, which might influence the overall survival of HSCT patients.
The current work includes also data from previous HSCT study on
What is more, the
The analysis in relation only to
Surprisingly, opposite genotypes of
The
In the literature, there is a limited number of studies about rs1129055 gene polymorphism and most of them are related to cancer risk. However, the results of the study in various cancers are different. The results for pancreatic cancer [
In our study of HSCT, donors’ rs1129055GG immunocompetent cells grafted to the recipients also increased the risk of enhanced immune response leading to aGvHD reaction.
On the other hand, the CD86 molecule is involved either in activation of T-cell response or in inhibition of this process. It depends on the balance between CD28 and CTLA-4 binding. Therefore, not only donors’ and recipients’ CD86 genetic background but also donors’ and recipients’
The third polymorphism, rs9831894, investigated by us which was described as the risk factor for Graves’ ophthalmopathy in a Taiwanese population [
The limitation of this study is the heterogenic group of donor-recipient pairs; however, we believe that the implementation of a multivariate logistic regression analysis, which includes other prognostic factors for aGvHD development, allows us to overcome this weakness. Moreover, probably due to the low relapse rate observed in our cohort of patients, we were not able to find any association between donor and recipient
In conclusion, the results of our study suggest that
The preliminary results of this study were presented as a mini-oral presentation during the 31st European Immunogenetics and Histocompatibility Conference (EFI) 25th Annual Meeting of the German Society for Immunogenetics (DGI) Mannheim/Heidelberg.
The authors declare that there is no conflict of interest regarding the publication of this article.
This work was supported by the Polish Ministry of Science and Higher Education, Poland (Grant no. N N402 285036). The cost of publication was financed by the Wrocław Centre for Biotechnology programme, the Leading National Research Centre (KNOW) for years 2014–2018. The authors are very grateful to their patients for the blood donation and participating in this study.
Supplementary Material 1: an analysis of the associations between two genetic factors and risk of aGvHD using the Svejgaard and Ryder method [