Reference
Complete the bibliographic reference for the article according to AJE format.

Lin M, et al. Relation of an interleukin-10 promoter polymorphism to graft-versus-host disease and survival after hematopoietic-cell transplantation. NEJM. 2003;349:2201-2210.

Category of HuGE information
Specify the types of information (from the list below) available in the article:

1. Prevalence of gene variant
2. Gene-disease association
3. Gene-environment interaction
4. Gene-gene interaction
5. Genetic test evaluation/monitoring

2. Gene-disease associations

Hypothesis:  Polymorphisms in cytokine promoter regions that enhance or suppress cytokine expression may affect the severity of the inflammatory response involved in GVHD and associated survival. This study is meant to replicate the findings of other studies showing associations between a variety of cytokine promoter-region single-nucleotide polymorphisms and GVHD outcomes .

Gene(s)
Identification of the following:

1. Gene name
2. Chromosome location
3. Gene product/function
4. Alleles
5. OMIM #

1. Gene name: IL10
2. Chromosome location: 1q31-q32
3. Gene product/function: Interleukin 10; anti-inflammatory cytokine, influences Th2 differentiation
4. Alleles: -592 A/C; -819T/C; -1082A/G; -2763C/A; -3575T/A
5. OMIM#: 124092

1. Gene name: IL1B
2. Chromosome location: 2q14
3. Gene product/function: Interleukin 1 type B; mediates acute-phase response
4. Alleles: not specified
5. OMIM#: 147720

1. Gene name: IL1RA
2. Chromosome location: 2q14.2
3. Gene product/function: Interleukin 1 Receptor Antagonist; competes with IL-1 for IL-1R binding
4. Alleles: not specified
5. OMIM#: 147679

1. Gene name: TNFA
2. Chromosome location: 6p21.3
3. Gene product/function: Tumor Necrosis Factor-alpha; pro-inflammatory cytokine
4. Alleles: not specified
5. OMIM#: 191160

Environmental factor(s)
Identification of the major environmental factors studied (infectious, chemical, physical, nutritional, and behavioral)

none

1. Acute Graft versus Host Disease (GVHD), grade III or IV
2. Chronic GVHD
3. Death in remission

1. Case-control
2. Cohort 
3. Cross-sectional
4. Descriptive or case series
5. Clinical trial
6. Population screening

2. Cohort

Cohort definition
For study designs 2, 3, and 6, the following are defined, where available:

1. Cohort selection criteria
2. Exclusion criteria
3. Gender
4. Race/ethnicity
5. Age
6. Time period
7. Geographic location
8. Number of participants

Cohort 1:

1. Cohort selection criteria: Recipients of HLA-matched sibling Hematopoeitic Cell Transplant (HLA-A2 positive); availability of pre-transplant blood samples; use of methotrexate or cyclosporine prophylaxis for GVHD; availability of GVHD scores
2. Exclusion criteria: not specified
3. Gender: (recipient/donor) m/m 196 (34%) m/f 140 (25%) f/m 120 (21%) f/f 114 (20%)
4. Race/ethnicity: not specified
5. Age: 1.3-67.8, median 35.8
6. Time period: retrospective follow-up, 1981 to 2000
7. Geographic location:  not specified
8. Number of participants: 570 (number eligible not specified)

Cohort 2:

1. Cohort selection criteria: Recipients of HLA-matched sibling HCT (primarily HLA-A2 negative); availability of pre-transplant blood samples; use of methotrexate or cyclosporine prophylaxis for GVHD; availability of GVHD scores
2. Exclusion criteria: not specified
3. Gender: (recipient/donor) m/m 136 (32%) m/f 110 (26%) f/m 69 (16%) f/f 108 (26%)
4. Race/ethnicity: not specified
5. Age: .6-65.5, median 41.4
6. Time period: retrospective follow-up, 1981 to 2000
7. Geographic location:  not specified
8. Number of participants: 423 (number eligible not specified)

1. Environmental factor
2. Exposure assessment
3. Exposure definition
4. Number of participants with exposure data (% of total eligible)

N/A

1. Gene
2. DNA source
3. Methodology
4. Number of participants genotyped (% of total eligible) 

1. Gene: IL10
2. DNA source: Whole Blood
3. Methodology: BslI-based PCR-RFLP
4. Number of participants genotyped: all

1. Gene: IL1B
2. DNA source: Whole Blood
3. Methodology: AlwNI-based PCR-RFLP; TaqI-based PCR-RFLP
4. Number of participants genotyped: not specified

1. Gene: IL1RA
2. DNA source: Whole Blood
3. Methodology: AlwNI-based PCR-RFLP; TaqI-based PCR-RFLP
4. Number of participants genotyped: not specified

1. Gene: IL6
2. DNA source: Whole Blood
3. Methodology: BslI-based PCR-RFLP
4. Number of participants genotyped: not specified

1. Gene: TNFA
2. DNA source: Whole Blood
3. Methodology: BslI-based PCR-RFLP
4. Number of participants genotyped: not specified

1. Prevalence of gene variant
2. Gene-disease association
3. Gene-environment interaction
4. Gene-gene interaction
5. Genetic test evaluation/monitoring

Proportional hazards regression models were used with adjustment for known risk factors to evaluate associations between single polymorphisms and the following disease outcomes: acute GVHD, chronic GVHD and death in remission.

• Table 1
  Results in Cohort 1
• Table 2
  The cohorts were combined for further analyses. Two additional promoter polymorphisms were analyzed.
• Table 3
  Three proximal haplotypes (A-T-A, A-C-C, and G-C-C at positions -1082, -819, and -592) and the six resulting genotypes were analyzed for association with acute GVHD (see table 3).

Increased levels of IL-10 production resulting from single-nucleotide polymorphisms in the IL-10 promoter region, mitigate GVHD-associated inflammation and mortality.

Screening for relevant genotypes could be usefully incorporated into patient risk-assessment.

It is unlikely that a genetic test for IL10 promoter polymorphisms will ultimately prove useful, because the associations were very weak, and because the genotype associated with the highest risk is the most prevalent. Though this test could be used to assess risk, no alternative or additional treatment options are currently available for these individuals. Though prophylactic use of exogenous IL-10 is one possible treatment option, it would be advisable to test endogenous IL-10 rather than genotype to determine need and dosage, as IL-10 production is affected by several polymorphisms in the IL10 gene, and by production of myriad regulatory cytokines and other immune factors.

There is little evidence that a high-IL-10 phenotype in the relevant post-transplant period is associated with the -592A genotype. Tests of association between endogenous IL-10 production and the -592 polymorphisms have had conflicting results, possibly because they have been carried out in populations of patients with systemic lupus erythematosis and of patients with rheumatoid arthritis, both of which are inflammatory conditions likely to affect cytokine profiles. Testing endogenous IL-10 production pre-transplant in HCT recipients is problematic because patients have been undergoing extreme immunosuppressive treatments prior to transplant. However, this circumstance represents the environment in which IL-10 production post-transplant is hypothesized to affect GVHD outcomes. Thus, it may be appropriate to monitor IL-10 production as it develops post-transplant and as it varies according to genotype.

This study contributes to the body of literature suggesting an important role for IL-10 in GVHD outcomes and related immune responses. If it does not have immediate clinical applications, this finding adds to theoretical understanding of how IL-10 mediates inflammatory responses in a novel and immunologically interesting circumstance, that of immune-cell transplant.

Findings such as these may be useful in future therapeutic applications of IL-10, such as prophylaxis for GVHD in transplant recipients.