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Felix edited this page Jan 25, 2016 · 15 revisions

1 Interaction Test

When an allele or residual was associated (p < 0.05) with the disease, tests for independence, difference in association, combined action, interaction and linkage disequilibrium (LD) are used to determine the strongest association.

Table 1 Number of individuals with/without (+/-) factor A and/or factor B.

Factor A Factor B Number of Cases Number of Controls
+ + x1 y1
+ - x2 y2
- + x3 y3
- - x4 y4

Table 2 Summary of the ten tests (2x2 Tables)

Comparison a b c d Test [Number]
A vs. non-A x1+x2 x3+x4 y1+y2 y3+y4 [1] A associated?
B vs. non-B x1+x3 x2+x4 y1+y3 y2+y4 [2] B associated?
++ vs. -+ x1 x3 y1 y3 [3] A associated in B-positives?
+- vs. -- x2 x4 y2 y4 [4] A associated in B-negatives?
++ vs. +- x1 x2 y1 y2 [5] B associated in A-positives?
-+ vs. -- x3 x4 y3 y4 [6] B associated in A-negatives?
+- vs. -+ x2 x3 y2 y3 [7] Difference between A and B association?
++ vs. -- x1 x4 y1 y4 [8] Combined A-B association?
Association A and B in Cases x1 x2 x3 x4 [9] Linkage disequilibrium in cases
Association A and B in Controls y1 y2 y3 y4 [10] Linkage disequilibrium in controls
Both test 3 and test 4 are significant: A is associated with the disease independently of B.
Both test 5 and test 6 are significant: B is associated with the disease independently of A.
Both test 3 and test 5 are significant: A and B show interaction.
Test 7 is significant: Difference between A and B is associated with the disease.
Test 8 is significant: A and B have combined action.
Test 9 is significant: A and B are in LD in cases.
Test 10 is significant: A and B are in LD in controls.

2 Options

--file input0.txt      [Mandatory]
--interaction           [Mandatory]
--test                  [Default]
--level                 [Default]
--out output.txt        [Default]
--print                 [Optimal]
--consensus             [Optimal, for residual level only]
--digit                 [Default, for allele level only]
--freq                  [Default, for allele level only]    

2.1 Level to test (--level)

Two levels --level residue and --level allele for amino acid and allele test, respectively. Default is --level residue.

2.2 Test to be used (--test)

Only --test fisher and --test chisq can be used here. Default is --test fisher.

2.3 Digits resolution (--digit)

Test of association using two digits, four digits or six digits. When two was used, alleles such as A*02:01 and A*02:06 will be combined as A*02. Default value is 4.

2.4 Minimal allele/allele group frequency (--freq)

A value between 0 and 1. Only alleles/allele groups have frequency higher than this threshold will be included in association analysis. Default value is 0.

2.5 Output file name (--out)

Default value is output.txt.

2.6 Print output to screen (--print)

Specify --print will print all results to screen (still write results to the output file).

2.7 Consensus sequence (--consensus)

When low resolution HLA typing was used in the input file, the program takes the consensus string of all possible high-resolution HLA typings, marking polymorphic amino acid positions as unknown.

3 Examples

3.1 Residue level

python PyHLA.py --file input0.txt --interaction --consensus

By default, Fisher's exact test was used. Each ID contains three parts: gene, position and residue. OR is the odds ratio calculated with Haldane's correction of Woolf's method. P3-P10 and OR3-OR10 are the p-value and odds ratio for tests listed in table 2, respectively.

ID1         ID2                   P3          P4          P5          P6          P7          P8          P9         P10       OR3       OR4       OR5       OR6       OR7       OR8       OR9      OR10
A_57_P      B_45_T            0.3897      0.0365      0.0456      1.0000      0.4365      0.0234      1.0000      1.0000      4.71     11.64      1.21      3.00      3.88     14.14      0.58      1.44
A_57_P      B_62_G            1.0000      0.0148      0.0473      1.0000      1.0000      0.0076      1.0000      1.0000      1.69     14.61      1.27     11.00      1.33     18.59      0.23      1.97
A_57_P      B_65_R            1.0000      0.0148      0.0473      1.0000      1.0000      0.0076      1.0000      1.0000      1.69     14.61      1.27     11.00      1.33     18.59      0.23      1.97
A_57_P      B_66_N            1.0000      0.0148      0.0473      1.0000      1.0000      0.0076      1.0000      1.0000      1.69     14.61      1.27     11.00      1.33     18.59      0.23      1.97
A_57_P      B_67_M            1.0000      0.0148      0.0473      1.0000      1.0000      0.0076      1.0000      1.0000      1.69     14.61      1.27     11.00      1.33     18.59      0.23      1.97
A_57_P      B_67_Y            0.2025      0.0646      0.0330      1.0000      0.1607      0.0913      1.0000      1.0000      6.14     10.49      0.82      1.40      7.49      8.59      0.61      1.04
A_57_P      B_70_Q            0.2025      0.0646      0.0330      1.0000      0.1607      0.0913      1.0000      1.0000      6.14     10.49      0.82      1.40      7.49      8.59      0.61      1.04
A_57_P      B_70_S            1.0000      0.0148      0.0473      1.0000      1.0000      0.0076      1.0000      1.0000      1.69     14.61      1.27     11.00      1.33     18.59      0.23      1.97
A_57_P      B_74_D            0.1988      0.0636      0.0363      1.0000      0.1590      0.0888      1.0000      1.0000      6.24     10.59      0.82      1.40      7.56      8.73      0.78      1.33
A_57_P      B_77_S            0.0146      1.0000      0.0490      1.0000      0.0071      1.0000      1.0000      1.0000     14.67      1.74      0.77      0.09     19.13      1.33      5.57      0.66
A_57_P      B_80_I            1.0000      0.0162      0.0148      1.0000      1.0000      0.0080      1.0000      0.3334      1.65     14.16      1.28     11.00      1.29     18.12      0.46      3.98
A_57_P      B_80_N            0.0346      0.3667      0.0279      1.0000      0.0186      0.4307      1.0000      0.5405     11.91      5.22      0.76      0.33     15.65      3.97      4.53      1.98
A_57_P      B_82_R            0.0346      0.3667      0.0279      1.0000      0.0186      0.4307      1.0000      0.5405     11.91      5.22      0.76      0.33     15.65      3.97      4.53      1.98
A_57_P      B_83_G            0.0346      0.3667      0.0279      1.0000      0.0186      0.4307      1.0000      0.5405     11.91      5.22      0.76      0.33     15.65      3.97      4.53      1.98
A_57_P      B_152_V           0.0347      0.3631      0.0228      1.0000      0.0179      0.4312      1.0000      0.5309     11.89      5.30      0.75      0.33     15.89      3.96      4.59      2.04
A_57_P      C_1_G             1.0000      0.0129      0.0243      1.0000      1.0000      1.0000      1.0000      1.0000      0.23     15.31      0.17     11.00      1.39      2.54      0.00      0.09
A_57_P      C_165_E           1.0000      0.0129      0.0243      1.0000      1.0000      1.0000      1.0000      1.0000      0.23     15.31      0.17     11.00      1.39      2.54      0.00      0.09
A_57_P      DQA1_25_Y         0.0120      1.0000      0.0219      1.0000      0.0599      1.0000      1.0000      1.0000     15.72      0.98      1.46      0.09     10.74      1.43     12.88      0.80
A_57_P      DQB1_14_M         0.0123      1.0000      0.0046      1.0000      0.1487      1.0000      1.0000      1.0000     15.58      0.69      2.06      0.09      7.57      1.42     42.74      1.89
A_57_P      DQB1_53_L         0.0287      0.4765      0.0488      1.0000      0.0528      0.4110      1.0000      0.5746     12.91      3.32      1.30      0.33      9.96      4.30      6.97      1.79
...

3.2 Allele level

python PyHLA.py --file input0.txt --interaction --level allele --freq 0.01

By default, Fisher's exact test and 4 digit allele was used.

ID1         ID2                   P3          P4          P5          P6          P7          P8          P9         P10       OR3       OR4       OR5       OR6       OR7       OR8       OR9      OR10
A*11:77     B*35:01           1.0000      0.0793      1.0000      0.0595      0.7396      0.4127      0.6210      1.0000      0.39      0.67      0.35      0.59      1.13      0.23      0.44      0.76
A*11:77     B*58:01           0.8144      0.0493      0.3127      0.0879      0.0072      1.0000      0.1053      0.6684      0.87      0.61      1.79      1.25      0.49      1.09      1.83      1.28
A*11:77     DQA1*02:01        0.5562      0.1022      0.7598      0.1128      0.6857      0.2500      0.4217      0.3392      0.66      0.68      0.75      0.78      0.87      0.51      1.49      1.54
A*11:77     DRB1*04:66        0.2609      0.1014      1.0000      0.0209      0.0033      0.4209      0.6364      0.5004      0.11      0.69      0.35      2.18      0.32      0.24      0.35      2.20
B*35:01     DQA1*02:01        1.0000      0.0359      1.0000      0.0851      0.3555      0.6945      0.5018      1.0000      0.92      0.56      1.24      0.76      0.74      0.70      1.52      0.92
B*35:01     DRB1*04:66        0.2609      0.0813      1.0000      0.0209      0.0027      0.4214      1.0000      0.3831      0.11      0.62      0.39      2.18      0.28      0.24      0.58      3.20
B*58:01     DQA1*02:01        0.1916      0.1199      1.0000      0.0622      0.0091      0.6062      0.2718      1.0000      1.69      1.23      0.99      0.72      1.70      1.22      1.37      0.99
B*58:01     DRB1*04:66        0.4124      0.0413      1.0000      0.0192      0.1095      1.0000      0.8205      0.3967      0.51      1.29      0.94      2.39      0.54      1.21      0.86      2.19
DQA1*02:01  DRB1*04:66        0.1732      0.1198      1.0000      0.0144      0.0045      0.6998      1.0000      0.1343      0.30      0.79      0.92      2.39      0.33      0.72      1.17      3.05

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