1. Context
2. Evidence Acquisition
2.1. Search Strategy
2.2. Inclusion and Exclusion Criteria
2.3. Data Extraction
2.4. Quality Assessment
2.5. Statistical Analysis
3. Results
3.1. Search Results and Study Selection
| References | Year | Country (Ethnicity) | Spontaneous Clearance a (n) | Chronic HCV Infections b (n) | HLA Typing | HLA Class II Loci Studied | NOS |
|---|---|---|---|---|---|---|---|
| Alric et al. (10) | 1997 | France (European) | 25 | 103 | PCR-SSOP | DQB1, DRB1 | 7 |
| Cramp et al. (11) | 1998 | United Kingdom (European) | 49 | 55 | PCR-SSOP | DQA1, DQB1, DRB1 | 7 |
| Minton et al. (12) | 1998 | United Kingdom (European) | 35 | 138 | PCR-SSOP | DQB1, DRB1 | 7 |
| Lechmann et al. (13) | 1999 | Germany (European) | 9 | 18 | PCR‐SBT | DRB1 | 7 |
| Mangia et al. (14) | 1999 | Italy (European) | 35 | 149 | PCR-SSP | DQB1, DRB1 | 6 |
| Thursz et al. (15) | 1999 | Mix (European) | 85 | 170 | PCR-SSP | DQB1, DRB1 | 8 |
| Alric et al. (16) | 2000 | France (European) | 63 | 282 | PCR-SSOP | DQB1, DRB1 | 6 |
| Vejbaesya et al. (17) | 2000 | Thailand (Asian) | 43 | 57 | PCR-SSOP | DQA1, DQB1, DRB1 | 6 |
| McKiernan et al. (18) | 2000 | Ireland (European) | 95 | 148 | Reverse line probe hybridization | DQB1, DRB1 | 8 |
| Thio et al. (19) | 2001 | USA (American) | 200 | 374 | PCR-SSP | DQA1, DQB1, DRB1 | 6 |
| Azocar et al. (20) | 2003 | USA | 40 | 72 | PCR-SSOP | DQB1 | 6 |
| Spada et al. (21) | 2004 | Italy (European) | 10 | 24 | PCR-SSP | DQB1, DRB1 | 6 |
| Romero et al. (22) | 2008 | USA | 39 | 121 | PCR-SSP, PCR-SSOP | DQB1, DRB1 | 7 |
| Mangia et al. (23) | 2011 | Italy (European) | 49 | 68 | Reverse line probe hybridization | DQB1, DRB1 | 7 |
| Mangia et al. (24) | 2013 | Italy (European) | 47 | 122 | Reverse line probe hybridization | DQB1, DRB1 | 7 |
| Samimi-Rad et al. (25) | 2015 | Iran (Asian) | 54 | 63 | PCR-SSP | DQA1, DQB1, DRB1 | 7 |
| Huang et al. (26) | 2016 | China (Asian) | 231 | 429 | PCR‐SBT | DQB1, DRB1 | 7 |
| El-Bendary et al. (27) | 2019 | Egypt (African) | 108 | 235 | PCR‐SBT | DRB1 | 6 |
| Huang et al. (28) | 2019 | China (Asian) | 59 | 84 | PCR‐SBT | DQB1, DRB1 | 7 |
Abbreviations: SSP, sequence-specific primers; SSOP, sequence-specific oligonucleotide probe; SBT, sequence-based typing; NOS, Newcastle-Ottawa Scale.
a Anti-HCV positive and HCV-RNA negative
b Anti-HCV and HCV-RNA positive
3.2. Meta-analysis of Association of Class II HLA-DQ Locus Polymorphisms with HCV Clearance
| HLA Alleles | Number of Studies | Spontaneous Clearance | Chronic HCV Infections | Odds Ratio (95% CI) | P Value | I2 Value (%) | Heterogeneity P Value | ||
|---|---|---|---|---|---|---|---|---|---|
| Number | Positive | Number | Positive | ||||||
| DQA1*0101 | 4 | 346 | 64 | 549 | 99 | 1.032 (0.729 - 1.461) | 0.859 | 45.6 | 0.138 |
| DQA1*0102 | 4 | 346 | 65 | 549 | 116 | 0.863 (0.615 - 1.212) | 0.442 | 0 | 0.566 |
| DQA1*0103 | 4 | 346 | 18 | 549 | 40 | 0.698 (0.394 - 1.239) | 0.265 | 0 | 0.703 |
| DQA1*0201 | 4 | 346 | 68 | 549 | 93 | 1.199 (0.848 - 1.696) | 0.326 | 74.5 | 0.008 |
| DQA1*0401 | 3 | 146 | 8 | 175 | 20 | 0.449 (0.192 - 1.053) | 0.074 | 0 | 0.681 |
| DQA1*0501 | 4 | 346 | 99 | 549 | 140 | 1.171 (0.866 - 1.584) | 0.314 | 52.9 | 0.095 |
| DQA1*0601 | 3 | 292 | 3 | 486 | 17 | 0.286 (0.083 - 0.986) | 0.036 | 55.4 | 0.106 |
| DQB1*0201 | 14 | 1052 | 219 | 2041 | 563 | 0.690 (0.578 - 0.824) | 0.000 | 52.7 | 0.011 |
| DQB1*0202 | 4 | 415 | 36 | 717 | 69 | 0.892 (0.585 - 1.361) | 0.671 | 71.1 | 0.016 |
| DQB1*0301 | 17 | 1164 | 416 | 2421 | 596 | 1.703 (1.464 - 1.981) | 0.000 | 57.5 | 0.002 |
| DQB1*0302 | 13 | 920 | 84 | 1829 | 167 | 1.000 (0.760 - 1.317) | 1.000 | 11.9 | 0.326 |
| DQB1*0303 | 10 | 786 | 67 | 1474 | 109 | 1.167 (0.850 - 1.603) | 0.365 | 0 | 0.897 |
| DQB1*0401 | 5 | 245 | 10 | 331 | 12 | 1.131 (0.481 - 2.662) | 0.828 | 0 | 0.726 |
| DQB1*0402 | 7 | 436 | 19 | 860 | 39 | 0.959 (0.547 - 1.681) | 1.000 | 0 | 0.917 |
| DQB1*0501 | 13 | 776 | 171 | 1538 | 281 | 1.264 (1.021 - 1.565) | 0.035 | 52.6 | 0.013 |
| DQB1*0502 | 12 | 885 | 57 | 1608 | 148 | 0.679 (0.495 - 0.933) | 0.018 | 0 | 0.887 |
| DQB1*0503 | 5 | 333 | 12 | 612 | 30 | 0.725 (0.366 - 1.436) | 0.411 | 5.4 | 0.376 |
| DQB1*0601 | 10 | 790 | 45 | 1365 | 72 | 1.085 (0.739 - 1.591) | 0.694 | 0 | 0.884 |
| DQB1*0602 | 12 | 953 | 112 | 1885 | 242 | 0.904 (0.712 - 1.148) | 0.434 | 31.2 | 0.142 |
| DQB1*0603 | 12 | 762 | 42 | 1528 | 130 | 0.627 (0.438 - 0.899) | 0.011 | 0 | 0.760 |
| DQB1*0604 | 10 | 624 | 29 | 1323 | 51 | 1.216 (0.763 - 1.937) | 0.463 | 0 | 0.824 |
| DQB1*0605 | 4 | 157 | 2 | 275 | 6 | 0.578 (0.115 - 2.901) | 0.716 | 0 | 0.983 |
| DRB1*0101 | 12 | 866 | 109 | 1667 | 132 | 1.674 (1.281 - 2.189) | 0.000 | 60.4 | 0.002 |
| DRB1*0102 | 5 | 342 | 10 | 664 | 19 | 1.023 (0.470 - 2.224) | 1.000 | 0 | 1.000 |
| DRB1*0103 | 2 | 144 | 8 | 203 | 12 | 0.936 (0.373 - 2.352) | 1.000 | 0 | 0.914 |
| DRB1*0301 | 11 | 995 | 129 | 1924 | 303 | 0.797 (0.638 - 0.995) | 0.048 | 41.8 | 0.063 |
| DRB1*0304 | 2 | 104 | 1 | 166 | 1 | 1.602 (0.099 - 25.892) | 1.000 | 0 | 0.356 |
| DRB1*0401 | 5 | 309 | 41 | 521 | 35 | 2.124 (1.321 - 3.416) | 0.003 | 56.2 | 0.058 |
| DRB1*0403 | 3 | 127 | 3 | 274 | 5 | 1.302 (0.306 - 5.533) | 0.712 | 0 | 0.616 |
| DRB1*0404 | 2 | 138 | 17 | 205 | 13 | 2.075 (0.973 - 4.424) | 0.078 | 0 | 0.802 |
| DRB1*0405 | 5 | 490 | 29 | 873 | 49 | 1.058 (0.659 - 1.698) | 0.809 | 59.7 | 0.042 |
| DRB1*0406 | 2 | 78 | 1 | 206 | 7 | 0.369 (0.045 - 3.051) | 0.453 | 0 | 0.714 |
| DRB1*0701 | 13 | 965 | 109 | 1929 | 276 | 0.763 (0.602 - 0.966) | 0.027 | 52.3 | 0.014 |
| DRB1*0801 | 2 | 104 | 1 | 118 | 3 | 0.372 (0.038 - 3.634) | 0.625 | 0 | 0.684 |
| DRB1*0803 | 2 | 274 | 21 | 486 | 33 | 1.139 (0.645 - 2.011) | 0.661 | 0 | 0.770 |
| DRB1*0901 | 7 | 744 | 52 | 1297 | 81 | 1.128 (0.787 - 1.618) | 0.515 | 0 | 0.997 |
| DRB1*1001 | 8 | 547 | 12 | 1019 | 22 | 1.016 (0.499 - 2.070) | 1.000 | 0 | 0.896 |
| DRB1*1101 | 14 | 1042 | 158 | 2150 | 201 | 1.733 (1.387 - 2.166) | 0.000 | 45.4 | 0.033 |
| DRB1*1102 | 2 | 209 | 7 | 392 | 10 | 1.324 (0.496 - 3.530) | 0.610 | 10.2 | 0.291 |
| DRB1*1103 | 2 | 235 | 1 | 523 | 5 | 0.443 (0.051 - 3.811) | 0.672 | 0 | 0.946 |
| DRB1*1104 | 6 | 384 | 30 | 794 | 63 | 0.983 (0.625 - 1.547) | 1.000 | 56.5 | 0.042 |
| DRB1*1201 | 8 | 430 | 29 | 965 | 34 | 1.980 (1.190 - 3.295) | 0.011 | 27 | 0.213 |
| DRB1*1202 | 2 | 274 | 29 | 486 | 51 | 1.010 (0.623 - 1.635) | 1.000 | 0 | 0.429 |
| DRB1*1301 | 10 | 560 | 32 | 1162 | 142 | 0.435 (0.292 - 0.648) | 0.000 | 24.9 | 0.214 |
| DRB1*1302 | 10 | 560 | 35 | 1162 | 122 | 0.568 (0.385 - 0.840) | 0.004 | 16.5 | 0.291 |
| DRB1*1303 | 5 | 245 | 8 | 630 | 7 | 3.004 (1.078 - 8.376) | 0.040 | 0 | 0.971 |
| DRB1*1305 | 2 | 52 | 4 | 75 | 6 | 0.958 (0.257 - 3.579) | 1.000 | 66.7 | 0.083 |
| DRB1*1401 | 7 | 412 | 15 | 966 | 47 | 0.739 (0.408 - 1.337) | 0.394 | 0 | 0.712 |
| DRB1*1501 | 8 | 582 | 65 | 1117 | 154 | 0.786 (0.577 - 1.071) | 0.147 | 0 | 0.595 |
| DRB1*1502 | 6 | 494 | 7 | 967 | 17 | 0.803 (0.331 - 1.950) | 0.828 | 0 | 0.531 |
| DRB1*1601 | 7 | 397 | 17 | 855 | 22 | 1.694 (0.889 - 3.227) | 0.116 | 0 | 0.837 |
| DRB1*1602 | 3 | 111 | 25 | 159 | 36 | 0.993 (0.556 - 1.774) | 1.000 | 0 | 0.404 |
