Table 1.
Characteristics of Enrolled Studies and Meta-Analyzed Studies
| Characteristics | Group 1: HHV-6 Reactivation Analyzed as a Risk Factor for aGVHD | Group 2: aGVHD Analyzed as a Risk Factor for HHV-6 Reactivation | Group 3: No Temporal Specification for HHV-6 vs. aGVHD Analysis | |||
|---|---|---|---|---|---|---|
|
|
||||||
| Whole* | Meta-analysis* | Whole* | Meta-analysis*,† | Whole* | Meta-analysis* | |
| Total studies | 14 | 11 | 1 | N/A | 18 | 12 |
| Median patients in cohort (range) | 103 (49–315) | 108 (68–315) | 44 | N/A | 48.5(15–366) | 64.5 (23–366) |
| Prospective cohort | 10(71.4) | 7 (63.6) | 1 (100) | N/A | 12(66.7) | 9 (75) |
| Retrospective cohort | 4 (28.6) | 4 (36.4) | 0 | N/A | 4(22.2) | 2(16.7) |
| Case control | 0 | 0 | 0 | N/A | 2(11.1) | 1 (8.3) |
| Studies that administered HHV-6 antiviral prophylaxis (ganciclovir, foscarnet, or cidofovir) | 3*(21.4) | 3‡ (27.3) | 1§(100) | N/A | 0 | 0 |
| Studies that found a significant association between HHV-6 and aGVHD (P < .05) | 10(71.4) | 8 (72.7) | 0 | N/A | 8 (44.4) | 6 (50) |
| Median year of publication (range) | 2013(1997–2017) | 2014(2005–2017) | 2015 | N/A | 2006(1995–2016) | 2008(1999–2016) |
| Total patients | 1773 | 1605 | 44 | N/A | 1553 | 1303 |
| Patients who reactivated HHV-6 | 784 (44.2) | 702 (43.7) | 29 (65.9) | N/A | 668(43.1) | 555 (42.6) |
| Median reactivation, % (range) | 47.7 (16.7–93.6) | 47(16.7–93.6) | 65.9 | N/A | 56(13.9–87) | 58(13.9–87) |
| Total CBT patients | 521 (29.4) | 491 (30.6) | 44(100) | N/A | 307(19.8) | 306 (23.5) |
| Median CBT, % (range) | 21 (0–100) | 20.1 (.9–100) | 100 | N/A | 1.1 (0–100) | 23.4(0–100) |
| Type of PCR used to diagnose HHV-6 reactivation | ||||||
| qPCR | 13 (92.9) | 11 (100) | 1 (100) | N/A | 11 (61.1) | 8 (66.7) |
| Qualitative PCR | 0 | 0 | 0 | N/A | 2(11.1) | 2 (16.7) |
| Nested PCR | 1 (7.1) | 0 | 0 | N/A | 5 (27.8) | 2 (16.7) |
| Sample used for PCR | ||||||
| Plasma | 12(85.7) | 10(90.9) | 1 (100) | N/A | 7 (38.9) | 5(41.7) |
| Whole blood | 0 | 0 | 0 | N/A | 5 (27.8) | 4(33.3) |
| PBMCs/PBLs | 1 (7.1) | 1 (9.1) | 0 | N/A | 5 (27.8) | 2 (16.7) |
| Plasma + PBMC/PBLs | 1 (7.1) | 0 | 0 | N/A | 1 (5.6) | 1 (8.3) |
Values are n (%) unless otherwise defined. N/A indicates not applicable as meta-analysis was not performed for this group; PBLS, peripheral blood leukocytes.
*
“Whole” and “meta-analysis” indicate all enrolled studies and studies providing sufficient data to perform meta-analysis, respectively.
†
Meta-analysis for group 2 was not performed because of an insufficient number of studies.
‡
Two studies [11,12] administered HHV-6 prophylaxis before HCT, and 1 study [13] administered HHV-6 prophylaxis until day+100 after HCT.
§
Ganciclovir was administered during conditioning followed by valacyclovir for first 100 days after HCT.