Human herpesvirus 6 in biopsies from patients with gastrointestinal symptoms after allogeneic stem cell transplantation

From human herpes virus-6 reactivation to autoimmune reactivity against tight junctions and neuronal antigens, to inflammation, depression, and chronic fatigue syndrome due to Long COVID

Inflammation and autoimmune responses contribute to the pathophysiology of Long COVID, and its affective and chronic fatigue syndrome symptoms, labeled "the physio-affective phenome." To investigate whether Long COVID and its physio-affective phenome are linked to autoimmunity to the tight junction proteins, zonulin and occludin (ZOOC), and immune reactivity to lipopolysaccharides (LPS), and whether the latter are associated with signs of human herpes virus-6 (HHV-6) reactivation, autoimmunity directed against oligodendrocyte and neuronal proteins, including myelin basic protein. IgA/IgM/IgG responses to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), HHV-6, ZOOC, and neuronal proteins, C-reactive protein (CRP), and advanced oxidation protein products (AOPPs), were measured in 90 Long COVID patients and 90 healthy controls. The physio-affective phenome was conceptualized as a factor extracted from physical and affective symptom domains. Neural network identified IgA directed to LPS (IgA-LPS), IgG-ZOOC, IgG-LPS, and IgA-ZOOC as important variables associated with Long COVID diagnosis with an area under the ROC curve of 0.755. Partial Least Squares analysis showed that 40.9% of the variance in the physio-affective phenome was explained by CRP, IgA-myelin basic protein (MBP), and IgG-MBP. A large part of the variances in both autoimmune responses to MBP (36.3%-39.7%) was explained by autoimmunity (IgA and IgG) directed to ZOOC. The latter was strongly associated with indicants of HHV-6 reactivation, which in turn was associated with increased IgM-SARS-CoV-2. Autoimmunity against components of the tight junctions and increased bacterial translocation may be involved in the pathophysiology of Long COVID's physio-affective phenome.

[Significance of PCR detection of HHV6 in gastro biopsy on the course of diarrhea in patients with severe diarrhea after allogeneic hematopoietic stem cell transplantation]

目的

探讨肠黏膜人疱疹病毒6型（HHV6）检测在异基因造血干细胞移植（allo-HSCT）术后重度腹泻患者中的意义。

方法

回顾性分析2015年2月至2016年8月于北京大学血液病研究所行allo-HSCT后出现重度腹泻并行肠镜检查及肠黏膜活检的患者资料；HHV6、CMV、EBV检测采用RT-PCR方法；肠黏膜病理检查也包括免疫组化方法检测CMV早期抗原、CMV晚期抗原，原位杂交检测EBV。

结果

共有45例患者纳入研究，其中21例（46.7%）肠黏膜活检HHV6阳性，包括男13例，女8例，中位年龄29（14~54）岁；肠黏膜HHV6阳性与阴性组患者血CMV阳性检出率差异无统计学意义（76.2%对87.5%，P>0.05），但EBV血症发生率前者（6/21，28.6%）明显高于后者（1/24，4.2%）（P=0.028）；两组患者在腹泻发生的时间、次数及量方面差异无统计学意义（P值均>0.05）。45例患者中44例接受了膦甲酸钠和（或）更昔洛韦抗病毒治疗，抗病毒治疗并没有影响腹泻的进程。

结论

肠黏膜HHV6阳性在allo-HSCT术后重症腹泻患者中发生率高，未发现其对于治疗及预后有临床意义。肠黏膜HHV6阳性并不能证明HHV6在肠道的感染。

Long-term prognosis of human herpesvirus 6 reactivation following allogeneic hematopoietic stem cell transplantation

BACKGROUND

Patients undergoing hematopoietic stem cell transplantation (HSCT) frequently have HHV-6 reactivation typically during the early phase following HSCT. The long-term clinical complications and prognosis, however, remain unclear.

METHODS

Between September 2010 and October 2012, whole blood samples from 105 patients collected weekly from prior to 6 weeks after HSCT underwent multiplex polymerase chain reaction (PCR) to screen for viral DNA, followed by real-time PCR for quantitative estimation. In 48 patients, only HHV-6 was detected in at least one sample. In 30 patients, no viral DNA was detected. Long-term clinical records were reviewed in March 2016. All 48 HHV-6-positive patients, and 24 patients in whom no viral DNA detected, were followed up.

RESULTS

Median maximum HHV-6 DNA load in the blood of the HHV-6 reactivation group (n = 48) was 11 800 copies/μg peripheral blood leukocyte DNA (range, 52-310 000 000). Hemophagocytic syndrome (HPS) was diagnosed in two subjects with HHV-6 reactivation. Acute graft-versus-host disease (GVHD) developed more frequently in patients with HHV-6 reactivation than in patients without viral reactivation (P = 0.002), but there was no difference in incidence of chronic GVHD. There was no difference in engraftment of neutrophils and platelets between groups. There was also no difference in overall survival between groups. Onset of HPS, however, was associated with lower overall survival (P = 0.009).

CONCLUSIONS

Human herpesvirus 6 reactivation was associated with acute GVHD, but not with chronic GVHD, engraftment or overall survival. Onset of HPS, however, predicts lower overall survival.

Graft versus Host Disease: From Basic Pathogenic Principles to DNA Damage Response and Cellular Senescence

Graft versus host disease (GVHD), a severe immunogenic complication of allogeneic hematopoietic stem cell transplantation (HSCT), represents the most frequent cause of transplant-related mortality (TRM). Despite a huge progress in HSCT techniques and posttransplant care, GVHD remains a significant obstacle in successful HSCT outcome. This review presents a complex summary of GVHD pathogenesis with focus on references considering basic biological processes such as DNA damage response and cellular senescence.