A chronic "postinfectious" fatigue syndrome associated with benign lymphoproliferation, B-cell proliferation, and active replication of human herpesvirus-6

Lymphoproliferative Syndromes Associated with Human Herpesvirus-6A and Human Herpesvirus-6B

Human herpesvirus 6A and 6B (HHV-6A and HHV-6B) have been noted since their discovery for their T-lymphotropism. Although it has proven difficult to determine the extent to which HHV-6A and HHV-6B are involved in the pathogenesis of many diseases, evidence suggests that primary infection and reactivation of both viruses may induce or contribute to the progression of several lymphoproliferative disorders, ranging from benign to malignant and including infectious mononucleosis-like illness, drug induced hypersensitivity syndrome/drug reaction with eosinophilia and systemic symptoms (DIHS/DRESS), and nodular sclerosis Hodgkin's lymphoma. Herein, we discuss the conditions associated with the lymphoproliferative capacity of HHV-6, as well as the potential mechanisms behind them. Continued exploration on this topic may add to our understanding of the interactions between HHV-6 and the immune system and may open the doors to more accurate diagnosis and treatment of certain lymphoproliferative disorders.

Human herpesvirus 6 infection and associated pathogenesis following bone marrow transplantation

Human herpesvirus 6 (HHV-6) infections following bone marrow transplantation (BMT) have been shown to be associated with fever, skin rash, graft versus host disease, encephalitis, delay in engraftment, marrow suppression, and pneumonia. Unfortunately several of these studies were case reports and although the results were suggestive they prompted us to study these pathological events systematically. These associations were primarily based on either HHV-6 isolation, HHV-6 DNA detection, antigen detection or increases in HHV-6 specific antibodies. HHV-6 activity was more frequent during the post- rather than the pre-transplantation period. All HHV-6 isolates from BMT patients have been shown to be variant B. A better understanding of HHV-6 associated pathogenesis gained by larger prospective trials is needed to facilitate proper treatment of cases of idiopathic illnesses or those associated with symptoms (fever, skin rash) similar to those caused by HHV-6.

The in vitro immunomodulatory effects of glyconutrients on peripheral blood mononuclear cells of patients with chronic fatigue syndrome

In humans, eight monosaccharides are required for the synthesis of glycoproteins. Dietary supplements that supply these crucial sugars are known as glyconutrients. A glyconutrient compound was added to Peripheral Blood Mononuclear Cells (PBMC) isolated from normal controls and patients with the Chronic Fatigue Syndrome (CFS), a disease associated with immune dysregulation. The in vitro immunomodulatory effects were investigated. Cell surface expression of the glycoproteins CD5, CD8, and CD11a were significantly lower in patients with CFS compared to normal controls. Addition of glyconutrient homogenate to PBMC from patients with CFS stimulated with phytohemagglutinin significantly increased the expression of each glycoprotein. Furthermore, natural killer (NK) cell function was reduced in CFS patients. The glyconutrient preparation significantly enhanced NK cell activity versus human herpes virus 6 (HHV-6)-infected H9 cells in an 8 h 51Cr release assay compared to placebo for PBMC from patients with CFS (p< .01). Finally, apoptosis was significantly higher in patients with CFS. The percentage of apoptotic cells was significantly decreased in PBMC from patients with CFS that had been incubated for 48 h with glyconutrients. Thus, glyconutrients improved abnormal immune parameters in vitro in patients with CFS.

alpha-Interferon treatment of patients with chronic fatigue syndrome

Thirty patients who fulfilled clinical criteria defined by the CDC for Chronic Fatigue Syndrome were treated with alfa 2a interferon or placebo in a double-blind crossover study. Outcome was evaluated by Natural Killer (NK) cell function, lymphocyte proliferation to mitogens and soluble antigens, CD4/CD8 counts and a 10 item Quality of Life (QOL) survey. Although mean NK function rose from 87.8 +/- 19.6 to 129.3 +/- 20.7 lytic untis (LU; p < .05) with 12 weeks of interferon therapy, there was no significant change in the other immunologic parameters or QOL scores. When the 26 patients who completed the study were stratified according to their baseline NK function and lymphocyte proliferation, 4 groups were identified: 3 patients had normal NK cell function and lymphocyte proliferation when compared to normal, healthy controls, 9 had isolated deficiency in lymphocyte proliferation, 7 had diminished NK function only, and 7 had abnormalities for both parameters. QOL scores were not significantly different for the four groups at baseline. After 12 weeks of interferon therapy, QOL score significantly improved in each of the seven patients with isolated NK cell dysfunction (mean score, 16.3 +/- 7.9) compared to baseline (39.7 +/- 12.1; p < .05). In these patients the mean NK function increased from 35.1 +/- 11.7 to 91.5 +/- 22.7 LU (p < .01). Significant improvement was not recorded for QOL in the other three groups. Thus, therapy with alpha interferon has a significant effect on the QOL of that subgroup of patients with CFS manifesting an isolated decrease in NK function.

The chronically fatigued patient

This article illustrates that the diagnostic evaluation as well as the management of the patient presenting with chronic fatigue can be done in an orderly manner. If a medical illness is the cause of the patient's fatigue, this is usually evident on initial presentation. A thorough history and complete physical examination, in conjunction with some screening laboratory tests, can rule out most medical causes of fatigue, and any remaining cases declare themselves over the next several visits. If a medical cause is not evident, a further "fishing expedition" is fruitless. Psychiatric illness, such as depression or generalized anxiety disorder, accounts for another significant proportion of cases of chronic fatigue. As with medical illness, psychiatric illness should be suspected based on history and is not a diagnosis of exclusion. Some patients presenting with chronic fatigue have a history and symptom pattern consistent with the diagnosis of CFS. The cause of this syndrome is controversial and is still unknown. The clinician, however, can offer the patient care in an environment that is respectful of their physical and psychological discomfort and can provide significant symptomatic improvement to the patient. Lastly, some patients with fatigue do not fit any diagnostic category, including CFS. As with many other common complaints, such as headaches or abdominal pain, although a diagnosis may not be given to the patient, the clinician can do a lot to reassure the patient and assist the patient in living with his or her symptoms. As Solberg eloquently wrote: "[E]valuation of the fatigued patient requires all of a physician's best attributes--a broad view of disease, psychosocial sensitivity, and a good ongoing relationship with the patient."

Human herpesvirus 6 in lung tissue from patients with pneumonitis after bone marrow transplantation

BACKGROUND

Human herpesvirus 6 (HHV-6) is a recently described herpesvirus that is epidemiologically and biologically similar to cytomegalovirus. It is the cause of exanthem subitum (roseola) in children.

METHODS

To evaluate the possible role of HHV-6 infection in pneumonitis in immunocompromised patients, we used quantitative HHV-6 polymerase chain reactions to study lung-biopsy specimens from 15 patients with pneumonitis after bone marrow transplantation and lung tissue from 15 immunocompetent subjects without pneumonitis and 6 fetuses.

RESULTS

HHV-6 DNA was detected in lung tissue from all 15 patients, from 14 seropositive control subjects, and from none of the 7 seronegative control subjects. Six patients had levels of HHV-6 DNA in lung tissue that were 10 to 500 times higher than those in any of the other patients or control subjects. Increased levels of HHV-6 DNA correlated with a decreased risk of death from pneumonitis (P = 0.015), an increased severity of graft-versus-host disease (P = 0.023), and the presence of idiopathic pneumonitis (P = 0.037). Levels of HHV-6 DNA correlated directly with the changes in HHV-6 antibody titers in the interval between the pretransplantation period and the open-lung biopsy (P = 0.002). Low levels of HHV-6 antibody at the time of the open-lung biopsy were also associated with the diagnosis of idiopathic pneumonitis (P = 0.002).

CONCLUSIONS

The concentrations of HHV-6 genome in lung tissue and their relation to changes in serologic titers support an association between HHV-6 infection and idiopathic pneumonitis in immunocompromised hosts.

Fatal disseminated infection with human herpesvirus-6

A 13-month-old immunocompetent girl had fever, rash, and multisystem disease, and she eventually died of cardiac failure. Autopsy revealed intracellular viral inclusions of the herpesvirus group, with results of in situ hybridization positive for human herpesvirus-6. This is apparently the first case of fatal disseminated herpesvirus-6 infection.