Non-specific effects of BCG vaccination on morbidity among children in Greenland: a population-based cohort study

Background

The potential non-specific effects of BCG (Bacillus Calmette-Guérin) vaccination, with reported reduction of infectious disease morbidity among vaccinated children, in addition to the protective effect against tuberculosis (TB), are highly debated. In Greenland, BCG vaccination was introduced in 1955, but temporarily discontinued from 1991 to 1996 due to nationwide policy changes. Using the transient vaccination stop, we aimed to investigate possible non-specific effects of BCG vaccination by measuring nation-wide hospitalization rates due to infectious diseases other than TB among vaccinated and unvaccinated children.

Methods

A retrospective cohort study including all children born in Greenland aged 3 months to 3 years from 1989 to 2004. A personal identification number assigned at birth allowed for follow-up through national registers. Information on hospitalization due to infectious diseases was obtained from the Greenlandic inpatient register using ICD-8 and ICD-10 codes. Participants with notified TB were censored. Incidence rate ratios (IRR) were estimated using Poisson regression.

Results

Overall, 19 363 children, hereof 66% BCG-vaccinated, were followed for 44 065 person-years and had 2069 hospitalizations due to infectious diseases. IRRs of hospitalization in BCG-vaccinated as compared with BCG-unvaccinated children were 1.07 [95% confidence interval (CI) 0.96-1.20] for infectious diseases overall, and specifically 1.10 (95% CI 0.98-1.24) for respiratory tract infections. Among BCG-vaccinated children aged 3 to 11 months, the IRR of hospitalization due to infectious diseases was 1.00 (95% CI 0.84-1.19) as compared with BCG-unvaccinated children.

Conclusion

Our results do not support the hypothesis that neonatal BCG vaccination reduces morbidity in children caused by infectious diseases other than TB.

Presence of Epstein-Barr virus and human herpesvirus 6B DNA in multiple sclerosis patients: associations with disease activity

OBJECTIVE

To assess the presence of Epstein-Barr virus (EBV) and human herpesvirus 6B (HHV-6B) DNA in saliva and plasma from multiple sclerosis (MS) patients enrolled in a randomized, double-blind, placebo-controlled valacyclovir treatment study.

METHODS

DNA was prepared following ultracentrifugation of saliva and plasma. EBV and HHV-6B DNAs were determined by real-time polymerase chain reaction.

RESULTS

EBV and HHV-6B DNAs were detected in 41% and 65% of saliva samples, respectively. In patients treated with valacyclovir, the percentage of saliva samples with EBV was significantly reduced (9%; P = 0.000017), whereas the frequency of HHV-6B positive samples was unchanged (57%; P = 0.38). Longitudinal studies demonstrated a time-dependent reduction in the frequency of saliva samples containing EBV following valacyclovir treatment. In contrast, plasma contained EBV and HHV-6B DNAs in 17% and 25% of the samples, respectively, and these numbers were not significantly reduced following valacylovir treatment (13% and 16%, respectively), nor were they different from those of healthy controls (6% and 39%, respectively). Patients with high disease activity had a significantly higher frequency of EBV (P = 0.018) and HHV-6B (P = 0.023) positive samples than did patients with low disease activity. The presence of EBV and HHV-6B was strongly correlated in plasma (P < 0.00000001), but not in saliva (P = 0.41).

CONCLUSION

MS patients express EBV and HHV-6B in both saliva and plasma, but only the expression of EBV in saliva is significantly reduced following valacyclovir treatment. Although EBV and HHV-6B DNAs can be detected in plasma from healthy individuals, the co-expression of both these viruses in MS patients is highly significant and further associated with clinical activity. The observations of viral DNA in plasma are consistent with an underlying immunologic defect in MS.

A role of late Epstein-Barr virus infection in multiple sclerosis

OBJECTIVE

To assess Epstein-Barr virus (EBV) seroconversion in a high multiple sclerosis (MS) prevalence area and to evaluate the recall of diagnosed infectious mononucleosis in MS patients.

METHODS

The study was based on information or blood samples, or both, from schoolchildren, young MS patients and matched controls. EBV serology was performed on 1154 blood samples.

RESULTS

We demonstrate that more than one third of the population in a high MS prevalence area is seronegative to EBV at puberty. This is in contrast to the virtually complete seroconversion to EBV early in life in individuals from areas with a low prevalence of MS. Furthermore, we demonstrate that recall of diagnosed infectious mononucleosis (IM), but not recall of common childhood diseases, is significantly more frequent among MS patients than healthy controls. All MS patients, including patients without prior immunosuppressive treatment, were EBV seropositive.

CONCLUSION

During or after puberty, EBV is transmitted to a major proportion of the population in an MS high-prevalence area. Together with our previous documentation of an association between late infection with EBV and an increased risk of developing MS, these data support a role of EBV infection in MS.

Altered CD8+ T cell responses to selected Epstein-Barr virus immunodominant epitopes in patients with multiple sclerosis

An increased frequency of antiviral CD8+ T cells is seen in chronic viral infections. During herpes virus infections the expanded CD8+ T cells are thought to control the reactivation of the latent infection. Because multiple sclerosis (MS), a presumed autoimmune disease of the central nervous system, has been associated with a late Epstein-Barr virus (EBV) infection, we wished to examine whether the CD8+ T cell response to EBV epitopes differed between MS patients and healthy controls. Here we report an increased frequency of CD8+ T cells responding to EBV epitopes from nuclear antigen 3 A (HLA-A2/CLG) and latent membrane protein 2 (HLA-B7/RPP) in MS patients. Noticeably, the altered CD8+ T cell response occurred to some but not all EBV epitopes and did not reach the high level seen during acute infection. The responses towards two immunodominant epitopes from human cytomegalovirus (HCMV) were similar in MS patients and normal controls. Together, our data demonstrate the presence of an increased frequency of CD8+ T cells reacting with two epitopes from EBV in patients with MS. The altered response to only two of the tested EBV epitopes would be consistent with the presence of cross-reactive epitopes.

A randomized, double-blind, placebo-controlled MRI study of anti-herpes virus therapy in MS

OBJECTIVE

To evaluate the effect of treatment with the antiherpes drug valacyclovir on MRI-evident lesions in patients with relapsing-remitting MS in a phase 2, randomized, double-blind, placebo-controlled study.

BACKGROUND

It has been postulated from virologic studies that herpesvirus infection could play a role in the progression of MS.

METHODS

Patients were eligible for the study if they had had two or more MS relapses in the 2-year period before enrollment. Seventy patients with Expanded Disability Status Scale scores of 0 to 5.5 were randomly assigned to receive 1 gram of valacyclovir (n = 36) or placebo (n = 34) three times daily for 24 weeks. Patients underwent MRI every fourth week for 32 weeks: twice during pretreatment, six times during treatment, and once after treatment. Scoring of neurologic disability was performed at the start and end of the treatment period. The primary endpoint was the number of new active MRI-evident lesions over 24 weeks of treatment. Secondary endpoints included other MRI measures and clinical endpoints.

RESULTS

The mean number of new active lesions +/- SD per patient during 24 weeks of treatment with valacyclovir was 11.9 +/- 17.6 and that during placebo treatment was 14.5 +/- 21.4. A protocol-planned exploratory analysis stratified patients according to baseline activity; this analysis showed that patients with high levels of disease activity in the valacyclovir treatment group (n = 17) developed fewer new active lesions per scan than did those in the placebo treatment group (n = 11). The median number (Q(1), Q(3) range) of active lesions was 2.0 (1.38, 3.96) in the valacyclovir treatment group and 6.5 (2.63, 9.0) in the placebo treatment group.

CONCLUSIONS

Valacyclovir treatment did not reduce the formation of active lesions in patients with relapsing-remitting MS who had two or more relapses during the previous 2-year period. In a subgroup of patients with high levels of disease activity who had more than one active MRI-evident lesion during 4 weeks, valacyclovir treatment was associated with a reduced number of new active MRI-evident lesions and with an increase in the number of scans free of new active lesions. The results of the exploratory subgroup analysis provide support for further studies of antiherpes therapy for patients with MS and high levels of MRI-evident disease activity.

The association between multiple sclerosis and infection with Epstein-Barr virus and retrovirus

B-lymphoblastoid cell-lines may develop spontaneously in mononuclear cells from patients with multiple sclerosis, an observation rarely seen in healthy individuals. Examination of such spontaneously established B-cell lines reveal the presence of Epstein-Barr virus and retrovirus particles. We have speculated that in predisposed individuals, a dual infection with retrovirus and late acquired Epstein-Barr virus plays an aetiological role in the development of multiple sclerosis. This hypothesis is supported by a number of observations, including the finding that infection with Epstein-Barr virus may be a prerequisite for developing multiple sclerosis. The association between multiple sclerosis and infection with Epstein-Barr virus and retrovirus is evaluated in this study.

Molecular characterization of HERV-H variants associated with multiple sclerosis

Our objective was to characterize retroviral sequences by RT-PCR with gag and env primers on RNA from RT-positive retroviral particles produced by multiple sclerosis (MS) derived B-lymphoblastoid cell lines. Sequence variants with high homology to the potentially functional subgroup RGH of the human endogenous retrovirus RTVL-H/HERV-H family were found. The same sequences were also specifically found in the particulate fraction of a series of MS patient plasma samples and were absent in controls. South-Western blots demonstrate the presence of a nucleic acid binding protein, corresponding in size and function to the nucleocapsid protein, Gag NC, of other retroviruses. We also present indications for transmission of the retrovirus to PHA-stimulated lymphocytes from healthy individuals.

A single subtype of Epstein-Barr virus in members of multiple sclerosis clusters

OBJECTIVES

Epidemiological studies strongly indicate an infectious involvement in multiple sclerosis (MS). Epstein-Barr virus (EBV), to which all multiple sclerosis patients are seropositive, is also interesting from an epidemiological point of view. We have reported a cluster of MS patients with 8 members from a small Danish community called Fjelsø. To further evaluate the role of EBV in MS we have investigated the distribution of EBV subtypes in cluster members and in control cohorts.

MATERIALS AND METHODS

Blood mononuclear cells were isolated from cluster members, unrelated MS patients, healthy controls, including healthy schoolmates to the Fjelsø cluster patients and finally from persons with autoimmune diseases in order to investigate the number of 39 bp repeats in the EBNA 6-coding region in the EBV seropositive individuals.

RESULTS

We observed a preponderance of the subtype with 3 39 bp repeats in the EBNA 6-coding region both in the MS patients and the healthy controls. In the Fjels cluster all 8 cluster members were harbouring this subtype, which is significantly different from the finding in healthy controls (n = 16), which include 8 schoolmates to the cluster members and 8 randomly selected healthy persons (Fischer's exact test P = 0.0047), and also compared to all non-clustered individuals studied (P = 0.017).

CONCLUSION

Infection with the same subtype of EBV links together the 8 persons from the Fjelsø cluster who later developed MS. This finding adds to the possibility that development of MS is linked to infection with EBV.

The significance of Epstein-Barr virus seropositivity in multiple sclerosis patients?

The objective of this study was to evaluate and investigate the significance of the previously found 100% seropositivity toward Epstein-Barr virus (EBV) found in multiple sclerosis (MS) patients in contrast to healthy controls. Using a commercially available ELISA-test (Biotest), which differentiates infections with EBV into previous infections, primary infections, reactivated infections and no previous infection, we found 137 of 138 MS patients and 124 of 138 healthy controls seropositive. A primary infection in 4 of the 124 EBV seropositive healthy controls in contrast to no primary infections in the MS EBV seropositive group was significant (P=0.049652, Fishers exact test). This may be suggestive of a lack of primary infections in MS patients, and thus strengthens the idea that MS patients are infected with EBV before development of MS. Further studies are in progress to analyse whether EBV infection is a prerequisite for the development of this disease.

The implications of Epstein-Barr virus in multiple sclerosis--a review

The objective of this article is to bring together knowledge about Epstein-Barr virus (EBV) in relation to multiple sclerosis (MS) in order to evaluate its implications in this disease. All MS patients are EBV seropositive, but EBV is not normally detected in the brain. EBV can explain many of the epidemiological dogmas known in MS. In addition, other studies point towards the involvement of EBV in MS. Despite this, other co-actors seem also to be involved. We still need to know whether EBV may be an initiating factor in MS or whether it is a factor in the pathogenesis. Possible ways of EBV involvement are discussed: direct involvement, an autoimmune inducing factor or a transactivating factor. A current treatment study of MS patients with a specific herpes antiviral drug may add further information to the etiology and pathogenesis of MS.

Characterization of retroviruses from patients with multiple sclerosis

These studies were performed to characterize retroviruses found in cell lines spontaneously developed from peripheral blood mononuclear cells (PBMNC) from 6 multiple sclerosis patients, a patient with progressive myelopathy and a healthy control. The cell lines are B-lymphoblastoid and produce Epstein-Barr virus (EBV) particles or express EBV proteins. The B-lymphoblastoid cell lines are also characterized by production of low, fluctuating amounts of retrovirus. The low productivity complicates purification and characterization, but implementation of product-enhanced reverse transcriptase (PERT) assays has provided a highly useful tool for monitoring retrovirus production. By electron microscopy, the retroviral particles appear type-C-like. Functional assays indicate the presence of Pol, Gag and Env. Indirect ELISA demonstrates a significant relation between disease activity and reactivity towards retroviral peptides. Molecular characterization is primarily based on RT-PCR, cloning, sequencing and Northern- or Southern analyses. Molecular characterization is continuing.

Increased risk of multiple sclerosis after late Epstein-Barr virus infection: a historical prospective study

An association between infectious mononucleosis (IM) and MS has been proposed. In a historical prospective study we used records from the Danish State Serum Institute on heterophile antibody (HA) tests for IM performed in all Danish patients over a number of years. Included in the analysis were 6853 HA-positive persons analyzed from 1968 to 1978 (except 1975) and 12,886 HA-negative per sons analyzed in the years 1968, 1969, 1970 and 1978. A search for these persons in the central nationwide Danish Multiple Sclerosis Registry (DMSR) was performed. Among the HA-positive persons 16 cases of MS which met the diagnostic criteria were found with onset of MS after the year of the HA test and before follow-up on 1 January 1991. The expected number for a Danish population, matched by sex, age and year at start of observation, was 5.70 (P < 0.05), the risk ratio being 2.81. No patient had developed MS before contracting IM. Among the HA-negative persons 12 were registered with onset of MS after the year of the HA test and before follow-up, the expected number being 10.47 (P > > 0.05). Although Epstein-Barr virus is not suggested in itself to be the cause of MS, we propose that it is a co-factor in the pathogenesis of this disease.

B-lymphoblastoid cell lines from multiple sclerosis patients and a healthy control producing a putative new human retrovirus and Epstein-Barr virus

On several occasions we have observed retrovirus-like particles (RVLPs) by transmission electron microscopy (EM) of cultured T cells from a patient with MS. Later we established spontaneously formed B-lymphoblastoid cell lines (LCLs) from a patient with an MS-like disease and from another patient with MS who had a reactivated Epstein-Barr virus (EBV) infection. Both LCLs were found by EM to produce RVLP and EBV particles. Reverse transcriptase (RT) assays were positive in purified viral material from both LCLs. To substantiate these findings we initiated an intensified culturing procedure and were able to establish LCLs from 5 out of 21 consecutive MS patients and 1 out of 13 consecutive healthy controls. All LCLs were found to produce both RVLP and EBV particles by EM. Whether the putative new retrovirus(es) and EBV have any causal relationship to MS is still not known, but the findings support this possibility.

A retroviral implication in multiple sclerosis?

The etiology of multiple sclerosis (MS) is still unexplained. Epidemiological studies indicate that environmental agents are involved, and MS shares both clinical and histopathological features with retrovirus-mediated neurological diseases in animals and humans. Thus, combining the fields of microbiology and epidemiology may throw new light on the many unanswered questions posed by MS.

A putative new retrovirus associated with multiple sclerosis and the possible involvement of Epstein-Barr virus in this disease

Since tropical spastic paraparesis in 1985 was found to be associated with HTLV-I infection, it has been suggested that a retrovirus might be involved in multiple sclerosis (MS). Our group has studied long-term cultures of cerebrospinal fluid cells and peripheral blood mononuclear cells from MS patients and controls with the purpose of elucidating the possible involvement of a retrovirus in MS. For an extended period electron microscopical analysis (EM) of T-cell lines, derived from MS patients and controls and cultured for 4 weeks was performed. In two cultures obtained 8 months apart from a patient with progressive MS, retrovirus-like particles were observed in 1-2% of the cells examined. Recently a B-lymphoblastoid cell line (LCL) producing retrovirus-like particles and EBV was established from a 30-year-old male patient with a chronic progressive myelopathy, clinically resembling multiple sclerosis. Similar cell lines have now been established from two MS patients. The retrovirus-like particles produced by the LCL have been purified by gradient ultracentrifugation. In the purified material reverse transcriptase assays are clearly positive in the gradients where EM shows retrovirus-like particles. Antigen characterization, nucleic acid sequence analysis and antibody studies are now being performed. The retrovirus found is definitively different from other known human retroviruses. It has previously been found that 100% of patients with MS have antibodies against EBV, in contrast to controls where only 86-95% have antibodies against this virus. Previous epidemiological studies have pointed toward a post-pubertal primary EBV infection as an important event in the induction of MS disease. These studies have now been substantiated by our group. Though it is still unknown whether EBV infection is a prerequisite for development of MS or whether the 100% EBV seropositivity is a consequence of the MS disease, we have put forward the hypothesis that the etiological agent for development of MS and MS-like diseases is a new hitherto uncharacterized retrovirus, whereas development of neurologic disease is related to or even dependent on a delayed infection with a virus from the herpes group, most likely EBV. This dual infection hypothesis has been analyzed and was found to be in accordance with the most consistent epidemiological characteristics of MS. We have previously, also from epidemiological data, negated retroviruses, behaving as the known human retroviruses, as an independent cause of MS.

Retrovirus-like particles in an Epstein-Barr virus-producing cell line derived from a patient with chronic progressive myelopathy

A B-lymphoblastoid cell line (LCL) of polyclonal origin was isolated from a 30-year-old male patient with a chronic progressive myelopathy clinically resembling multiple sclerosis (MS). The LCL expresses Epstein-Barr virus (EBV) encoded proteins and on transmission electron microscopy (EM) the LCL was shown to produce both EBV particles and retrovirus-like particles spontaneously. The LCL was negative for human retrovirus (HIV-I and HTLV-I) sequences by polymerase chain reaction (PCR). Furthermore the patient was seronegative to these retroviruses including HTLV-II and HIV-II. We, therefore, suggest that the LCL is double-infected with EBV and a hitherto uncharacterized human retrovirus. The possible implications of these two viruses on development of diseases are discussed.

[Disseminated sclerosis and retrovirus]

Multiple sclerosis is a disease characterized by neurologic dysfunction due to focal CNS lesions with demyelination. The cause of the disease is unknown; but it may be due to a virus and/or autoimmune reactions. The latter cause is suspected on account of family- and ethnical studies, the first on account of locally produced antibodies in the cerebrospinal fluid, and also epidemiologic investigations. The newly discovered human retroviruses, especially HTLV-I which is the cause of tropical spastic paraparesis, has been suspected as a possible cause; but this has been disproved by multiple antibody- and PCR-studies. An uncharacterized exogenous or an endogenous retrovirus is still considered to be a possible cause or possibly partial cause of the disease which could be multifactorial.

Is multiple sclerosis caused by a dual infection with retrovirus and Epstein-Barr virus?

Although the etiology of multiple sclerosis is as yet unknown, epidemiological observations strongly point toward one or more infectious agent(s) being involved in the disease. In recent years some studies have indicated involvement of retrovirus in multiple sclerosis (MS). However, an intrafamilial epidemiological study revealed that MS and the known human retroviruses had a divergent epidemiology. Some studies have shown the association of Epstein-Barr virus (EBV) with MS and one recent study revealed dual infection by retrovirus and EBV in a cell line established from a patient with an MS-like disease. Our hypothesis for the development of MS and MS-like diseases is that a hitherto uncharacterized retrovirus is the etiological agent, but development of neurologic disease is related to or even dependent on a delayed EBV infection. The dual infection hypothesis is analyzed and found to be consistent with the epidemiological characteristics of MS.

Multiple sclerosis as a retroviral disease? Epidemiological considerations in relation to HTLV-I epidemiology

The intrafamilial epidemiology of multiple sclerosis was compared with the known intrafamilial epidemiology of infections with HTLV-I. Infections with this retrovirus most often have a subclinical course, but can cause leukemia or a neurological disease resembling multiple sclerosis. Through the Danish Multiple Sclerosis Registry, information was obtained on 79 parent-child cases of multiple sclerosis, and in 55 cases further information was obtained through questionnaires. The study did not reveal any common intrafamilial pattern of MS and HTLV-I infections. It can be concluded that if multiple sclerosis is associated with a specific 'MS virus', it is hardly one with the same epidemiology as HTLV-I, maybe because MS could be a multifactorial disease only developing if various factors coincide in the same person.

Search for a retrovirus in long-term cultured cerebrospinal fluid cells and peripheral blood mononuclear cells from patients with multiple sclerosis

Long-term peripheral blood mononuclear cell (MNC) cultures stimulated with interleukin 2 (IL-2) or IL-2 + phytohemagglutinin were established from 33 multiple sclerosis (MS) patients, 9 with other neurological diseases (OND), and 24 normal controls (C). Cultures were analysed for growth characteristics, reverse transcriptase (RT) in the culture medium, 2'-5' oligoadenylate synthetase in the cells, and cell morphology. None of these parameters differed in the MS group compared with the OND and C groups. Furthermore, 11 cerebrospinal fluid cell cultures were established without feeder cells. Morphology studies of the cells and RT assays of the supernatants from these cultures were normal. Induction studies by dexamethasone and 2-bromo-5'-deoxyuridine in 2 of these cultures did not reveal any signs of a virus. The significance of these results for the retrovirus hypothesis is discussed.

The phagocytic activity of monocytes and polymorphonuclear leucocytes against viral antigens as measured by chemiluminescence in patients with multiple sclerosis

Twenty-two patients with Multiple Sclerosis in different stages of the disease were investigated in a chemiluminescence-assay and compared with a similar number of healthy individuals. The reactivity of peripheral blood monocytes to different viral antigens was followed by measurement of both the immediate oxidative activity and the development of activity through a 85-minutes period. The patients with a progressive course of the disease showed a high activity and reached maximum activity in a shorter time than the other groups, indicating an activation of the monocytes in these patients.--The patients in steady state showed a rather low activity, compared with both the other patient groups and the control group. A possible significance of these findings is discussed. The activity of the polymorphonuclear cells did not show differences in activity between the groups.

Tubuloreticular inclusions in skin biopsies from patients with HIV infection

Skin biopsies obtained from apparently normal skin from 15 HIV infected patients and 6 anti-HIV negative patients were examined by electron microscopy. Tubuloreticular inclusions (TRI) were detected within the cytoplasm of capillary endothelial cells in 5/5 AIDS patients and in 2/5 patients with AIDS related conditions. Biopsies from 5 asymptomatic HIV positive patients and the 6 control subjects were without ultrastructural alterations. The occurrence of TRI was related to low numbers of CD 4+ lymphocytes. 5/7 patients with TRI had elevated serum interferon activity, and in all of the patients without TRI, interferon activity was below detection level. The occurrence of TRI was not dependent on the presence of free p24 antigen in serum. It is concluded that the occurrence of TRI in entothelial cells of skin capillaries is associated with late stages of HIV infection and this may indicate a generalization of this change.

MS and the group-specific component

Sera from 95 MS patients and 227 control persons were examined by IEF to determine the Gc genotype. There was no correlation between MS and the distribution of Gc genotype (0.70 less than P less than 0.80) nor Gc alleles (0.80 less than P less than 0.90) although such a correlation is generally accepted on the basis of a smaller material. Furthermore, Gc correlated with neither disease course nor with the age of disease onset.

The influence of human allergic encephalitogenic peptide on cell-mediated cytotoxicity reactions in patients with multiple sclerosis

Multiple sclerosis patients and normal control persons were assayed for cell-mediated cytotoxicity against target cells coated with human allergic encephalitogenic peptide. Coating of different types of target cells resulted in increased cytotoxicity, most clearly seen against homologous lymphocytes and virus-infected fibroblasts. Both patients and controls showed reactivity against coated targets. A possible role for this type of reaction in the pathogenesis of multiple sclerosis is proposed.

Interferon induction, 2'-5' oligo A synthetase and lymphocyte subpopulations in out-patients with multiple sclerosis in a longitudinal study

Nine patients with multiple sclerosis, four with relapsing-remitting disease, and five with chronic progressive disease, together with eight healthy control, were followed for nearly a year with monthly clinical and laboratory examinations. Alpha- and gamma-interferon was induced in lymphocytes with different viruses and PHA, no differences were found between healthy controls and multiple sclerosis patients. The alpha- and gamma-interferon induced enzyme 2'-5' oligo A synthetase in lymphocytes was found to have a tendency to be lower in multiple sclerosis patients than in healthy controls. When medians of ratios of helper/suppressor blood lymphocytes in multiple sclerosis patients were compared with healthy controls, the same results were found, although higher values of ratios were found among the patients and the highest value was found in a patient with chronic progressive disease. No correlation to disease activity could be found in interferon inductions, 2'-5' oligo A synthetase concentrations and ratios of OKT4/OKT8. In particular no change in ratio was found in relation to five exacerbations taking place in the four multiple sclerosis patients with acute relapses.

Late-onset rubella syndrome: coexistence of immune complex disease and defective cytotoxic effector cell function

We studied a classical case of late-onset rubella syndrome characterized by multi-organ disease and persistence of live rubella virus in spite of high titres of specific antirubella antibodies and presence of large amounts of circulating immune complexes. When first studied at the age of 5 months there was a low proportion of T8+ lymphocytes. Functional studies revealed decreased activity of K and NK cells as well as alloreactive direct cytotoxic cells (CTL). Removal of cell-bound immunoglobulin and immune complexes tended to improve K and NK cell function in vitro. Plasma exchange transfusions carried out at 9 months of age resulted in clinical improvement. Normalization of cytotoxic effector cell functions and cessation of viremia accompanied recovery from active disease. The results indicate that defective cytotoxic effector cell function is the primary cause for the defective virus elimination in this syndrome.

Hodgkin's disease: in vitro susceptibility of skin fibroblasts to infection with virus and to lysis by autologous lymphocytes

Fibroblast cultures established from the skin of 16 untreated stage 1 and stage 2 Hodgkin's patients (HD) and 60 healthy controls were studied in their 3rd, 4th and 5th in vitro passage. HD cultures were similar to control cultures with respect to transformation with Simian sarcoma virus (SSV) and SV40 and with respect to interferon release. HD cultures, however, showed a depressed replication of both herpes simplex virus (HSV) type 1 and type 2. Preliminary evidence for enhanced immune interaction with fibroblasts in HD was a more frequent injury of HD than control fibroblast cultures when incubated 4 hours with autologous mononuclear leucocytes in the presence of autologous serum.

X-linked resistance of mice to high doses of herpes simplex virus type 2 correlates with early interferon production

Mice inoculated intraperitoneally with herpes simplex virus type 2 develop focal necrotizing hepatitis and eventually die from ascending myelitis and encephalitis. The genetics of resistance to the infection were analyzed in crosses between resistant C57BL/10 mice and susceptible BALB/c mice. It was shown that the resistance of C57BL/10 mice to hepatitis induction was influenced by an X-linked dominant gene as previously shown for the GR mouse strain. The course of infection in the liver pointed to early, natural defense mechanisms as being responsible for the difference between the mouse strains, whereas the clearance of virus from the liver, probably mediated by specific immunity, was exerted at the same time and with equal efficiency for all groups of mice. In mortality experiments, resistance was shown to be an autointerference phenomenon in that a considerable number of C57BL/10 mice survived an intraperitoneal injection of 10(6) PFU, whereas all mice were killed by 10(5) PFU. This resistance of C57BL/10 mice to high doses of HSV-2 was retrieved in all groups of F1 mice in crosses between C57BL/10 and BALB/c mice except the (BALB/c female X C57 male) male group, in which the mice receive the X chromosome from the susceptible BALB/c female. Thus, the autointerference phenomenon also seems to be influenced by loci on the X chromosome. A similar pattern of inheritance was observed when early interferon induction (4 to 5 h after infection) in response to HSV-2 was measured. The possible relevance of this early interferon response in conjunction with other potential natural defense mechanisms is discussed.

The influence of general anesthesia and surgery on cell-mediated cytotoxicity and interferon production

The effect on cell-mediated cytotoxicity of surgery and anesthesia for removal of a primary malignant melanoma was studied in 47 patients. The cytotoxic ability of peripheral blood lymphocytes has been investigated using 2 melanoma cell lines or 2 leukemia cell lines as target cells, with or without addition of interferon or specific antibodies. The cytotoxic ability was clearly reduced in all assays 1 day after the operation. After 6 days about half the patients were totally restored; others showed increase in cytotoxicity without reaching the initial values, whereas one fourth of the patients were still heavily depressed with only a small or no increase at all. The number of macrophages in the effector cell population was followed, and the ability to produce interferon on stimulation with viral or melanoma antigens was investigated, as alterations in these parameters could influence cytotoxicity. There were no fluctuations in these parameters.

Immunological parameters in multiple sclerosis patients with special reference to the herpes virus group

A group of multiple sclerosis (MS) patients (n = 50), most of them in a stable or slightly progressive phase was studied together with a group of neurological control (NC) patients with CNS lesions (n = 38) comparable in age and disability and an age matched group of healthy persons (n = 46). On stimulation of lymphocytes with herpes simplex virus (HSV), cytomegalovirus (CMV) and varicella zoster virus (VZV) a significantly lower interferon production was found in MS patients compared with the NC patients and the healthy controls; when the NC patients were compared with the healthy controls a significantly lower production was also found. The lymphocyte transformation reaction in seropositive MS patients was significantly lower than that seen in the seropositive control groups when HSV was used as antigen. Lower responses, although insignificant, were found when CMV and VZV were used as antigens. There were no differences among the three groups when Con A was used as mitogen in three different concentrations. Likewise spontaneous lymphocyte transformations were equal. The lower interferon production and the lower transformation reactions in MS patients could not be correlated to age, duration of disease, disability, disease activity or impairment. No significant differences in humoral immunity to HSV, CMV and VZV were found in the three groups, a few MS patients were 'true' seronegative to HSV type 1 and 2. Suppressor cell activity induced by Con A and measles virus was comparable in the three groups, although a few MS patients in an active relapsing phase were found to have low suppressor cell activity. Natural killer cell activity against two different cell lines was found equal in the three groups, and there was no difference in the potentiating effect of interferon.

Interferon production, cellular and humoral immunity in splenectomized patients

Undetectable levels of circulating interferon were found in 35 splenectomized patients and in 14 controls. In addition, no differences in virus, purified protein derivative (PPD), and phytohaemagglutinin (PHA) induced interferon production were observed between the patients and the controls. Virus induced lymphocyte transformation tended to be reduced after splenectomy, but only the herpes simplex virus (HSV) induced transformation index was significantly reduced in splenectomized patients without residual splenic tissue (P less than 0.05). In contrast, the PHA lymphocyte transformation was unchanged in patients and controls. The number of natural viral antibodies in splenectomized patients did not differ from that of controls. Furthermore, there were no major differences in the magnitude of the titers of the sero-positive cases between the various groups. Thus, splenectomy does not interfere with interferon production in vitro, and as seen from natural viral antibodies, no impairment of humoral immunity was observed. The reduced HSV lymphocyte transformation may indicate an impaired lymphocyte function after splenectomy.

Severe acquired immunodeficiency in European homosexual men

Four previously healthy Danish homosexual men developed Kaposi's sarcoma or opportunistic infections with fever of unknown origin and lymphadenopathy. One patient died of a Pneumocystis carinii pneumonia. Three patients had defective cell-mediated immunity with absent leucocyte interferon production and decreased proliferative response to mitogens and antigens. T lymphocyte helper subsets and natural killer cell activity were reduced. Unstimulated mononuclear cells produced leucocyte migration inhibitor factor. Two patients were sexual partners and three had never been to the USA, where cases of severe acquired immunodeficiency have been reported. Thus, the syndrome must also be suspected in European homosexual men who present with fever of unknown origin, opportunistic infections, or Kaposi's sarcoma.

Interferon in rabbit sera after inoculation with Treponema pallidum suspensions contaminated with PED virus

Paired rabbits sera were examined for the presence of interferon and pathogenicity for rabbits. The sera were obtained before and 48 hours after inoculation with Treponema pallidum suspensions of rabbit origin in 12 selected laboratories. Classical interferon, detectable in dilutions from 1/9 to 1/81, were found in 27 out of 39 postinoculation sera from which the pleural effusion disease (PED) virus was isolated. Serum interferon was not detectable in dilutions greater than or equal to 1/9 in 16 virus-negative postinoculation sera or in any of the 55 preinoculation sera. Interferon was found more often in sera from which highly virulent strains of PED virus were isolated than in sera from which strains of low virulence were isolated. The serum interferon assay provides useful presumptive evidence of contamination of rabbit-passaged treponemes with PED virus, but the assay is least useful when PED virus is present subclinically.

Cellular and humoral immunity in Hodgkin's disease. I Patients in continuous long-term remission

Cell-mediated and humoral immunity to herpes simplex virus (HSV), cytomegalovirus (CMV) and varicella zoster virus (VZV) were examined in 37 patients with Hodgkin's disease in continuous long term remission. This group had lower blast-transformation than a matched control group to all 3 antigens. Patients originally showing B-symptoms had higher transformation to VZV than those with A-symptoms. Patients treated with irradiation only had higher transformation than those treated with either chemotherapy or a combination of chemotherapy and irradiation. There was a clear tendency towards lower transformation in patients having been in remission for 2 years or less. Phytohaemagglutinin (PHA) stimulation gave lower response in the patient group than in the control group. Patients with B-symptoms had lower response than those with A-symptoms. Interferon production was specially impaired in patients with B-symptoms. The patient group had higher CF titers against HSV and CMV while the control group had higher titers against VZV. B-symptom patients had higher titers against VZV than A-symptom patients. It is concluded that HD patients have impaired immune function many years after discontinuation of therapy, but there are certain differences regarding the in vitro immunity within the patient groups.