Coxsackie B4 virus induces short-term changes in the metabolic functions of mouse pancreatic islets in vitro.

Mouse pancreatic islets cultured in vitro were infected with a tissue culture-adapted or a mouse pancreas-adapted strain of Coxsackie B4 (CB4) virus. The effects of the viruses on the islets were assessed by examination of their biochemical functions. It was found that the mouse pancreas-adapted strain of CB4 induced a 'leakage' of insulin from islets incubated at a basal (2 mmol l-1) glucose concentration, both at two and four days following infection. However, at a stimulatory concentration of glucose (20 mmol l-1) the rate of insulin secretion appeared to be normal in these islets. At two days the rate of total protein synthesis in islets infected with mouse pancreas-adapted CB4, incubated at high glucose concentration, was reduced; at four days the degree of inhibition was more severe, the rate at basal glucose concentration falling to half that of the control islets and at the stimulatory glucose concentration to a quarter of the control islets. (Pro)insulin biosynthesis was also inhibited, the rate being reduced to less than half the mean control value in islets infected with mouse pancreas-adapted CB4 virus at 20 mmol l-1 glucose at two days; at four days the rate was greatly reduced at both 2 and 20 mmol l-1 glucose. It is concluded from this study that only certain strains of CB4 virus can infect mouse pancreatic islets in vitro and that infection with strains of virus tropic for the islets leads to an impairment of metabolic functions of the B-cells, and is not necessarily lytic.

In situ characterization of autoimmune phenomena and expression of HLA molecules in the pancreas in diabetic insulitis.

After the death of a 12-year old girl with newly discovered insulin-dependent diabetes mellitus, we used monoclonal antibodies in an effort to identify the cells invading the pancreas. The majority of infiltrating lymphocytes were of the T cytotoxic/suppressor phenotype, but other T-cell subpopulations were present. Some of the T cells were "activated" (positive for HLA-DR antigen, and the interleukin-2 receptor). Immunocytes bearing IgG were scattered in the gland, and complement-fixing IgG antibodies were deposited in some islets. Increased expression of Class I (HLA-A, B, and C) molecules was observed in the affected islet cells, and in damaged islets showing scant lymphocytic infiltration, some beta cells (still producing insulin), but not glucagon or somatostatin cells, were HLA-DR positive. The capillary endothelium was markedly dilated and strongly HLA-DR positive. These findings may contribute to an understanding of the sequence of events leading to the destruction of beta cells in classic Type I diabetes mellitus.

Biochemical changes induced by Coxsackie B4 virus in short-term culture of mouse pancreatic islets.

Isolated mouse pancreatic islets were infected in vitro with two strains of Coxsackie B4 virus--a tissue culture-adapted strain and a mouse pancreas-adapted strain. Within 48 h of infection changes had occurred in the biochemical activities of islets infected with the mouse pancreas-adapted strain of virus. Basal insulin release was increased two-fold in these islets, while glucose-induced insulin secretion remained unchanged. Insulin biosynthesis was greatly reduced at a stimulatory concentration of glucose (20 mM), thus leading to a reduced insulin content in these islets. These effects are of importance because they demonstrate that certain strains of Coxsackie B4 virus, like encephalomyocarditis virus, may selectively alter beta-cell function in vitro.

An epidemiological study of childhood diabetes affecting two or more siblings.

The incidence, prevalence, and ages and dates of onset of diabetes, were studied in 184 families with 2 or more affected children. Results suggested that the siblings of children who developed diabetes before the age of 16 years were 26 times more likely to develop diabetes than other children. Of all siblings surveyed it was estimated that 5.6% became diabetic by the age of 16. The distribution of ages at onset in these siblings was similar to that in the general population, and within sibships, age at onset appeared to be independently determined. An interval of less than a year between the dates of onset in siblings occurred with more than twice the expected frequency, and in most the interval was less than 6 months. These results suggest that age at onset is determined by non-genetic factors and that, in at least some cases, aetiological environmental factors may lead to the development of diabetes within a period of a few months.

An outbreak of post-operative sepsis due to a staphyloccoccal disperser.

A staphylococcal disperser employed as a theatre technician appeared to have been the source of 11 cases of wound sepsis over a period of about 3 years. He was primarily a nasal carrier and after attempts to eradicate Staphylococcus aureus from his nose failed, his skin dispersal was controlled by daily washing with 4% chlorhexidine detergent ('Hibiscrub') and he was allowed to resume his theatre duties under careful bacteriological surveillance. Over the following 2 years 173 dispersal tests showed a mean dispersal of 1 . 7 c.f.u. per 2800 l air compared with a mean of 152 c.f.u. per 2800 l air in the mouth immediately preceding treatment and 55 c.f.u. per 2800 l in the period after cessation of treatment. One case of wound sepsis was attributed to the technician during the 2 years in which he received skin disinfection treatment.

Serum immunoreactive trypsin concentrations in diabetic children.

Serum immunoreactive trypsin (SIT) concentrations measured in 616 children with diabetes of recent onset were low, in both boys and girls, in comparison with reference ranges established in patients with non-diabetic, non-infectious illnesses. The mean SIT concentration was 60% of the mean reference level in children tested within three weeks of the onset of diabetes, and about 40% in patients tested six months after the onset of diabetes. Very low SIT levels were found in about 10% of patients, most of whom had no measurable SIT by the assay procedure employed. These very low SIT concentrations were more frequent in older children aged 6-15 years, and in children tested at about 5-6 months after onset. Repeat tests on some of the children showed that the very low SIT levels were generally present for only a limited period.

Relation of antecedent illness to development of diabetes in children.

Information was obtained by postal questionnaire in 1663 cases of childhood diabetes of recent onset about other illnesses for which the family doctor was consulted in the six months before onset. Consultation rates in each of these six months were compared with each other and with rates reported in a concurrent study of morbidity in general practices. There was a significant excess of consultations for mumps in the six months before onset of diabetes (p < 0.001), the greatest excess being in the month before onset. These results support the suggestion that diabetes starting in childhood may result in a small proportion of cases from recent mumps infection.

Serum immunoreactive trypsin concentrations in infectious and non-infectious illnesses and in juvenile diabetes.

Serum immunoreactive trypsin (SIT) concentrations were measured in 244 patients with infectious illnesses and in 281 children with diabetes of recent onset. Results were compared with reference ranges established in 107 patients with non-infectious, non-diabetic illnesses, in whom SIT concentrations were found to increase with advancing age. Reduced or undetectable concentrations of SIT were associated with diabetes in children and with a few cases of severe childhood infection. Increased SIT concentrations were associated with virologically confirmed cases of infection with mumps and Coxsackie B virus infection, and with clinical diagnoses of mumps, PUO, and meningitis in children, and with Bornholm disease, cardiac infection, and respiratory infection in adults. It is suggested that silent invasion of the exocrine pancreas with elevation of the SIT concentration may accompany infection by Coxsackie B, mumps, and, possibly, other viruses.

Viruses in drinking-water. Reconsideration of evidence for postulated health hazard and proposals for virological standards of purity.

Stringent virological standards for drinking-water have been proposed by the World Health Organisation and by others, but there is no evidence of the spread of virus infection by drinking-water that has been adequately treated to conventional bacteriological standards. There is evidence for waterborne transmission of hepatitis and viral gastroenteritis but the case for the introduction of virological standards is critically examined. It is concluded that there is no evidence that drinking-water in the U.K. contributes to the spread of virus infection, and that the introduction of virological standards for drinking-water could not at present be justified. Moreover, in the absence of any information relating the degree of viral contamination to disease, there is no logical basis on which to set the level of a practical virological standard.

Aetiology of juvenile-onset diabetes. A prospective study.

110 people in whom insulin-dependent diabetes developed when they were less than 30 years old were studied as soon as possible after diagnosis. There was evidence for clustering of cases with BW15-positive phenotypes during the winter peak (1976) but not during the autumn peak (1975). Subjects who were BW15-positive, and in particular those who were both B8 and BW15-positive, had higher neutralising antibody titres to Coxsackle virus types B1-B4 58% of cases had islet-cell antibodies (I.C.A.), but the presence of I.C.A. was not correlated with HLA phenotypes or viral antibody titres. In 41 subjects (37%), who gave a definite history of antecedent illness, evidence indicated that this was a precipitating infection and not the initiating event producing islet-cell damage. Nearly half the subjects had had diabetic symptoms for more than 4 weeks before diagnosis.

Islet-cell antibodies in diabetes mellitus.

Islet-cell antibodies (I.C.A.) were found in 38% (319/829) of insulin-dependent diabetic patients, in 5% (6/112) of insulin-independent diabetics, and in 1.7% (3/177) of non-diabetic subjects. In the insulin-dependent group I.C.A. were found in 85% of patients immediately after the onset of symptoms and they became less common as the duration of disease increased I.C.A. were equally common in both sexes and the decline in their prevalence was independent of age. The antibodies were directed against cytoplasmic components of islet cells but not against insulin itself. The appearance of I.C.A. probably follows cell damage occurring before the onset of symptoms. By contrast, thyroid and gastric autoantibodies were more common in older patients and females. There was no correlation between the presence of these antibodies and I.C.A. in patients with either diabetes of recent onset or longstanding disease.

HLA-linked genes and islet-cell antibodies in diabetes mellitus.

In a random series of 139 insulin-dependent diabetics aged 30 or under at the onset of disease islet-cell antibody (ICA) was detected in 33 cases (24%). In 27 patients who had had diabetes for less than one year 16 (59%) had ICA. Only one out of 51 patients with maturity onset diabetes who were not dependent on insulin were positive for ICA. Four out of 19 patients with late onset insulin-dependent diabetes had ICA. There was no association between the presence of ICA and any particular HLA phenotype. Within families containing two or more HLA haploidentical siblings with juvenile onset diabetes ICA was a variable finding both in its occurrence and in its relation to the duration of disease. A possible mode of action for the HLA-linked gene may be to permit a rapid immunological destructive process, possibly associated with viral infection.

Islet-cell, thyroid, and gastric autoantibodies in diabetic identical twins.

Sera from 54 pairs of identical twins, 29 discordant and 25 concordant for insulin-dependent diabetes, and 11 pairs of concordant non-insulin dependent identical twins were examined for pancreatic islet-cell antibodies (ICAs). ICAs were found in 10 of the 29 diabetic discordant and eight of the 50 concordant twins (difference not significant P greater than 0-05). Six out of nine twins tested within one year of onset of diabetes were positive, whereas nine out of 29 tested after one to 10 years and three out of 41 tested after 10 years were positive. Only one of the 22 non-insulin-dependent twins had ICAs. Repeat ICA testing in five pair of insulin-dependent twins and in the siblings of one pair showed that ICAs may be present in people with normal glucose tolerance' may precede clinical diabetes by several years; and may decline in titre or disappear with increasing duration of disease. Thyroid or gastric autoantibodies, or both, were found in 36 out of 108 insulin-dependent twins and three out of 22 non-insulin dependent twins (difference not significant P less than 0-05). Only four twins had both ICAs and thyrogastric antibodies. There were no significant associations between autoantibodies and HLA histocompatibility types. As ICAs are more common in the diabetic than the non-diabetic twins of the discordant pairs they must be associated with juvenile onset diabetes. ICAs may appear some years before the onset of diabetes, but their prevalence declines with increasing duration of diabetes. The factors determining the production of ICA differ from those for thyroid and gastric autoantibodies.

Epidemiological background to diabetes.

Earlier seasonal inoidence studies indicated that juvenile diabetes is acquired mainly in the autumn and winter months, and more recent and extensive further studies conducted throughout Great Britain have confirmed these earlier findings. Studies relating the incidence of the disease to age among juveniles suggest that an initiating factor, probably viral in origin, is operative in early childhood and that after a latent period, a precipitating factor may then uncover the disease. This might explain the peak of juvenile diabetes which appears at age 11, in Britain. Studies on families in which diabetes has appeared almost simultaneously in two or more members, lends some support to the view that the disease may be precipitated by some infective process.

Viruses and the aetiology of diabetes: a study in identical twins.

Sera were collected from 49 pairs of identical twins, 27 of whom were discordant (only one twin affected) and 22 concordant (both diabetic) for insulin-dependent diabetes. All were tested for antibodies to mumps, cytomegalovirus, rubella, Coxsackie virus types B1-5, and Mycoplasma pneumoniae. The diabetic co-twins had no more antibodies to any of the viruses than the non-diabetic co-twins of the discordant pairs. Antibodies to Coxsackie B2, rubella virus, and M pneumoniae were found more often in the discordant than in the concordant twins. In 30 of the 71 diabetic twins symptoms began when they were aged 4-6 years or 10-15 years. More concordant than discordant twins were diagnosed during the months January to March. Hence there was no direct evidence of a virus aetiology of juvenile onset diabetes in these twins, and the difference in antibody titres between the concordant and discordant twins was in keeping with a genetic difference between them. The age and time of onset suggested that environmental factors may be important in causing diabetes in the twins.

Register of newly diagnosed diabetic children.

In November 1972 the British Diabetic Association sponsored a register to which notification was invited of all new cases of diabetes occurring in children aged 0-15 years in Great Britain and Ireland. More than 2000 cases were notified in the first two years. Notification suggested that there was a minimum yearly incidence of 7-67 cases per 100 000, though incidences varied from year to year and by geographical area. Several reports of simultaneous onset of diabetes in sibs of different ages provided evidence of clustering. A seasonal variation in incidence was found in children aged 5-15 years with peaks in the autumn and winter. The age distribution was bimodal with a main peak at about 11 years and a secondary peak at about 5 years. The sex ratio showed a male excess from 0-4 years and from 11-15 years and a female excess from 5-10 years. Overall there were slightly more male cases. Altogether 11% of patients had a first-degree relative with diabetes. The register and several investigations based on it will continue.