An outbreak of coxsackievirus B infection followed by one case of diabetes mellitus

Development of a new method for diagnosis of Group B Coxsackie genome by reverse transcription loop-mediated isothermal amplification

BACKGROUND

Coxsackie B viruses (genus, Enterovirus; family, Picornaviridae) can cause aseptic meningitis, encephalitis, pleurodynia, and fatal myocarditis, and are implicated in the pathogenesis of dilated cardiomyopathy. The differentiation of the group B Coxsackieviruses into their subtypes has potential clinical and epidemiological implications.

OBJECTIVE

In this study, we developed a one-step, single-tube genogroup-specific reverse transcription loop-mediated isothermal amplification (RT-LAMP) assay for the detection of group B Coxsackie genomes targeting 5' UTR region.

MATERIALS AND METHODS

The amplification can be obtained in less than 1 hour by incubating all the reagents in a single tube with reverse transcriptase and Bst DNA polymerase at 63°C. Detection of gene amplification could be accomplished by agarose gel electrophoresis and the monitoring of gene amplification can also be visualised with the naked eye by using SYBR green I fluorescent dye.

RESULTS

A total of 40 samples comprising 31 positive samples and 9 negative samples were used in this study for comparative evaluation. The results were compared with those from Real-Time Polymerase Chain Reaction (RT-PCR). None of the RT-PCR-positive samples were missed by RT-LAMP, thereby indicating a higher sensitivity of the RT-LAMP assay.

CONCLUSION

Thus, due to easy operation without a requirement of sophisticated equipment and skilled personnel, the RT-LAMP assay reported here is extremely rapid, cost-effective, highly sensitive, and specific and has potential usefulness for rapid detection of non-polio enterovirus (NPEV) not only by well-equipped laboratories but also by peripheral diagnostic laboratories with limited financial resources in developing countries.

Simultaneous type 1 diabetes onset in mother and son coincident with an enteroviral infection

Enterovirus (EV) infections have been implicated in the development of type 1 diabetes. (T1D). They may cause beta-cell destruction either by cytolytic infection of the cells or indirectly by triggering the autoimmune response. Virus was isolated from a woman at diagnosis of T1D (Tuvemo 1) and in addition, virus was isolated from her son at diagnosis of T1D at the same day (Tuvemo 2). None of the isolates could initially be serotyped by conventional methods. The Tuvemo 1 virus was genotyped and after sub-cultivation it was also serotyped as Coxsackievirus B5. The mother revealed antibodies against GAD65. The boy and the father both revealed a significant increase in neutralization antibody titre against two strains of CBV-4, clearly indicating a recent or ongoing EV infection. In addition, the brother showed such a titre rise against another CBV-4 strain (E2) and against a CBV-5 strain (4429). These results show that the whole family had a proven EV infection at the time of T1D diagnosis of the mother and the 10-years-old boy, indicating that the infection might cause or accelerate the T1D.

A new look at viruses in type 1 diabetes

Type 1 diabetes (T1D) results from the destruction of pancreatic beta cells. Genetic factors are believed to be a major component for the development of T1D, but the concordance rate for the development of diabetes in identical twins is only about 40%, suggesting that nongenetic factors play an important role in the expression of the disease. Viruses are one environmental factor that is implicated in the pathogenesis of T1D. To date, 14 different viruses have been reported to be associated with the development of T1D in humans and animal models. Viruses may be involved in the pathogenesis of T1D in at least two distinct ways: by inducing beta cell-specific autoimmunity, with or without infection of the beta cells, [e.g. Kilham rat virus (KRV)] and by cytolytic infection and destruction of the beta cells (e.g. encephalomyocarditis virus in mice). With respect to virus-mediated autoimmunity, retrovirus, reovirus, KRV, bovine viral diarrhoea-mucosal disease virus, mumps virus, rubella virus, cytomegalovirus and Epstein-Barr virus (EBV) are discussed. With respect to the destruction of beta cells by cytolytic infection, encephalomyocarditis virus, mengovirus and Coxsackie B viruses are discussed. In addition, a review of transgenic animal models for virus-induced autoimmune diabetes is included, particularly with regard to lymphocytic choriomeningitis virus, influenza viral proteins and the Epstein-Barr viral receptor. Finally, the prevention of autoimmune diabetes by infection of viruses such as lymphocytic choriomeningitis virus is discussed.

Agenesis of the dorsal pancreas in a woman with diabetes mellitus and in both of her sons

Complete agenesis of the dorsal pancreas has rarely been described. Complete agenesis of the dorsal pancreas in a female who developed insulin-dependent diabetes mellitus at the age of 39 years is reported. The diagnosis of agenesis of the dorsal pancreas was suspected by abdominal ultrasound and confirmed by abdominal computed tomography (CT), magnetic resonance imaging, and endoscopic retrograde pancreatography. Her exocrine pancreatic function was essentially normal. Both of the patient's sons also had agenesis of the body and tail of the pancreas verified by abdominal CT but had no evidence of diabetes mellitus. This familial occurrence of agenesis of the dorsal pancreas suggests that hereditary mechanisms may play a role in the pathogenesis of this anomaly.

Insulin mRNA content in pancreatic beta cells of coxsackievirus B4-induced diabetic mice

Molecular hybridization was used to measure poly(A)-containing mRNA and insulin mRNA, and to evaluate viral persistence, in pancreatic beta cells of coxsackievirus B4-induced diabetic mice. Cellular RNA was hybridized with [3H]poly(U) to measure poly(A)-containing total mRNA, 32P-labeled preproinsulin I and II probes to measure insulin mRNA, and a 32P-labeled virus-specific probe to evaluate persistence. The infected mice (80-90%) showed subnormal blood glucose at 72 h postinfection and were hyperglycemic at 6 and 8 weeks. Poly(A)-containing total mRNA decreased by about 26% at 72 h and 6 weeks and by 49% at 8 weeks, while preproinsulin I mRNA by 30% and preproinsulin II by 46% at 8 weeks postinfection compared to control. Viral sequences were abundant at 72 h and in fair amounts later. It appears that persistent viral infection produces a pathological state, which impairs beta cell function to reduce insulin mRNA and consequently insulin synthesis apparently leading to hyperglycemia.

Matching of host genotype and serotypes of Coxsackie B virus in the development of juvenile diabetes

Thirty-six consecutive paediatric patients (0-16 years old) with recently contracted juvenile diabetes (IDDM) during 1982-84 were included in the study. Sera were assayed for recent or current Coxsackie B virus (CBV) infection using a specific and sensitive IgM RIA. Eighteen patients (50%) had IgM against CBV 1-5. The patients were also assayed for restriction fragment length polymorphism (RFLP) patterns with DNA probes coding for HLA-DR and DQ beta chains. The CBV-positive patients (n = 18) had either RFLP patterns associated with HLA-DR 3 or 4 or HLA-DQ patterns III or IV beta. Two of the CBV negative patients had neither HLA-DR 3 nor DR 4 and four of them had neither DQ patterns III nor IV. Eleven out of 18 CBV-positive patients had HLA-DQ III and DR 3 (61%) versus 5 out of 18 (28%) of the CBV-negative patients. All 11 patients with serology positive for CBV 2, 3, and 5 had HLA-DR 4 and DQ IV patterns. This was significantly (P less than 0.01) different from all five CBV 4-positive patients, who in contrast all had HLA-DR 3 or HLA-DQ III patterns. CBV 1-positive patients (n = 2) all had HLA-DR 3, 4, and HLA-DQ III, IV patterns. Thus CBV 4 seems to be significantly associated with a different host genetic constitution from at any rate CBV 2, 3, and 5, and possibly CBV 1.