Immunoprotection of Pancreatic Islet Grafts within Artificial Microcapsules

To circumvent pancreatic islet graft-directed immune destruction we enveloped porcine islets within highly biocompatible and selectively permeable algin/polyaminoacid microcapsules. These special microspheres were deposited between the inner (permeable) and the outer (impermeable) layers of an artificial, coaxial vascular prosthesis, directly anastomized to blood vessels. Five dogs with spontaneous, insulin-dependent diabetes received microencapsulated porcine islets in arterio-vein iliac prosthesis by-passes. One showed complete and the remainder partial, sustained reversal of hyperglycemia. Microencapsulation may be a potential solution to immunological problems related to islet transplantation.

Misdiagnosis in fibromyalgia: a multicentre study

BACKGROUND

Fibromyalgia (FM) is the second most common cause of visits to rheumatologists after osteoarthritis, and may be difficult to diagnose in many patients. It is associated with various rheumatic disorders such as rheumatoid arthritis, spondyloarthropathies (SpA) and connective tissue disease (CTD), and a late diagnosis or misdiagnosis is a common and underestimated problem.

OBJECTIVES

The aim of this study was to investigate the 'underdiagnosis' of FM, and which rheumatic diseases tend to be confused with it.

METHODS

The following data were collected at baseline: symptoms, disease duration, physical examination findings, previous and current investigations and management, laboratory tests, tender point count, tender and swollen joint counts, and spinal pain. The clinimetric evaluation included the Fibromyalgia Impact Questionnaire (FIQ) and Fibromyalgia Assessment Status (FAS).

RESULTS

The study population consisted of 427 outpatients (418 females and 9 males; mean age 49.3 years; mean disease duration 8.5 years). Fifty-seven patients (13.3%) had been previously misdiagnosed as having other musculoskeletal disorders (MSDs); 370 patients had been previous correctly diagnosed as having FM, or were diagnosed as having it during the course of the study. The FM and MSD groups were comparable in terms of demographic data and referral patterns. Disease duration was longer and the erythrocyte sedimentation rate was higher in the MSD patients, who also had less severe FIQ and lower pain visual analogue scale scores. Moreover, the FIQ and FAS scores correlated in the MS group.

CONCLUSIONS

The findings of this study suggest that, although FM is a wellknown clinical entity, differential diagnosis with SpA, CTD and inflammatory arthritis can still be a challenge for rheumatologists and general practitioners.

Platelet-leukocyte interactions in hemodialysis patients: culprit or bystander?

The formation of circulating platelet-leukocyte complexes has been observed in a variety of conditions and may be pathophysiologically significant. Platelet-leukocyte interactions in fact facilitate metabolic cooperation and mutual activation, which may be of relevance in many biological processes including inflammation, atherogenesis and hemostasis. During hemodialysis procedure, the series of reactions that can occur upon blood contact with the foreign membrane surface may involve a variety of changes affecting almost every cellular and plasmatic component of the blood. This article reviews the evidence for abnormal interactions between circulating platelets and leukocytes in uremic patients undergoing maintenance hemodialysis and the pathophysiologic implications which may stem from such interactions.

The use of colony stimulating factors in elderly patients with cancer

Hematological toxicity is the most common and the most frequent fatal complication of chemotherapy. It is observed with increased frequency with age, it is a significant independent predictor of the development of febrile neutropenia, and may contribute to a reluctance to administer chemotherapy in the elderly patient population. The authors analyze published data on effectiveness and results of the use of colony stimulating factors for preventing and treating elderly patients affected by tumors during chemotherapy.

Reduced thymic expression of islet antigen contributes to loss of self-tolerance

Type 1 diabetes (T1DM) results from a failure of central and peripheral tolerance to islet cell antigens. ICA69 belongs to a group of molecules expressed predominantly in neuroendocrine tissues (including pancreatic islets), which are targets of autoimmune responses in T1DM. These molecules are also expressed in the thymus and peripheral lymphoid organs by dendritic cells. The aim of the present study was to evaluate possible variation in thymic ICA69 expression, comparing diabetes-resistant controls to T1DM-prone NOD mice. Thymic tissue was retrieved from 3- to 6-week-old female B6, NOD-H2(b), and NOD mice. Paraffin-embedded sections were stained with an ICA69-specific antibody in an immunoperoxidase assay. ICA69 staining of thymic sections from B6 and NOD.H2(b) showed strong and continual staining, yet the sections from the NOD mice showed significantly reduced staining for ICA69. Corroboration of the reduced level of ICA69 in the thymus of NOD mice has been obtained via analysis for the expression of ICA69 versus other candidate autoantigens (glutamic acid decarboxylase 65, glutamic acid decarboxylase 67, and insulin 2) in the thymus. Real-time PCR analysis, using cDNA generated from the thymus, displayed that the expression of GAD65, GAD67, and INS2 were equivalent when comparing NOD at any age to B6, BALB/cJ, and ALR/LtJ. In marked contrast, the level of ICA69 in the thymus of the NOD mice examined was significantly reduced when compared to the controls. In fact, the real-time PCR analysis strongly suggested that ICA69 was not expressed in the thymus of NOD mice. These findings support the hypothesis that the level of thymic ICA69 expression may be of importance in regulating self-tolerance in T1DM.

Geriatric oncology: a clinical approach to the older patient with cancer

Due to the ageing of the population and the sharp increase in life expectancy, cancer in the older person has become an increasingly common problem in the Western world. Although several authors have stressed that elderly cancer patients deserve special attention as a target group for research efforts, older aged patients are still less likely to be offered participation in clinical trials. The cellular and molecular mechanisms regulating the physiological process of ageing and senescence are far from understood, although inflammation is likely to play an important role, at least in some cancers. In addition, the relationship between ageing and cancer risk is also far from understood. One of the most intriguing aspects of ageing is how different the ageing process is from person to person; the basis for this variation is largely unknown. Population-based studies and longitudinal surveys have shown that comorbidity and physical and mental functioning are important risk factors; thus, a meaningful assessment of comorbidity and disability should be implemented in clinical practice. Modern geriatrics is targeted towards patients with multiple problems. Such patients are not simply old, but are geriatric patients because of interacting psychosocial and physical problems. As a consequence, the health status of old persons cannot be evaluated by merely describing the single disease, and/or by measuring the response, or survival after treatment. Conversely, it is necessary to conduct a more comprehensive investigation of the 'functional status' of the aged person. A geriatric consultation provides a variety of relevant information and enables the healthcare team to manage the complexity of health care in the elderly; this process is referred to as the Comprehensive Geriatric Assessment (CGA). The use of CGA is now being introduced into oncological practice. The definition of frailty is still controversial and represents a major issue of debate in clinical geriatrics. As the frail population increases, clinical trials in frail persons are needed. The usefulness of these trials requires a consensus as to the definition of frailty. Clearly, the management of older persons with cancer requires the acquisition of special skills in the evaluation of the older person and in the recognition and management of emergencies as well as experience in geriatric case management.

Pathogenesis of diabetes: our current understanding

Understanding the pathogenesis of any disease is of prime importance when considering treatment. Recent breakthroughs in the evaluation and management of diabetes and the availability of new therapeutic regimens make it imperative that the primary care physician be aware of these advances to improve patient care. This article discusses our current understanding of the pathogenesis of both type 1 and type 2 diabetes mellitus. A glossary of pertinent genetic terms is included.

Therapeutic strategies for Type 1 and Type 2 diabetes mellitus

Although diabetes mellitus is a manageable disorder, the associated complications that result in significant morbidity and mortality worldwide necessitate novel approaches of pharmacologic, cell, and gene therapy for an eventual cure. A significant number of animal studies have demonstrated the potential of restoring normoglycemia by islet transplantation in the context of immunoregulation achieved by gene transfer of immunoregulatory genes to allo- and xenogeneic islets ex vivo. Examples include viral vector-mediated gene transfer of immunosuppressive cytokines, proteins that block co-stimulation and molecules that prevent apoptotic cell death. Additionally, gene and cell therapy has also been used to induce tolerance to auto- and alloantigens and to generate the tolerant state in autoimmune rodent animal models of Type 1 diabetes mellitus (T1DM) or rodent recipients of allogeneic/xenogeneic islet transplants. Gene transfer of putative autoantigens is one example. The achievements of gene and cell therapy in Type 2 diabetes mellitus (T2DM) are less evident, but seminal studies promise that this modality can be relevant to treat and perhaps prevent the underlying causes of the disease including obesity and insulin resistance. Herein, we present an overview of the current status of drug, gene and cell therapy for T1DM and T2DM and we propose novel therapeutic options that could be clinically useful.

Is type 2 diabetes a chronic inflammatory/autoimmune disease?

The classification of diabetes mellitus into 2 main types, defined as Type 1 and 2 diabetes (T1DM, T2DM) relies mostly on the requirement of insulin therapy and on the presence of detectable immunologic abnormalities. However, this distinction is far from straightforward and there is considerable overlap between these 2 types of diabetes. Islet cell autoimmunity, which is characteristic of T1DM, appears in fact to be present in up to 10-15% of subjects diagnosed clinically with T2DM. In the UK Prospective Diabetes Study (UKPDS), it was reported that in patients diagnosed with in T2DM, the presence of autoantibodies to the enzyme glutamic acid decarboxylase (GAD) and cytoplasmic islet cell antibodies (ICA) were a predictor of insulin requirement as compared with patients not carrying these autoantibodies. These results are strikingly similar to a number of prospective studies carried out in childhood diabetes. If islet cell autoimmunity is truly present in 10-15% of subjects clinically diagnosed with T2DM, up to two million Americans might have an unidentified autoimmune form of T2DM, a prevalence similar to that of recent onset childhood diabetes. In addition, we found that in a subset of T2DM patients, a pronounced activation of the acute phase response that seems to be associated with islet cell autoimmunity. These results may in part explain the defect in insulin secretion as well as insulin resistance seen in T2DM. The identification of a subgroup of individuals at risk of developing T2DM using autoantibody as well as inflammatory markers is of public health interest, not only for the correct classification of diabetes, but also because immunomodulatory therapeutic strategies could potentially be instituted sufficiently early in a large number of patients diagnosed as having T2DM and most likely delay the onset of insulin requirement and the complications related with hyperglycemia.

Progression to insulin-requiring diabetes in seronegative prediabetic subjects: the role of two HLA-DQ high-risk haplotypes

AIMS/HYPOTHESIS

Most Caucasians with Type I (insulin-dependent) diabetes mellitus develop an autoimmune form of diabetes known as Type IA diabetes, based on the presence of humoral responses to islet autoantigens. Alleles at the HLA locus account for the strongest susceptibility to this form of diabetes, which requires insulin therapy. Because a number of patients who develop insulin-requiring diabetes are islet autoantibody negative, the HLA class II haplotypes, DQA1*0501-DQB1*0201 and DQA1*0301-DQB1*0302, were evaluated to assess whether they are an independent risk factor for progression to insulin requirement in first-degree relatives of Type I diabetic patients.

METHODS

Both HLA-DQ genotyping and islet cell autoantibody assessment (insulin, GAD65, IA-2 autoantibodies and cytoplasmic islet cell antibodies) were evaluated prospectively in 74 relatives of Type I diabetic patients who developed diabetes treated with insulin (prediabetics) and in 426 control subjects who did not develop insulin-requiring diabetes. Based on the presence of DQA1*0501-DQB1*0201 and/or DQA1*0301-DQB1*0302, the number of HLA-DQ high-risk haplotypes was assigned as 0, 1 or 2.

RESULTS

A higher prevalence of 2 HLA-DQ high-risk haplotypes was present in seronegative prediabetic subjects as compared to non-diabetic autoantibody negative first-degree relatives (33.3 % vs 10.1 % respectively; p < 0.05). Moreover, in seronegative relatives who developed insulin-requiring diabetes, the presence of 2 HLA-DQ high-risk haplotypes conferred an increased cumulative risk of developing insulin requirement of 27 % at 12.5 years of follow-up, compared to a risk of 6 % for non-diabetic relatives who were antibody-negative and had 0 or 1 HLA-DQ high-risk haplotypes (Log rank p = 0.01).

CONCLUSION/INTERPRETATION

These data provide evidence for a phenotype, which is associated with the absence of conventional islet autoantibodies at initial screening, while usually remaining seronegative, and the presence of 2 HLA-DQ high-risk haplotypes with progression to clinical Type I diabetes after a prolonged follow-up. Given the fact that in humans the highest risk-conferring locus associated and linked to the disease is the HLA cluster, and that HLA-DQ molecules play a key role in the development of autoimmune diabetes, our observations imply that as yet unidentified immunologic abnormalities could well exist in seronegative relatives at risk of developing clinical diabetes and carrying 2 HLA-DQ high-risk haplotypes.

Intratracheal administration to the lung enhances therapeutic benefit of an MBP peptide in the treatment of murine experimental autoimmune encephalomyelitis

The treatment of autoimmune diseases by targeted down-regulation of autoantigen-specific cells has been accomplished by the administration of high doses of autoantigen. We performed direct comparisons between injection of myelin basic protein peptide and administration by several nonparenteral routes to determine whether route impacted benefit in the treatment of murine allergic encephalomyelitis, a model for multiple sclerosis. The range of effective peptide doses spanned over 1000-fold, and route of delivery played a major role in determining optimal dose. The oral route of administration was the least effective, requiring at least 50- to 100-fold more antigen than subcutaneous injection, which in turn required at least 10-fold more antigen than delivery of peptide to the lung using an intratracheal instillation. Intratracheal delivery was also considerably more effective than inhalation of peptide, and, unlike inhalation, resulted in obvious penetration of delivered material deep into the lung. The increase in therapeutic efficacy did not appear to result from slower systemic delivery of antigen. Accumulation of peptide on antigen presenting cells in the spleen and in the brain was less efficient using the intratracheal route of administration compared to subcutaneous injection, implicating a special role for the lung microenvironment in the induction of immune nonresponsiveness.

Evidence of islet cell autoimmunity in elderly patients with type 2 diabetes

In light of an occurring growth of elderly people affected by type 2 diabetes and recent observations indicating that type 2 diabetes may be a disease of the innate immune system, we evaluated whether signs of islet cell autoimmunity are associated with an abnormal glucose control, the presence of insulin requirement, or an activation of the acute-phase response in older individuals with type 2 diabetes. GAD65 and IA-2 autoantibodies along with the acute-phase response markers fibrinogen and C-reactive protein were tested in 196 serum samples from patients with type 2 diabetes and in 94 nondiabetic control subjects over the age of 65 years from the Pittsburgh cohort of the Cardiovascular Health Study. Of the diabetic patients, 12% (24 of 196) had autoantibodies against GAD65 and/or IA-2, a prevalence significantly higher than that found in nondiabetic individuals (1 of 94, 1.1%; P = 0.001). Type 2 diabetic patients who were positive for GAD65 and/or IA-2 autoantibodies (Ab+), as compared with those negative for these autoantibodies (Ab-), had an abnormal oral glucose tolerance test (OGTT) (P = 0.03) before and a higher frequency of oral hypoglycemic treatment (P = 0.003) at the time of autoantibody testing. No differences were seen in the percentage of insulin requirement in the two groups. Moreover, a statistically significant increase in fibrinogen (P = 0.005) and C-reactive protein levels (P = 0.025) was found in type 2 diabetic patients with high levels of GAD65 and/or IA-2 autoantibodies as compared with Ab-patients and control subjects. In conclusion, in type 2 diabetic subjects > or =65 years old, the presence of islet cell autoimmunity is associated with an impairment of the acute-phase insulin secretion, as revealed by an OGTT. A pronounced activation of the acute-phase response, found to be associated with islet cell autoimmunity, may in part explain this defect in insulin secretion. These findings not only have direct implications for adequate classification and treatment of diabetes in the elderly, but also for understanding the autoimmune/inflammatory mechanisms involved in the pathogenesis of hyperglycemia.

Persistent T cell anergy in human type 1 diabetes

An anergic phenotype has been observed in nonobese diabetic (NOD) mice and some autoreactive T cells from patients with type I diabetes. To better understand this phenomenon, we measured T cell proliferative responses to 10 diabetes-associated and up to 9 control Ags/peptides in 148 new diabetic children, 51 age- and MHC (DQ)-matched siblings (sibs), 31 patients with longstanding diabetes, and 40 healthy controls. Most (78-91%) patient and sib responses to glutamate decarboxylase of 65 kDa (GAD65), islet cell cytoplasmic autoantibody (ICA) 69, diabetes-associated T cell epitopes in ICA69 (Tep69), and heat shock protein (Hsp) 60 involved anergic T cells that required exogenous IL-2 to proliferate. Responses to proinsulin, IA-2 (and tetanus toxoid) required no IL-2 and generated sufficient cytokine to rescue anergic T cell responses. Most new patients (85%) had autoreactive T cells, three quarters targeting more than half of the diabetes Ags. Only 7.8% of the sibs and none of the controls had such multiple T cell autoreactivities, which thus characterize overt disease. Multiple anergic and nonanergic T cell autoreactivities were sustained during 2 yr follow-up after onset and in patients with longstanding (3-26 yr) diabetes. Activated patient T cells survived severe IL-2 deprivation, requiring 20-100 times less IL-2 than normal T cells to escape apoptosis. Diabetic T cell anergy thus persists for decades and is Ag and host specific but not related to disease course. Rescue by IL-2 from bystander T cells and high resistance to apoptosis may contribute to this persistence. These data explain some of the difficulties in the routine detection of disease-associated T cells, and they emphasize challenges for immunotherapy and islet transplantation.

Sequence analysis of the diabetes-protective human leukocyte antigen-DQB1*0602 allele in unaffected, islet cell antibody-positive first degree relatives and in rare patients with type 1 diabetes

The human leukocyte antigen (HLA)-DQA1*0102/DQB1*0602/DRB1*1501 (DR2) haplotype confers strong protection from type 1 diabetes. Growing evidence suggests that such protection may be mostly encoded by the DQB1*0602 allele, and we reported that even first degree relatives with islet cell antibodies (ICA) have an extremely low diabetes risk if they carry DQB1*0602. Recently, novel variants of the DQB1*0602 and *0603 alleles were reported in four patients with type 1 diabetes originally typed as DQB1*0602 with conventional techniques. One inference from this observation is that DQB1*0602 may confer absolute protection and may never occur in type 1 diabetes. By this hypothesis, all patients typed as DQB1*0602 positive with conventional techniques should carry one of the above diabetes-permissive variants instead of the protective DQB1*0602. Such variants could also occur in ICA/DQB1*0602-positive relatives, with the implication that their diabetes risk could be significantly higher than previously estimated. We therefore sequenced the DQB1*0602 and DQA1*0102 alleles in all ICA/DQB1*0602-positive relatives (n = 8) previously described and in six rare patients with type 1 diabetes and DQB1*0602. We found that all relatives and patients carry the known DQB1*0602 and DQA1*0102 sequences, and none of them has the mtDNA A3243G mutation associated with late-onset diabetes in ICA-positive individuals. These findings suggest that diabetes-permissive DQB1*0602/3 variants may be very rare. Thus, although the protective effect associated with DQB1*0602 is extremely powerful, it is not absolute. Nonetheless, the development of diabetes in individuals with DQB1*0602 remains extremely unlikely, even in the presence of ICA, as confirmed by our further evaluation of ICA/DQB1*0602-positive relatives, none of whom has yet developed diabetes.

Genetics of Type 1 diabetes mellitus

Type 1 diabetes or insulin-dependent diabetes mellitus (IDDM) is the archetypal example of a T cell-mediated autoimmune disease characterised by selective destruction of a single cell type: the insulin-producing beta-cells of the pancreatic islets of Langerhans. The pathogenic equation for IDDM presents a complex interrelation of genetic and environmental factors, most of which have yet to be identified. Based on the observed familial aggregation of IDDM, it is certain that there is a decided heritable genetic susceptibility for developing autoimmune diabetes. The well-known association of IDDM with certain human histocompatibility leukocyte antigen (HLA) alleles of the major histocompatibility complex (MHC) was a major step toward understanding the role of inheritance in IDDM. Landmark molecular biological investigations of diabetes HLA susceptibility genes provided great potential for insights into the molecular basis for the autoimmune nature of the disease, beginning a story that continues to unfold. Although the association of certain HLA alleles with IDDM is very strong, this genetic locus is estimated to account for less than 50% of genetic contributions to disease susceptibility. The search for non-HLA susceptibility genes has received great attention in recent years. Albeit genome wide searches are wrought with controversy, such studies have suggested the association of numerous non-MHC loci with Type 1 diabetes that will require careful follow-up investigation. Cell biological and genetic functional analyses will provide clues that are indispensable for further progress. The necessary studies include research on immunological abnormalities that are present many years before the clinical onset of Type 1 diabetes.

Islet cell autoimmunity in white and black children and adolescents with IDDM

OBJECTIVE

To compare the frequency of islet cell antibodies (ICA) and antibodies to GAD65 and IA-2(ICA512) between black and white children and adolescents at the diagnosis of IDDM in a large consecutive series of cases from Children's Hospital of Pittsburgh.

RESEARCH DESIGN AND METHODS

ICA and antibodies to GAD65 and IA-2 were measured in 437 white and black children and adolescents who were diagnosed with IDDM at < 19 years of age at Children's Hospital of Pittsburgh from January 1983 to December 1985, from January to December 1989, and from January 1996 to December 1997.

RESULTS

The prevalence of ICA(H), GAD65, and IA-2 antibodies was significantly lower in blacks than whites at onset of the disease. In contrast, the prevalence of ICA(R) alone was higher in blacks. None of the antibodies were present in 12% of the blacks compared with 4% in whites. The same pattern was seen in both sexes. The prevalence of antibodies in white patients with onset of IDDM at <11 years of age was no different than in those who developed IDDM during adolescence. In contrast, black patients showed a significantly lower prevalence of almost all antibodies in the adolescent group.

CONCLUSIONS

Black adolescents were more likely to not have antibodies, suggesting either that they have a nonautoimmune type of diabetes or that antibodies are not being detected by these assays.

Epidemiological aspects of cutaneous malignant melanoma (review)

There is an increasing interest in the etiology of cutaneous malignant melanoma (CMM). Once considered a rare tumour, CMM is now the fourth commonest cancer in Australia and New Zeland, the tenth in the Usa, Canada and Scandinavia and the eighteenth in Great Britain. The growing scientific concern on the urgent need to highlight the cause/s of CMM is well documented by the large number of well-designed and well-conducted epidemiological studies reported in the last two decades. Such studies facilitated testing of many etiological hypotheses derived from earlier descriptive investigations and contributed to significant progress in understanding the etiology of such disease. The quantification of the extent to which the increases in CMM incidence and mortality rates are related to new lifestyles and to new patterns of exposure to potential carcinogenetic agents is essential in order to establish an appropriate preventive strategy. In population of mainly European origin a substantial proportion of the increased incidence of CMM is attributable to steady change from predominantly occupational to predominantly recreational exposure to solar radiation. Therefore the present review puts particular emphasis on exposure to sunlight as well as to artificial ultraviolet light, as modifiable causes of CMM. Incidence and mortality data and other potential risk factors for the development of CMM will also be briefly reviewed.

Autonomic function and autoantibodies to autonomic nervous structures, glutamic acid decarboxylase and islet tyrosine phosphatase in adolescent patients with IDDM

Recent studies have linked autoimmunity to nervous tissue structures and diabetic autonomic neuropathy, but data on the early stage of IDDM and on the natural history of this association are not available. For this reason, we investigated autonomic nervous function, and the presence of autoantibodies to sympathetic and parasympathetic nervous structures, to glutamic acid decarboxylase (GAD) and tyrosine phosphatase (IA-2/ICA512) in 85 adolescents with insulin-dependent diabetes mellitus (IDDM) (mean age 14.7+/-1.6 yr, mean duration of diabetes 6.8+/-3.5 yr), and 45 age and sex-matched healthy subjects. Nervous tissues autoantibodies were detected using an indirect immunofluorescent complement-fixation technique, with monkey adrenal gland, rabbit cervical ganglia and vagus nerve as substrates. GAD and IA-2/ICA512 autoantibodies were detected by radioimmunoprecipitation assay. Seven patients (8%) had anti-vagus nerve autoantibodies, 7 other patients (8%) had anti-cervical ganglia autoantibodies, while all controls were negative (P < 0.05). Anti-adrenal medulla antibodies were detected in 16 patients (19%) and in 2 control subjects (P<0.02). None of the patients had autonomic symptoms. When patients were divided according to the presence or absence of autoantibodies, values of the cardiovascular tests (deep breathing, 30:15 ratio, Valsalva ratio) were similar in the two groups and similar to those in healthy subjects. However, when considered together, patients positive for one or more autoantibody showed a trend for lower values of deep breathing test and 30:15 ratio test, compared with healthy control subjects, which failed to reach conventional significance values (P=0.17 and P=0.07, respectively). No correlation was found between cardiovascular parameters and metabolic control or diabetes duration. There was no association between autoimmunity to nervous tissue structures and presence of GAD and IA-2/ICA512 Ab, and no correlation between these two autoantibodies and values of cardiovascular tests. Our data indicate that autonomic dysfunction is not a characteristic of young diabetic patients, but that autoantibodies against autonomic nervous structures are present during the first 1 to 15 yr of diabetes. GAD and tyrosine phosphatase appear to be excluded as target autoantigens within autonomic structures. Follow-up studies are required to evaluate future autonomic dysfunction and symptoms in these patients, and to establish whether the subtle autonomic dysfunction detected and/or the nervous tissue autoantibodies, are predictive of the development of this complication.

Identification of a novel serine protease-like molecule in human brain

Proteolysis of the amyloid beta protein precursor (APP) is a key event in the development of Alzheimer's disease. In our search for proteases that can cleave APP and liberate the amino terminus of the amyloidogenic beta protein, we characterized a calcium-dependent serine protease (CASP) which is present in reactive astrocytes and cross-reacts with anti-cathepsin G antibodies. We wanted to take advantage of this cross-reactivity to clone the cDNA of CASP and eventually evaluate its tissue distribution. Screening of two human fetal brain cDNA libraries with anti-cathepsin G antibodies led to the identification of a cDNA coding for a novel protein whose only homology to known proteins is to the active site of trypsin-type serine proteases. We called this protein the novel serine protease (NSP). NSP exists in at least three differentially spliced forms, one of which is expressed predominantly in brain and testis. Immunohistochemistry and immunoprecipitation with antibodies generated against NSP show that it is expressed and secreted by a variety of cells and that, in brain, it is found primarily in cerebrovascular smooth muscle cells and reactive astrocytes.

Dual-parameter model for prediction of type I diabetes mellitus

The recent cloning and recombinant expression of novel islet autoantigens [glutamic acid decarboxylase (GAD) 65 and islet-cell autoantibody 512 (ICA512)] has made possible the determination of whether the quantitative expression of autoantibodies to these molecules is correlated with age of diabetes onset and rate of progression to diabetes, similar to insulin autoantibodies (IAAs). We measured autoantibodies reacting with GAD65 (GAD65AA), ICA512 (ICA512AA), and insulin in patients who recently had received a diagnosis of diabetes and in first-degree relatives prospectively identified and then followed because of the expression of high titers of ICA. Levels of IAAs (but not GAD65AA or ICA512AA) correlated inversely with age at diagnosis of diabetes and directly with time to diabetes onset among the ICA-positive relatives. In multiple linear regression models, the level of IAAs remained a significant predictor of the time to diabetes after allowing for first-phase insulin secretion. The unique and dramatic association of IAAs with progression to diabetes suggests that IAAs contribute directly to disease pathogenesis or that levels of IAAs are influenced uniquely by the process, leading--at different rates in different prediabetic individuals--to type I diabetes. In addition, the linear regression model described (involving two variables, first-phase insulin secretion and levels of IAAs) aids in the prediction of time to diabetes among ICA-positive relatives.

Combined analysis of GAD65 and ICA512(IA-2) autoantibodies in organ and non-organ-specific autoimmune diseases confers high specificity for insulin-dependent diabetes mellitus

There is evidence that insulin-dependent diabetes mellitus (IDDM) may develop in association with other non-beta-cell-specific autoimmune diseases. We aimed to assess whether autoantibodies to the islet cell antigens glutamic acid decarboxylase (Mr 65,000 isoform) (GAD65) and ICA512(IA-2), present alone or in combination, are limited to IDDM or also occur in other organ- or non-organ-specific autoimmune disorders. We determined the frequency of these autoantibodies by radioimmunoassay in 199 sera from patients with autoimmune thyroid diseases (AITD), rheumatoid arthritis (RA), systemic lupus erythematosus (SLE) and primary biliary cirrhosis (PBC), and compared the results with those from 507 newly diagnosed patients with IDDM and 280 healthy controls. ICA512(IA-2) autoantibodies were detected exclusively in AITD with concurrent IDDM, but not in other autoimmune diseases without IDDM, whereas GAD65 autoantibodies exceeded the limit of normal in 67.7% (21 of 31) of patients with AITD who also had IDDM and in 5.5% (three of 55) of patients with PBC. The frequency of either GAD65 and/or ICA512(IA-2) autoantibodies was significantly higher in patients with AITD who also had IDDM (27 of 31, 87.1%) than in those with AITD alone (one of 53, 1.9%; P<10(-6)), but was not significantly different from those patients with newly diagnosed IDDM (418 of 507, 82.4%). Neither patients with organ- or non-organ-specific autoimmune diseases without IDDM nor healthy controls had autoantibodies against both GAD65 and ICA512(IA-2). Despite the fact that one of the two autoantibodies was occasionally detected in patients with non-beta-cell-specific autoimmune diseases without IDDM, combined determination of GAD65 and ICA512(IA-2) autoantibodies specifically identified IDDM in the majority of patients with AITD. In conclusion, because of the strong association of IDDM with AITD, testing for multiple islet autoanti-bodies could be useful as a predictive marker for risk of progression to IDDM onset amongst patients with autoimmune thyroid disorders.

The insulin gene is transcribed in the human thymus and transcription levels correlated with allelic variation at the INS VNTR-IDDM2 susceptibility locus for type 1 diabetes

Type 1, or insulin-dependent diabetes mellitus (IDDM) is an autoimmune disease associated with loss of tolerance to several pancreatic islet cell molecules, including insulin, glutamic acid decarboxylase (GAD), ICA69 and the tyrosine phosphatase IA-2 (refs 1-3). Among several predisposing loci, IDDM2 maps to the insulin gene (INS) VNTR (variable number of tandem repeats) minisatellite on chromosome 11p15 (refs 4-9). Allelic variation at this VNTR locus correlates with steady-state levels of INS mRNA in pancreas and transfected rodent cell lines, but it is difficult to reconcile the association of lower INS mRNA levels in the pancreas with class III VNTRs that are dominantly protective from IDDM. We show that during fetal development and childhood, mRNAs for insulin and other islet cell autoantigens (GAD, ICA69, IA-2) are expressed at low levels in the human thymus. Critically, we also detect proinsulin and insulin protein. VNTR alleles correlate with differential INS mRNA expression in the thymus where, in contrast to the pancreas, protective class III VNTRs are associated with higher steady-state levels of INS mRNA expression. This finding provides a plausible explanation for the dominant protective effect of class III VNTRs, and suggests that diabetes susceptibility and resistance associated with IDDM2 may derive from the VNTR influence on INS transcription in the thymus. Higher levels of (pro)insulin in the thymus may promote negative selection (deletion) of insulin-specific T-lymphocytes which play a critical role in the pathogenesis of type-1 diabetes.

Identification of 3 beta-hydroxysteroid dehydrogenase as a novel target of steroid cell autoantibodies: association of autoantibodies with endocrine autoimmune disease

Autoantibodies directed against steroid hormone-producing cells (SCA) detectable by immunofluorescence are typically found in a small proportion of patients with premature ovarian failure (POF) as well as in other endocrine autoimmune diseases. The SCA pattern stains cells in the outer zones of the adrenal cortex, ovary, and testis. To identify the molecular target of SCA, an adrenal complementary DNA expression library was screened using SCA-positive serum, and the steroid enzyme 3 beta-hydroxysteroid dehydrogenase (3 beta HSD) was identified. Only 1 of 48 (2%) patients with idiopathic POF, not pre-selected for the presence of other autoimmune diseases, had SCA by immunofluorescence, whereas 10 of 48 (21%) had anti-3 beta HSD autoantibodies detectable by immunoblot using recombinant human enzyme compared with 6 of 115 (5%) control subjects (P = 0.002). Absorption of SCA-positive serum with recombinant human 3 beta HSD abolished the immunofluorescence pattern. We also examined the prevalence of anti-3 beta HSD autoantibodies in other endocrine autoimmune diseases. Two of 112 (2%) diabetic patients, but none of the thyroid or Addisonian patients, had SCA by immunofluorescence. Twenty-six (23%) diabetic subjects (P < 0.001 vs. controls), 3 of 18 thyroid patients (P > 0.05 vs. controls), and none of 4 Addisonian patients had anti-3 beta HSD autoantibodies. 3 beta HSD is the first steroid cell autoantigen defined at the molecular level to be associated with idiopathic POF occurring in the absence of other polyglandular diseases. Autoantibodies to 3 beta HSD in patients with other organ-specific autoimmune diseases indicate that the enzyme behaves as a typical target of polyendocrine autoimmunity. Anti-3 beta HSD autoantibodies in patients with POF may provide a marker of those subjects whose ovarian failure is autoimmune in origin and, as recent studies suggest, may be salvageable with glucocorticoid treatment.

Prediction of type I diabetes in first-degree relatives using a combination of insulin, GAD, and ICA512bdc/IA-2 autoantibodies

Islet cell antibodies (ICAs) are predictive of type I diabetes in first-degree relatives, but this immunohistochemical assay has proven difficult to standardize. As an alternative, we assessed the use of radioassays for antibodies against three molecularly characterized islet autoantigens, including ICA512bdc (amino acid residues 256-979 of the IA-2 molecule, incorporating the intracellular domain). We measured insulin autoantibodies (IAAs), GAD autoantibodies (GAAs), and ICA512bdc autoantibodies (ICA512bdcAAs) by radioassay, in addition to ICAs, in 882 first-degree relatives of patients with type I diabetes, 50 of whom later developed diabetes with a median follow-up of 2.0 years (maximum 11.3 years). The cutoff for each radioassay was determined by testing >200 control subjects. When autoantibody frequencies among the relatives were analyzed according to relationship to the proband, the offspring of diabetic fathers had a higher frequency of ICA5I2bdcAAs (P = 0.008), IAAs (P = 0.0001) and GAAs (P = 0.0001) than the offspring of diabetic mothers. ICA512bdcAAs and IAAs both showed a significant association with HLA-DR4-DQ8 (P = 0.0005). Among relatives developing diabetes, 98% had one or more of IAAs, GAAs, or ICA512bdcAAs, and 80% had two or more of these autoantibodies, compared with none of the control subjects. Using survival analysis to allow for different lengths of follow-up, there was a significant increase in the risk of diabetes with the number of these autoantibodies present, comparing zero, one, two, and three autoantibodies (P < 0.0001, log-rank test), and by Cox regression analysis, this was independent of ICAs and age. For relatives with two or more of these autoantibodies, the risk of diabetes within 3 years was 39% (95% CI, 27-52) and the risk within 5 years was 68% (95% CI, 52-84). Relatives with all three autoantibodies had a risk within 5 years estimated to be 100%. The presence of low first-phase insulin release further increased the risk for relatives with one or two autoantibodies. We conclude that the presence of two or more autoantibodies (out of IAAs, GAAs, and ICA512bdcAAs) is highly predictive of the development of type I diabetes among relatives.

Number of autoantibodies (against insulin, GAD or ICA512/IA2) rather than particular autoantibody specificities determines risk of type I diabetes

We previously evaluated radioassays for insulin autoantibodies (IAA), glutamate decarboxylase autoantibodies (GAA) and ICA512bdc autoantibodies (ICA512bdcAA) in the prediction of type I diabetes. Among first degree relatives, the five year risk of diabetes was 0% if no autoantibody was positive, 15% if only one was positive, 44% if two were positive and 100% if all three were positive. We measured IAA, GAA and ICA512bdcAA in 45 patients with new onset type I diabetes (sampled within 7 days of insulin therapy), 882 first degree relatives of patients with type I diabetes, and 217 control subjects. ICA512bdc is a construct of the ICA512/IA2 molecule (amino acid residues 256-979), including the intracellular domain. Based on receiver-operating characteristic plots, there was no significant difference between the three assays in their ability to discriminate between disease and control subjects. The upper limits of normal for the assays were determined as the 99th percentile of levels in the control subjects or higher. Using these cut-offs, 76% of new onset patients were positive for two or more autoantibodies, and 98% were positive for one or more. In comparison, none of 198 control subjects tested for all three assays were positive for more than one autoantibody. In relatives with a single autoantibody, or exactly two autoantibodies, there was no difference in diabetes-free survival according to which one of the autoantibodies was present (P = 0.70, logrank test), or which particular combination of autoantibodies was present (P = 0.56, logrank test) respectively. Our conclusions were as follows: the number of autoantibodies (counting IAA, GAA and ICA512bdcAA) is important in prediction, rather than the particular autoantibody specificities present. Among patients with new onset insulin-dependent diabetes, the absence of any of these autoantibodies justifies the consideration of non-autoimmune forms of diabetes in the differential diagnosis.

Viral elements in autoimmunity of type I diabetes

The involvement of viruses in the etiology of insulin-dependent diabetes was hypothesized more than 15 years ago based on solid scientific evidence, however; the true existence and the real nature of this involvement still eludes our efforts. This may be due to the frequently long interval between viral exposure and diabetes onset that makes the direct cause-effect relationship difficult to prove.

Monoclonal antibodies against the human metalloprotease EC 3.4.24.15 label neurofibrillary tangles in Alzheimer's disease brain

Alzheimer's disease is characterized neuropathologically by the presence of neuritic and amyloid plaques, vascular amyloid, and neurofibrillary tangles in specific brain areas. The main constituent of amyloid deposits is amyloid beta protein, a 40-42 amino acid proteolytic product of the amyloid beta-precursor protein. In our search for proteases that can generate the N-terminus of amyloid beta protein (beta-secretases), we discovered a thiol-dependent metalloprotease that was identified, by peptide sequencing, as metalloendopeptidase EC 3.4.24.15. In vitro, the metalloprotease cleaves the methionine-aspartic acid bond in a 10 amino acid synthetic peptide, indicating that it could generate the N-terminus of amyloid beta protein, and generates amyloidogenic fragments from full-length recombinant amyloid beta-precursor protein. Mouse monoclonal antibodies produced against a unique synthetic peptide from the metalloprotease labeled various monkey tissues as detected by western blots and immunohistochemistry. Unexpectedly, two monoclonal antibodies, IVD6 and IIIF3, immunolabeled strongly intracellular neurofibrillary tangles, neurites of senile plaques, and neuropil threads, but not "ghost" tangles or amyloid in sections taken from Alzheimer's disease brain. This finding provides further evidence for the metalloprotease's relevance to Alzheimer's disease pathology, although the connection between tangle staining and the formation of amyloid beta protein remains to be elucidated.

Gene expression of islet cell antigen p69 in human, mouse, and rat

Based on the detection of specific antibodies and T-cell sensitization in patients with IDDM, islet cell antigen p69 (ICAp69) has been suggested to be a target antigen of diabetic autoimmunity. The biological function, tissue expression, and developmental kinetics of ICAp69 are largely unknown. We analyzed ICAp69 expression at the gene transcription and protein level in human and rodent tissues. By using template-calibrated quantitative reverse transcriptase polymerase chain reaction (RT-PCR), high levels of ICAp69 mRNA were found in human pancreatic islets and brain. In mouse and rat, ICAp69 gene expression peaked in islet cell lines followed by testis, islets, and brain. ICAp69 mRNA was found at low levels in other organs by RT-PCR but not by Northern blot analysis. In mice, ICAp69 transcription becomes detectable in fetal life, and fetal and adult gene expression patterns are similar. Western blot analysis of human and mouse tissues showed high expression of ICAp69 in brain, testis, pancreatic tissue, and islet cell lines. In these organs, ICAp69 immunoreactivity is predominately localized at the blood brain barrier (capillary endothelium), at the blood testis barrier (Sertoli cells and spermatids), and in pancreatic islets (beta-cells). The subcellular localization of ICAp69 to endoplasmic reticulum, Golgi complex, and vesicles by immune electron microscopy suggests a role of this neuroendocrine molecule in cellular protein traffic and processing.off

ICA512 autoantibody radioassay

As part of a general program of screening islet expression libraries we have identified a clone from a lambda gt11 human islet expression library that reacts with human diabetic sera and, upon sequencing, was determined to be the neuroendocrine islet autoantigen ICA512 (islet cell antigen 512). In the current communication, we describe the development of a radioassay for autoantibodies to ICA512 (ICA512AA) using in vitro transcribed and translated protein for production of labeled antigen. Our initial results indicate that this radioassay is significantly more sensitive than the enzyme-linked immunosorbant assay, which uses a COOH-terminal fragment of ICA512. The ICA512AA radioassay uses a 96-well format with membrane separation of antibody bound from free antigen and should be readily adaptable to automated large-scale screening. Only 7 microliters of serum is required for triplicate determinations. In order to determine the specificity and sensitivity of this assay and estimate its positive predictive value, we have studied 42 new-onset diabetic patients, 33 first-degree relatives of diabetic patients followed to diabetes, 694 islet cell antibody-negative (ICA-) relatives, and 205 normal control subjects. Thirty-eight percent of new-onset patients and 48% of relatives followed to diabetes express autoantibodies to ICA512 exceeding the 99th percentile of the normal control subjects. In contrast, only 1.4% of ICA- first-degree relatives were positive for ICA512 autoantibodies.(ABSTRACT TRUNCATED AT 250 WORDS)

Late progression to diabetes and evidence for chronic beta-cell autoimmunity in identical twins of patients with type I diabetes

Previous studies suggest that after 6 years of discordance, identical twin pairs rarely become concordant for type I diabetes. With up to 39 years of follow-up from the onset of diabetes in the index twin, we determined how many discordant twins have evidence of beta-cell autoimmunity and how many develop overt diabetes. We longitudinally followed 23 pairs of identical twins (or triplets) that were selected from a total group of 30 pairs because they were discordant for type I diabetes when first ascertained. Seven developed diabetes after 3, 3, 7, 8, 9, 31 and 36 years of discordance. By survival analysis, the concordance after 10 years from the onset of diabetes in the index twin was estimated as 23% (95% confidence interval, 5-40%), increasing to 38% (95% confidence interval, 8-69%) after 31 years. Among 16 twins remaining nondiabetic at last follow-up (8-39 years of discordance), 12 were assessed with serial intravenous glucose tolerance tests and a total of 407 measurements by radioassay of antibodies against three defined autoantigens (glutamic acid decarboxylase, insulin, and the recently cloned molecule ICA512). Two-thirds (8 of 12) had evidence of beta-cell autoimmunity (persistently positive autoantibody levels) and/or first-phase insulin release less than the 1st percentile of control subjects. In summary, identical twins may develop diabetes after a prolonged period of discordance and approximately two-thirds of long-term discordant twins have evidence of persistent beta-cell autoimmunity and/or beta-cell damage. The concordance for beta-cell autoimmunity, therefore, is much higher than for overt diabetes.(ABSTRACT TRUNCATED AT 250 WORDS)

Synaptotrophic effects of human amyloid beta protein precursors in the cortex of transgenic mice

The amyloid precursor protein (APP) is involved in Alzheimer's disease (AD) because its degradation products accumulate abnormally in AD brains and APP mutations are associated with early onset AD. However, its role in health and disease appears to be complex, with different APP derivatives showing either neurotoxic or neurotrophic effects in vitro. To elucidate the effects APP has on the brain in vivo, cDNAs encoding different forms of human APP (hAPP) were placed downstream of the neuron-specific enolase (NSE) promoter. In multiple lines of NSE-hAPP transgenic mice neuronal overexpression of hAPP was accompanied by an increase in the number of synaptophysin immunoreactive (SYN-IR) presynaptic terminals and in the expression of the growth-associated marker GAP-43. In lines expressing moderate levels of hAPP751 or hAPP695, this effect was more prominent in homozygous than in heterozygous transgenic mice. In contrast, a line with several-fold higher levels of hAPP695 expression showed less increase in SYN-IR presynaptic terminals per amount of hAPP expressed than the lower expressor lines and a decrease in synaptotrophic effects in homozygous compared with heterozygous offspring. Transgenic mice (2-24 months of age) showed no evidence for amyloid deposits or neurodegeneration. These findings suggest that APP may be important for the formation/maintenance of synapses in vivo and that its synaptotrophic effects may be critically dependent on the expression levels of different APP isoforms. Alterations in APP expression, processing or function could contribute to the synaptic pathology seen in AD.

Preventive effects of azathioprine (AZA) on the onset of diabetes mellitus in NOD mice

We have studied the effects of long-term treatment with azathioprine (AZA) vs cyclosporin A (CSA) vs placebo (PL), in three groups of 10 week old, prediabetic NOD mice. One of 8 AZA, none of 8 CSA and 7 of 11 PL treated mice developed overt diabetes (IDDM). Quantitative morphometric analysis conducted on mouse pancreatic histologic sections documented that extent and degree of islet beta-cell damage were incomparably less severe in the mice that received AZA or CSA compared to those treated with PL. Since early and prolonged treatment with AZA seems to prevent the onset of DM in NOD mice as nearly effectively as CSA, AZA, which is significantly safer than CSA, could replace the latter as a potential approach for the immunotherapy of IDDM.

Pancreatic beta-cell destruction in non-obese diabetic mice

We determined the natural history of the widespread pancreatic islet beta-cell destruction that precedes the onset of spontaneous putative autoimmune diabetes mellitus in NOD mice. For this purpose, we performed both histological and immunocytochemical examinations of pancreata retrieved from mice at 2 through 30 weeks of age. An overexpression of la antigens was identified on islet beta cells at 4 weeks of age, without evidence of mononuclear cell infiltration. The abnormal expression of la antigens was age-related and was associated with hyperexpression of class I antigens and progressive islet cell histologic damage after 17 weeks of age. Immunocytochemical examination of islet cell infiltrate showed that the number of macrophages did not increase during the early phase of islet cell damage in these mice. The L3T4/Lyt-2 ratio increased after 7 weeks of age, but was 1:1 in the late stage of insulitis. These findings suggest that widespread islet beta-cell destruction is a process that begins primarily with derangements of the pancreatic beta-cell immune pattern, which may trigger a mononuclear cell reaction.

Islet cell autoantigen 69 kD (ICA69). Molecular cloning and characterization of a novel diabetes-associated autoantigen

We have identified a novel 69-kD peptide autoantigen (ICA69) associated with insulin-dependent diabetes mellitus (IDDM) by screening a human islet lambda gt11 cDNA expression library with cytoplasmic islet cell antibody positive sera from relatives of IDDM patients who progressed to the overt disease. The deduced open reading frame of the ICA69 cDNA predicts a 483-amino acid protein. ICA69 shows no nucleotide or amino acid sequence relation to any known sequence in GenBank, except for two short regions of similarity with BSA. The ICA69 cDNA probe hybridizes with a 2-kb mRNA in poly(A+) RNA from human pancreas, brain, heart, thyroid, and kidney, but not with skeletal muscle, placenta, spleen, or ovary. Expression of ICA69 was also detected in beta cells and cell lines, as well as in tumoral tissue of islet cell origin. The native ICA69 molecule migrates to 69 kD in SDS-PAGE as detected with specific antibodies. Serum samples from relatives of IDDM patients specifically reacted with affinity-purified recombinant ICA69 on Western blotting. The structural gene for ICA69 was designated ICA1. A homologue in the mouse, designated Ica-1 was mapped to the proximal end of chromosome 6 (within 6 cM of the Met protooncogene). ICA69 adds a novel autoantigen to the family of identified islet target molecules, and by the manner of its identification and characterization large amounts of antigen are available for development of quantitative, convenient predictive assays for autoantibodies and analysis of the role of this molecule in diabetes autoimmunity, as well as its physiologic function.

Immunoprotection of pancreatic islet grafts within artificial microcapsules

To circumvent pancreatic islet graft-directed immune destruction we enveloped porcine islets within highly biocompatible and selectively permeable algin/polyaminoacid microcapsules. These special microspheres were deposited between the inner (permeable) and the outer (impermeable) layers of an artificial, coaxial vascular prosthesis, directly anastomized to blood vessels. Five dogs with spontaneous, insulin-dependent diabetes received microencapsulated porcine islets in arterio-vein iliac prosthesis by-passes. One showed complete and the remainder partial, sustained reversal of hyperglycemia. Microencapsulation may be a potential solution to immunological problems related to islet transplantation.

[Islands of Langerhans transplant in the treatment of diabetes mellitus: current status, indications, future perspectives]

Islet cell transplantation is a potential and attractive alternative to exogenous insulin administration for the therapy of IDDM. Large scale clinical applicability of this approach has been hampered, so far, by technical problems such as separation of massive islet concentrations and immune rejection. Microencapsulation within algin/polyaminoacids has provided islets with selective permeable biomembranes thus allowing prevention of the host's immune response and circumvention of general immunosuppression of the recipient. This progress could offer new opportunities for islet cell transplantation in patients with IDDM.

A method for the massive separation of highly purified, adult porcine islets of Langerhans

A method for the massive and reproducible isolation of highly purified, adult porcine islets of Langerhans is described. The successful combination of donor animal-strain selection with original procedures for pancreas retrieval and enzymatic digestion permitted us to separate uniquely massive concentrations of pure porcine islets with no need for mechanical disruption of the pancreatic tissue. Following our procedure, porcine islets, which fully retain viability and function, can be harvested easily and rapidly. Xenotransplantation of such islets, immunoprotected within algin/polyaminoacidic microcapsules, was associated with complete reversal of hyperglycemia in rodents with either spontaneous or streptozotocin-induced diabetes mellitus.