Distinct local immunogenic stimuli dictate differential requirements for CD4+ and CD8+ T cell subsets in the pathogenesis of spontaneous autoimmune diabetes

Lymphocyte subpopulations in Sheehan's syndrome

The role of autoimmunity in the development of Sheehan's syndrome is obscure. There are a limited number of studies investigating the immunological alterations accompanying Sheehan's Syndrome. Our objective was to evaluate lymphocyte subsets in these patients. We conducted a cross-sectional clinical study. Cytofluorometry was used for the immunophenotyping of peripheral blood leukocytes from patients with Sheehan's syndrome followed up in the endocrine clinic during 2005-2009. Fifteen consecutive patients (mean age 61.6 ± 11.3, range 34-75 years) and 25 healthy controls (mean age 56.7 ± 10.6, range 34-80 years) were included. There was no statistically significant difference between the groups in terms of mean age. The percentages of CD19(+), CD16(+)/56(+), CD8(+)28(-), γδTCR(+), CD8(+); the total lymphocyte counts; and the ratio of CD8(+)28(-)/CD8(+)28(+) were similar (p > 0.05) between patients and controls. Whereas the leucocyte counts (p = 0.003), the percentage of CD3 (+) DR (+) (p < 0.001), CD8(+)28(+) (p = 0.030), CD4(+)CD25(+) (p = 0.007), the ratio of CD3 (+) DR(+)/CD3 (p < 0.001) were higher; the percentage of CD3 (p = 0.020), CD4 (p < 0.001) and the ratio of CD4/CD8 (p = 0.006) were lower in patients with Sheehan's syndrome compared to healthy controls. There was a positive correlation between the duration of illness and the percentage of CD3(+)DR(+) (r = 0.53, p = 0.03) expression. Some peripheral lymphocyte cell subsets show marked variation in patients with Sheehan's syndrome in comparison to matched healthy subjects, which may have implications for altered immune regulation in these patients. High CD3 (+) DR (+) expression that correlates with the duration of illness in Sheehan's patients is suggestive of an ongoing inflammation accompanying the slow progression of pituitary dysfunction in Sheehan's syndrome. It is not clear if these cellular alterations contribute to the cause or consequence of pituitary deficiency in Sheehan's syndrome.

Helminth infections: therapeutic potential in autoimmune disorders

Knowledge of immunity enables us to predict that the reactions set in response to infection with helminth would prevent concomitant disease driven by an opposing spectrum of immune events. In another way, the immune response generated to combat the helminth infection could counteract the immunopathological reactions that drive autoimmune diseases. Rodent model systems recapitulate many aspects of human autoimmune diseases and have been enormously useful in defining mechanisms of immunopathology after infection. From this theoretical perspective, many researchers have proved that infection with a variety of helminth can ameliorate disease in murine model systems. Thus, helminth-evoked Th2 events were shown to improve disorders in which Th1 events predominated. This raised the question, 'Can this information be translated into therapies for autoimmune diseases in humans via actual infection, cell delivery or drug intervention?' In this review, we will present some experimental trails to treat autoimmune disorders through establishment of some parasitic infections.

Helminth infection can reduce insulitis and type 1 diabetes through CD25- and IL-10-independent mechanisms

Parasitic helminth infection has been shown to modulate pathological inflammatory responses in allergy and autoimmune disease. The aim of this study was to examine the effects of infection with a helminth parasite, Heligmosomoides polygyrus, on type 1 diabetes (T1D) in nonobese diabetic (NOD) mice and to elucidate the mechanisms involved in this protection. H. polygyrus inoculation at 5 weeks of age protected NOD mice from T1D until 40 weeks of age and also inhibited the more aggressive cyclophosphamide-induced T1D. Moreover, H. polygyrus inoculation as late as 12 weeks of age reduced the onset of T1D in NOD mice. Following H. polygyrus inoculation of NOD mice, pancreatic insulitis was markedly inhibited. Interleukin-4 (IL-4), IL-10, and IL-13 expression and the frequency of CD4(+) CD25(+) FoxP3(+) regulatory T cells were elevated in mesenteric and pancreatic lymph nodes. Depletion of CD4(+) CD25(+) T cells in vivo did not abrogate H. polygyrus-induced T1D protection, nor did anti-IL-10 receptor blocking antibody. These findings suggest that infection with H. polygyrus significantly inhibits T1D in NOD mice through CD25- and IL-10-independent mechanisms and also reduces the severity of T1D when administered late after the onset of insulitis.

Celiac sprue: a unique autoimmune disorder

Celiac sprue (CS) is a gluten-sensitive enteropathy with many autoimmune features. CS involves multiple organs through immune and nonimmune processes, and is frequently associated with other autoimmune disorders. This article reviews the co-occurrence of CS with autoimmune disorders of the cutaneous, nervous, endocrine, musculoskeletal, gastrointestinal and cardiovascular systems. The types of autoimmune disorders associated with CS and the prevalence of CS in other autoimmune disorders are also discussed. A brief review of the literature on the potential mechanisms behind these associations and the therapeutic effects of a gluten-free diet for autoimmune comorbidities in CS is also provided.