Abnormal expression and function of Fas ligand of lacrimal glands and peripheral blood in Sjögren's syndrome patients with enlarged exocrine glands

Unsolved mystery of Fas: mononuclear cells may have trouble dying in patients with Sjögren's syndrome

BACKGROUND

Patients with Sjögren's syndrome, like other patients with autoimmune disorders, display dysregulation in the function of their immune system. Fas and Fas Ligand (FasL) are among the dysregulated proteins.

METHODS

We studied Fas and FasL on IL-2Rα+ cells and in serum of patients with Sjögren's syndrome (n = 16) and healthy individuals (n = 16); both from same ethnic and geographical background. We used flow cytometry and enzyme-linked immunosorbent for this purpose. We also measured the expression of Bcl-2 and Bax by reverse transcription quantitative real-time PCR (RT-qPCR) and percentage of apoptotic and dead cells using Annexin V and 7-AAD staining in lymphocytes.

RESULTS

FasL was increased in patients' T and B cells while Fas was increased in patients' monocytes, T and B cells. No signs of increased apoptosis were found. sFas and sFasL in patients' serum were increased, although the increase in sFasL was not significant. We suspect an effect of non-steroidal anti-inflammatory therapy on B cells, explaining the decrease of the percentage Fas+ B cells found within our samples. In healthy individuals, there was a noticeable pattern in the expression of FasL which mutually correlated to populations of mononuclear cells; this correlation was absent in the patients with Sjögren's syndrome.

CONCLUSIONS

Mononuclear cells expressing IL-2Rα+ had upregulated Fas in Sjögren's syndrome. However, the rate of apoptosis based on Annexin V staining and the Bcl-2/Bax expression was not observed in mononuclear cells. We suspect a functional role of abnormal levels of Fas and FasL which has not been cleared yet.

Elevated IgG4 serum levels among primary Sjögren's syndrome patients: do they unmask underlying IgG4-related disease?

OBJECTIVE

To determine IgG4 levels in a cohort of consecutive patients with primary Sjögren's syndrome (SS) and other autoimmune diseases and explore whether they associate with distinct clinical, serologic, and histopathologic features.

METHODS

Serum IgG4 levels were measured in 133 primary SS patients and 49 healthy donors (HDs). Seventy-four lupus and 54 rheumatoid arthritis (RA) patients served as disease controls. Immunohistochemical IgG4 analysis was performed in paraffin-embedded minor salivary gland (MSG) tissues.

RESULTS

Raised IgG4 serum levels (>135 mg/dl) were detected in 10 (7.5%) of 133 primary SS patients (high-IgG4 group), in 8 (10.8%) of 74 lupus patients, in 7 (12.9%) of 54 RA patients, and in 1 (2%) of 49 HDs. Compared to the normal-IgG4 (<135 mg/dl) primary SS group, high-IgG4 patients exhibited increased prevalence of IgG4-related features (autoimmune cholangitis, autoimmune pancreatitis, and interstitial nephritis), lower rates of antinuclear antibody positivity, and higher IgG2 and IgE levels. Positive staining for IgG4+ plasma cells with an IgG4:IgG ratio ≥40% was detected in 3 of 6 available MSG tissues in the high-IgG4 group. Criteria of possible or definite IgG4-related disease (IgG4-RD) were fulfilled by 10 (7.5%) of 133 of our primary SS cohort.

CONCLUSION

Raised IgG4 serum levels were detected in 7.5% of primary SS patients in association with IgG4RD-reminiscent clinical, serologic, and histopathologic features. Whether this high-IgG4 primary SS group represents a misclassified IgG4-RD group or a distinct primary SS subtype remains to be further explored in future studies.

A novel clinical entity, IgG4-related disease (IgG4RD): general concept and details

IgG4-related disease (IgG4RD) is a novel clinical disease entity characterized by elevated serum IgG4 concentration and tumefaction or tissue infiltration by IgG4-positive plasma cells. IgG4RD may be present in a certain proportion of patients with a wide variety of diseases, including Mikulicz’s disease, autoimmune pancreatitis, hypophysitis, Riedel thyroiditis, interstitial pneumonitis, interstitial nephritis, prostatitis, lymphadenopathy, retroperitoneal fibrosis, inflammatory aortic aneurysm, and inflammatory pseudotumor. Although IgG4RD forms a distinct, clinically independent disease category and is attracting strong attention as a new clinical entity, many questions and problems still remain to be elucidated, including its pathogenesis, the establishment of diagnostic criteria, and the role of IgG4. Here we describe the concept of IgG4RD and up-to-date information on this emerging disease entity.

A novel concept of Mikulicz's disease as IgG4-related disease

Since Morgan's report in 1953, Mikulicz's disease (MD) has been considered part of primary Sjögren's syndrome (SS). However, MD has a unique presentation, including persistent swelling of the lacrimal and salivary glands, and is characterized by good responsiveness to glucocorticoids, leading to recovery of gland function. Recently, it has been revealed that MD patients show elevated serum immunoglobulin G4 (IgG4) levels and prominent infiltration of IgG4-positive plasmacytes. The complications of MD include autoimmune pancreatitis, retroperitoneal fibrosis, tubulointerstitial nephritis, autoimmune hypophysitis, and Riedel's thyroiditis, all of which show IgG4 involvement in their pathogenesis. Thus, MD is a systemic "IgG4-related disease." In addition, recent analyses have revealed that Küttner's tumor (KT), a chronic sclerosing sialadenitis that presents with asymmetrical firm swelling of the submandibular glands, is also associated with prominent infiltration of IgG4-positive plasmacytes. MD and KT differ from SS and are thought to be singular systemic IgG4-related plasmacytic diseases. Here we discuss the results of recent studies and provide an overview of MD as an IgG4-related disease.

Clinicopathologic similarities between Mikulicz disease and Küttner tumor

PURPOSE

Recent studies have revealed that Mikulicz disease (MD) differs from Sjögren syndrome and is an immunoglobulin G(4) (IgG(4))-related systemic disease. Küttner tumor (KT) is also reported to be an IgG(4)-related disease. In this study, we examined the clinicopathologic and serologic findings in MD (39 patients) and KT (6 patients) and attempted to discern the similarities between MD and KT.

MATERIALS AND METHODS

We diagnosed 39 patients with MD and 6 patients with KT. We analyzed the clinicopathologic and serologic findings (IgG subclasses) in 39 patients with MD and 6 patients with KT. Submandibular and labial salivary gland specimens obtained from patients with MD and KT were stained with anti-IgG(4) antibodies.

RESULTS

The mean IgG(4) concentration (±SD) was 931.1 ± 796.2 mg/dL in patients with MD and 756.2 ± 449.2 mg/dL in patients with KT. Abundant infiltration of IgG(4)-positive plasmacytes into the salivary glands was observed in both patients with MD and patients with KT.

CONCLUSION

The serologic and histopathologic findings in MD and KT are very similar, and these 2 conditions may be IgG(4)-related systemic diseases.

The birthday of a new syndrome: IgG4-related diseases constitute a clinical entity

IgG4-related disease is a distinct clinical entity, whose characteristic features are the following; Serum IgG4 is prominently elevated, IgG4-positive plasma cells infiltrate in involved tissues, various mass-forming lesions with fibrosis develop in a timely and spatial manner and the response to corticosteroids is prompt and good. IgG4-related diseases mainly target two organs. One is the pancreas (autoimmune pancreatitis; AIP), and the other comprises the lacrimal and salivary glands, the clinical phenotype is Mikulicz's disease (MD). MD has long been considered a manifestation of Sjögren's syndrome (SS). However, we noticed several clinical differences in case of MD from SS; no deflection of female sex differences, mild sicca syndrome, good response to corticosteroids, no positivity of anti-SS-A/SS-B antibodies. In addition, elevated level of serum IgG4 and abundant infiltration of plasma cells expressing IgG4 were reported in MD patients. Those are common features of IgG4-related diseases. MD often coexisted with IgG4-related diseases such as AIP, retroperitoneal fibrosis, and IgG4-associated nephropathy. Based on those findings, it has been considered to recognize IgG4-related diseases including MD as a new clinical entity. The etiology of IgG4-related systemic diseases remains to be elucidated. It is necessary to accumulate and analyze larger data from patients worldwide.

IgG4-related diseases including Mikulicz's disease and sclerosing pancreatitis: diagnostic insights

Since the first report of serum IgG4 elevation in sclerosing pancreatitis in 2001, various systemic disorders have been reported to elevate IgG4, and many names have been proposed from the perspective of the systemic condition. Despite similarities in the organs damaged in IgG4-related Mikulicz's disease and Sjögren's syndrome, there are marked clinical and pathological differences between the 2 entities. The majority of cases diagnosed with autoimmune pancreatitis in Japan are IgG4-related sclerosing pancreatitis, and it should be recognized that this is distinct from the Western type. Diagnosis of IgG4-related disease is defined by both elevated serum IgG4 (> 1.35 g/l) and histopathological features, including lymphocyte and IgG4+ plasma cell infiltration (IgG4+ plasma cells/IgG+ plasma cells > 50% on a highly magnified slide checked at 5 points). Differential diagnosis from other distinct disorders is necessary: these include sarcoidosis, Castleman's disease, Wegener's granulomatosis, lymphoma, cancer, and other existing conditions. The Japanese IgG4 research group has begun multicenter prospective studies to improve diagnostic criteria and treatment strategies.

A case of Mikulicz's disease, IgG4-related plasmacytic syndrome, successfully treated by corticosteroid and mizoribine, followed by mizoribine alone

We report a case of Mikulicz's disease, IgG4-related plasmacytic syndrome, successfully treated with corticosteroid and mizoribine, followed by mizoribine alone. A 56-year-old woman experienced persistent bilateral swelling in the eyelids and submandibular region accompanied by lymphadenopathy without pain. The patient was diagnosed as having Mikulicz's disease since her bilateral lacrimal glands showed persistent swelling and biopsy specimens of the submandibular glands and lymph node showed diffuse infiltration of lymphocytes and plasma cells. Symptoms and laboratory data were improved with corticosteroids (30 mg). However, after tapering prednisolone to 5 mg, submandibular swelling developed. Adding mizoribine resulted in clinical improvement. Prednisolone was tapered and finally discontinued. Since the levels of IgG4 in peripheral blood were increased even after corticosteroid therapy and IgG4 was positive in a submandibular gland specimen obtained before the start of corticoid therapy. Thus, this case may be associated with IgG4. The present case is the first case in which mizoribine was effective for Mikulicz's disease and IgG4-related plasmacytic syndrome.

[IgG4-related disease-the diagnostic confusion and how to avoid it]

Since Hamano et al. have first reported serum IgG4 elevation in sclerosing pancreatitis in 2001, various systemic disorders have been reported to be related to elavated IgG4, and many names have been proposed from the point of view of the systemic condition. Despite similarities in the organs damaged in IgG4-related Mikulicz's disease and Sjögren's syndrome, there are marked clinical and pathological differences between the two entities. IgG4-related Mikulicz's disease and Küttner's tumor are related diseases and complete differentiation is very difficult. The majority of cases diagnosed with autoimmune pancreatitis in Japan are IgG4-related sclerosing pancreatitis, and it should be recognized that this is distinct from the western type. There is a likelihood that cases once diagnose as Castleman's disease that showed good responsiveness to glucocorticoid treatment may have been IgG4-related lymphadenopathy, and should be re-assessed in light of recent findings. Diagnosis of IgG4-related disease is defined by both 1) Elevated serum IgG4 (>135 mg/dl) and 2) Histopathological features including lymphocyte and IgG4(+) plasma cell infiltration (IgG4(+) plasma cells/IgG(+) plasma cells >50% on a highly-magnified slide checked in five points), however differential diagnosis from other distinct disorders, such as sarcoidosis, Castleman's disease, Wegener's granulomatosis, lymphoma, cancer, and other existing conditions is necessary. To avoid diagnostic confusion, simpler and more scientific names should be used where disease-specific pathogenesis or markers have been ascertained.

Down-regulation of Fas-ligand mRNA in Sjögren's syndrome patients with enlarged exocrine glands

We have reported that Sjögren's syndrome (SS) patients with enlarged exocrine glands (EEG) formerly referred to as Mikulicz's disease were defective with Fas-ligand (FasL) expression in PBL and lacrimal glands (LGs). To investigate the mechanisms of reduced FasL expression in SS patients with EEG, FasL mRNA expression level was determined using real-time PCR. The FasL gene promoter region (from - 1197 to - 3) was also amplified using PCR and specific primers. Expression of the FasL mRNA in the LGs and PBLs of three SS patients with EEG was significantly decreased. Direct sequencing revealed a heterozygous point mutation ( - 259T/C) in the FasL gene promoter region in one SS patient with EEG. A luminescent beta-galactosidase (beta-gal) reporter assay using a pbetagal Enhancer Vector demonstrated that beta-gal activity from the vector including the mutant ( - 259C) FasL (pbetagal/mFasL) gene promoter region (735 +/- 42) was similar (p = 0.13) to that from a pbetagal Enhancer Vector without the gene promoter region (603 +/- 66). On the other hand, the beta-gal activity was significantly lower (p < 0.0001) than that from a vector including the wild-type ( - 259T) FasL (pbetagal/wFasL) (3226 +/- 148). In conclusion, the down-regulation of FasL in SS patients with EEG may be due to transcriptional regulation, and the point mutation at - 259T/C in the FasL gene promoter region may lead to the down-regulation of FasL mRNA expression and the lymphoproliferative process observed in SS patients with EEG.

Tearful relationships? Sex, hormones, the lacrimal gland, and aqueous-deficient dry eye

Sex and the endocrine system exert a significant influence on the physiology and pathophysiology of the lacrimal gland. The purpose of this article is to briefly review the nature and magnitude of these interactions between sex, hormones and lacrimal tissue, and to address how they may relate to the pathogenesis of aqueous-deficient dry eye. Towards this end, this article has a 3-fold approach: first, to summarize the influence of androgens, estrogens, glucocorticoids, mineralocorticoids, retinoic acid, prolactin, alpha-melanocyte stimulating hormone, adrenocorticotropic hormone, luteinizing hormone, follicle-stimulating hormone, growth hormone, thyroid-stimulating hormone, arginine vasopressin, oxytocin, thyroxine, parathyroid hormone, insulin, glucagon, melatonin, human chorionic gonadotropin and cholecystokinin on the structure and function of the lacrimal gland; second, to discuss the mechanism of action of each hormone on lacrimal tissue; and third, to discuss the clinical relevance of the endocrine-lacrimal gland interrelationship, with a particular focus on each hormone's role (i.e. if relevant) in the development of aqueous-tear deficiency.

A new conceptualization for Mikulicz's disease as an IgG4-related plasmacytic disease

Mikulicz's disease (MD) has been included within the diagnosis of primary Sjögren's syndrome (SS), but it represents a unique condition involving persistent enlargement of the lacrimal and salivary glands characterized by few autoimmune reactions and good responsiveness to glucocorticoids, leading to the recovery of gland function. Mikulicz's disease was recently reported to be associated with elevated immunoglobulin G4 (IgG4) concentrations in the serum and prominent infiltration of plasmacytes expressing IgG4 into the lacrimal and salivary glands. The following features were used for diagnosis: (1) visual confirmation of symmetrical and persistent swelling in more than two lacrimal and major salivary glands; (2) prominent mononuclear cell infiltration of lacrimal and salivary glands; and (3) exclusion of other diseases that present with glandular swelling, such as sarcoidosis and lymphoproliferative disease. These features are not observed in most SS cases. The complications of MD include autoimmune pancreatitis, retroperitoneal fibrosis, tubulointerstitial nephritis, autoimmune hypophysitis, and Riedel's thyroiditis, all of which show IgG4 involvement in their pathogenesis. Mikulicz's disease thus differs from SS and may be a systemic IgG4-related plasmacytic disease.

Clinical and pathological characteristics of Mikulicz's disease (IgG4-related plasmacytic exocrinopathy)

Mikulicz's disease (MD) has been considered part of primary Sjogren's syndrome (SS) since Morgan's report in 1953. MD represents a unique condition involving enlargement of the lacrimal and salivary glands, as is also seen in SS; however, MD is characterized by few autoimmune reaction and its good responsiveness to glucocorticoid. Recent reports have shown that the frequency of apoptosis in glands of MD patients is lower when compared with SS. This phenomenon reflects the histologically reversible gland secretion in MD. Elevated IgG4 concentrations in the serum and prominent infiltration by plasmacytes expressing IgG4 in the lacrimal and salivary glands have also been confirmed in MD. Plasma cells expressing IgG4 are also detected in lymph nodes and bone marrow. MD may be a systemic disease, rather than a lacrimal and salivary gland disease. We here propose the new entity "IgG4-related plasmacytic exocrinopathy" and expect future development with regard to its relationship with autoimmune pancreatitis, which similarly presents elevated serum IgG4 levels.

Clinical and pathological differences between Mikulicz's disease and Sjögren's syndrome

OBJECTIVE

Mikulicz's disease (MD) has been included within the diagnosis of primary Sjögren's syndrome (SS), but represents a unique condition involving enlargement of the lachrymal and salivary glands and characterized by few autoimmune reactions and good responsiveness to glucocorticoids. We have previously described elevated immunoglobulin (Ig) G4 in the serum of four patients with MD. In this paper, we accumulated more MD cases and undertook clinical and histopathological analysis of these patients to clarify differences between MD and SS.

METHODS

We diagnosed seven patients with MD according to the following criteria: (i) visual confirmation of symmetrical and persistent swelling in more than two lachrymal and major salivary glands; (ii) prominent mononuclear infiltration of lachrymal and salivary glands; and (iii) exclusion of other diseases that present with glandular swelling, such as sarcoidosis and lymphoproliferative disease. We summarized the clinical and serological characteristics (IgG subclasses and IFN-gamma/IL-4 ratio) of seven patients with MD, compared with SS with glandular swelling (SSw) and without glandular swelling (SSo). After steroid administration, we analysed changes in IgG subclasses in MD. Labial salivary gland specimens in MD, SSw and SSo were stained with anti-IgG4 antibodies.

RESULTS

The concentration (+/-s.d.) of IgG4 was 1169.7 +/- 892.2 mg/dl in MD, 24.4 +/- 7.0 mg/dl in SSw (P<0.005) and 82.6 +/- 189.7 mg/dl in SSo (P<0.005). The IFN-gamma/IL-4 ratio was 0.392 +/- 0.083 (0.78 +/- 0.23/2.14 +/- 0.31 IU/pg) in MD, 0.004 +/- 0.002 (0.20 +/- 0.07/57.02 +/- 14.05 IU/pg) in SSw (P<0.05) and 0.012 +/- 0.009 (0.58 +/- 0.86/116.24 +/- 207.65 IU/pg) in SSo (P<0.05). The concentration (+/-s.d.) of IgG4 in MD decreased to 254.0 +/- 50.3 mg/dl (P<0.05) after glucocorticoid treatment. Histopathologically, only MD was associated with prominent infiltration of IgG4-positive plasmacytes into lachrymal and salivary glands.

CONCLUSION

Mikulicz's disease is quite different from SS clinically and histopathologically. MD is suggested to be an IgG4-related systemic disease.

New Insights into the Diagnosis and Treatment of Dry Eye

Over the past decade, numerous advances have been made in relation to dry eye diagnostic markers, technologies, and treatment options. The mainstay of treatment of dry eye is the use of artificial tear solutions and punctum plugs. A goal is the development of agents that provide symptomatic treatment and, at the same time, improve ocular surface keratinization. It is the authors' opinion that the functional visual acuity tester and the new tear stability analysis system will be widely used to improve diagnosis and evaluate treatment outcomes in KCS. Advances in treatment will utilize anti-inflammatory agents, immune suppressants such as Cyclosporin A and FK-506, growth hormones, androgens, topical mucins and ocular surface stimulating drugs, like INS365. Although aqueous-deficient dry eye is most commonly not associated with Sjogren syndrome (SS), aqueous-deficient dry eye is often most severe in patients with SS; thus, this article focuses mainly on SS-associated dry eye.

New concepts in the pathogenesis of Sjögren syndrome: many questions, fewer answers

Although a modified European-American consensus classification of Sjögren syndrome has been introduced during the last year, the etiopathogenesis of this disease characterized by chronic lymphocytic inflammation, impaired function, and, finally, destruction of the salivary and lacrimal glands as well as systemic manifestations remains to be elucidated. Recent insights into the pathogenesis of Sjögren syndrome resulting from immunogenetic, hormonal, and epidemiologic evaluations as well as animal and in vitro studies are highlighted by this review. Evidence confirms that lymphocytic disturbances, including ectopic germinal center formation and aberrations of cellular signaling play a significant role in Sjögren syndrome. Although some of these features are unique to Sjögren syndrome, others are also found in a number of systemic autoimmune diseases, such as systemic lupus erythematosus, systemic sclerosis, and rheumatoid arthritis. The underlying cause of Sjögren syndrome remains largely enigmatic. However, distinct characteristics may provide the basis for the classification of the disease entities. Finally, an enhanced risk of lymphomagenesis is a well-known hallmark of primary Sjögren syndrome, indicating the central role of derangement of lymphocyte regulation. As demonstrated by the introduction of the new targeted therapeutic approaches in rheumatoid arthritis, solid insights into the pathogenesis of Sjögren syndrome may pave the way toward new therapeutic approaches.

Immunopathogenesis of Sjögren's syndrome

Sjögren's syndrome (SS) is an autoimmune disease characterized by the sicca symptoms of dry eyes and dry mouth. Glandular dysfunction is thought to arise from destruction associated with lymphocytic infiltration. The degree of glandular destruction, however, does not correlate with the severity of sicca symptoms, suggesting that other mechanisms are involved, including abnormalities in parasympathetic neurotransmission. Autoantibodies against the muscarinic acetylcholine receptor have been implicated in this process, but multiple other autoantibodies have been found. Cytokines elaborated in the inflammatory lesions also appear to be involved and dysregulation of apoptosis are also involved in the pathogenesis of SS. A new two-stage model of SS has been proposed. First, there is a lymphocyte-independent phase during which inappropriate apoptosis results in the generation of apoptotic autoantigens which then attract lymphocytes. Subsequently, in the second lymphocyte-dependent phase, an immune attack causes further cell death and salivary dysfunction. Although the disease generally takes a rather stable and benign course, patients with SS have a significant risk of developing B cell lymphoma.