Linkage studies of HLA and primary Sjögren's syndrome in multicase families

[Update on Sjögren's syndrome : Diagnostics, treatment, and challenges]

Sjögren's syndrome (SjS) is the most common connective tissue disease with a prevalence of 1:200. Predominantly affecting women, SjS is associated with destruction of the exocrine glands, leading to xerophthalmia and xerostomia. In over 50% of patients, there are also extraglandular manifestations, leading to multiple organ manifestations including polyneuropathies and interstitial lung disease as well as symptoms such as fatigue and arthralgia. Diagnostic procedures include biomarkers, in particular anti-SS-A/Ro antibodies, histology of salivary glands, and salivary gland sonography. There are currently no licensed immunosuppressive drugs for SjS, so current treatment is often based on off-label use of drugs. The European League Against Rheumatism (EULAR) has recently published treatment recommendations based on the prevailing organ manifestations. Several promising controlled trials with novel compounds and concepts are currently in progress.

[Sjögren's syndrome]

Sjögren's syndrome is an autoimmune disease characterized by lymphocytic infiltration of the tear and salivary glands leading to dryness of the mouth and eyes. The awareness that extraglandular manifestations, such as polyneuropathy, arthritis or recurrent airway infections may indicate Sjögren's syndrome is important. In the diagnostic procedure, the tear and saliva production and antibodies against Sjögren's syndrome A (SS-A) and SS-B should be measured. A salivary gland biopsy should be performed when the diagnosis is not still clear. The therapy of oral and ocular dryness is mainly symptomatic whereas the treatment of extraglandular manifestations is based on experience with treatment of these manifestations in systemic lupus erythematosus (SLE).

Sjögren's syndrome in older patients: aetiology, diagnosis and management

Sjögren's syndrome (SS) is a systemic autoimmune disease, characterized by chronic inflammation of exocrine glands that results in development of xerostomia and keratoconjunctivitis sicca. The disease activity of SS is not restricted to exocrine glands, and many other organs and organ systems can be involved. Diagnosis of SS in the elderly population can be challenging because xerostomia, dry eyes, symptoms of fatigue, weight loss and muscle pain are also common features of old age. Delay between clinical onset and diagnosis of SS in the elderly may be due to the shared features of SS and old age. The 2002 revised American-European Consensus Group (AECG) classification criteria for SS are the preferred tool used to confirm diagnosis of SS, but recently alternative criteria have been put forward by the American College of Rheumatology (ACR). The AECG criteria set combines subjective symptoms of dry eyes and dry mouth with objective signs of keratoconjunctivitis sicca, salivary gland dysfunction and histopathological (salivary gland biopsy) and serological (autoantibodies against SSA/Ro and SSB/La antigens) features. Treatment of SS in the elderly does not differ from that in younger patients. The aims of the treatment of SS are to control glandular and extraglandular manifestations, to prevent damage to organ systems and loss of function, and to decrease morbidity and mortality. Treatment of the elderly can be complicated by co-morbidities, an increased rate of adverse events related to therapeutic agents, and polypharmacy. Therefore, careful follow-up of the treatment is required.

The co-occurrence of Hashimoto thyroiditis in primary Sjogren's syndrome defines a subset of patients with milder clinical phenotype

To evaluate in a cohort of 100 consecutive patients affected by primary Sjogren's syndrome (pSS) the incidence of Hashimoto thyroiditis (HT) and to compare the clinical features and the laboratory parameters of patients affected by pSS with and without concomitant HT. In 100 consecutive patients affected by pSS, the occurrence of other autoimmune diseases was recorded and a full examination of thyroid function obtained. HT was associated with pSS in 27 cases. The comparison between pSS cases with and without HT showed that only patients with isolated pSS had low C4 level [p = 0.032, OR (IC 95 %) 230 (13.13-4,046)]. In addition, only patients affected by pSS without HT had evidence of cryoglobulins, cutaneous vasculitis with palpable purpura, peripheral neuropathy, and development of lymphoma, although all these manifestations were observed in a 4.1-8.2 % of the cases, without reaching statistical significance. The association of HT in patients suffering from pSS defines a subset of patients with milder disease and normal C4 levels.

Thyroid disease in Sjögren's syndrome

From 1960 to 2007, an important number of patients with primary Sjögren's syndrome (pSS) along with thyroid disease diagnosed by laboratory data and clinical presentation were reported. The most common thyroid disorder found was autoimmune thyroiditis and the most common hormonal pattern was subclinical hypothyroidism. The coexistence of SS and thyroiditis is frequent and suggests a common genetic or environmental factor predisposition with similar pathogenic mechanisms. pSS was ten times more frequent in patients with autoimmune thyroid disease and autoimmune thyroiditis was nine times more frequent in pSS. Therefore, SS should be studied in patients with thyroid disease and vice versa. Antigens are shared by both thyroid and salivary glands, which could be responsible for the association between both diseases. Immunogenetic studies had suggested that both diseases have a common genetic predisposition. pSS and thyroid disease patients were mostly women with positive antithyroglobulin, antiparietal cell and antithyroid peroxidase antibodies. Thyroid dysfunction is frequent in pSS patients and those prone to develop thyroid disorders are identified by thyroid-related autoantibodies or by rheumatoid factor and anti-Ro/SSA activity. Patients with pSS have an increased tendency to develop other autoimmune diseases. Hypothyroidism was the most common autoimmune disease developed in pSS patients during follow-up of 10.5 years. Lymphomas are also associated with SS and thyroiditis and a 67-fold increased risk for thyroid mucosa-associated lymphoid tissue (MALT) lymphoma and a 44-fold increased risk for parotid lymphoma is being attributed to autoimmune thyroiditis and pSS. It is suggested that immune mechanism deficiency is a causal factor for B cell lymphoma in pSS and autoimmune thyroid disease. Other studies are necessary to clarify the shared pathogenesis mechanism in SS and autoimmune thyroid disease and to understand this fascinating autoimmune association.

Genetic basis of Sjögren's syndrome. How strong is the evidence?

Sjögren's syndrome (SS) is a late-onset chronic autoimmune disease (AID) affecting the exocrine glands, mainly the salivary and lachrymal. Genetic studies on twins with primary SS have not been performed, and only a few case reports describing twins have been published. The prevalence of primary SS in siblings has been estimated to be 0.09% while the reported general prevalence of the disease is approximately 0.1%. The observed aggregation of AIDs in families of patients with primary SS is nevertheless supportive for a genetic component in its etiology. In the absence of chromosomal regions identified by linkage studies, research has focused on candidate gene approaches (by biological plausibility) rather than on positional approaches. Ancestral haplotype 8.1 as well as TNF, IL10 and SSA1 loci have been consistently associated with the disease although they are not specific for SS. In this review, the genetic component of SS is discussed on the basis of three known observations: (a) age at onset and sex-dependent presentation, (b) familial clustering of the disease, and (c) dissection of the genetic component. Since there is no strong evidence for a specific genetic component in SS, a large international and collaborative study would be suitable to assess the genetics of this disorder.

Primary Sjögren's syndrome and deficiency of ICA69

BACKGROUND

Sjögren's syndrome is a common (about 1% of the population) autoimmune disease of salivary and lacrimal glands. Its cause and pathogenesis are poorly understood, and treatments are mostly for symptoms of the disease. ICA69 is a self-antigen expressed in brain, pancreas, salivary, and lacrimal glands. NOD-strain mice are an animal model of spontaneous Sjögren's syndrome. We aimed to assess the role of ICA69 in autoimmunity against Sjögren's syndrome.

METHODS

We inactivated the genomic ICA69 locus, generated NOD congenic mice that were deficient in ICA69, and assessed development of Sjögren's syndrome. ICA69 autoimmunity was investigated in controls and in patients with primary Sjögren's syndrome or systemic lupus erythematosus, and in various NOD mice, some of which were given an ICA69-directed prototype peptide vaccine.

FINDINGS

Disruption of the ICA69 locus prevented lacrimal gland disease and greatly reduced salivary gland disease in NOD mice. In healthy NOD mice, ICA69-specific T cells accumulated in lymph nodes that drain salivary tissue. T-cell and B-cell autoreactivity against ICA69 was much the same in patients with primary Sjögren's syndrome, but not in those with systemic lupus erythematosus or in healthy controls. Immunotherapy with a high-affinity mimicry peptide targeting ICA69-specific T-cells reduced established Sjögren's syndrome in wild-type NOD mice in the long term.

INTERPRETATION

ICA69 is a new autoantigen in primary Sjögren's syndrome that has an important role in progression of disease and could be of diagnostic value. Immunotherapy of primary Sjögren's syndrome is promising, since autoimmunity in NOD mice with Sjögren's syndrome seems to be uniquely susceptible to such treatment even late in disease.

Prolactin up-regulates cathepsin B and D expression in minor salivary glands of patients with Sjögren's syndrome

Various proteases are expressed in the minor salivary glands (MSG) of patients with Sjögren's syndrome (SS), and as we have already shown, prolactin is neosynthesized in the acinar cells of patients with SS. The present study aims to characterize the influence of PRL on the expression of cathepsin B and D in the MSG of patients with SS. Cathepsin B and D expression was investigated immunohistochemically in MSG of 30 patients with SS and 15 healthy volunteers. The presence of cathepsin B and D mRNAs was checked in three SS patients and three control subjects by means of reverse transcription-polymerase chain reaction (RT-PCR). The specificity of the anti-cathepsin B and D antibodies used for the immunohistochemistry was checked by means of western blotting analysis. The influence of prolactin on the immunohistochemical expression of cathepsin B and D was quantitatively assayed by computer-assisted microscopy at three different doses (5, 50, and 500 ng/ml) on eight MSGs (four control subjects and four patients with SS) maintained ex vivo under organotypic cultures. This influence was also investigated at the mRNA level. Whereas cathepsin B immunopositivity was absent from glandular epithelial cells of healthy subjects and only slightly present in SS patients, cathepsin D immunoreactivity was considerably greater (p < 0.0001) in both the acini and the ducts of patients with SS as compared with control subjects. Cathepsin B, but not D, was also expressed in about 20% of infiltrating mononuclear cells of SS patients. Treatment of both healthy and SS minor salivary glands with PRL significantly (p < 0.05 top < 0.0001) enhanced cathepsin B and D expression in acinar and ductal cells at both protein and mRNA levels. PRL produced locally in MSGs of SS patients, but not those of healthy subjects, could play a role in the pathogenesis of Sjogren's syndrome, if only through the activation of proteolytic activity on the part of cathepsins B and D.

MHC class II molecules, cathepsins, and La/SSB proteins in lacrimal acinar cell endomembranes

Sjögren's syndrome is a chronic autoimmune disease affecting the lacrimal glands and other epithelia. It has been suggested that acinar cells of the lacrimal glands provoke local autoimmune responses, leading to Sjögren's syndrome when they begin expressing major histocompatibility complex (MHC) class II molecules. We used isopycnic centrifugation and phase partitioning to resolve compartments that participate in traffic between the basolateral membranes and the endomembrane system to test the hypothesis that MHC class II molecules enter compartments that contain potential autoantigens, i.e., La/SSB, and enzymes capable of proteolytically processing autoantigen, i.e., cathepsins B and D. A series of compartments identified as secretory vesicle membranes, prelysosomes, and microdomains of the trans-Golgi network involved in traffic to the basolateral membrane, to the secretory vesicles, and to the prelysosomes were all prominent loci of MHC class II molecules, La/SSB, and cathepsins B and D. These observations support the thesis that lacrimal gland acinar cells that have been induced to express MHC class II molecules function as autoantigen processing and presenting cells.

MHC class II alleles associated with clinical and immunological manifestations of HIV-1 infection among children in Catalonia, Spain

Children with perinatally-acquired HIV-1 infection were studied to determine if major histocompatibility complex (MHC) genes are involved in progression to pediatric AIDS. Molecular genetic techniques were used to genotype loci in the class II region (DRB1, DQA1, DQB1, DPA1, DPB1, LMP2 and LMP7). HIV-infected children were classified by clinical manifestations and degree of immunosuppression using age-specific CD4 T-lymphocyte counts at enrollment. Alleles at the DPB1 and DQB1 loci showed independent and opposite associations; DPB1*0301 showed a trend toward protection while DQB1*0201 appeared to be a risk factor for developing severe immunosuppression and severe clinical outcomes. Presence of DQB1*0201 conferred a greater than 10-fold increased odds of having severe clinical manifestations and a 2.8-fold increased odds of severe immunosuppression. Presence of DPB1*0301 was associated with a greater than 8-fold decreased odds of severe immunosuppression and severe clinical manifestations. These results support host genetic influences on HIV-1 outcomes in children.

Influence of host genotype on progression to acquired immunodeficiency syndrome among children infected with human immunodeficiency virus type 1

OBJECTIVE

To study the role of host genotype in pediatric infection with human immunodeficiency virus type 1 (HIV-1) and progression to acquired immunodeficiency syndrome (AIDS).

METHODS

Human leukocyte antigen (HLA) class II and complement C4 genotypes were determined by means of molecular genetic techniques for 243 black children born to HIV-1-infected mothers in New York City and San Francisco. Survival, cumulative incidences of opportunistic infections and encephalopathy, and rates of CD4+ T cell decline were compared in children of different genotypes.

RESULTS

Among HIV-1-infected children, the HLA-DR3 haplotype (DRB1*0301-DQA1*0501-DQB1*0201) was associated with increased incidence of encephalopathy, faster rate of CD4+ cell decline, and death before 2 years of age. Deletion of the C4A gene was independently associated with increased incidences of encephalopathy and early death. DPB1*0101 was associated with survival to at least 2 years of age. The presence of DQB1*0604 was associated with increased risk of HIV infection.

CONCLUSIONS

These results are consistent with previously reported associations between HLA genotypes and faster progression to AIDS among HIV-infected adults. The DR3 haplotype and C4A deletion may reflect the same underlying mechanism of susceptibility in that the DR3 haplotype is in linkage disequilibrium with other C4A null alleles. In addition, the class II locus DPB1 may have an independent effect on survival.

[Sjögren's syndrome and virus]

Virus are suspected to play a role in triggering lymphoid proliferation observed in Sjögren's syndrome (SS). In this paper, attention is focused on the potential role of herpes virus, retrovirus and hepatitis C virus (HCV) in the pathogenesis of SS. Genes and proteins of Epstein-Barr virus (EBV) are detected in epithelial cells of salivary or lacrymal glands more often in SS patients than in controls. However, it could just be a consequence of the destruction of the glands by another mechanism. Endogenous retroviral sequences are detected with a high frequency in salivary glands of SS patients, than in controls. Sicca syndrome may occur in HIV, HTLV-I and HCV-infected patients. We found the expression of the tax gene of HTLV-I in epithelial cells of salivary glands from two patients without any evidence of HTLV-I-associated disease and without any seric anti-HTLV-I antibodies. Anti-SSA and anti-SSB antibodies are usually not detected in serum of patients with sicca syndrome occurring during evolution of recognized viral diseases. Thus, this kind of sicca syndrome could be a little different from classical auto-immune SS. However, it is tempting to consider oropharynx like a site of latency of a lot of virus which could infect salivary epithelial cells. In some people with a particular genetic background, this could lead to a lymphoid proliferation and, secondary, to the destruction of the glands.

MHC genes in autoimmunity

In the last year progress has been made towards elucidating the roles of the MHC gene products in autoimmunity. A major advance has been the recent determination of the crystallographic structure of the human MHC class II molecule, which will be invaluable in delineating the minimum structural requirements for peptides that induce autoimmune disease. In addition, the use of animal models and transgenic mouse technology is continuing to increase our understanding of the involvement of the MHC gene products in immunopathogenesis.