Current concepts on diagnosis, autoantibodies and therapy in Sjögren's syndrome

A primary care approach to Sjögren's syndrome. Helping patients cope with sicca symptoms, extraglandular manifestations

Sjögren's syndrome is a chronic, systemic, autoimmune inflammatory disorder characterized by lymphocytic infiltration of exocrine glands, most notably the salivary and lacrimal glands. It results in loss of functional epithelium, diminished exocrine function, and gradual onset of dryness of the eyes, mouth, and other body parts (sicca syndrome). Because most patients with Sjögren's syndrome are female, this syndrome also represents a major women's health problem that is often misdiagnosed and undertreated. In this article, Drs Derk and Vivino review the criteria for diagnosis, common signs and symptoms, and strategies for increasing patient comfort.

Autoantibody testing

Recent advances in neuroimmunology have led to improvements in the pathogenesis, diagnosis, prognosis, and treatment of many neuromuscular disorders. The value of autoantibody testing is increasing steadily in neurologic practice. Not all antibodies have a high yield in diagnosis. In some disorders, such as generalized adult onset of myasthenia gravis, Lambert-Eaton myasthenic syndrome,Miller Fisher syndrome, and multifocal motor neuropathy,autoantibody tests provide accurate diagnosis and can be considered biologic markers of these disorders.

Myelopathy in Sj??gren??s Syndrome

The incidence, aetiology and optimal treatment of CNS Sjögren's syndrome, including myelopathy associated with Sjögren's syndrome, are unknown at the present time. CNS Sjögren's syndrome is thought to be the result of an autoimmune vasculitis, but other mechanisms may be important. Spinal cord involvement in CNS Sjögren's syndrome may present as acute transverse myelitis, progressive myelitis, Brown-Séquard syndrome, neurogenic bladder or lower motor neurone disease. Optic nerve pathology frequently accompanies spinal cord involvement. Acute transverse myelitis has a high mortality and appears to be the most frequent form of spinal cord involvement in CNS Sjögren's syndrome, occurring in about 1% of all patients with Sjögren's syndrome. The patient's symptomatology and clinical course dictate current treatment of myelopathy. First-line treatment appears to be corticosteroid therapy. However, when the patient's condition fails to improve or deteriorates a nonsteroidal immunosuppressant agent should be considered. Agents used to treat myelopathy include cyclophosphamide, chlorambucil, azathioprine, ciclosporin (cyclosporin) and methotrexate in conjunction with corticosteroids. Most data exist as anecdotal reports. The agent of first choice, based on adverse effect profile and efficacy, appears to be cyclophosphamide given intravenously in pulse doses. Other nonsteroidal immunosuppressant agents should be considered, especially when lack of efficacy of, or intolerance to, cyclophosphamide exists in the patient's history. Glandular and other extraglandular symptoms may benefit concomitantly from the immunosuppressant treatment. In addition, when acute relief of symptomatology is needed, the patient may benefit from a trial of plasmapheresis or intravenous immunoglobulin. Infliximab (anti-tumour necrosis factor-alpha antibodies) has not been used as a treatment modality for myelopathy, but has shown some usefulness in the treatment of extraglandular symptoms, as well as peripheral nervous system manifestations of Sjögren's syndrome. This agent might be considered when all other treatment modalities have failed given the presumed importance of tumour necrosis factor in the pathogenesis of Sjögren's syndrome.

An update of the etiology and management of xerostomia

Salivary gland disease gives rise to salivary gland enlargement, pain, and prolonged xerostomia (dry mouth). Xerostomia is the most common long-standing problem for the majority of affected patients. There are many causes of dry mouth, with long-standing xerostomia being a particular problem in Sjögren's syndrome and after radiation to the head and neck region. Xerostomia is usually managed with saliva substitutes, but a large number of potential systemic therapies of long-standing xerostomia now exist. Some-particularly immunosuppressants-are of fundamental interest for the potential reduction of gland damage in Sjögren's syndrome but as yet are of limited clinical usefulness. Others, particularly pilocarpine and cevimeline, are, or have the potential to be, clinically useful in stimulating salivation by virtue of their action on cholinergic receptors.

Sjögren's disease

In summary, Sjögren's syndrome is a chronic autoimmune disorder characterized by lymphocytic infiltration of the exocrine glands, particularly the salivary and lacrimal glands. The sicca complex of xerophthalmia and xerostomia are the hallmark features of Sjögren's symptomatology. In addition to these hallmark symptoms of oral and ocular dryness, one third of patients with Sjögren's syndrome present with extraglandular manifestations. Many osf these extraglandular manifestations, as well as the sicca symptoms, have otolaryngologic relevance. Because patients with Sjögren's syndrome may present with vague or nonspecific head and neck complaints, ranging from oral dryness to hoarseness to hearing loss, an otolaryngologist's high index of suspicion for this disorder may prevent delay in diagnosis, allow appropriate diagnostic evaluation, and optimize therapeutic intervention.

Parasympathetic nervous system dysfunction in primary Sjögren's syndrome

In the past sicca syndromes were attributed to destruction of glandular tissue. It is now thought that cytokines, autoantibodies, and parasympathetic nervous system dysfunction all have an important role in the xerostomia and xerophthalmia in Sjögren's syndrome.

14. Immunologic rheumatic disorders

We provide the basics for the clinician who might be called on to consider the diagnosis of diseases such as systemic lupus erythematosus (SLE) or rheumatoid arthritis (RA) in their practice. We will emphasize clinical recognition and first-line laboratory testing. Only characteristics of the classic rheumatic inflammatory diseases, RA, SLE, Sjögren syndrome, scleroderma, and dermatomyositis/polymyositis, will be covered. In the past decade, RA is the only disease for which treatment has substantially improved. The treatment of RA has been revolutionized by the use of methotrexate and, more recently, tumor necrosis factor inhibitors. The goal of RA treatment today is to induce a complete remission as early as possible in the disease process, with the mantra being "elimination of synovitis equals elimination of joint destruction." The hope is that if the major mediators of Sjögren syndrome or SLE or scleroderma can be identified and then blocked, as in the example of tumor necrosis factor inhibitors in RA, more specific treatments will become available. Thus, RA has become an excellent model of this evolving paradigm. Through the identification of major mediators in its pathogenesis, novel and highly efficacious therapeutic agents have been developed.

Pharmacotherapy of xerostomia in primary Sjögren's syndrome

We reviewed the current literature concerning the treatment of dry mouth in patients with primary Sjögren's syndrome (SJS). Computerized MEDLINE search engines were used with the terms Sjögren, xerostomia, dry mouth, and treatment. References from key articles were searched, and all pertinent articles were procured and reviewed. Primary SJS is an uncommon but serious disorder. Dry mouth caused by SJS can lead to dental erosion, dysphagia, oral infections, and discomfort. Preventing these complications is of paramount importance. Pharmacotherapy is limited to topical saliva substitutes, which are considered first, followed by muscarinic stimulators such as pilocarpine or cevimeline, if required. Immunosuppressive therapy is being investigated. Patients should have regular oral and dental examinations to detect complications. Satisfaction with the efficacy and tolerability of treatment should be monitored frequently. The clinician may have to use a trial-and-error approach to determine a successful regimen.

Genetic aspects of Sjögren's syndrome

Sjögren's syndrome is a multisystem inflammatory rheumatic disease that is classified into primary and secondary forms, with cardinal features in the eye (keratoconjunctivitis sicca) and mouth (xerostomia). The aetiology behind this autoimmune exocrinopathy is probably multifactorial and influenced by genetic as well as by environmental factors that are as yet unknown. A genetic predisposition to Sjögren's syndrome has been suggested on the basis of familial aggregation, animal models and candidate gene association studies. Recent advances in molecular and genetic methodologies should further our understanding of this complex disease. The present review synthesizes the current state of genetics in Sjögren's syndrome.

Minor Salivary Gland Punch Biopsy for Evaluation of Sjögren’s Syndrome

Incisional biopsy of labial salivary glands has been a valuable technique for diagnosis of Sjögren's syndrome. This report describes a new technique using punch biopsies that requires fewer resources and appears to be equally effective. Fifty patients evaluated by punch biopsy all yielded adequate pieces averaging 6 glands per specimen. Two patients had transient numbness of the lip. There were no other complications. Classical findings of Sjögren's histopathology were demonstrable with these specimens. This technique is safe, less expensive, and is proposed as a reliable alternative to incisional biopsy.

Novel fragments of the Sjögren's syndrome autoantigens alpha-fodrin and type 3 muscarinic acetylcholine receptor generated during cytotoxic lymphocyte granule-induced cell death

OBJECTIVE

To determine whether the Sjögren's syndrome autoantigens alpha-fodrin and the type 3 muscarinic acetylcholine receptor (M3R) are cleaved during cytotoxic lymphocyte granule-induced death, to yield novel fragments.

METHODS

Primary salivary gland epithelial cells, human salivary gland cells, and HeLa cells were incubated with granule contents. The susceptibility to cleavage and the generation of novel fragments of Sjögren's syndrome autoantigens in this form of apoptosis was assessed by immunoblotting. Cleavage of M3R was further characterized by assays performed on the M3R molecule generated by in vitro translation.

RESULTS

This study demonstrated that alpha-fodrin was uniquely cleaved during cytotoxic lymphocyte granule-induced cell death, generating a 155-kd fragment distinct from those generated by caspase 3 in other forms of apoptosis. The study also demonstrates that M3R (which is restricted in expression to the peripheral autonomic organs) was efficiently cleaved by granzyme B (but not by caspases) at several sites, both in vitro and in intact cells. This is the first description of cleavage of a transmembrane autoantigen by granzyme B.

CONCLUSION

The observation that both ubiquitously expressed autoantigens (e.g., alpha-fodrin, La, and nuclear mitotic apparatus protein) and tissue-restricted autoantigens (e.g., M3R) targeted in Sjögren's syndrome are specifically cleaved by granzyme B, generating unique fragments, strongly suggests that a common biochemical event (novel autoantigen cleavage during granule-induced epithelial cell death) is responsible for selecting this apparently unconnected group of molecules for a high-titer autoantibody response. The data focus attention on the role of cytotoxic lymphocytes in the initiation and propagation of Sjögren's syndrome.

Infliximab in patients with primary Sjögren's syndrome: a pilot study

OBJECTIVE

Tumor necrosis factor alpha (TNFalpha) is a proinflammatory cytokine involved in the pathogenesis of Sjögren's syndrome (SS), and blockade of TNFalpha may reduce the activity of the disease. The purpose of this study was to evaluate the safety and potential efficacy of infliximab, a chimeric human-mouse anti-TNFalpha monoclonal antibody, in patients with active primary SS.

METHODS

This was a single-center, open-label pilot study. Sixteen patients with active primary SS received 3 infusions of infliximab (3 mg/kg) at 0, 2, and 6 weeks. Standard clinical assessment, complete ophthalmologic testing, and functional evaluation of salivary flow were performed at baseline and at weeks 2, 6, 10, and 14.

RESULTS

All patients completed the study. There was statistically significant improvement in all clinical and functional parameters, including global assessments (patient's global assessment, patient's assessment of pain and fatigue, physician's global assessment), erythrocyte sedimentation rate, salivary flow rate, the Schirmer I test, tender joint count, fatigue score, and dry eyes and dry mouth. This clinical benefit was observed at week 2 and was maintained throughout the study and the 2-month followup period. The treatment was well tolerated in all patients, and no significant adverse events were seen. No lupus-like syndrome was observed, and no anti-double-stranded DNA antibodies were observed that were attributable to infliximab therapy.

CONCLUSION

In patients with active primary SS, a loading-dose regimen of 3 infusions of infliximab provided a fast and significant clinical benefit without major adverse reactions. It was possible to maintain statistically significant improvement for up to 8 weeks after the third infusion.

Role of viruses in systemic lupus erythematosus and Sjögren syndrome

Systemic lupus erythematosus and Sjögren syndrome remain elusive in the description of their underlying etiologic causes and pathogenic mechanisms. Although underlying genetic predisposition appears to contribute to both diseases based on twin and other genetic studies, additional factors must play a role. Over the decades additional factors, such as hormonal influence, UV light, environmental exposures (e.g., silica, solvents), and infectious agents have been postulated to play a role. Over the past few years additional information has been published concerning roles of various infectious agents in both lupus and Sjögren syndrome. Although the understanding of this field is still incomplete, significant advances are being made.

Cytokine polymorphisms in systemic lupus erythematosus and Sjögren's syndrome

Systemic lupus erythematosus (SLE) and Sjögren's syndrome (SS) are defined genetically as complex diseases where multiple genes are involved in their pathogenesis. Among the genes of interest are those coding for the cytokines, molecules involved in immunoregulation that have been shown to play important roles in these diseases. Whether abnormalities in cytokine production are owing to genetic polymorphisms within the genes themselves is a matter of intensive study. The finding of functional polymorphisms within cytokine genes and their potential association with disease will open new avenues in their treatment.