Update in Sjögren syndrome

Xerostomia: etiology, recognition and treatment

BACKGROUND

Clinicians may encounter symptoms of xerostomia, commonly called "dry mouth," among patients who take medications, have certain connective tissue or immunological disorders or have been treated with radiation therapy. When xerostomia is the result of a reduction in salivary flow, significant oral complications can occur.

TYPES OF STUDIES REVIEWED

The authors conducted an Index Medicus--generated review of clinical and scientific reports of xerostomia in the dental and medical literature during the past 20 years. The literature pertaining to xerostomia represented the disciplines of oral medicine, pathology, pharmacology, epidemiology, gerodontology, dental oncology, immunology and rheumatology. Additional topics included the physiology of salivary function and the management of xerostomia and its complications.

RESULTS

Xerostomia often develops when the amount of saliva that bathes the oral mucous membranes is reduced. However, symptoms may occur without a measurable reduction in salivary gland output. The most frequently reported cause of xerostomia is the use of xerostomic medications. A number of commonly prescribed drugs with a variety of pharmacological activities have been found to produce xerostomia as a side effect. Additionally, xerostomia often is associated with Sjögren's syndrome, a condition that involves dry mouth and dry eyes and that may be accompanied by rheumatoid arthritis or a related connective tissue disease. Xerostomia also is a frequent complication of radiation therapy.

CONCLUSIONS AND CLINICAL IMPLICATIONS

Xerostomia is an uncomfortable condition and a common oral complaint for which patients may seek relief from dental practitioners. Complications of xerostomia include dental caries, candidiasis or difficulty with the use of dentures. The clinician needs to identify the possible cause(s) and provide the patient with appropriate treatment. Remedies for xerostomia usually are palliative but may offer some protection from the condition's more significant complications.

Oral manifestations of systemic disease

Most systemic diseases can affect the oral cavity. Some oral changes are nonspecific, whereas others directly lead to the diagnosis of a particular disorder. A systems approach is used here to catalog these oral changes. In some instances it is difficult to separate the oral manifestations of pharmacotherapy for a particular disease from that entity. The oral manifestations of pharmacotherapy are presented for selected disease processes. This article introduces the most common oral manifestations of systemic disease.

Ocular manifestations of hepatitis C virus infection

Approximately 3.6 million persons in the United States are infected with the hepatitis C virus (HCV), a condition with both hepatic and extrahepatic sequelae. Although no pathognomonic manifestation of HCV infection in the eye has been demonstrated, associations between HCV infection and various ocular syndromes have been reported in small case series and individual patients. At this time, the ocular manifestations of HCV infections best supported by the literature include a dry eye syndrome similar to Sjögren syndrome, and ischemic retinopathy caused by either an HCV-induced vasculitis or treatment with interferon. Patients with diabetes seem to be more susceptible to interferon retinopathy and to subsequent permanent visual loss. There have been no cases of HCV transmission via corneal transplantation, suggesting that current cadaveric screening protocols are effective in preventing this route of transmission. Screening for HCV should be considered in patients with risk factors for HCV infection who suffer from unexplained ischemic retinopathy or dry eyes.

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.

Prevalence of seropositivity for hepatitis C virus in cataract patients and the general population

PURPOSE

To investigate the epidemiologic relationship between hepatitis C virus (HCV) infection and cataract.

SETTING

Yoshida Eye Clinic, Fukuoka, Japan.

METHODS

This study included 492 patients with age-related cataract and 2624 controls who had a municipal mass health screening. All subjects were 60 years or older and inhabitants of Chikugo City (population 45000), Fukuoka, Japan. Each subject was serologically tested for HCV using the third-generation enzyme immunoassay. Seropositivity was compared in subgroups consisting of patients by decade; that is 60 to 69 years of age, 70 to 79 years of age, and 80 to 90 years of age.

RESULTS

The prevalence of HCV in the cataract group and health-screening (control) group was 18.3% and 7.1%, respectively, in the 60- to -69 year subgroup; 17.8% and 6.6%, respectively, in the 70- to 79-year subgroup; and 15.1% and 3.7%, respectively, in the 80- to 90-year subgroup. In each subgroup, the prevalence of HCV was significantly higher in the cataract group than in the control group (P <.01, chi-square test). In the cataract group, the HCV seropositive and seronegative groups did not differ significantly in the prevalence of hepatitis B virus (P =.548, Fisher exact probability test).

CONCLUSIONS

Patients with age-related cataract had significantly higher seropositivity for HCV than an age-matched general population. This suggests that HCV infection may play a role in the development and/or progression of cataract.

Sicca syndrome associated with Tropheryma whipplei intestinal infection

The case of a 61-year-old woman with Whipple's disease-associated sicca complex is reported. Tropheryma whipplei infection was diagnosed by histological and ultrastructural examination of the jejunal mucosa and sequence analysis of the bacterial 16S ribosomal DNA. The role of vitamin A malabsorption in sicca complex secondary to Whipple's disease is discussed.

Diminished peripheral blood memory B cells and accumulation of memory B cells in the salivary glands of patients with Sjögren's syndrome

OBJECTIVE

To delineate the mechanism of the abnormalities in B cell biology found in patients with primary Sjögren's syndrome (SS).

METHODS

The distribution of peripheral B cell subpopulations in 21 patients with primary SS was analyzed by immunofluorescence labeling and flow cytometry. Immunoglobulin rearrangements were analyzed in single B cells isolated from the peripheral blood and parotid glands by fluorescence-activated cell sorting.

RESULTS

A significant reduction in the number of peripheral CD27+ memory B cells was found in SS patients, including a significantly reduced number of CD27+/IgD+/IgM+/CD5+ memory B cells. Remarkably, SS patients with secondary lymphoma uniquely exhibited an increase in CD27-expressing peripheral B cells, including CD27(high) plasmablasts. Molecular analysis for mutated Ig gene rearrangements confirmed that CD27 expression distinguished naive and memory cells in SS. In contrast to the peripheral blood, the majority of parotid B cells from 1 patient examined exhibited both the mutational status and phenotype of memory B cells. Accordingly, the mutational frequencies of V(H) rearrangements were significantly greater in parotid B cells than in peripheral blood B cells, whereas the V(H) gene repertoire appeared to be very similar between the compartments.

CONCLUSION

These data indicate that there is an accumulation/retention of memory B cells in the inflamed salivary glands of SS patients. It is possible that preferential accumulation of CD27+ memory B cells in the inflamed parotid gland explains their reduction in the peripheral blood.

The significance of saliva during sleep and the relevance of oromotor movements

Saliva is an essential component of the oroesophageal milieu and allows for normal speech, taste, mastication, food bolus formation and swallowing. Saliva has important functions in protecting the hard and soft tissues of the oral cavity from acids and pathogenic microbes. A large number of people suffer either subjective or objective alterations in quantity and/or quality of their saliva that may be secondary to disease, medications, medical treatments or emotional events. Sleep-related xerostomia is a sensation of dry mouth associated with a report of either mouth and/or throat discomfort that induces awakenings for water intake. The prevalence of self-reported dry mouth complaint during sleep (associated with awakening and water intake) in a Canadian survey was estimated at 23%. The biological significance of decreased saliva during sleep is unknown and it is unclear how the oral cavity compensates for this period of relative dryness. The amount of saliva produced is greatest during the waking hours of the day and diminishes dramatically during sleep and may represent another process in the human body that displays a circadian rhythmicity. Salivary secretion during wakefulness is, in part, associated with oromotor activity involving the masticatory muscles. Rhythmic masticatory muscle activity and swallowing are non-disruptive events that occur during normal sleep. We hypothesize herein that lubrication from saliva is necessary during sleep to protect tissue integrity and health of oroesophageal structures.

Xerostomia and the geriatric patient

Saliva is essential for the preservation of oral-pharyngeal health, and disorders of salivary physiology are associated with numerous oral and pharyngeal problems, particularly in older people. Although salivary function is remarkably intact in healthy aging, medical problems, medications, and head and neck radiotherapy can cause salivary dysfunction and complaints of xerostomia among older people. Sjögren's syndrome, an autoimmune exocrinopathy, is the most common medical disease associated with salivary dysfunction. Medications with anticholinergic side effects will impair salivary output, and head and neck radiotherapy for cancer will cause permanent destruction of salivary glands. Treatments for salivary problems are based upon establishing a diagnosis, protecting oral and pharyngeal health, stimulating remaining glands, and replacing lost salivary fluids.

Abnormalities of B cell phenotype, immunoglobulin gene expression and the emergence of autoimmunity in Sjögren's syndrome

Primary Sjögren's syndrome (pSS) is an autoimmune disorder characterized by specific pathologic features and the production of typical autoantibodies. In addition, characteristic changes in the distribution of peripheral B cell subsets and differences in use of immunoglobulin variable-region genes are also features of pSS. Comparison of B cells from the blood and parotid gland of patients with pSS with those of normal donors suggests that there is a depletion of memory B cells from the peripheral blood and an accumulation or retention of these antigen-experienced B cells in the parotids. Because disordered selection leads to considerable differences in the B cell repertoire in these patients, the delineation of its nature should provide important further clues to the pathogenesis of this autoimmune inflammatory disorder.

CNS involvement in primary Sjögren's syndrome: prevalence, clinical aspects, diagnostic assessment and therapeutic approach

Among the systemic manifestations of primary Sjögren's syndrome, neurological involvement is still an intriguing and debated issue. Although peripheral nervous system abnormalities are a well documented occurrence with a reported prevalence ranging from 10 to 20%, opinions differ as to the prevalence of CNS disease, with suggestions from 'nonexistent' to 'very common'. The lack of agreement probably reflects the different populations selected, different inclusion criteria and lack of rigorous epidemiological studies. In our experience, CNS involvement was detected in 7 of 87 (8%) unselected consecutive patients observed over a period of 5 years. The spectrum of CNS involvement is wide, including focal, diffuse, neuropsychiatric and spinal cord symptoms, frequently characterised by insidious onset, remitting course and, sometimes, progressive evolution. The diagnostic approach enabling early recognition of this complication relies on careful clinical assessment using history and physical examination combined with neuropsychological testing and instrumental, laboratory and imaging investigations such as magnetic resonance imaging, single photon emission computed tomography, electrophysiological testing and CSF analysis. The clinical picture often shows spontaneous remission, but when overt neurological symptoms occur or become progressive, therapeutic interventions with high dose corticosteroids and cytotoxic agents, such as intravenous cyclophosphamide pulse therapy, may be indicated.

Sjogern's syndrome

Sjogren's syndrome (SS) is a systemic autoimmune exocrinopathy that affects the salivary and lacrimal glands. It typically presents as the "sicca complex" of dry eyes (xerophthalmia) and dry mouth (xerostomia) along with other symptoms such as arthritis. SS is classified as either primary or secondary. In the primary form, dry eyes and dry mouth occur alone. In the secondary form, the dry eyes and dry mouth occur in the context of another rheumatic disease, most commonly rheumatoid arthritis. There is an increasing list of systemic manifestations affecting the lung, kidney, and nervous system in patients with SS. The skin is affected in half of SS patients. Despite this high frequency of cutaneous involvement, patients with SS are not commonly seen in dermatology practices. SS is underrecognized and underdiagnosed because the cutaneous manifestations are nonspecific (eg, xerosis, pruritus) and less severe than the oral, ocular, or musculoskeletal symptoms. Nonetheless, because of its high prevalence, risk of cutaneous vasculitis, and the increased risk of a lymphoproliferative disorder, it is important for dermatologists to be familiar with SS.