Dry eye after haematopoietic stem cell transplantation

Spontaneous lacrimal punctal occlusion associated with ocular chronic graft-versus-host disease

PURPOSE

To investigate the clinical features of spontaneous lacrimal punctal occlusion (SLPO) after allogeneic hematopoietic stem cell transplantation (HSCT).

METHODS

One hundred nineteen recipients after HSCT who visited Keio University between 2001 and 2004 were examined. The condition of the lacrimal punctum, severity of dry eye, meibomian gland secretion, and presence of systemic chronic graft-versus-host disease (cGVHD) were determined with or without SLPO by retrospective chart review.

RESULTS

Among the 119 recipients, SLPO was diagnosed in 8. All the patients with SLPO after HSCT had meibomian gland dysfunction (MGD), dry eye, and systemic cGVHD. The percentage of patients with dry eye, MGD, and systemic cGVHD were significantly higher in recipients with SLPO than non-SLPO recipients (p < 0.0013, p < 0.00015, p < 0.0008, respectively).

CONCLUSIONS

SLPO is a clinical presentation of ocular cGVHD and may be an indicator of the severity of dry eye and systemic cGVHD after HSCT.

Ocular graft vs. host disease

Acute graft vs host disease (GVHD) is thought to be mainly a Th1 inflammatory-mediated process, whereas chronic GVHD involves primarily Th2 inflammation. To elucidate new strategies for the treatment and prevention of ocular GVHD, it is important to understand the pathophysiologic connection between systemic and organ-specific acute and chronic GVHD. The two types of inflammatory processes, however, represent only a part of a highly intricate, complex disorder. Studies to further understand the inflammatory profile of ocular GVHD are ongoing.

The Definition and Classification of Dry Eye Disease: Report of the Definition and Classification Subcommittee of the International Dry Eye Workshop (2007)

The aim of the DEWS Definition and Classification Subcommittee was to provide a contemporary definition of dry eye disease, supported within a comprehensive classification framework. A new definition of dry eye was developed to reflect current understanding of the disease, and the committee recommended a three-part classification system. The first part is etiopathogenic and illustrates the multiple causes of dry eye. The second is mechanistic and shows how each cause of dry eye may act through a common pathway. It is stressed that any form of dry eye can interact with and exacerbate other forms of dry eye, as part of a vicious circle. Finally, a scheme is presented, based on the severity of the dry eye disease, which is expected to provide a rational basis for therapy. These guidelines are not intended to override the clinical assessment and judgment of an expert clinician in individual cases, but they should prove helpful in the conduct of clinical practice and research.

Anterior Uveitis

PURPOSE

To describe the occurrence of anterior uveitis along with systemic manifestations of chronic graft-versus-host disease (GVHD) after nonmyeloablative allogeneic hematopoietic stem cell transplantation (HSCT) in 3 patients with hematologic malignancies.

DESIGN

Retrospective small case series.

PARTICIPANTS

Three patients who underwent HSCT and 4 age- and gender-matched controls for cytokine analysis in ocular fluid.

METHODS

Interventional study of patients who underwent HSCT. Screening for evidence of infectious causes and immunological analysis of ocular fluid samples.

MAIN OUTCOME MEASURES

Clinical features of uveitis and results of aqueous analysis.

RESULTS

Anterior uveitis developed during an exacerbation of chronic GVHD in 3 patients after allogeneic HSCT for hematologic malignancies. Patients exhibited no abnormalities on extensive uveitis screening, and in addition, serologic and wide-ranging aqueous analysis showed no evidence of recent infections. We observed signs of inflammation in the ocular fluid in 2 of 3 patients by the determination of different cytokines. No other explanation for uveitis was found except the exacerbation of GVHD. Treatment, both systemic and topical, directed to chronic GVHD induced remission of uveitis in all patients along with amelioration of other signs of GVHD.

CONCLUSIONS

Anterior uveitis occurred in the wake of the acute exacerbation of chronic GVHD after HSCT and may represent an ocular manifestation of chronic GVHD.

Altered Toll-like receptor 9 responses in circulating B cells at the onset of extensive chronic graft-versus-host disease

B cells appear to play a role in chronic graft-versus-host disease (cGVHD) as shown in murine models and the success of anti-CD20 B cell antibody treatment in humans. Recent studies have shown that immunostimulatory microbial CpG-DNA splenic responses were enhanced in murine GVHD. We hypothesized that CpG-induced B cell responses are increased in human cGVHD. Newly diagnosed cGVHD patients enrolled on the COG protocol ASCT0031 were divided into early (3-8 months postblood and marrow transplant [BMT]) and late (> or =9 months post-BMT) onset groups and compared to time-matched control BMT patients. A significantly greater percentage of phosphorothioate (PS)-modified CpG stimulated B cells from cGVHD patients demonstrated an increased expression of CD86 compared to controls (P = .0004). This response had a significant correlation between B cell TLR9 expression (r(2) = 0.65; P = .002) and CD86 upregulation using the entirely TLR9-dependent native phosphodiester CpG (P = .003). The PS-modified CpG response at 2 months after initiation of cGVHD therapy demonstrated a trend toward predicting therapeutic response at 9 months post-BMT (P = .07). These findings suggest that an increased number of B cells, primed for a TLR9 response, may play a role in the pathophysiology of cGVHD.

Therapeutic effect of umbilical cord serum eyedrops for the treatment of dry eye associated with graft-versus-host disease

This study was performed to investigate the therapeutic effect of umbilical cord serum eyedrops on dry eye associated with graft-versus-host disease (GVHD). Twenty-four eyes of 12 patients with severe dry eye syndrome associated with GVHD were treated with 20% umbilical cord serum eyedrops. Symptom scoring, corneal sensitivity test, tear film break up time (BUT), Schirmer test, tear clearance rate (TCR), and corneal fluorescein staining were performed before and 2 and 6 months after treatment. Six months after treatment, significant improvement was observed in symptom score (from 3.83+/-0.38 to 0.83+/-0.57, P<0.01), corneal sensitivity (from 52.08+/-6.06 mm to 57.50+/-3.00 mm, P<0.01), tear film BUT (from 2.50+/-0.91 s to 5.71+/-1.04 s, P<0.01), and keratoepitheliopathy score (from 7.42+/-2.02 to 1.29+/-0.46, P<0.01). There was no siginificant change in Schirmer test and TCR results. No significant complications associated with the use of the eyedrops were observed. Umbilical cord serum eyedrops are safe and may be an effective way to treat severe dry eye associated with GVHD.

Corneal grafting and aggressive medication for corneal defects in graft-versus-host disease following bone marrow transplantation

PURPOSE

To evaluate the clinical outcomes of corneal grafting for severe dry eye complications in bone marrow transplant recipients.

METHODS

Eleven eyes of nine patients with severe corneal complications of chronic graft-versus-host disease were treated from 2000 to 2005. The subjects underwent penetrating keratoplasty (n=9 eyes; seven for perforation and two for leucoma) or deep anterior lamellar keratoplasty (n=2 eyes) for deep postinflammatory stromal scarring without endothelial abnormalities. Patients were observed for graft survival, visual acuity, and postoperative complications.

RESULTS

During the follow-up period (mean=21.6 months), nine grafts (82%) remained clear or almost entirely clear and gained more than two logarithmic units of best-corrected visual acuity. Two regrafts were necessary as the primary grafts became cloudy after 9 and 11 months. Persistent epithelial defects occurred in seven eyes (64%), cataract in six (55%), ocular hypertension in five (45%), corneal calcareous degeneration in two (18%), loss of clarity in two (18%), and sterile ulceration in one (9%).

CONCLUSION

Corneal grafting was effective for restoring corneal clarity and improving visual function in this series of patients. Although the complication ratio was high and some patients required regrafting, there was a clinical improvement in the majority of patients.

Efficacy of Topical Cyclosporine 0.05% in the Treatment of Dry Eye Associated With Graft Versus Host Disease

PURPOSE

To assess the efficacy of topical cyclosporine 0.05% (Restasis) in patients with dry eye associated with graft versus host disease after stem cell transplantation.

METHODS

After completing a 3-month run-in period of using only artificial tears to control dry eye symptoms in both eyes, patients who failed to achieve adequate relief (n = 8) were instructed to instill topical cyclosporine twice a day. Visual acuity, slit-lamp appearance, and intraocular pressure were evaluated every 2 weeks for a minimum of 3 months. In addition, Schirmer basal secretion tests, noninvasive fluorescein breakup time, and tear lysozyme were also performed. Patients were also given a dry eye questionnaire regarding symptoms of burning, tearing, and blurred vision.

RESULTS

Dry eye signs improved significantly with cyclosporine treatment in 7 of 8 patients. Cyclosporine provided statistically significant improvements in Schirmer basal secretion scores (P = 0.003), tear breakup time (P = 0.002), and tear lysozyme levels (P = 0.033) after 3 months of treatment.

CONCLUSION

The findings in this prospective study suggest that dry eye associated with graft versus host disease can be effectively treated with topical cyclosporine, especially in patients unresponsive to other treatment modalities. These findings should be further evaluated in large-scale, controlled clinical trials.

Ophthalmic Cyclosporine Use in Ocular GVHD

PURPOSE

To evaluate the safety and efficacy of topical ophthalmic cyclosporine in patients with dry eyes secondary to graft-versus-host disease (GVHD).

METHODS

Records of consecutive patients with ocular GVHD treated with topical cyclosporine were reviewed.

RESULTS

Thirty-two eyes of 16 patients were included with a mean follow-up of 90 days. Dry eye symptoms improved in 10 patients (62.5%), and corneal fluorescein staining improved in all eyes (P = 0.0039). Global physician impression was favorable in 12 patients (75%). Ocular burning or irritation was noted in 3 patients (19%), which improved with either continuation of cyclosporine at the current dosing regimen or reduction in dose and/or concentration of cyclosporine.

CONCLUSION

Ophthalmic cyclosporine seems to be safe and may be beneficial for patients with ocular GVHD, particularly those with more severe dry eyes.

Risk factors and characteristics of ocular complications, and efficacy of autologous serum tears after haematopoietic progenitor cell transplantation

The objective of the study was to evaluate the frequency and clinical characteristics of ocular complications and their risk factors, as well as autologous serum tears (AST) for the treatment of dry eye in these patients. Data from the files of 124 patients who had undergone allogeneic haematopoietic progenitor cell transplantation (HPCT) were evaluated. In addition, 33 HPCT patients were examined and their data were compared with controls. Analysis of tears and AST was performed. Dry eye manifestation occurred in 32% of patients and was positively correlated with age over 27 years (P = 0.05), peripheral blood progenitor cell transplant (P = 0.002), chronic graft-versus-host disease (P = 0.0027), and chronic or acute myeloid leukaemia (P = 0.001). Dry mouth and Schirmer test < 5 mm were predictive factors for dry eye in HPCT patients (P = 0.002 and odds ratio 3.9 and P = 0.007, odds ratio = 5.9, respectively). Microbiological analysis revealed that six of 11 AST samples were contaminated after 30 days of use. The present study supports the role of potential risk factors for ocular complications and key elements to detect alterations in the tear film from HPCT patients. In addition, AST contamination must be considered after longer periods of use.

Upregulation of ICAM-1 expression in the conjunctiva of patients with chronic graft-versus-host disease

PURPOSE

To correlate conjunctival intercellular adhesion molecule 1 (ICAM-1) expression with cytologic and clinical findings of chronic graft-versus-host disease (GVHD).

METHODS

Seven patients with chronic GVHD-related keratoconjunctivitis and five age-matched normal controls were recruited for the study. Clinical examination included medical history, visual acuity, evaluation of ocular signs and symptoms (scored from 0 to 3), corneal fluorescein staining (scored from 0 to 5 on the basis of the number of corneal sectors involved), Schirmer test type I, and break-up time (BUT). Impression cytology samples were collected from the nasal and inferior bulbar conjunctiva of patients and controls. Goblet cells were counted in three randomly selected fields and averaged. Immunofluorescent staining for ICAM-1 was carried out and the percentage of cells expressing the marker was evaluated.

RESULTS

All patients showed signs and symptoms of keratoconjunctivitis sicca. Schirmer test type I and BUT were reduced (4.8+/-6.7 mm/5 min and 3.9+/-2.7 seconds, respectively). Goblet cells were significantly reduced in GVHD eyes with respect to normal eyes (65+/-30.5 and 192+/-16.9 cells/field respectively; p<0.001). Goblet cell number was directly related to Schirmer test values (p<0.01, rho=0.817) and inversely related to total sign score (p<0.01, rho=-0.939). ICAM-1 expression was increased in GVHD eyes with respect to normal controls, in which no staining was observed. ICAM-1 expression showed an inverse relation to goblet cell number (p<0.01, rho=-0.852) and Schirmer test values (p<0.01, rho=-0.926), and was directly correlated to total sign score (p<0.01, rho=0.982).

CONCLUSIONS

Conjunctival ICAM-1 expression is increased in GVHD patients. The severity of the disease is associated with tear parameters, goblet cell decrease, and inflammatory markers, such as ICAM-1.

Recurrent corneal perforation and acute calcareous corneal degeneration in chronic graft-versus-host disease

Keratoconjunctivitis sicca (KCS) is a common complication of graft-versus-host disease (GVHD), and may lead to corneal epithelial defect and melting. In contrast, recurrent corneal calcareous degeneration and perforation is rare. A 46-year-old woman developed chronic GVHD after bone marrow transplantation for aplastic anemia. Severe KCS with corneal melting and calcium deposits were noted in the left eye. Penetrating keratoplasty was performed because of corneal perforation, but poor re-epithelialization and calcium deposition recurred. Lamellar keratectomy and amniotic membrane transplantation (AMT) were performed, but acute calcareous degeneration developed with subsequent recurrence of corneal perforation. After regraft, AMT and tarsorrhaphy, the corneal graft remained clear for 3 months. However, breakdown of the corneal epithelium occurred 3 weeks after spontaneous separation of tarsorrhaphy. Six months later, corneal perforation recurred again along with exacerbation of GVHD. Regraft was performed, but the patient refused tarsorrhaphy and AMT. Poor re-epithelialization persisted after regraft. Corneal melting with impending corneal perforation ensued. Further corneal surgery was refused and the patient chose to undergo evisceration. This case demonstrates that the ocular complications of GVHD may be severe enough to lead to corneal perforation and calcareous degeneration that is recalcitrant to medical and surgical treatment.

Effect of inflammation on lacrimal gland function

The lacrimal gland is the main contributor to the aqueous layer of the tear film. It secretes proteins, electrolytes and water, which helps to nourish and protect the ocular surface. Lacrimal gland secretion is primarily under neural control, which is achieved through a neural reflex arc. Stimuli to the ocular surface activate afferent sensory nerves in the cornea and conjunctiva. This in turn activates efferent parasympathetic and sympathetic nerves in the lacrimal gland to stimulate secretion. Sex steroid hormones are also important regulators of lacrimal gland functions. A decrease or lack of lacrimal gland secretion is the leading cause of aqueous tear deficient dry eye syndrome (DES). It has been suggested that DES is an inflammatory disorder that affects the ocular surface and the lacrimal gland. In several pathological instances, the lacrimal gland can become a target of the immune system and show signs of inflammation. This can result from autoimmune diseases (Sjögren's syndrome), organ transplantation (graft versus host disease), or simply as a result of aging. The hallmarks of lacrimal gland inflammation are the presence of focal lymphocytic infiltrates and increased production of proinflammatory cytokines. The mechanisms leading to lacrimal gland dysfunction are still poorly understood. Apoptosis, production of autoantibodies, hormonal imbalance, alterations in signaling molecules, neural dysfunction, and increased levels of proinflammatory cytokines have been proposed as possible mediators of lacrimal gland insufficiency in disease states.

Cell populations and adhesion molecules expression in conjunctiva before and after bone marrow transplantation

We were interested to analyse the composition of the cellular infiltrate and adhesion molecules expression in the conjunctiva before and at least one hundred days after autologous and allogenic bone marrow transplantation (BMT) and its relation with the presence of dry eye. We used immunohistochemistry on cryopreserved human conjunctiva with monoclonal antibodies to T-lymphocytes (CD3, CD4 and CD8), B-lymphocytes (CD19), macrophages (CD14), natural killer cells (NK, CD57), intercellular adhesion molecule 1 (ICAM-1), E-selectin, vascular cell adhesion molecule-1 (VCAM-1), lymphocyte function associated antigen-1 (LFA-1), very late antigen-4 (VLA-4), interleukin 2 receptor (IL2r, CD25) and HLA-DR. Our autologous recipients had no graft-versus-host disease (GVHD) but allogenic patients had chronic GVHD. After autologous BMT the conjunctiva had significantly more: (1) T lymphocytes (CD3+, CD4+, CD8+) in the epithelium; (2) CD4+ and CD14+ cells in the stroma; and (3) VLA-4 expression in the stroma than before BMT. After allogenic BMT, the conjunctiva exhibited a significant increase of: (1) CD3+ and CD14+ cells in the epithelium; (2) T lymphocytes (CD3+, CD4+, CD8+) and CD14+ cells in the stroma; and (3) VLA-4 and LFA-1 expression in the stroma than before BMT. After the engraftment, the comparison between autologous and allogenic recipients revealed that: (1) there were no significant differences in adhesion molecule expression; (2) the epithelium of autologous recipients had significantly more CD3+ cells; and (3) the stroma of allogenic patients had significantly more CD3+ and CD8+ cells. Among allogenic recipients, CD14+ cells were significantly increased both in the epithelium and in the stroma of patients with signs or symptoms of dry eye in comparison with patients without ocular involvement. Additionally, those having keratoconjunctivitis sicca (KCS) had CD4/CD8 ratios significantly higher than those without KCS. In conclusion, in the conjunctiva after autologous BMT a subclinical cell mediated immune reaction seems to take place. The conjunctivitis of chronic GVHD is complex, with T cells and macrophages dramatically contributing to the process.

Chronic Ocular Surface Disease after Allogeneic Bone Marrow Transplantation

Graft-versus-host disease (GVHD) is a common complication of allogeneic bone marrow transplantation (allo-BMT). Ocular surface disease (OSD) is one of the most common manifestations of chronic ocular GVHD, yet little is known about it. In this article, we review the available literature on this condition and present results from our study of the manifestations of OSD in the chronic phase (>3 months duration) post allo-BMT. Our study consisted of a retrospective chart review of 62 allo-BMT patients with chronic OSD evaluated at our center between 1995 and 2002. The clinical features, systemic associations, treatment, and status of OSD at the last follow-up are presented and discussed in the context of other reports of OSD in GVHD.

Dry eye as a major complication associated with chronic graft-versus-host disease after hematopoietic stem cell transplantation

PURPOSE

To review the condition of dry eye associated with chronic graft-versus-host disease (GVHD).

METHODS

The immunopathogenic processes and therapeutic options for lacrimal gland chronic GVHD are discussed.

RESULTS

Dry eye is the most frequent ocular complication after hematopoietic stem cell transplantation. The condition typically occurs around 6 months post-operation and is recognized as a complication of chronic GVHD. Lacrimal gland specimens from patients with dry eye show prominent fibrosis and an increase in CD34+ stromal fibroblasts in the glandular interstitium in addition to infiltration of T cells into the periductal areas. In periductal areas, CD4+ and CD8+ T cells colocalize with stromal fibroblasts that express the full component of surface molecules necessary for antigen presentation. These findings strongly suggest that periductal fibroblasts are involved in fibrogenic and immune processes by interacting with T cells in the lacrimal gland of patients with chronic GVHD, resulting in rapidly progressive dry eye. Current therapies for dry eye related to chronic GVHD include tear supplements and nonspecific immunosuppressants.

CONCLUSION

We report a significant role for stromal fibroblasts in the pathogenic processes of dry eye related to chronic GVHD. Although several supportive therapies can reduce the symptoms, specific therapies that suppress fibrotic and immune processes in the lacrimal glands are necessary to control dry eye associated with chronic GVHD.

Autologous serum eye drops for the treatment of severe dry eye in patients with chronic graft-versus-host disease

We investigated the efficacy and safety of autologous serum eye drops for the treatment of severe dry eye after allogeneic haematopoietic stem cell transplantation (SCT). A total of 14 patients (four males and 10 females; median age, 31.0 years) with severe dry eye associated with chronic graft-versus-host disease (cGVHD) were enrolled in this study. All patients were refractory to treatment with conventional artificial tears. Autologous serum eye drops, a solution made of 20% autologous serum in sterile saline, were applied 10 times per eye per day. The patients were evaluated every 4 weeks according to visual acuity, corneal sensitivity, vital staining of the ocular surface, tear dynamics, and subjective assessments of symptoms (complaints scores). The median follow-up period was 19.4 months (range: 4-41 months). After 4 weeks of treatment, significant improvement was observed in both complaint scores (from 33.7+/-12.3 to 23.6+/-10.6 points; P<0.01) and fluorescein scores (from 5.8+/-2.0 to 2.4+/-0.9 points; P<0.005). Significant improvements were observed also in rose-bengal staining and tear break-up time. In seven of the 14 patients, the responses were maintained for 6-41 months (median:19.4+/-8.3 months), while six of the other seven patients required treatment with punctal plugs in addition to autologous serum eye drops. One of these other seven patients developed eczema around the eyelids, after which the treatment was discontinued. No serious adverse events were observed. We conclude that autologous serum eye drops are safe and effective for treating severe dry eye associated with cGVHD and that more efficient control of dry eye may be achieved by the combined use of autologous serum eye drops with punctal plugs.

Successful treatment of dry eye in two patients with chronic graft-versus-host disease with systemic administration of FK506 and corticosteroids

PURPOSE

We present two cases of severe dry eye in patients with chronic graft-versus-host disease (CGVHD) after hematopoietic stem cell transplantation (SCT) who were successfully treated by the systemic administration of FK506 and corticosteroids.

METHODS AND RESULTS

A 29-year-old man with chronic myelogenous leukemia underwent SCT. Oral and lung CGVHD developed on approximately day 130, and dry eye associated with CGVHD was diagnosed on day 168. The patient began receiving cyclosporin A (150 mg/d) for the treatment of oral and lung CGVHD. Treatment with prednisolone (1 mg/kg/d) began on approximately day 300. Oral and lung GVHD improved slightly, but worsened again although systemic administration of cyclosporin A and prednisolone were continued. Cyclosporin A was discontinued, and systemic administration of FK506 was started on day 376. Forty-four days later, marked improvement in the ocular surface and other organs was observed. However, the dry eye worsened while tapering FK506, with no flare of other affected organs. A 43-year-old woman with myelodysplastic syndrome underwent SCT. She received FK506 for prophylaxis of CGVHD. She had mild dry eye before SCT. Oral and intestinal CGVHD developed, and the dry eye worsened significantly on approximately day 150 while tapering FK506. Treatment with prednisolone (1 mg/kg/d) began, and the dose of FK506 was increased. By day 240, the symptoms of dry eye and the findings of the ocular surface markedly improved, and CGVHD in other organs was completely resolved. However, the improvement in the dry eye was lost when FK506 was tapered for the second time.

CONCLUSION

Systemic administration of FK506 with corticosteroids is an effective treatment of severe dry eye in patients with CGVHD, but long-term administration may be required to achieve a lasting response. These cases also suggest that further investigation into the use of topical FK506 and prednisolone as a maintenance therapy should be pursued.

Lack of evidence for an increased microchimerism in the circulation of patients with Sjögren's syndrome

OBJECTIVE

To examine the hypothesis that fetal microchimerism plays a part in the pathogenic process of Sjögren's syndrome (SS).

METHODS

Genomic DNA samples were extracted from peripheral blood whole nucleated cells and the CD34+ cell enriched fraction of patients with SS and healthy women who had male offspring as well as nulliparous women. A Y chromosome-specific sequence was detected as a marker for fetal cells by a nested polymerase chain reaction (PCR) and by DNA hybridisation combined with PCR using specific primers and probes. All procedures were performed with great care to avoid the contamination of male DNA.

RESULTS

A nested PCR and DNA hybridisation combined with PCR was established that can detect a single male cell out of 1.67x10(5) female cells. It was not possible to increase the sensitivity further because the amount of template DNA held in the PCR was limited. When these methods were used, no fetal cells were detected in any samples from patients with SS, though they were detected in whole nucleated cells from two healthy women who had delivered sons previously.

CONCLUSIONS

The findings indicate that circulating fetal cells in patients with SS are uncommon (<1 in 1.67x10(5)), if they exist. With the conventional PCR based methods that were used, it is difficult to evaluate the quantitative difference in circulating fetal cells between patients with SS and healthy women.

Update in Sjögren syndrome

Sjögren syndrome (SS), the second most common autoimmune rheumatic disease, refers to keratoconjunctivitis sicca and xerostomia resulting from immune lymphocytes that infiltrate the lacrimal and salivary glands. However, differential diagnosis remains confusing due to the high prevalence of vague symptoms of dryness, fatigue, and myalgias in the general population. The problems of diagnosis are further compounded by the finding of "positive" antinuclear antibodies in a high percent of the general population. Unless minor salivary gland biopsies are read by experienced observers, nonspecific changes of sialadenitis are frequently confused with the focal lymphocytic infiltrates that are characteristic of SS. The distinction between fibromyalgia patients with low titer antinuclear antibodies and primary SS remains difficult. Even in patients fulfilling strict criteria for SS, the genomic search for critical genes has proven difficult due to the multigenic pattern of inheritance and strong role of currently undefined environmental factors. No single environmental factor has been detected in the majority of SS patients. SS-like syndrome has been detected in certain patients with HTLV-1 and hepatitis C infection, providing clues to pathogenesis. Even in SS patients with marked sicca symptoms, minor salivary gland biopsy shows that almost 50% of glandular cells are still detected on biopsy. These results imply the importance of immune factors such as cytokines and autoantibodies in decreasing neuro-secretory circuits and induction of glandular dysfunction. Of potential importance, an antibody against muscarinic M3 receptor that can decrease secretory function when injected into rodents is frequently found in the sera of SS patients. Newly developed topical and oral therapies can ease the oral and ocular dryness. Orally administered agonists of the muscarinic M3 receptor (pilocarpine and cevimeline) have recently been approved by the US Food and Drug Administration to increase salivary secretion. Topical ocular use of low-dose corticosteroids or cyclosporin may decrease conjunctival surface inflammation. In a Phase II double-blind study, orally administered interferon alpha (150 U) led to improved saliva flow and symptoms. In pregnant patients with evidence of fetal distress, oral dexamethasone is preferred because this agent crosses the placenta effectively. In animal models, antagonists of tumor necrosis factor and inhibitors of de novo pyrimidine synthesis appear promising.