Immunologic profile of tears and conjunctiva in Sjögren*s syndrome

Sjögren*s syndrome (SS) is a chronic autoimmune disease affecting the exocrine
glands, primarily the salivary and lacrimal glands. The disease can be primary
or secondary to other auto-immune diseases as rheumatoid arthritis, systemic
lupus erythematosus, or others. The precise mechanism responsible for the
reduced tear production in SS is not known.
The diagnosis requires 3 areas of speciality practice: rheumatology, oral
medicine and ophthalmology. Currently, diagnosis is made on American-European
Consensus Sjögren*s Classification Criteria. These criteria include ocular and
oral symptoms, objective ocular and oral signs, histopathology of the salivary
glands and the presence of auto-antibodies, anti-SSA and anti-SSB in serum.
Ocular diagnosis is made on subjective findings and objective measurements.
Ocular symptoms are labelled positive if one of the following questions is
answered positive: Do you have dry eyes >3 months? Do you have foreign body
sensation in the eyes? Do you use artificial tears >3x per day?
The objective measurements are the ocular staining score with Lissamine green
(>= 3 either eye) and tear production with Schirmer*s test (<= 5mm/5 minutes).
Recently preliminary new criteria have been introduced by the American College
of Rheumatology (ACR)1. In these new criteria, the ocular criteria for making
diagnosis have been changed and have become one of the major criteria in
classifying Sjögren*s syndrome. Ocular staining score according to the
preliminary ACR criteria is composed of Lissamine green staining on the
conjunctiva and fluorescein staining on the corneal surface. This new scoring
system is called SICCA. Although these preliminary ACR criteria are an
considered improvement in scoring eye involvement, Lissamine green staining can
be difficult to perform if the investigator is not experienced.
Moreover, Schirmer testing is not always reliable; several studies showed low
sensitivity and specificity, which was one of the major reasons of excluding
this test in the preliminary ACR criteria.
It is known that patients with primary Sjögren*s syndrome have an immunological
profile in their blood and saliva dissimilar of that from healthy subjects.
Although it is known that the tear fluid has a different immunologic profile in
patients with keratoconjunctivitis sicca compared to healthy subjects, it
hasn*t been investigated yet if there is a difference between
keratoconjunctivitis sicca due to Sjögren*s syndrome and other dry eye
diseases. This is an important issue, as differences in the immunological
profile between Sjögren*s patients and non Sjögren*s patients with dry eyes may
provide clues for earlier and better diagnosis and treatment decisions of this
disorder in Sjögren*s patients.
It is known that the cytokines, including BAFF and APRIL play a major role in
the pathology of Sjögren*s syndrome and that they can be detected in a
significant higher level in serum of patients with Sjögren*s syndrome compared
to healthy individuals. But is this also true for tears?
Therefore we would like to assess whether this different serological
immunological profile is applicable for tear composition and is rather specific
for Sjögren*s syndrome. Several biomarkers, including BAFF, APRIL and
chemokine CXCL10 can be detected in tear fluid of dry eye patients. Until now,
it has not been investigated if there is a difference between the different
causes of dry eye disease and between these groups and healthy subjects. If
this can be detected, it might be a new objective tool, non invasive and easy,
in diagnosing Sjögren*s syndrome. Also, in the future it could help developing
new treatments.
Another point of interest is the conjunctival epithelial cell. It is known that
metaplasia of the conjunctival cell takes place in dry eye disease, also
overexpression of inflammatory markers has been seen. We would like to asses if
primary Sjögren*s patients have a different immunologic profile of their
epithelial cells in comparison to non Sjögren*s patients with dry eye disease.
These findings could also be a new tool in diagnosing or give clues on the
pathophysiology Sjögren*s syndrome.

Primary Objective: Detect a difference in immunological profile between primary
Sjögren*s syndrome patients in comparison with subjects from the other study
groups.

Secondary Objective(s): Other objectives will be the assessment tear osmolarity
in the tears of primary Sjögren*s syndrome patients in comparison to non
Sjögren*s syndrome dry eye patients and healthy subjects as well as an
assessment of immunological characteristics in conjunctival epithelial cells in
these three patient/control groups.

We will assess the difference between immunological profile of tears and
conjunctival epithelial cells between patients with dry eye disease due to
Sjögren*s syndrome and non Sjögren*s syndrome dry eye disease and healthy
subjects. To accomplish this we need three groups. These groups will be age and
sex matched. The Sjögren*s syndrome group will be recruited from the
rheumatology and clinical immunology outpatient department through random
selection. The non Sjögren*s syndrome dry eye group will be recruited from our
outpatient department for dry eye disease.
Healthy subjects will be recruited through social media, like Facebook and
Twitter.
Primary Sjögren patients will be included if they are diagnosed by our
department of rheumatology and clinical immunology with primary Sjögren*s
syndrome according to the American-European classification criteria for
Sjögren*s syndrome . The non Sjögren*s syndrome dry eye patients are included
if they are diagnosed with dry eye disease without Sjögren*s syndrome criteria:
tear production should be normal (Schirmer >=10mm) and staining with Lissamine
green should be less than 3. Exclusion criteria are: use of topical steroid eye
drops, use of anti-glaucomatous eye drops, ocular surgery in the year before
participation, chronic contact lens wear, history of ocular herpes keratitis.
Healthy subjects should have no ocular history or complaints and cannot use
artificial tears.
The measurements needed to investigate this will be analysis of tear osmolarity
and sampling of tears. Routine investigation would be Schirmer testing,
measuring tear break up time, lissamine green testing and quantification of
mucus in the conjunctival sac. Also, ocular impression cytology will be
performed. Subjective symptoms will be measured with the Ocular Surface Disease
Index and the Xerostomia Index.
These examinations will take place on one single occasion during the visit to
our outpatient clinic.
Tear samples and impression cytology samples will be stored appropriately with
our lab rheumatology en clinical immunology and will be analyzed on a later
occasion.

The aim of our study is to make diagnostics in Sjögren*s syndrome easier in the
future. We also hope this study will give us some more insight in the disease
and clues for better therapy.
Although patients don*t benefit directly from this study, it could be that the
results could be used in future investigations on medication and their
efficacy. Non Sjögren*s syndrome dry eye disease patients will benefit because
the study will provide insight in their immunological tear profile and tear
osmolarity which can also give insight in their disease and may benefit the
choice of the most appropriate treatment for that specific subject.
Healthy subjects will benefit from the study because they will undergo an
ophthalmic exam. If there is found something wrong with their eye, they will be
helped sooner in contrast to when they don*t participate in this study.