Session Title: Sjögren's Syndrome: Clinical Aspects
Session Type: Abstract Submissions (ACR)
In the clinical diagnostic criteria of IgG4-related disease (IgG4-RD), Sjögren’s syndrome (SS) appears as one of the exclusion criteria. However, in Europe, where Mikulicz’s disease and SS were merged into one syndrome, some of the IgG4-RD patients might be hidden as a subset of SS.
There are special symptoms during the disease course of SS that raise the possibility of IgG4-RD whereas other symptoms identify certain SS patients as having high risk for developing malignant lymphoma (lymphoma high risk – LHR).
The aim of this study was to identify patients with IgG4-RD among patients followed up because of SS and to compare the aforementioned two subsets, with special attention on their IgG4 levels.
Data of 65 SS patients were analysed. Patients are followed up in the University o Debrecen, Hungary. Patients were divided into 4 subgroups:
– IgG4-RDsusp (n=15): patients at whom IgG4-RD can be raised (male gender, negative anti-Ro/SS-A and anti-La/SS-B, autoimmune pancreatitis, autoimmune hepatitis or sclerotizing cholangitis, persisting salivary gland swelling (SGS), lymphadenopathy)
– LHR (n=16): patients with high risk of malignant lymphoma: persisting leukopenia, low complement levels, polyneuropathy, vasculitis, gammopathy, cryoglobulinemia, persisting SGS or lymphadenopathy
– IgG4-RDsusp+LHR (n=20): patients eligible for both IgG4-RD and LHR group
– Control (n=14): patients with SS who are not eligible for any of the aforementioned groups.
Clinical course, total IgG and IgG4 levels, IgG4/IgG ratios and EULAR SSDAIs were compared.
Statistical analyses were performed with SPSS 19.0 software. P<0.05 was considered statistically significant.
Four patients fulfilled the diagnostic criteria for IgG4-RD.
Total IgG level of the LHR group was significantly higher than that of IgG4-RDsusp patients (18.7 g/l vs. 11.6 g/l, p=0.0033). IgG4 concentrations were significantly higher at the IgG4-RDsusp patients than in the LHR group (0.46 g/l vs. 0.12 g/l, p=0.032).
IgG4/IgG ratio was significantly higher both in the IgG4-susp and in the IgG4-susp+LHR group compared to the other two groups.
The two common features of the IgG4-RDsusp and the LHR group, namely SGS and lymphadenopathy, were analysed separately, too.
Among patients with SGS (n=35), IgG4/IgG ratio was significantly higher (p=0.036). Neither total IgG, nor IgG4 levels differed significantly. Lymphadenopathic patients (n=10) had significantly higher IgG4 levels than those without lymphadenopathy (p=0.042).
ESSDAI median was higher in patients with elevated IgG4 concentrations (2 vs. 6, p=0.026). Average ESSDAI score was elevated in the LHR group (4.0 vs. 1.3, p=<0.001).
Our results support the hypothesis that some patients may be “hidden” under the diagnosis of SS unless their serum IgG4 level is measured. Measurement of IgG4 serum level is recommended before the introduction of any immunosuppressive treatment.
Based on our findings, although patients with LHR and patients with possible IgG4-RD share some clinical symptoms (SGS and lymphadenopathy), they differ significantly regarding their IgG and IgG4 levels such as IgG4/IgG ratio.
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