Background IgG4 related disease (IgG4-RD) primary Sjogren’s syndrome (pSS) share some common clinical, serological and histopathological characteristics.
Objectives To determine whether a subset of primary Sjogren’s syndrome patients fulfill the recently proposed criteria for IgG4 related disease.
Methods Serum IgG4 levels were measured in 133 pSS patients and 49 healthy blood donors (HBD). 74 lupus patients and 54 patients with rheumatoid arthritis (RA) were served as disease controls. Immunohistochemical IgG4 analysis was performed in paraffin-embedded minor salivary gland (MSG) tissues.
Results Raised IgG4 serum levels (>135mg/dl) were detected in 10 out of 133 pSS patients [(7.5%), “High-IgG4” group), in 8 out of 74 lupus patients (10.8%), in 7 out of 54 (12.9%) RA patients and in one out of 49 HBD (2%). Compared to the “Normal-IgG4” pSS group (<135mg/dl), “High-IgG4” patients exhibited increased prevalence of IgG4-related features (autoimmune cholangitis and pancreatitis, interstitial nephritis), lower rates of ANA positivity (p=0.03) and higher IgG2 (p=0.02) and IgE (p=0.04) levels. When the cut-off for IgG4 positivity was defined as 270 mg/ dl, the corresponding rates were 5 out of 133 (3.7%) for pSS, 3 out of 74 (4.1%) for SLE, 1 out of 54 RA (1.9%) and 0 out of 49 HBD (0%). Positive staining for IgG4+ plasma cells, with an IgG4/IgG ratio ≥40% was detected in 3/5 available MSG tissues in the “High-IgG4” group. Criteria of possible or definite IgG4-RD were fulfilled by 10 out of 133 (7.5%) of our pSS cohort.
Conclusions Criteria for IgG4-RD were fulfilled by a small subset of our pSS cohort characterized by high prevalence of IgG4-related clinical, serological and histopathological features.
Disclosure of Interest None Declared