IgG4-immunoglobulin-related disease (IgG4-IRD) is a relatively new pathology, characterized by intense inflammation, fibrosis, infiltration and elevated IgG4 levels in peripheral blood. Despite the interest in the disease, these diagnostic criteria are not without discrepancies and false negatives. In fact, despite the fact that elevated serum IgG4 concentrations can provide an important clue for the diagnosis of the disease,described that the specificity and positive predictive value of elevated serum IgG4 concentrations are 60 % and 34 % respectively. And, when they increased the cut-off values to double to improve specificity, the sensitivity of IgG4 levels drops to 35 %. In 2014, was described the presence of elevated concentrations of plasmablasts (CD19 low, CD20 -, CD38+ and CD27+) in the serum of patients with active ER-IgG4, even in patients with normal IgG4 levels, compared with healthy patients and with other autoimmune pathologies. Furthermore, several studies have shown that follicular T helper (Thf) cells are increased in both peripheral blood and affected tissue of patients with ER-IgG4. These cells appear responsible for the development of germinal centers in lymph nodes and for the production of interleukins that drive IgG4 class switching, and creation of IgG4-secreting plasmablasts and plasma cells. This suggests that interleukins IL4, IL5, IL 10, IL13 might also be relevant in discerning ER-IgG4 from other immune-mediated processes with similar symptoms. ACTION GOALS: 1. To evaluate the diagnostic validity of plasmablast count and other immunological markers (B lymphocyte differentiation stage, follicular T helper lymphocytes (Thf) and IL-4, IL5, IL-10 and IL-13) in peripheral blood for IgG4-Related Disease. 2. To evaluate the correlation of these biomarkers with inflammatory activity, clinical manifestation and diagnostic certainty (possible, probable or definite) of IgG4-Related Disease. 3. To evaluate whether high counts or concentrations of these biomarkers at diagnosis are prognostic factors for relapse during the first 12 months of follow-up in patients with IgG4-Related Disease.
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Change in IgG4 in peripheral blood
Timeframe: Change from Baseline at one year after the study began
Change in IL-4
Timeframe: Change from Baseline at one year after the study began
Change in IL-5
Timeframe: Change from Baseline at one year after the study began
Change in IL-10
Timeframe: Change from Baseline at one year after the study began
Change in IL-13
Timeframe: Change from Baseline at one year after the study began
Change in plasmablast
Timeframe: Change from Baseline at one year after the study began