Follicular Helper T Cells: Biological Marker and Involvement in the Physiopathology of the IgG4-related Disease

IgG4-related disease is a rare and very recently identified pathology, whose frequency is certainly underestimated.

The clinical presentation varies among affected organs, and most often, patients have at least three organ damage.

These organs exhibit tissue infiltration mononuclear polymorphic cells with often severe fibrosis progression resulting in a loss of function.

The biomarker, though not specific, is a polyclonal elevated serum IgG4, and histological marker, currently held by several teams, is the presence within the inflammatory infiltrate, of a predominance of IgG4-expressing plasma-cells with a relative plasma-cells IgG4 + / IgG +> 50% on tissue immunostaining.

The investigators project provides a global assessment of T lymphocyte abnormalities and specifically the TFH (Follicular Helper) during this IgG4-related disease compared to so-called groups "control" subjects suffering from Sjogren syndrome or healthy subjects.