Table 2.

Distinction between IgG4-related disease and hyper-IL-6 syndromes.

	IgG4-related disease	Hyper-IL-6 syndromes
Serum immunoglobulin	IgG↑(IgG4↑), IgE↑	IgG↑(IgG1∼IgG4↑), IgA↑, IgM -/↑, IgE↑
Serum IgG4/IgG ratio	Elevated	Normal (~sightly elevated)
Serum IL-6	Normal (~sightly elevated)	Elevated
Serum CRP	Normal (~sightly elevated)	Elevated
Thrombocytosis	No	Yes
Anemia	No	Yes
Hypoalbuminemia	No	Yes
Hypocholesterolemia	No	Yes

Hyper IL-6 syndromes; multicentric Castleman's disease, rheumatoid arthritis, and other immune-mediated conditions.