Type 1 diabetes and associated autoimmune diseases

Table 1 Relevant autoantibodies in type 1 diabetes[10,11,72-75,77,78]

Autoantibody against	Antigen	Sensitivity (%)	Specificity (%)	Normal range	Occurrence
Glutamic acid decarboxylase	Glutamic acid decarboxylase (65 kd)	65-75	99	< 10 IE/mL	70% more common after adolescence
Islet cell	Islet cells	70	99	Negative	80% at diagnosis
Protein tyrosine phosphatase	Tyrosine phosphatase-related islet antigen 2	50-90	99	< 1.0 U/mL	60% at diagnosis
Insulin	Pro-/insulin	74	99	< 0.4 U/mL	50% at diagnosis. First Ab detected in children. Less common after adolescence
Zinc transporter 8	C terminal domain of the zinc transporter 8	65-75	99	< 15 U/mL	Up to 80% at diagnosis
Thyroglobulin	Thyroglobulin	90	99	< 4.1 IU/mL	10%-20% in GD and up to 50% in HT at diagnosis
Thyroperoxidase	Thyroperoxidase	90	99	< 6 IU /mL	70% in GD and 90% in HT at diagnosis
TSH-receptor	TSH-receptor	99	99	< 1.8 IU/mL	More than 90% in GD and 10% in HT at diagnosis
Adrenal cortex	21-hydroxylase and 17 alpha hydroxylase	87	99	Negative	Up to 90% at diagnosis of AD
Transglutaminase IgA	Tissue transglutaminase	90	99	< 20 CU	Common at diagnosis of CD. 6% of patients have an IgA deficiency
Parietal cell	Parietal cells	90	50	Negative	> 90% patients with autoimmune gastritis
Intrinsic factor	Intrinsic factor	80	90	Negative	In 50%-70% of patients with autoimmune gastritis
CCP	CCP	20-25	95	< 20.0 U	In 50%-90% of patients with rheumatoid arthritis
Anti-ro; anti-la	Heterogeneous nuclear ribonucleoproteins	89	99	Negative	70% of patients with Sjögren's syndrome and 50% of patients with lupus erythematosus
Smooth muscle	Smooth muscle	80	99	Negative	In 50%-85% of patients with autoimmune hepatitis
DNA	Double-stranded DNA	65	99	< 30.0 IU/mL	In 50%-70% of patients with systemic lupus erythematosus

CCP: Cyclic citrullinated peptide; GD: Graves‘ disease; Ab: Antibodies; HT: Hashimoto’s thyroiditis; AD: Addison disease; CD: Celiac disease.