Table 2.

Immunoglobulin content of salivary gland stones.

Immunoglobulin/Protein Total (Pure Mass Fraction) in Sample
	IgG (µg/mg)	IgA (µg/mg)	Secretory IgA (µg/mL)
Sample 2	not available	not available	not available
Sample 3	not available	0.32	0.24
Sample 5	7.33	18.03	3.86

Both serum IgA and secretory IgA were detected in two of the three samples, with one of the samples also showing significant amounts of IgG. The absence of immunoglobulins in sample No.2 found by ELISA may be due to the detection limit of the ELISA kits used. Complete data with calibration curves and normalization data for total protein in the samples are presented in Supplementary S2 (Figure S1, Tables S1–S3).