Table 1.

Demographic, clinical and serological characteristics of pSS patients

	All pSS	IFI16 neg	IFI16 pos	p	anti-IFI16 neg	anti-IFI16 pos	p
Patient number (n)	67	53	14	–	44	23	–
Age (years)a	59 ± 1	60 ± 2	55 ± 3	0.2	60 ± 2	56 ± 2	0.2
Age at diagnosis (years)a	49 ± 2	50 ± 2	45 ± 3	0.3	51 ± 2	46 ± 2	0.3
Disease duration (years)a	9 ± 1	9 ± 1	10 ± 1	0.1	9 ± 1	10 ± 2	0.1
Xerophtalmia	92.5	94.3	85.7	0.3	86.4	82.6	0.7
Xerostomia	85.1	88.7	71.4	0.2	90.9	95.7	0.6
Salivary gland swelling	47.8	49.1	42.9	0.8	50.0	43.5	0.8
Extraglandular manifestationsb	76.1	77.3	71.4	0.7	79.5	69.5	0.4
Leukopenia	37.3	37.7	35.7	0.9	38.6	34.8	0.8
Hypergammaglobulinemia	61.2	56.6	78.6	0.2	61.4	60.9	0.8
Hypocomplementemia	26.9	22.6	42.9	0.2	25.0	30.4	0.7
Autoantibodies
Neither anti-SSA nor anti-SSB	16.4	17.0	14.3	0.9	18.2	13	0.7
Anti-SSA only	26.9	28.3	21.4	0.7	20.5	39.1	0.1
Anti-SSA and anti-SSB	56.7	54.7	64.3	0.6	61.4	47.8	0.3
RF ± anti-SSA ± anti-SSB	68.7	60.4	100	0.003	70.5	65.2	0.8

^aValues are reported as mean ± standard error of the mean and corresponding p values are calculated with Mann Whitney U test. All other values are reported as percentage of patients and corresponding p values are calculated with chi square test. ^bPercentage of patients with at least one extraglandular manifestation including articular, pulmonary or esophageal involvement, purpura, Raynaud’s phenomenon and lymphadenopathy. IFI16 interferon gamma-inducible protein 16, neg negative, pos positive, pSS primary Sjögren’s syndrome, RF rheumatoid factor