## 4 Discussion
The findings obtained in the present study are consistent with those shown by [PERSON] et al., who revealed that abnormal biopsies were more frequent in SS patients with serologic abnormalities than in patients with sicca symptoms or systemic illnesses [31]. Similar results were obtained by [PERSON] et al., who found that FS \(\geq\) 1 was strongly associated with positive serum anti-SSA and anti-SSB but not with symptoms of dry mouth [32]. Patients with positive anti-SSA/SSB were nine times more likely to have an FS \(\geq\) 1 than FS \(<\) 1. Patients with USWSF \(<\)0.1 mL/min were only twice as likely to have an FS \(\geq\) 1 than FS \(<\) 1. Moreover, only a diagnosis of FSL with FS \(\geq\) 1 was associated with the ocular and serological components of SS. FS \(<\) 1 reflected a similar correlation to the serological symptoms of SS as other types of sialadentis, such as nonspecific chronic sialadentis and sclerosing chronic sialadentis [32]. Dry eye as a component of sicca syndrome was a stronger predictor of FLS and FS \(\geq\) 1 than dry mouth. These findings are consistent with previous results that FLS and FS did not influence xerostomia occurrence or its severity, as assessed by USWSF. Furthermore, this possible correlation must be explored separately in seronegative and seropositive SS patients. The main indication for labial salivary gland biopsy appears to be the occurrence of sicca syndrome in seronegative patients. Similarly to serological and histopathological symptoms in SS, xerostomia did not correlate with other clinical or laboratory features. There were no statistically significant differences in positive RF, anemia, leukopenia, and clinical symptoms such as extragalundular manifestations, fatigue, and arthritis between SS patients with and without xerostomia. Previous studies showed divergent results related to the correlation between the coexistence of ANA positivity, FLS, and other phenotypic features in SS. According to [PERSON] et al., a positive RF is more likely to be present in SS seropositive patients with FSL [33]. The co-occurrence of RF positivity, anti-SSA, and anti-SSB positivity is associated with a more active immunologic profile predisposed to systemic complications [34; 35]. RF does not correlate with arthritis in SS patients. Previous studies revealed no correlation between elevated inflammatory markers, FLS, RF, or arthritis [31; 36; 37; 38]. There was a group of SS patients with FLS and elevated inflammatory markers with negative RF and non-erosive inflammatory arthritis. In turn, there was a positive correlation between anti-CCP antibodies and arthritis in SS patients [36; 37]. Although there were no statistically significant differences in ANA titer and seropositivity to SS-specific antibodies between patients with and without dry mouth, it proves that neither positive serology nor the presence of dry mouth predicts a positive labial salivary gland biopsy. However, previous studies found that sicca symptoms, ANA profile, and FSL must be included in comprehensive analysis. [PERSON] et al. showed that among patients with FLS, seronegative patients had a significantly higher proportion of dry mouth than seropositive patients [31]. Furthermore, FSL and higher FS results more often correlate with serological components of SS, including positive anti-SSA/SSB, rheumatoid factor (RF)serology, higher ANA titers, and IgG concentration than subjective and objective tests for diagnosing sicca syndrome [31; 32]. This finding proves that FSL in salivary gland biopsy should not be treated as a synonym for xerostomia in SS. Other methods for defining the salivary component of SS and dry mouth must be introduced. These methods include defining whole salivary or parotid flow rates with and without stimulation, measuring technetium uptake and secretion with salivary scintigraphy, and ultrasound images of the salivary glands. Although FSL does not reflect xerostomia severity in SS, it appears that FSL and FS are good markers for assessing the autoimmune activity of salivary glands.