[Clinical characteristics of primary Sjögren syndrome with leukopenia]

To analyze the clinical characteristics of leukopenia in a large cohort of patients with primary Sjögren syndrome (pSS), to discuss its pathogenic mechanism, and to enhance clinicians ' understanding of the disease, and reduce missed diagnosis and misdiagnosis.

A total of 401 inpatients and outpatients who were initially diagnosed with pSS at the Department of Rheumatology and Immunology, Ninth People' s Hospital, Shanghai Jiaotong University School of Medicine, from November 2019 to March 2023 were selected for this study. The clinical data and laboratory examinations of these patients were analyzed retrospectively.

Of the 401 patients, 107 (26.68%) were complicated with blood leukopenia. The reasons for the first diagnosis were analyzed. The patients with leukopenia had a lower xerostomia and xerophthalmia (39.25% vs. 54.76%, P=0.006), but a higher incidence of fatigue (26.17% vs. 12.59%, P=0.001) and thrombocytopenia (11.21% vs. 2.72%, P=0.001) than those without leukopenia. There were no significant differences in arthralgia, oral ulcer, caries, chest tightness, asthma and anemia between the two groups (P>0.05). The laboratory test indicators were analyzed. The patients with leukopenia had a higher prevalence of anti-SSA/Ro52+ (81.31% vs. 68.35%, P=0.040), anti-SSB+ (47.66% vs. 28.57%, P < 0.001), immunoglobulin G (IgG)+ (68.22% vs. 51.02%, P=0.002), erythrocyte sedimentation rate (ESR) elevation (67.29% vs. 41.32%, P=0.001), and thrombocytopenia (22.43% vs. 13.27%, P=0.026) than those without leukopenia. There were no significant differences in antinuclear antibody (ANA)+, anti-SSA/Ro60+, centromere protein B(CENP-B)+, rheumatoid factor (RF)+, and anemia between the two groups (P>0.05). The positive rate of abnormal salivary gland ultrasound in pSS with leukopenia group was higher than that in normal group (P=0.029). There was no significant difference in salivary flow rate, dry eye test and lip gland biopsy between the two groups (P>0.05). The incidence of pSS combined with leukopenia and autoimmune hepatitis (10.28% vs. 3.40%, P=0.006) was higher than that of the normal group, and the incidence of interstitial pneumonia (16.82% vs. 14.97%, P=0.649), renal tubule acidosis (2.80% vs. 3.06%, P=0.649) and renal tubule acidosis (2.80% vs. 3.06%, P=0.893) were no significant differences between the two groups (P>0.05). Analysis of the effect of antibody on leukopenia showed that the proportion of leukopenia was higher in anti-SSA/Ro52+ group (30.00% vs. 18.02%, P=0.015). The percentages of leukopenia (37.78% vs. 21.05%, P < 0.001), neutropenia (31.85% vs. 16.92%, P < 0.001) and lymphocytopenia (24.44% vs. 21.03%, P=0.001) in anti-SSB+ group were significantly higher than those in anti-SSB- group.

In certain patients with pSS, leukopenia manifested as the initial clinical symptom, as opposed to the typically expected dry mouth and eyes. When compared to the group with normal leukocyte levels, the group of pSS patients with leukopenia demonstrated a higher susceptibility to fatigue symptoms and exocrine gland involvement. Additionally, this leukopenia group exhibited a higher rate of antibody positivity, increased disease activity, and a greater likelihood of developing liver disease complicated by autoimmunity. These findings underscore the need for heightened clinical attention.