Abnormal White Blood Cell Counts in Sjögren's Syndrome

Pathophysiological Significance

Sjögren's syndrome is characterized by lymphocytic infiltration of the lacrimal and salivary glands, leading to gland dysfunction and systemic manifestations, as noted by the American Academy of Ophthalmology 1

High neutrophil count often indicates an acute bacterial infection requiring investigation, particularly in immunocompromised patients with Sjögren's syndrome, according to the American College of Chest Physicians 2, 3
Patients with Sjögren's syndrome receiving immunosuppressive therapies like rituximab are at increased risk for bacterial, viral, and fungal infections, as reported by the American College of Chest Physicians 2, 3

Immunosuppressive medications used to treat Sjögren's syndrome can cause cytopenias, including lymphopenia, as noted by the American College of Chest Physicians 2, 4
Medications like azathioprine and mycophenolate mofetil (MMF) can cause bone marrow suppression, affecting lymphocyte counts, according to the American College of Chest Physicians 4, 5

Decreased C4 levels at diagnosis of Sjögren's syndrome are associated with higher lymphoma risk, as reported by the American Academy of Ophthalmology 1

Complete blood count with differential to confirm and track abnormal cell counts is recommended by the American Academy of Allergy, Asthma, and Immunology 6
Comprehensive metabolic panel to assess organ function, and inflammatory markers (ESR, CRP) to evaluate disease activity, are recommended by the American College of Chest Physicians 2
Evaluation for infection through appropriate cultures and imaging studies is necessary, as noted by the American College of Chest Physicians 2
Consider lymphoma screening if clinically indicated, especially with risk factors like decreased C4 levels, as reported by the American Academy of Ophthalmology 1

Co-management with a rheumatologist is essential for patients with Sjögren's syndrome due to potential systemic complications, as noted by the American Academy of Ophthalmology 1
If infection is suspected, appropriate antimicrobial therapy should be initiated based on culture results, according to the American College of Chest Physicians 2
Adjustment of immunosuppressive medications may be necessary if drug-induced cytopenia is suspected, as reported by the American College of Chest Physicians 2, 4

Overlooking the possibility of medication-induced hematologic abnormalities in patients on immunosuppressive therapy, as noted by the American College of Chest Physicians 2, 4
Neglecting to screen for lymphoma in patients with Sjögren's syndrome who develop unexplained hematologic abnormalities, as reported by the American Academy of Ophthalmology 1

Sjögren's syndrome is characterized by lymphocytic infiltration of the lacrimal and salivary glands with secondary compromise of gland function, leading to dry eyes and dry mouth, and carries approximately a 5% risk of developing lymphoid malignancy, with primary Sjögren's syndrome being the rheumatic disease most strongly associated with lymphoma development 7, 8, 9
The American College of Rheumatology defines Sjögren's syndrome as an autoimmune disorder defined by chronic inflammatory cellular infiltration of exocrine glands, particularly the lacrimal and salivary glands, resulting in diminished tear and saliva production 7, 8

Autoantibodies, particularly anti-Ro/SSA and anti-La/SSB, are key serological markers in the diagnostic criteria for Sjögren's syndrome 10
The condition can present as primary Sjögren's syndrome or secondary to other autoimmune diseases such as rheumatoid arthritis, scleroderma, or systemic lupus erythematosus 7, 11
Systemic manifestations beyond sicca symptoms include arthralgia, myalgia, fatigue, and potential involvement of multiple organs including the lungs, kidneys, liver, nervous system, and vasculature 12, 13

About 5% of patients with Sjögren syndrome will develop some form of lymphoid malignancy, representing a significant increase in risk compared to the general population 8, 9
A meta-analysis found that primary Sjögren's syndrome is the risk factor most strongly associated with lymphoid malignancy among rheumatic diseases, with an incidence rate of 18.9% (95% CI, 9.4–37.9) 8, 9
Decreased C4 levels at the time of diagnosis of Sjögren's syndrome are associated with a higher risk of developing lymphoma 7, 13

Ophthalmologists caring for patients with clinically significant dry eye should maintain a high index of suspicion for Sjögren's syndrome and have a low threshold for serological workup 8, 9
Patients with Sjögren's syndrome should be co-managed with a rheumatologist due to the many possible comorbid systemic conditions and the increased risk of lymphoma 7, 12
Regular monitoring for signs of lymphoma development is essential in the management of Sjögren's syndrome patients 8, 10