Hello @di341, I did find some information on the topic that may be helpful.

"SS-B antibodies are less common, being found in approximately 30-50% of Sjögren's syndrome patients. SS-A antibodies thus occur commonly by themselves. However, it is very uncommon for SS-B antibodies to occur alone. Accordingly, 20-40% of Sjögren's syndrome patients may lack SS-A and/or SS-B antibodies."
-- Blood and Urine Tests - Johns Hopkins Sjögren's Center: https://www.hopkinssjogrens.org/disease-information/diagnosis-sjogrens-syndrome/blood-and-urine-tests/

Have you thought about seeking help at a local teaching hospital or major health facility like Mayo Clinic?