Persistent high levels of IgM antiphospholipid antibodies in a patient with recurrent pregnancy losses and rheumatoid arthritis.
OBJECTIVE
Recurrent pregnancy losses (RPL) and unexplained infertility (UI) are often associated with the presence of antiphospholipid antibodies (APA). We report one case with RPL, UI, and persistent IgM APA without B-cell isotype switch.


METHOD OF STUDY
(i) A case report of a woman with RPL and UI who eventually developed rheumatoid arthritis and B-cell phenotype study of the case and controls by flow cytometric analysis; (ii) a retrospective cohort study of 1067 subjects with APA test.


RESULTS
A 44-year-old woman with a history of RPL and UI was revealed to have high levels of APA, primarily of IgM isotype: IgM autoantibodies were specific to cardiolipin, phosphatidylglycerol, phosphatidylserine, and phosphatidylinositol. The monitoring of the patient's serological characteristics for 28 months did not reveal the development of IgG APA. B-cell phenotype analysis revealed decreased switched and double negative memory B cells and increased non-switched memory B cells in comparison with normal controls and reported ranges. A retrospective analysis of APA test revealed that total five patients (5/1067, 0.47%) with similar persistent IgM-only pattern were detected.


CONCLUSION
Persistent IgM APA without isotype switch may be a rare variant form of APA manifestation, which is associated with dysregulated B-cell subsets.
['Ota|Kuniaki|K|', 'Dambaeva|Svetlana|S|', 'Lee|Jennifer|J|', 'Gilman-Sachs|Alice|A|', 'Beaman|Kenneth|K|', 'Kwak-Kim|Joanne|J|']
D000026:Abortion, Habitual D000328:Adult D017152:Antibodies, Antiphospholipid D001172:Arthritis, Rheumatoid D001324:Autoantigens D001402:B-Lymphocytes D002308:Cardiolipins D005260:Female D006801:Humans D017578:Immunoglobulin Class Switching D007075:Immunoglobulin M D007156:Immunologic Memory D016130:Immunophenotyping D010715:Phosphatidylglycerols D010716:Phosphatidylinositols D010718:Phosphatidylserines D011247:Pregnancy D012189:Retrospective Studies
IgM Antiphospholipid antibodies recurrent pregnancy losses rheumatoid arthritis memory B cell