Azathioprine metabolite levels and outcomes during pregnancies with rheumatic disease.

OBJECTIVE: Despite widespread use of azathioprine (AZA) during pregnancy, no studies evaluated the impact of pregnancy on AZA metabolites 6-thioguanine nucleotide (6-TGN) and 6-methylmercaptopurine nucleotide (6-MMPN) disposition in rheumatic diseases. This study characterises changes in AZA metabolite concentrations throughout pregnancy in women with rheumatic disease and explores relationships between metabolite concentrations, maternal disease activity, and neonatal outcomes. METHODS: Patients with rheumatic disease from a single centre prescribed AZA prior to pregnancy and ≥1 blood sample during pregnancy (5/2016 to 4/2022) were included. Commercial laboratories quantified AZA metabolite concentrations. The upper safety limit for 6-MMPN was >5700 pmol/8×108 RBC. The therapeutic target for 6-TGN was ≥159 pmol/8×108 RBC. Repeated correlation measures were used to evaluate the relationship between metabolite concentrations and pregnancy duration, and the relationship between 6-TGN concentration and SLE Physician Global Assessment (PGA). The relationship between pregnancy average 6-TGN and neonatal gestational age at birth was analysed using linear regression. RESULTS: Thirty-seven pregnancies in 35 women with 108 serum samples were included. There was no significant difference in dose-adjusted 6-TGN concentrations across pregnancy and peripartum, whereas 6-MMPN concentrations appeared higher during pregnancy. No elevated transaminases or cholestasis were observed concurrently with 6-MMPN above 5700 pmol/8×108 RBC. Metabolite concentrations were related to total AZA dosage, weight-based dosage and TPMT phenotype. In pregnant women with SLE achieving average 6-TGN in the therapeutic range, we observed a non-significant reduction in PGA and increase in neonatal gestational age at birth. CONCLUSIONS: In this exploratory study, we did not observe systematic changes in 6-TGN concentrations throughout pregnancy and peripartum, whereas 6-MMPN concentrations were higher during pregnancy. Monitoring AZA metabolite concentrations in pregnancy is a potential tool to identify medication non-adherence as well as patients with high 6-MMPN in whom dosage adjustment or close laboratory monitoring may optimise safety.

The impact of pregnancy planning and medical readiness on reproductive outcomes in women with systemic lupus erythematosus.

Women with systemic lupus erythematosus (SLE) who get pregnant while SLE is active or while on teratogens have higher risk of poor pregnancy outcomes. The American College of Rheumatology (ACR) Reproductive Health Guidelines recommend women conceive when SLE is well controlled and treated with pregnancy-compatible medications. The Healthy Outcomes in Pregnancy with SLE Through Education of Providers (HOP-STEP) Intervention was created to ascertain pregnancy interest and contraceptive use followed by a personalized pregnancy prevention and/or planning discussion (https://www.LupusPregnancy.org). All study participants were adult females enrolled in a prospective registry who met ACR or SLICC criteria. Women were defined as "not medically ready for pregnancy" if they were currently prescribed a teratogen, had proteinuria ≥500 mg, or had elevated SLE activity according to the physician's global assessment. Two time periods were assessed: 2/2018-12/2019 and 10/2020-4/2021 to evaluate pre- and post-pandemic periods, with some post-pandemic visits taking place via telehealth. The interest in pregnancy was similar between the first time period (17%) and the second time period, whether in-person (18%) or virtual (18%). Pregnancy interest was assessed significantly more frequently during in-person visits (90%) compared to virtual encounters (67%) (p = .02). Contraceptive use was not significantly different during either time period with use of a teratogen or increased SLE activity. Of the 52 women in both time periods who were not medically ready for pregnancy and were not on effective contraception, three women (5.8%) conceived. None of the women who were using moderate or highly effective contraception became pregnant. Pregnancy outcomes were similar between unintended or high-risk and well-timed pregnancies. The HOP-STEP Intervention effectively identified pregnancy interest, giving rheumatologists the opportunity to address patient reproductive goals, optimize disease activity, and adjust medication regimens prior to conception.

Vasculitis and Pregnancy: Disease State and Management.

Family planning in women with vasculitis requires an interdisciplinary approach. This article summarizes recommendations and guidance for each phase of family planning in persons with vasculitis including preconception counseling, birth control, pregnancy, and breastfeeding. Pregnancy complications are presented by category of vasculitis with accompanying diagnostic and therapeutic recommendations. Birth control and assisted reproductive technology options are reviewed with special considerations for women who are high risk or have a history of blood clots. This article can be used as a clinical reference for reproductive discussions in all patients with vasculitis.

Location of auxilin within a clathrin cage.

The Dna J homologue, auxilin, acts as a co-chaperone for Hsc70 in the uncoating of clathrin-coated vesicles during endocytosis. Biochemical studies have aided understanding of the uncoating mechanism but until now there was no structural information on how auxilin interacts with the clathrin cage. Here we have determined the three-dimensional structure of a complex of auxilin with clathrin cages by cryo-electron microscopy and single particle analysis. We show that auxilin forms a discrete shell of density on the inside of the clathrin cage. Peptide competition assays confirm that a candidate clathrin box motif in auxilin, LLGLE, can bind to a clathrin construct containing the beta-propeller domain and also displace the well-characterised LLNLD clathrin box motif derived from the beta-adaptin hinge region. The means by which auxilin could both aid clathrin coat assembly and displace clathrin from AP2 during uncoating is discussed.