Pregnancy After CAR-T in Autoimmune Disease: 14 Pregnancies, No Flares Save

The first multicenter series of pregnancies after CAR T-cell therapy for autoimmune disease reports 8 healthy births and no maternal flares. It is the first dataset of its kind, and the numbers are small.

CAR T-cell therapy for autoimmune disease is reaching a younger, mostly female population than in hematology, many with lupus and many for whom pregnancy is part of the treatment plan. Whether a woman can conceive after CAR-T, and what happens to the child, is now a consent question. At ACR Convergence 2026, Melanie Hagen (Erlangen) presented the first multicenter data (Abstract 1848), published by Schett and colleagues in the New England Journal of Medicine.

The oncology experience is thin. An EBMT survey by Orofino and colleagues (EClinicalMedicine) contacted 247 centers. Of these, 99 (40%) responded and reported 24 pregnancies in 19 CAR-T recipients: 18 in female recipients and 6 in partners of male recipients. There were 18 live births, 4 miscarriages and 2 ongoing pregnancies, and 22 of 24 conceptions were spontaneous. Those patients had often received extensive cytotoxic therapy before CAR-T, so the figures do not transfer directly to rheumatology.

The autoimmune series included 13 patients with 14 pregnancies in 6 countries. Eight patients had SLE, 2 systemic sclerosis, 1 inflammatory myopathy, 1 antiphospholipid syndrome and 1 SSc/RA overlap. Median age at pregnancy was 29 years (range 17 to 35). Median time from CAR-T to pregnancy was 16.5 months (range 1 to 42). All 14 conceptions were spontaneous, with no assisted reproduction. No mother flared (0/14). Pregnancy complications were 1 case of preeclampsia, 1 of hypertension and 1 of nausea.

Eight pregnancies ended in live births, at a median of 37 weeks (IQR 36.25 to 39.75) and a median birth weight of 2,995 g (IQR 2,778 to 3,268). All 8 newborns were healthy, with no infections at birth. Median IgG at birth was 692 mg/dL (IQR 424 to 903), and the median CD19+ B-cell count was 252 (IQR 173 to 449). No CAR-T cells were detected in any newborn (0/8). In 3 neonates studied by flow cytometry, 90.2% to 95.8% of B cells were naïve, which Hagen described as physiological B-cell development.

At conception, maternal B cells had already returned in 10 of 14 pregnancies, and CAR-T cells were still detectable in 3. One conception happened 1 month after infusion.

The hematology and autoimmune cohorts come from different studies, with no head-to-head comparison. Hagen called the data reassuring first evidence and said longer follow-up is needed.

For now, a young woman with refractory lupus can be told that pregnancy after CAR-T has occurred spontaneously, without flares, and with healthy babies carrying no detectable CAR-T cells. A first series of 14 pregnancies is too small to quote her a risk. The next data to watch are larger cohorts with a denominator of treated women, and immune development in these children beyond the newborn period.