Lupus. 2026 Jul 28:9612033261474084. doi: 10.1177/09612033261474084. Online ahead of print.
ABSTRACT
IntroductionComplete heart block (CHB) is an exceptionally rare manifestation of adult systemic lupus erythematosus (SLE), typically occurring in less than 1% of patients. While classically associated with anti-SSA/Ro antibodies, we report a rare case of inaugural CHB in a young woman with anti-SSA-negative SLE, highlighting the diagnostic importance of anti-PM-Scl 100 antibodies and microvascular assessment.Case DescriptionA 21-year-old woman with a strong family history of SLE presented with symptomatic CHB (40 bpm). Cardiac MRI and standard workup ruled out myocarditis, infiltrative diseases, and common reversible causes. The patient showed subtle "sentinel" signs, including alopecia and inflammatory arthralgia. Immunological profiling revealed positive ANA (1/160) and elevated anti-dsDNA, but strict negativity for anti-SSA/Ro and anti-SSB/La. However, anti-PM-Scl 100 antibodies were strongly positive. Nailfold capillaroscopy demonstrated organic microangiopathy, supporting a microvascular-driven pathogenic process. A dual-chamber pacemaker was implanted due to irreversible conduction failure.DiscussionThis case challenges the diagnostic reliance on classic Ro/La antibodies for autoimmune CHB. The presence of anti-PM-Scl 100 and microvascular alterations on capillaroscopy suggests that nodal damage may result from an insidious fibrotic or microvascular process rather than acute inflammatory myocarditis. This "microvascular hit" can induce structural degradation even when systemic disease activity is quiescent.ConclusionCHB can be the inaugural sign of SLE even in the absence of anti-SSA antibodies. We recommend integrating extended antibody profiling and nailfold capillaroscopy into the diagnostic workup of unexplained heart block in young adults to bridge the current "diagnostic gap" in atypical autoimmune presentations.
PMID:42522210 | DOI:10.1177/09612033261474084