The study team, led by Mehrnaz Adib and Payman Sadeghi, enrolled 171 neonates between March 2023 and March 2024 at a single center. Crucially, they deliberately excluded babies whose mothers had active or newly diagnosed autoimmune disease, or who had experienced a disease flare during pregnancy. That design choice is what makes the study distinctive: most existing knowledge about neonatal ANA positivity comes from high-risk pregnancies where mothers have known conditions such as lupus or Sjögren’s syndrome, and where antibodies like anti-Ro/SSA can cause congenital heart block and neonatal lupus rashes. By focusing on a clinically lower-risk population, the researchers asked a more fundamental question: how often does cord blood from apparently unremarkable pregnancies test positive for antinuclear antibodies, and does that positivity translate into any detectable illness?

The technical backbone of the study was the indirect immunofluorescence assay, or ANA-IFA, performed on human epithelial type 2, or HEp-2, cells. This method remains the gold standard for ANA detection because it exposes the patient’s serum to whole cells and lets trained observers see exactly where fluorescently labeled antibodies bind within the nucleus. The assay is broad by design; it detects reactivity against many nuclear antigens at once, which makes it sensitive but not specific for any particular disease. Out of 171 cord-blood samples, 26 came back positive, a prevalence of 15.2 percent, with an exact 95 percent confidence interval ranging from 10.2 to 21.5 percent. In other words, roughly one in six newborns in this low-risk cohort carried detectable antinuclear reactivity at birth.

That number alone is striking, but the researchers went further. Each ANA-IFA-positive infant was then subjected to a multiparameter antigen-specific antibody panel, a line-immunoassay approach that probes for reactivity against individual molecular targets. Only four of the 26 positive infants, or 15.4 percent, showed reactivity on this finer-grained panel. All four carried antibodies against double-stranded DNA, a target classically associated with systemic lupus erythematosus. Two also had anti-histone antibodies, and single infants showed reactivity against anti-nucleosome, anti-Jo-1, and anti-Ro52. Notably, none of the infants had reactivity against Ro60 or La/SSB, the two antigens most tightly linked to congenital heart block and neonatal lupus when transferred across the placenta. The absence of those particular specificities is perhaps the single most clinically comforting detail in the entire dataset.

All 26 ANA-IFA-positive infants then underwent a protocol-driven evaluation that most newborn screening programs would consider exhaustive. It included hematologic assessment with complete blood counts, liver enzyme measurement, electrocardiography, echocardiography, and structured clinical examination, repeated through the first 12 months of life. The results were remarkably benign. Four infants showed transient elevations in liver enzymes, specifically alanine and aspartate aminotransferases, but these abnormalities normalized within a single month and were not accompanied by any other signs of disease. Beyond that, no clinically relevant autoimmune manifestations were detected in any of the 26 positive infants, giving a rate of zero out of 26, with an exact 95 percent confidence interval of 0.0 to 13.2 percent. Hearts were structurally normal on echocardiography, conduction was normal on electrocardiography, and blood counts stayed within expected ranges.

The 145 ANA-IFA-negative infants received routine clinical follow-up, with investigations ordered only when symptoms warranted. None was recorded as developing autoimmune manifestations during the first year, but the authors are careful to acknowledge an important asymmetry in their design: because the negative group did not undergo systematic laboratory and cardiac screening, subclinical abnormalities in that group cannot be formally excluded. This differential outcome ascertainment, where positive infants were scrutinized far more intensively than negative ones, is a standard feature of such exploratory designs but limits how confidently the two groups can be compared. It is one of several caveats the researchers list when explaining why their findings cannot yet be turned into firm risk estimates.

The maternal side of the equation adds another layer of complexity. Mothers of the 26 positive infants underwent ANA-IFA testing themselves, and three of the 26 came back positive. Intriguingly, all three of those mothers had infants with antigen-specific panel reactivity, suggesting some degree of mother-to-infant concordance in antibody profiles, exactly what one would expect if placental transfer were the source of the cord-blood signal. However, antigen-specific testing of the mothers was incomplete, which prevented the team from performing a comprehensive concordance analysis. Without paired, complete maternal and neonatal panels, it remains impossible to say definitively whether every cord-blood ANA reflects passive maternal transfer, fetal immune activity, or some mixture of both. The authors also note that limited run-level assay documentation constrains the interpretability of individual results.

What, then, should clinicians and anxious parents take away from this work? The authors are explicit: these findings do not support routine ANA-IFA testing of asymptomatic neonates, and they do not justify any change to established surveillance protocols for babies with confirmed maternal anti-Ro/SSA or anti-La/SSB exposure. The reason is straightforward. Cord-blood ANA positivity in a low-risk population turns out to be relatively frequent, roughly 15 percent, but almost entirely nonspecific, and in this cohort it carried no measurable clinical consequence within the first year. Screening every newborn would therefore generate a substantial number of positive results, trigger extensive and costly workups, and create parental anxiety, all in pursuit of a signal that, on current evidence, rarely means anything. The transient liver enzyme elevations seen in four infants resolved without intervention and did not correspond to any antigen-specific pattern of obvious concern.

The study’s limitations are candidly enumerated and worth understanding. Beyond the differential ascertainment between positive and negative infants, the sample size of 171, while respectable for an exploratory single-center cohort, is too small to detect rare outcomes such as congenital heart block, which occurs in only a small fraction of anti-Ro-exposed pregnancies even in high-risk populations. The single-center design means the findings may not generalize to populations with different genetic backgrounds, referral patterns, or assay practices. And the twelve-month follow-up window, though it covers the period when neonatal lupus manifestations typically appear, cannot speak to longer-term risks of autoimmunity that might emerge in childhood or later.

For that reason, the research team calls for larger multicenter studies with paired maternal-neonatal testing, uniform assessment protocols, documented assay runs, serial antibody measurements over time, and follow-up extending well beyond infancy. Such work would settle whether the 15 percent of newborns with cord-blood ANA reactivity represent a truly silent majority whose antibodies simply fade as maternal immunoglobulin is catabolized over the first months of life, or whether a small subset harbors a subtle signal that only longer observation can reveal. Until then, this study provides a valuable baseline: in babies born without any hint of maternal autoimmune disease, antinuclear antibodies in cord blood are common, their antigen-specific signatures are uncommon, and clinically meaningful illness in the first year of life appears to be vanishingly rare. The placenta, it seems, delivers far more reassurance than alarm.

Subject of Research: Cord-blood antinuclear antibody positivity and first-year clinical outcomes in newborns without maternal autoimmune disease

Article Title: Cord-blood ANA-IFA positivity and first-year clinical findings in a selected lower-risk population: an exploratory prospective cohort study

Article References: Adib, M., Sheykhian, T., Assari, R., Alimadad Tafreshi, A., Ashkboos, K., Raeeskarami, S. R., Ziaee, V., Habibi, A., & Sadeghi, P. (2026). Cord-blood ANA-IFA positivity and first-year clinical findings in a selected lower-risk population: an exploratory prospective cohort study. BMC Pediatrics. https://doi.org/10.1186/s12887-026-07735-0

Image Credits: AI Generated

DOI: 10.1186/s12887-026-07735-0

Keywords: antinuclear antibodies, cord blood, neonates, autoimmunity, ANA-IFA, HEp-2 cells, anti-dsDNA, neonatal lupus, anti-Ro/SSA, cohort study, pediatrics, placental antibody transfer

The new analysis, published in BMC Pediatrics by Yılmaz Seçilmiş, Gülşah Kartal and Muhammet Sami Kayan of Erciyes University in Kayseri, Türkiye, takes the form of a scoping review. Following the Joanna Briggs Institute methodology and reporting to the PRISMA-ScR standard, the team searched PubMed, Scopus and Web of Science on 14 March 2026 without date or language restrictions, supplementing the search with hand-searching that included regional Turkish journals. Their PROSPERO-registered protocol (CRD420261340727) focused on a very specific triad: individual cases of methemoglobinemia following prilocaine administered for circumcision in infants aged zero to twelve months. Two reviewers screened studies independently, achieving an inter-rater agreement of kappa equal to 0.849, a level conventionally regarded as very strong.

The search identified twenty-four studies published between 1989 and 2026 that together documented thirty-eight cases. Strikingly, thirty-three of those cases—86.8 percent—came from Türkiye, a concentration the authors caution reflects the geography of the published literature rather than any measured difference in incidence. No reliable incidence rate can be extracted from case reports, which are subject to publication bias: dramatic recoveries get written up, routine events do not. Still, the consistency of the clinical picture across reports is what makes the review valuable. In every single case that reported presentation details, the defining feature was the same: cyanosis that did not respond to oxygen therapy, the classic fingerprint of methemoglobinemia.

The biochemistry explains why oxygen fails. Under normal conditions, hemoglobin carries iron in its ferrous (Fe2+) state, binding oxygen in the lungs and releasing it in tissues. Oxidizing agents can convert some of that iron to the ferric (Fe3+) state, producing methemoglobin, which binds oxygen tightly but cannot unload it. Worse, methemoglobin shifts the oxygen-dissociation curve of the remaining normal hemoglobin to the left, compounding the tissue hypoxia. Infants are especially vulnerable because their red cells contain fetal hemoglobin, which oxidizes more readily, and because the NADH-dependent reductase pathway that normally reduces methemoglobin back to hemoglobin is not fully mature in the first months of life. Glucose-6-phosphate dehydrogenase (G6PD) deficiency, which is more common in some populations, adds a further layer of susceptibility.

Prilocaine enters this picture because it is an amide local anesthetic whose metabolites, notably o-toluidine, are known oxidizing agents capable of overwhelming red-cell defenses. In the reviewed cases, prilocaine was given by injection—typically as a dorsal penile nerve block or subcutaneously—in 89.5 percent of reports, while 10.5 percent involved topical application of EMLA, the eutectic mixture of lidocaine and prilocaine that is widely marketed for procedural pain relief in infants. Both routes have been implicated, though dosing detail was surprisingly scarce: the prilocaine dose was reported in only 44.7 percent of cases, a gap the authors highlight as a failure of case-report completeness with direct consequences for understanding dose-response relationships.

The severity of the episodes was considerable. Among thirty-seven cases with laboratory data, the mean methemoglobin fraction was 33.6 percent, with individual values ranging from 11.9 to 62.0 percent. Normal levels sit below about one to two percent, and clinical signs such as cyanosis generally appear above ten to fifteen percent, with levels above roughly thirty percent considered clinically significant and above fifty percent potentially life-threatening. That the reported episodes reached such heights underscores how quickly a routine analgesic injection in a healthy infant can escalate into a pediatric emergency requiring immediate recognition and intervention.

Treatment in the published cases followed two main paths. Methylene blue, the established first-line antidote for clinically significant acquired methemoglobinemia, was administered in twenty cases. The drug works as an exogenous electron carrier, accepting electrons from NADPH via the hexose monophosphate shunt and reducing methemoglobin back to functional hemoglobin—essentially providing the infant red cell with an enzymatic shortcut it cannot yet perform efficiently on its own. Ascorbic acid, a slower-acting reducing agent described mainly in isolated reports and sometimes used as adjunctive therapy, was given in twenty-one cases, either alone or in combination with methylene blue. Every published case ended in full recovery, but the authors are careful to note that uncontrolled case reports cannot disentangle the effects of treatment from spontaneous recovery, supportive care, or the natural course of the condition, and no claim of comparative efficacy between antidotes can be made from such data.

To widen the lens beyond the formal case literature, the team also queried three major pharmacovigilance databases: the World Health Organization’s VigiBase, the US Food and Drug Administration’s FAERS, and the European EudraVigilance system. These spontaneous-report databases contained reports extending beyond the circumcision-specific literature, including some with fatal outcomes. The authors treat these as contextual reference only, stressing that spontaneous reports cannot confirm causality, cannot verify the procedural context, and must not be used as a quantitative comparator. The distinction matters: pharmacovigilance signals can justify scrutiny, but they are not evidence of risk magnitude, and conflating them with verified clinical case series distorts the risk picture for both clinicians and parents.

The completeness assessment is one of the review’s most practically useful contributions. Methemoglobin level and treatment were each documented in 97.4 percent of cases, reflecting awareness that both are central to the diagnosis and management narrative. But the prilocaine dose was reported in fewer than half the cases, and other details—timing of onset, use of screening for G6PD deficiency, cumulative exposure, and follow-up—varied widely. The authors argue that better-structured case reporting would allow future syntheses to move beyond description toward genuine risk characterization. Their quality appraisal used the Murad et al. tool for case reports, and the full charted dataset, search strategy and PRISMA-ScR checklist are available as supplementary files with the open-access article.

For clinical practice, the authors’ conclusions are measured rather than alarmist. The published reports describe a recurring, recognizable presentation—cyanosis poorly responsive to oxygen in a recently anesthetized infant—but cannot establish how often it occurs or which treatment is superior. Methylene blue remains the established first-line antidote for clinically significant acquired methemoglobinemia. Depending on the clinical context, indication and dose, minimizing prilocaine exposure and observing infants for post-procedure cyanosis may be considered, with clinical decisions individualized. The uniformly positive outcomes recorded in the literature, the team warns, may well reflect publication and survivorship bias rather than an inherently benign course. In other words, the absence of documented deaths in the case series should not be read as reassurance; it may simply mean that the worst outcomes go unreported. The review received no specific funding, and the authors declare no competing interests. Its message for clinicians is simple and urgent: when a circumcised infant turns blue and oxygen does not help, think methemoglobinemia, check a methemoglobin level, and act fast.

Subject of Research: Prilocaine-associated methemoglobinemia in neonates and infants undergoing circumcision

Article Title: Prilocaine-associated methemoglobinemia after neonatal and infant circumcision: a scoping review of published cases with pharmacovigilance context

Article References: Seçilmiş, Y., Kartal, G., & Kayan, M. S. (2026). Prilocaine-associated methemoglobinemia after neonatal and infant circumcision: a scoping review of published cases with pharmacovigilance context. BMC Pediatrics. https://doi.org/10.1186/s12887-026-07741-2

Image Credits: AI Generated

DOI: 10.1186/s12887-026-07741-2

Keywords: prilocaine, methemoglobinemia, circumcision, neonates, infants, methylene blue, ascorbic acid, EMLA cream, pharmacovigilance, scoping review, cyanosis, pediatric emergency