Link Between Nailfold Capillaries and Autoantibodies Less Significant in Pediatric Raynaud Phenomenon

The correlation between nailfold capillary aberrations and antinuclear antibody (ANA) concentrations was found to be less significant among children than adults with Raynaud phenomenon, according to study findings published in RMD Open.

In adults, diagnosing Raynaud phenomenon is based on well-established predictive markers, such as nailfold capillaroscopy and immunologic markers. However, a diagnosis in children typically includes evaluating ANA, as the predictive value of nailfold capillaroscopy is not fully understood in pediatric populations.

Patients with incident Raynaud phenomenon at the Medical University of Vienna, Austria, without a known connective tissue disease were enrolled in the study.

Venous blood samples for ANA-titer assessment were collected and patients underwent nailfold capillary evaluation for 8 aberrations (eg, reduced density, avascular fields, dilated capillaries, giant capillaries, hemorrhages, tortuous capillaries, ramifications, and capillary edema) in all fingers except the thumbs.

A total of 2971 patients with Raynaud phenomenon were included in the study. The pediatric (n=113) and adult (n=2858) patients had a median age of 15 and 48 years; 77% and 78% were girls or women; and 11% and 35% were smokers, respectively.

Overall, 1 or more types of aberrations were detected among 64% of children and 75% of adults (P <.05). Of the 8 aberrations, the pediatric vs adult patient groups differed significantly in the prevalence of tortuous capillaries (7% vs 15%; P <.05) and tended to differ for the presence of dilations (61% vs 70%; P =.05) and capillary edema (0% vs 3%; P =.08), respectively. All other aberrations were observed at similar rates.

The ANA-titer level of 1:80 and greater was observed among 29% of children and 37% of adults (P <.09). Similar findings were observed for ANA-titer levels of 1:160 or 1:320 and greater. Of 7 ANA subsets evaluated, no significant differences were observed between pediatric and adult patients.

Researchers did not observe an association between irregular nailfold capillary aberrations and ANA-titers of 1:80 and greater (odds ratio [OR], 0.78; 95% CI, 0.34-1.81; P =.57), 1:160 and greater (OR, 1.03; 95% CI, 0.40-2.70; P =.95), or 1:320 and greater (OR, 0.84; 95% CI, 0.30-2.36; P =.74) among pediatric patients. However, among adults, nailfold capillary aberrations were associated with ANA-titers of 1:80 and greater (OR, 1.68; 95% CI, 1.39-2.02; P <.001), 1:160 and greater (OR, 1.83; 95% CI, 1.48-2.27; P <.001), and 1:320 and greater (OR, 2.24; 95% CI, 1.77-2.84; P <.001).

For individual types of nailfold capillary aberrations, only torturous capillaries were associated with ANA-titers of 1:160 and greater among children (OR, 4.53; 95% CI, 1.04-19.73; P <.05). For adults, all nailfold capillary aberrations, except torturous capillaries, were associated with ANA-titers at all 3 levels (OR range, 1.44-14.52; all P <.05).

The study may have been limited by the lack of clinical follow-up data.

The study authors concluded, “[C]hildren with incipient [Raynaud phenomenon] screening examinations for and underlying [connective tissue disease] should involve nailfold capillaroscopy and ANA, since there appears to be no clear association between both markers.”