Nailfold Capillary Damage a Mortality Predictor in Scleroderma, Study Shows

José Lopes, PhD avatar

by José Lopes, PhD |

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Nailfold capillary damage was found to be a predictor of mortality in scleroderma patients, according to researchers from Australia.

The study, “The role of Nailfold Capillary Dropout on Mortality in Systemic Sclerosis,” was published in the Internal Medicine Journal.

Microvasculopathy, which refers to the degeneration or inflammatory damage in small blood vessels, is an early feature in scleroderma, or systemic sclerosis (SSc). This symptom of SSc is predominantly recognized in the nailfold using a noninvasive imaging technique called nailfold capillaroscopy (NFC).

Despite the widely accepted utility of NFC in the diagnosis of SSc, the technique’s validity in the prognosis of SSc is still unclear. In particular, researchers still debate whether specific NFC indices are independent risk factors for mortality, or if they mediate the effects of autoantibodies — antibodies developed against the body’s own proteins or molecules, typical of autoimmune diseases like SSc.

Researchers studied the correlation of nailfold capillary damage with antibody status in a group of 150 SSc patients. They also investigated whether NFC predicts mortality or mediates antibody status.

The analysis used a population-based database — the South Australian Scleroderma Register. All studied patients underwent NFC between 1991 and 2015, and had either limited (99 patients), diffuse (30 patients), or overlap SSc (23 patients), depending on the extent of skin involvement.

The team collected demographic and diagnosis data, as well as information on antibody and mortality status. A total of 56 patients died during the study period (through June 2015) across all SSc subtypes.

Results showed that patients with diffuse SSc — a subtype linked with increased mortality — had significantly greater capillary dropout (areas without capillaries) compared with limited and overlap SSc patients.

A subsequent analysis showed that capillary dropout was associated with worse survival.

Regarding specific autoantibodies, patients with autoantibodies against RNA polymerase III (RNAP3, an enzyme involved in gene expression), or those with Scl 70 (characteristic of diffuse SSc), showed particularly elevated capillary damage.

The findings add relevant information to the association of capillary dropout with SSc. Previous research had shown that patients with more severe capillary damage were at greater risk of severe organ involvement.

“We have been able to demonstrate specifically that capillary dropout and the severity of dropout is a predictor of mortality,” the investigators wrote.

The team emphasized that the findings need confirmation in additional studies.