Antibody Test Identifies Scleroderma Patients at High Risk for Pulmonary Hypertension

By LabMedica International staff writers
Posted on 02 May 2022

Image: Histopathology showing a pulmonary arteriole from a patient with systemic sclerosis-associated pulmonary artery hypertension showing significant medial hypertrophy (Photo courtesy of University of Colorado)

Scleroderma is caused by the immune system attacking the connective tissue under the skin and around internal organs and blood vessels. This causes scarring and thickening of the tissue in these areas.

There are several different types of scleroderma that can vary in severity. Some types are relatively mild and may eventually improve on their own, while others can lead to severe and life-threatening problems. Detection of certain auto-antibodies flagged patients with scleroderma (also known as systemic sclerosis) who were especially likely to develop pulmonary hypertension over long-term follow-up, have been studied.

Clinical Immunologists at the University of Pittsburgh School of Medicine (Pittsburgh, PA, USA) performed a case-control study where cases were new anti-Th/To antibody (Laboratory Corporation of America, Burlington, NC, USA) positive referrals to Pittsburgh Scleroderma Center from 1980-2015. Controls were the next two consecutive anti-Th/To negative patients seen after a case. Long-term disease manifestations and survival were compared. The scientists identified 204 anti-Th/To positive systemic sclerosis (SSc) patients were and 408 controls. The mean age of the entire cohort was 52 ±12.9 years and 76% were female.

The scientists reported that Anti-Th/To positive patients more often presented without skin thickening and had higher rate of pulmonary hypertension (PH) and interstitial lung disease ILD than controls. They had less frequent muscle and joint involvement. After a median clinical follow-up of 6.1 years, 38% of Th/To patients had developed PH compared to 15% of other SSc patients. The rates of WHO Group 1 pulmonary arterial hypertension (PAH) were 23% in Th/To patients versus 9% in controls. After adjustment for age and gender, anti-Th/To antibody was associated with a 3.3 increased risk of developing PH at 10 years of follow-up from the first SSc center visit. Mortality was also higher in the antibody-positive patients.

The authors concluded that this was the largest cohort of anti-Th/To positive SSc patients with long-term follow-up data. The very high rate (38%) and associated independent risk of anti-Th/To patients developing PH in follow-up, particularly Group 1 PAH was particularly noteworthy. Patients presenting with limited skin involvement should be tested for Th/To antibody. If present, careful monitoring for PH is warranted. The study was published on April 25, 2022 in the journal Arthritis & Rheumatology.

Related Links:
University of Pittsburgh School of Medicine
Laboratory Corporation of America