The Relationship Between ILD and MDA5 Antibody-Positive DM

Anti-melanoma differentiation-associated gene 5 (MDA5) antibody-positive dermatomyositis (DM) is a rare type of skin and muscle disease called dermatomyositis, which is associated with lung problems known as interstitial lung disease (ILD), that can be either rapidly progressing (RPILD) or chronic (CILD).

RPILD in MDA5 antibody-positive DM is known for its high death rate because it worsens quickly and causes breathing difficulties within three months of initial lung symptoms. However, there isn't much information about the timing between the diagnosis of ILD and MDA5 antibody-positive DM because most research focuses on either the frequency or the death rates rather than the timing of onset.

That was what prompted the study, “Assessing Time of Onset for Interstitial Lung Disease in Anti-MDA5 Antibody-Positive Dermatomyositis,” led by Rachel R. Lin a medical student and research fellow and Dr. Scott Elman, a double board-certified internist and dermatologist, both at the University of Miami Miller School of Medicine. Their study examined the time interval between onset of ILD and diagnosis of MDA5 antibody-positive DM.

“MDA5 patients tend to have less muscle involvement,” Lin says. “Some of them have features like ulcerations of the hands and also ILD. Associated clinical signs and positive MDA5 autoantibodies on serology were the criteria we used.”

The cohort study utilized all available electronic medical records from the University of Miami, and 774 patients diagnosed with DM between 2008 and 2023 were evaluated to learn more about the time interval between ILD and the time of an MDA5 antibody-positive DM diagnosis.

The study measured the median time between ILD and MDA5 antibody-positive DM diagnoses as 163 days, with the most common skin symptoms being Gottron’s papules and redness in the middle of the face. There was no link found between these skin symptoms and the type of ILD a person has.

In our retrospective chart review, we looked at the time that they were diagnosed with MDA5 and the time they were diagnosed with ILD,” Lin explains. “ILD is very prevalent in MDA5 dermatomyositis, and a little under half the ones we saw had RPILD, so it’s very important for any dermatomyositis patient to receive imaging and screening for MDA5.”

Given the high mortality rate associated with RPILD, Lin suggests clinicians manage patients with this condition differently from those with chronic ILD, because if you catch it early, there are things you can do.

“It’s hard to say there is a specific treatment that those with RPILD need over patients with chronic ILD,” Lin says. “The focus of our study is to encourage dermatologists or other specialists once a patient is diagnosed with dermatomyositis, particularly if they know they have MDA5. The biggest step they can take if starting to develop symptoms is to start managing care with a pulmonologist.”

By establishing an accurate timeline between MDA5 antibody-positive DM and ILD, Lin adds, it will promote urgency to evaluate extracutaneous manifestations in dermatologists’ management of patients with DM for more accurate risk stratification and appropriate treatment.

“Knowing the subtype of your dermatomyositis patients can help influence treatment,” she says. “Early understanding of this disease and its association is important.”