DISCUSSION
Anti-MAD5 antibody-positive DM has a rapid onset, more severe disease,
and worse prognosis. ILD is the leading cause of death in patients with
anti-MDA5 antibody-positive DM patients(Motegi et al., 2019, Yamaoka et
al., 2014). DM is a rare disease, and many drugs have been recommended
for its treatment, including glucocorticoids, methotrexate, tacrolimus,
cyclosporine, and intravenous immunoglobulin, which have been proven to
be clinically effective(Lundberg et al., 2017). However, when the
abovementioned adverse reactions occur or are ineffective, there are few
drugs to choose from. Tofacitinib has been shown to have good efficacy
in patients with DM patients(Paik et al., 2021, Kurasawa et al., 2018).
On this basis, we selected tofacitinib with the full informed consent of
the patients and achieved a good curative effect.
Reviewing this patient, although serum muscle enzymes were not elevated
throughout, our diagnosis was considered despite the consistent absence
of elevated serum myosin and the presence of fatigue, neck rash,
electromyography suggestive of myogenic lesions, muscle biopsy
suggesting inflammatory myopathy, changes in ILD, and positive myositis
antibody and anti-MDA5 antibody. Anti-MDA5 antibody was positive for DM.
Initially, the patient responded well to treatment, but as the steroids
were tapered, the patient’s symptoms and imaging findings did not
resolve significantly. The patient did not experience significant relief
even with the addition of cyclophosphamide and tacrolimus. However, we
attempted tofacitinib because of the prolonged use of tacrolimus and the
negative effects of steroid hormones, and we were able to successfully
reduce and cease using steroid hormones after 16 weeks of tofacitinib
treatment. The anti-MDA5 antibody test was effectively negative after 96
weeks, but the patient’s symptoms persisted. The remission, lung CT, and
ILD manifestations were successfully reversed. Therefore, we believe
that it plays a potential role in the maintenance therapy of anti-MDA5
antibody-positive DM-ILD.
In conclusion, we report a patient with anti-MDA5 antibody-positive
DM-ILD and conclude for the first time that tofacitinib may be an option
for anti-MDA5 antibody-positive conversion during maintenance therapy.
However, further clinical and experimental studies are needed to confirm
this hypothesis.