Anti-OJ Antisynthetase Syndrome with Dermatomyositis-Pattern Skin Lesions and Interstitial Lung Disease

A 65-year-old woman presented with an 8-month history of hyperkeratotic, fissured plaques over the radial aspects of her fingers (mechanic’s hands; Figure 1a), Raynaud’s phenomenon, inflammatory pain in the small joints of the hands, proximal muscle weakness, and an unintentional weight loss of 10 kg. She denied dyspnea, dysphagia, sicca symptoms, fever, and photosensitivity. On examination, the mechanic’s hands and erythematous-violaceous patches in the V-sign (Figure 1b) and shawl sign (Figure 1c) distributions were evident, without a heliotrope rash or Gottron papules. Additionally, fine bibasilar crackles and mild tenderness of the proximal interphalangeal joints were observed.

Figure 1.

(a-d) Cutaneous and pulmonary findings of anti-OJ antisynthetase syndrome. (a) Mechanic’s hands: hyperkeratosis, fissuring, and scaling over the lateral aspects of the fingers. (b) V sign: erythematous-violaceous patches over the anterior chest and neck. (c) Shawl sign: confluent erythematous-violaceous rash over the upper back and shoulders. (d) High-resolution chest computed tomography (axial, lung window) showing peripheral, basal-predominant ground-glass opacities and fine reticulation with relative subpleural sparing (arrows), consistent with a fibrotic non-specific interstitial pneumonia pattern.

High-resolution computed tomography (CT) of the chest showed peripheral and basal ground-glass opacities and fine reticulation with relative subpleural sparing, consistent with a fibrotic non-specific interstitial pneumonia pattern (Figure 1d). Pulmonary function testing revealed mild restriction (forced vital capacity, 77% predicted) and reduced diffusing capacity for carbon monoxide (51% predicted). Proximal muscle strength was graded as 4/5 in the upper and lower limbs, with elevated creatine kinase (954 U/L; reference, ≤ 180 U/L) and aldolase (8.9 U/L; reference, < 7.6 U/L). Electromyography, muscle magnetic resonance imaging, and muscle biopsy were not performed, and inflammatory myopathy was diagnosed on the basis of clinical and biochemical findings. Indirect immunofluorescence on HEp-2 cells showed a fine cytoplasmic speckled pattern. A myositis-specific line immunoblot was positive only for anti-OJ (anti-isoleucyl-tRNA synthetase); anti-Ro52 was not detected, and immunoprecipitation confirmation was unavailable. A separate immunoassay was strongly positive for anti-Ro/SSA (240; reference, > 10). Because anti-Ro52 was negative, this finding corresponded to anti-Ro60. A comprehensive age-appropriate malignancy screening, including mammography, upper endoscopy, colonoscopy, abdominopelvic CT, and transvaginal ultrasonography, was negative, as were tests performed to exclude infection (negative tuberculosis and human immunodeficiency virus testing). The skin findings were clinically assessed without dermatologic consultation or biopsy.

A diagnosis of anti-OJ antisynthetase syndrome was made, encompassing inflammatory myopathy, interstitial lung disease (ILD), inflammatory arthritis, Raynaud’s phenomenon, and dermatomyositis-pattern skin lesions. ILD followed a chronic, non-rapidly progressive course, and high-dose oral prednisone (subsequently tapered) and azathioprine (2 mg/kg/day) were initiated. Azathioprine was selected as a steroid-sparing agent appropriate for this non-rapidly progressive course, reflecting the limited availability of mycophenolate mofetil and rituximab at our institution during the coronavirus disease 2019 pandemic, and it was continued because of the favorable clinical response. At the 1-year follow-up, muscle and joint symptoms had resolved, muscle enzyme levels had normalized (creatine kinase, 63 U/L; aldolase, 4.6 U/L), the cutaneous findings had improved, forced vital capacity had increased from 77% to 93% predicted, and repeat high-resolution CT demonstrated radiologic stability.

Anti-OJ antisynthetase syndrome is uncommon and diagnostically challenging because myositis, arthritis, mechanic’s hands, Raynaud’s phenomenon, and ILD may appear asynchronously.^{1, 2} Non-Jo-1 specificities, such as anti-OJ, account for only approximately 2-6% of antisynthetase-positive ILD and are associated with a higher risk of severe or fibrosing lung disease and poorer survival.^{3, 4} In this patient, the dermatomyositis-pattern V-sign and shawl sign eruptions represented a diagnostic pitfall because they could have suggested classic dermatomyositis-associated ILD.^{5, 6} However, the combination of mechanic’s hands, cytoplasmic HEp-2 staining (often reported as a negative antinuclear antibody result), inflammatory myopathy, and isolated anti-OJ positivity supported a diagnosis of antisynthetase syndrome.⁷ Although Raynaud’s phenomenon and anti-Ro60 positivity can occur in overlap connective tissue disease, other connective tissue disease-associated autoantibodies were negative, and there were no sicca symptoms or other defining features, arguing against a distinct overlapping disorder; both manifestations are recognized within the antisynthetase syndrome spectrum. Because lung involvement is the major determinant of prognosis⁸ and widespread mechanic’s hands may herald anti-OJ disease,⁹ a comprehensive antisynthetase antibody panel should be performed in patients with ILD and cutaneous or systemic autoimmune features, even when myositis is clinically quiescent.