Autoimmune diseases, autoantibody status and silicosis in a cohort of 1238 workers from the artificial stone benchtop industry.

OBJECTIVES: Autoimmune disorders are multifactorial but occupational exposures have long been implicated, including respirable crystalline silica (RCS). A modern epidemic of silicosis is emerging internationally, associated with dry processing of engineered stone with high (>90%) RCS content. We aimed to investigate the prevalence of clinical autoimmune disease and common autoantibodies in exposed workers. METHODS: Stone benchtop industry workers in Victoria, Australia were offered free screening for silicosis and related disorders. Symptoms or diagnoses of autoimmune disease were evaluated by questionnaire and blood tests taken for rheumatoid factor (RF), antinuclear antibodies (ANAs) and extractable nuclear antigens (ENAs). RESULTS: Among 1238 workers (93.3% male) screened from 2019 to 2021, 0.9% were confirmed with autoimmune disease. Among those without clinical disease, 24.6% had detectable ANAs (93.5% male), 4.6% detectable ENAs and 2.6% were positive for RF. Silicosis was diagnosed in 253 workers (24.3% of those with diagnostic information available). Of those with ANA readings, 54 (6.6%) had ANA titre >1:320. The likelihood of positive autoantibodies increased with age; smoking; higher exposure to RCS and silicosis diagnosis. CONCLUSION: The proportion of workers with detectable ANAs or ENAs was considerably higher than the 5%-9% expected in the general population. Some of the antibodies detected (eg, Scl-70, CENPB) have high sensitivity and specificity for systemic sclerosis. Long-term follow-up will be needed to estimate incidence. Rheumatologists should explore occupational history in new cases of autoimmune disease. Screening for autoimmune disease is indicated in workers exposed to RCS as these individuals need specialised management and may be entitled to compensation.

Anti-melanoma differentiation-associated gene 5 (anti-MDA5) positive dermatomyositis: early detection is crucial.

Anti-melanoma differentiation-associated gene 5-positive (Anti-MDA5) dermatomyositis (DM) is an aggressive phenotype of DM associated with rapidly progressive interstitial lung disease (RP-ILD). It is a rare condition that carries high mortality. Diagnosis and management of patients with anti-MDA5 DM RP-ILD presents several challenges, including uncertainty around treatment algorithms and a lack of evidence to inform practice. This case report of a patient with anti-MDA5 DM RP-ILD highlights these challenges, emphasising the fulminant course of this disease despite aggressive immunosuppression. Further research is required to guide management and to minimise morbidity and mortality, and greater awareness of the condition is required to minimise delays in diagnosis.