Anti-signal recognition particle antibody-positive immune-mediated necrotising myopathy with inclusion body myositis-like features in a patient with human immunodeficiency virus and syphilis infection.

Inclusion body myositis (IBM) and immune-mediated necrotising myopathy (IMNM) are inflammatory myopathies characterized by specific clinical and pathological features. IBM is associated with human immunodeficiency virus (HIV) infection, whereas IMNM is extremely rare in individuals positive for HIV. To date, no reports have described the coexistence of IMNM and IBM-like pathological features in patients positive for HIV. Herein, we report a rare case of a 40-year-old man with HIV-associated subacute progressive myopathy presenting with simultaneous proximal and distal muscle weakness, dysphagia, and markedly elevated creatine kinase levels. Serological testing revealed strong positivity for anti-signal recognition particle antibodies. Muscle biopsy revealed coexisting pathological features suggesting both IMNM and IBM. The patient showed insufficient response to antiretroviral therapy and glucocorticoids; however, intravenous immunoglobulin therapy resulted in a marked clinical response. This case highlights the possible coexistence of IMNM and IBM-like pathology in the context of HIV infection and provides insights into the pathophysiology of HIV-associated myopathy. Furthermore, this report suggests the potential effectiveness of intravenous immunoglobulin treatment in such cases.