[Clinical analysis of immunoglobulin G₄-related disease with neurological involvement]

Objective: To improve the understanding of the clinical manifestation of immunoglobulin G₄-related disease (IgG₄-RD) with neurological involvement. Methods: Patients presenting with neurological symptoms and biopsy-confirmed IgG₄-RD were enrolled between March 2014 and March 2024 from the Department of Neurology of Xuanwu Hospital of Capital Medical University. Medical record data of all patients were retrospectively reviewed, including clinical manifestations, laboratory findings, radiological results, pathology, treatments, and outcomes. RD were enrolled between March Results: Nine patients (five males, four females; median age at onset: 63 years) were included in the study. Neurological manifestations consisted of pachymeningitis in six cases, peripheral nerve involvement in two, and brain parenchyma involvement in one. Four patients displayed isolated neurologic symptoms. The most common clinical manifestations were headache and cranial nerve palsy, each involving five cases. Magnetic resonance imaging showed thickening and enhancement of the dura mater in the six patients with pachymeningitis. Four of these cases involved the posterior cranial fossa, 3 presented with an inflammatory pseudotumor, and 2 involved the spinal cord. Four patients with pachymeningitis had normal serum IgG₄ concentrations. Eight patients exhibited elevated serum C-reactive protein or erythrocyte sedimentation rates, with some also showing decreased complement C3 and C4 levels. Cerebrospinal fluid immunoglobulin was elevated in all nine cases. In all cases, histopathologic biopsy results showed extensive infiltration of lymphocytes and plasma cells, with the latter displaying IgG₄⁺abnormalities. All patients received glucocorticoid therapy, with six also receiving immunosuppressants. All patients were followed up for a median of 30 months, with outcomes including two complete remissions, five partial remissions, one unchanged condition, and one death. Six patients experienced a relapse. Conclusions: Isolated hypertrophic pachymeningitis is the most common manifestation of IgG₄-RD, often occurring in the absence of elevated serum IgG₄ levels. Peripheral nerve and brain parenchyma involvement can also be seen. Clinical manifestations are non-specific, and histopathologic biopsy is frequently required for diagnosis. Although the disease responds well to hormone treatment, recurrence is common. Early combined immunosuppressive therapy can improve prognosis.