Clinical Characteristics of Autoimmune Gastroparesis and Response to Immunomodulation

Autoimmune factors may be involved in the development of gastroparesis, a subtype known as autoimmune gastrointestinal dysmotility (AGID). Small open label studies in AGID have demonstrated intravenous immunoglobulin (IVIG) therapy may lead to improvement in symptoms and gastric emptying. We aimed to evaluate the effects of IVIG therapy on symptom severity in patients with gastroparesis.

We conducted a retrospective case series involving patients with AGID through medical chart review. All patients had evidence of delayed gastric emptying through gastric scintigraphy (GES) and had evidence of autoimmune dysfunction through seropositive antibody bloodwork, including glutamic acid decarboxylase (GAD), neuronal voltage-gated calcium channel, acetylcholine receptor, and neuronal voltage gated potassium channel autoantibodies. All patients received at least 12 weeks of IVIG therapy. Gastroparesis Cardinal Symptom Index (GCSI) scores were collected pre-IVIG and post-IVIG treatment.

We analyzed 24 AGID patients. 100% female; 79.2% White; mean age=38.5 (SD=13.7). GAD was the most common serum abnormality (41.7%). Mean 4-hour retention on GES was 42.9%. Following IVIG therapy, mean GCSI scores improved by over 1.5 points (pre-IVIG: 3.64, post-IVIG: 2.01, P<0.001). 67% had an improvement of ≥1 point on the GCSI post-IVIG. Patients who were GAD positive (41.7%) had the most significant symptom improvement (mean change in GCSI: -2.3 compared with -1.1, P=0.02).

In this retrospective analysis of a small cohort of patients with AGID, IVIG therapy was associated with symptom improvement, especially in those who were GAD+. Randomized, placebo-controlled trials are needed to understand the effectiveness of IVIG in treating AGID.