# Chronic Inflammatory Demyelinating Polyradiculoneuropathy (CIDP) Developing During Tacrolimus Treatment: A Case Series

## TL;DR

A case series shows that CIDP, a rare neurological disorder, can develop during long-term tacrolimus treatment in transplant patients and often improves with IVIg.

## Contribution

This is the first case series documenting CIDP onset during tacrolimus treatment in solid organ transplant recipients.

## Key findings

- CIDP developed between 5 months and 13 years after starting tacrolimus in six transplant patients.
- Five out of six patients improved with IVIg treatment.
- Switching to alternative immunosuppressants led to no active disease in four patients.

## Abstract

Chronic Inflammatory Demyelinating Polyradiculoneuropathy (CIDP) can occasionally emerge during treatment with tacrolimus, a commonly used immunosuppressant for solid organ transplantation, and this association is poorly recognized. We describe the clinical presentation, investigations, and disease course of a series of patients who developed CIDP during tacrolimus treatment.

This is a retrospective case series of six patients with electrophysiologically confirmed CIDP (=2021 EFNS/PNS criteria) during tacrolimus use for solid organ transplantation, evaluated at two UK National Health Service (NHS) trusts between 2017 and 2023. We describe the clinical characteristics, laboratory investigations, neurophysiological features, treatment response, and association with tacrolimus treatment.

CIDP was diagnosed between 5 months and 13 years after initiation of tacrolimus, post cardiac (2), renal (2), lung (1), and combined kidney‐pancreas (1) transplantation. All patients met diagnostic criteria for CIDP. 5/6 patients improved clinically following intravenous immunoglobulin (IVIg). 4/6 patients were switched to either sirolimus or azathioprine without evidence of active disease despite no further treatment. 2/6 patients continued tacrolimus, and both required ongoing IVIg treatment.

CIDP may be associated with tacrolimus use in organ transplantation and can occur after years of treatment. IVIg was usually effective in our cohort, and in those who switched to alternative immunosuppression, there was no evidence of active disease after initial treatment.