Non-anti-MAG DADS neuropathy as a variant of CIDP: clinical, electrophysiological, laboratory features and response to treatment in 10 cases

BACKGROUND AND PURPOSE

Some patients within the spectrum of chronic inflammatory demyelinating polyradiculoneuropathies (CIDP) have distal acquired demyelinating symmetric (DADS) neuropathy, usually associated with anti-myelin-associated-glycoprotein (MAG) IgM monoclonal gammopathy. The aim of this retrospective study was to investigate patients with DADS neuropathy without anti-MAG antibodies, and study their response to immunotherapy.

METHODS

Patients were selected on the basis of (i) 'Definite CIDP' according to the EFNS/PNS Guideline criteria, (ii) The presence of disproportionately prolonged motor latencies resulting in a terminal latency index (TLI) ≤ 0.25 in at least two motor nerves and (iii) The absence of anti-MAG antibodies on ELISA. Response to immunotherapy was defined as persistent improvement by at least one point on the INCAT disability score.

RESULTS

Data from 146 CIDP patients were analysed, and 10 patients were included. Six had clinically pure sensory neuropathy, and four had sensorimotor neuropathy. Ataxia was present in nine patients, generalized areflexia in seven and postural tremor in two. Five of the 10 patients had abnormal sensory potentials only in the upper limbs. An associated condition was found in nine patients: two chronic lymphocytic leukaemias, four IgG monoclonal gammopathies (one associated with non-Hodgkin's lymphoma) and two IgM monoclonal gammopathies of unknown significance. Patients were mostly improved with intravenous immunoglobulin (IVIg), corticosteroids, plasma exchanges, or a combination thereof.

CONCLUSION

DADS neuropathy without anti-MAG antibodies is more likely to be considered a variant of CIDP. In addition, such patients should be systematically investigated for an associated haematological or immunological condition.

Hepatitis C virus-associated polyarteritis nodosa

OBJECTIVE

To analyze the main characteristics and outcome of polyarteritis nodosa (PAN)-type vasculitis associated with hepatitis C virus (HCV).

METHODS

We reported the characteristics and outcome of 31 patients chronically infected with HCV who satisfied the American College of Rheumatology and Chapel Hill criteria for PAN, seen between 1990 and 2009 in a university center.

RESULTS

Among a cohort of 161 patients with HCV-related vasculitis, 31 (19.3%) were diagnosed as having PAN. The median age was 64.5 years (interquartile range 49.5-70.5 years), with 54.8% women. Compared with HCV-associated mixed cryoglobulinemia (HCV-MC) vasculitis, HCV-PAN displayed a more severe and acute clinical presentation with more frequent fever and weight loss (P < 0.0001), severe hypertension (P = 0.0006), gastrointestinal tract involvement (P < 0.0001), severe acute sensory-motor multifocal mononeuropathy (P < 0.0001), kidney and liver microaneurysms (P = 0.002), and increased C-reactive protein level (P < 0.0001). Complete clinical remission of vasculitis was achieved in 79.3% of HCV-PAN patients compared to 57.5% of HCV-MC patients (P = 0.05). In multivariate analysis, skin involvement (odds ratio [OR] 2.81, 95% confidence interval [95% CI] 1.27-6.33) and PAN-type vasculitis (OR 3.01, 95% CI 1.16-8.96) were independently associated with a complete clinical response of HCV vasculitis. A glomerular filtration rate <70 ml/minute (OR 0.54, 95% CI 0.24-1.21) was negatively associated with a complete clinical response of HCV vasculitis. The 5-year survival rate was 86% in the entire cohort, regardless of the vasculitis type.

CONCLUSION

HCV-PAN accounts for 19.3% of our cohort of HCV vasculitis. HCV-PAN displays a more severe and acute clinical presentation and a higher rate of clinical remission.