Systemic lupus erythematosus with anti-Hu antibodies and polyradiculoneuropathy

Acute and chronic polyradiculopathies

Polyradiculopathies are uncommon peripheral nervous system syndromes that result from a variety of conditions. The clinical manifestations are variable but often include symmetric or asymmetric distal and proximal weakness with a variable degree of sensory loss and reduction or loss of reflexes. The most common cause of an acute polyradiculopathy is acute inflammatory demyelinating polyradiculopathy (also known as Guillain-Barré syndrome); however, other inflammatory, infectious, or neoplastic causes can present with similar features. Chronic polyradiculopathies include chronic inflammatory demyelinating polyradiculopathy as well as paraprotein-related syndromes and other inflammatory and infectious causes. Evaluation using a combination of serologic studies, electrodiagnostic testing, and CSF evaluation can help to identify the underlying etiology and implement the appropriate treatment. This article reviews the approach to patients with suspected polyradiculopathy and the features of the more common causes of acute and chronic polyradiculopathies.

Clinical relevance of non-neuronal auto-antibodies in patients with anti-Hu or anti-Yo paraneoplastic diseases

About half of the patients with paraneoplastic diseases develop an immune response against neuronal antigens expressed by both the tumor and the nervous system. In 31 patients with anti-Hu antibodies and 19 patients with anti-Yo antibodies, we searched for the presence of additional non-neuronal auto-antibodies and further studied whether the presence of such auto-antibodies was correlated with a specific oncological or neurological presentation. Positive antinuclear antibodies (ANA) were found at a titer of 1:40 or above in 48% patients with anti-Hu antibodies, and in 37% patients with anti-Yo antibodies. Anti-cytoplasmic antibodies were also detected in 42% patients with anti-Yo antibodies. No specific correlation between the presence of non-neuronal auto-antibodies and clinical characteristics of the patients could be identified. In particular, neither the type of underlying cancer, the overall survival, the tumor response to treatment, nor the neurological presentation were related to the serological status.

Paraneoplastic Neurological Antibodies: A Laboratory Experience

Antineuronal antibodies are associated with rare paraneoplastic neurological syndromes, and their identification alerts clinicians to examine for the presence of a tumor. Presented here is laboratory experience (prevalence, difficulties, and procedures) and several interesting but inconclusive results. A total of 1045 samples were screened over a 2-year period; 91 showed a degree of binding of antibodies to the cerebellum, and 22 of these 91 were confirmed, by Western blot, to have specific antineuronal antibodies. Thirteen of 22 were Hu-positive, and 6 of these also had antinuclear antibodies. Six were Yo-positive, 2 had anti-Ma antibodies, and 1 was Tr-positive. An additional 27 of 91 patients had cerebellar antibodies giving recognized staining patterns (Hu, Yo, and Ma). However, Western blot did not confirm these specificities, and hence they were reported as atypical. Six of 27 of these patients had neoplasms; 3 of the 6 gave nucleolar patterns (not Ma). Two appeared similar to Yo, and 1 similar to Hu. Antineuronal antibodies are rare, and in the absence of a specific etiology patients should be examined further for the possible presence of an underlying tumor. Methodical classification of the antibodies must be conducted to avoid incorrect reporting. Further criteria on the typing/reporting of atypical results may aid diagnosis of paraneoplastic neurological syndromes.

Paraneoplastic antineuronal antibodies in patients with systemic autoimmune diseases

Sera from 71 patients with primary Sjögren's syndrome (PSS) and from 102 patients with systemic lupus erythematosus (SLE) were tested by immuno-dot blotting against HuD, Ri, Yo and amphiphysin recombinant proteins. For Ri, Yo and amphiphysin antigens, no immunoreactivity was found in the 173 sera tested. One PSS patient with a clinical picture of subacute sensory neuronopathy had high titers of anti-Hu antibodies. An extensive search for an underlying tumor was initially negative but a small cell lung cancer was eventually discovered three years later. Another patient with SLE and a clinical picture of demyelinating polyradiculoneuropathy had anti-Hu antibodies. Repeated search for an underlying tumor remains negative after five years follow-up in this young non-smoking patient. In addition, the neuropathy progressively improved and the anti-Hu antibodies titer slowly decreased from 1:8000 to 1:2000, making the diagnosis of paraneoplastic syndrome unlikely in this patient. This study indicates that the detection of anti-Hu antibodies in patients with known symptomatic systemic autoimmune diseases such as PSS or SLE should induce the same work-up than the detection of these antibodies in the absence of other immune diseases, i.e. repeated search for occult cancer during several years. As illustrated by our first patient, this strategy may be fruitful. Nevertheless, the clinician should know that anti-Hu antibodies may exceptionally (0.6% in this series) occur in systemic autoimmune disorders with neurological complications, in the absence of an underlying neoplastic disease.