Using sera from 11 patients with Hu-positive PEM, we found that the majority of samples (73%) were weakly or non-reactive for recombinant HuR on Western blot, in contrast to consistently strong immunoreactivity with the neural-specific members HuD and Hel-N1.
In the current study we examined (1) the reactivity of anti-Hu sera with HuD, HuC, and Hel-N1; (2) the expression of HuD, HuC, and Hel-N1 messenger RNA in small-cell lung cancer of patients with and those without paraneoplastic encephalomyelitis/sensory neuronopathy; (3) the correlation between anti-Hu serum reactivity with these three Hu antigens and the type of neurological symptoms; and (4) the major immunogenic sites of HuD.