Poliovirus-specific immunoglobulin M antibodies during diagnosis of acute poliomyelitis or postpoliovirus syndrome or monitoring of vaccine responsiveness.

The ,-capture assay to measure poliovirus-specific immunoglobulin M (IgM) antibodies for three poliovirus serotypes in serum and cerebrospinal fluid (CSF) in 114 patients with clinically determined acute poliomyelitis at Karachi, Pakistan, employed 35S-methionine-radiolabelled polioviruses. In the microwell format, the appearance of poliovirus-specific IgM antibodies appeared a sensitive and specific test procedure for laboratory confirmation of poliomyelitis. During the first 15 days of patient illness, more poliomyelitis cases were confirmed by an intrathecal immune IgM response than by isolation of virus in the stool specimens (3). The microwell poliovirus IgM format (3) might also be ideal for monitoring the intrathecal IgM response in patients with postpoliomyelitis syndrome who manifest progressive muscular dystrophy decades after the initial episode of acute poliomyelitis (1). Presently, intrathecal immune reactivity is measured in CSF during electrophoresis of undiluted CSF specimens in agarose gel followed by a passive transfer to polyvinyl difluoride membrane coated with the poliovirus antigen. Following glutaraldehyde-induced cross-linkage of immunoglobulin with the membrane, it is possible to stain the poliovirus-specific IgM oligoclonal bands. Investigations with 36 patients, 16 men and 20 women, of postpoliomyelitis syndrome for intrathecal immune reactivity enabled detection of IgM oligoclonal bands in 21 patients, with no bands in any of the control group with a childhood poliomyelitis or a neuromuscular disease (4). The ,u-capture assay would enable extended monitoring of intrathecal IgM response in patients with postpoliomyelitis syndrome in industrialized countries. The use of radiolabelled materials in the ,u-capture assay for poliomyelitis (3) is an obstacle against its extended diagnostic use in developing countries, where the routine diagnostic laboratories lack facilities for handling radioactive materials. Appropriate modifications would be needed in order to eliminate the use of radioactive materials and toward adaptation of the assay format for quantification of poliovirus IgM in saliva. The immune response in serum and CSF pairs in 114 patients in Pakistan (3) has been distinct, with no correlation in antibody titers in CSF-serum pairs. The salivary IgM quantum might well be an equally useful marker for a specific diagnosis of poliomyelitis. The sensitivity and specificity for hepatitis A virus-specific IgM in saliva samples obtained with a treated absorbent pad have been 100% (51 of 51 samples) and 98% (46 of 47 samples) in relation to serum antibody titers. Moreover, the decline of hepatitis A IgM in oral samples was parallel to, although somewhat more rapid than, that of hepatitis A IgM in serum samples (5). The utility of the ,u-capture immunoassay for saliva rather than blood or CSF would be obvious in remote locations with poor facilities for health care and the absence of trained personnel to obtain CSF by lumbar puncture from patients labelled clinically as patients with acute poliomyelitis. Conventionally, the immune response to live attenuated or enhanced potency inactivated poliovirus vaccine has been monitored through the quantification of IgG-class poliovirus antibodies in serum (2). Ready availability of simplified salivabased techniques for poliovirus-specific IgM and IgA would enable one to ascertain whether there was a "window" phase between IgM and Ig response or some vaccinees responded by a selective IgA response. Even the patients with live poliovirus vaccine-induced or associated paralytic poliomyelitis might demonstrate an abnormal immune response.