Anti-peripheral nerve myelin antibodies and terminal activation products of complement in serum of patients with acute brachial plexus neuropathy

OBJECTIVE

To determine if complement-fixing antibodies to peripheral nerve myelin (anti-PNM antibodies) and terminal complement activation products were increased in serum of patients with brachial plexus neuropathy compared with normal controls.

DESIGN

Case series.

SETTING

University medical center.

PATIENTS

Three patients (aged 6, 39, and 51 years) with acute brachial plexus neuropathy were studied during the acute and recovery phase of their disease.

METHODS

Anti-PNM antibodies were measured in serum samples obtained from three patients and 25 normal controls with the C1 fixation and transfer assay. Soluble terminal complement activation products, SC5b-9, were measured by enzyme-linked immunosorbent assay (ELISA) in serum samples of one patient with brachial plexus neuropathy and of five normal controls.

RESULTS

Both serum anti-PNM antibodies and soluble terminal complement activation products were increased in the acute phase of brachial plexus neuropathy compared with normal control values and decreased several months later during clinical recovery.

CONCLUSION

Complement dependent, antibody-mediated demyelination may participate in the peripheral nerve damage of brachial plexus neuropathy.

Serum antibodies to GM1, GD1b, peripheral nerve myelin, and Campylobacter jejuni in patients with Guillain-Barré syndrome and controls: correlation and prognosis

Serum antibodies to monosialoganglioside (GM1), disialoganglioside (GD1b), and Campylobacter jejuni, measured by enzyme-linked immunosorbent assay and serum antibodies to peripheral nerve myelin, measured by the C1 fixation and transfer assay, were studied in 58 acute-phase patients with Guillain-Barré syndrome (GBS), 42 disease controls, and 29 normal controls. Anti-peripheral nerve myelin antibodies were elevated in 57 of 58 patients with GBS compared with controls, whereas only 8.6% had increased antibody titers to GM1 and 10.3% to GD1b. Only low antibody titers (GM1) or no antibodies (GD1b) were found in controls. More GBS patients (17.2%) than controls (7%) had antibodies to C jejuni. Poor recovery with inability to walk at 1 year after onset of symptoms was seen in 3 (5%) of the patients with GBS. All 3 patients had serological evidence of recent C jejuni infection but no antibodies to GM1 or GD1b. GBS patients with antibodies to GM1 or GD1b had excellent recovery. Our data indicate that antibodies to GM1 or GD1b do not necessarily mediate the extensive axonal damage seen in these severely affected patients.

Serologic evidence of previous Campylobacter jejuni infection in patients with the Guillain-Barré syndrome

OBJECTIVE

To determine if patients with the Guillain-Barré syndrome are likely to have had Campylobacter jejuni infection before onset of neurologic symptoms.

DESIGN

A case-control study.

SETTING

Several university medical centers.

PATIENTS

Case patients met clinical criteria for the Guillain-Barré syndrome between 1983 and 1990 and had a serum sample collected and frozen within 3 weeks after onset of neurologic symptoms (n = 118). Disease controls were patients with other neurologic illnesses (n = 56); healthy controls were hospital employees or healthy family members of patients (n = 47).

MEASUREMENTS

Serum IgA, IgG, and IgM antibodies to C. jejuni were determined by enzyme-linked immunosorbent assays. Assays were done in a blinded manner.

RESULTS

Optical density ratios > or = 2 in two or more immunoglobulin classes were seen in 43 (36%) of patients with the Guillain-Barré syndrome and in 10 (10%) of controls (odds ratio, 5.3; 95% CI, 2.4 to 12.5; P < 0.001). Increasing the optical density ratio or the number of immunoglobulin classes necessary to yield a positive result increased the strength of the association. The number of patients with the Guillain-Barré syndrome who had positive serologic responses was greatest from September to November (P = 0.02). Male patients were three times more likely to have serologic evidence of C. jejuni infection (P = 0.009); the proportion of patients with the syndrome who had a positive serologic response increased with age.

CONCLUSIONS

Patients with the Guillain-Barré syndrome are more likely than controls to have serologic evidence of C. jejuni infection in the weeks before onset of neurologic symptoms. Campylobacter jejuni may play a role in the initiation of the Guillain-Barré syndrome in many patients.

Humoral mechanisms in immune neuropathies

Antibody and complement are implicated in the pathogenesis of a number of human, primarily demyelinating neuropathies. The ability of serum and purified, primarily IgM, antibodies to mediate demyelination was demonstrated in both in vitro and in vivo model systems. Complement activation to produce channel-forming terminal complement complexes, C5b-8 and C5b-9, was required for demyelination in vitro. Antibodies implicated in the demyelination of peripheral nerve of GBS patients and patients with monoclonal gammopathy-associated neuropathy bind carbohydrate epitopes on various neutral or acidic glycolipids and glycoproteins of peripheral nerve. In acute monophasic GBS, antibodies of multiple specificities may be induced to different infectious agents. These Ab, following penetration of a damaged blood-nerve barrier, are proposed to bind determinants of human peripheral nerve and participate in demyelination of nerve through activation of complement. These antibodies correlate with the clinical course, the generation of complement activation products, and the response to plasmapheresis. The mechanism by which the blood-nerve barrier is broken in GBS and other inflammatory demyelinating neuropathies and the extent of the role of the cellular immune system remain to be determined. Recent experiments demonstrated that T cells, antibody, and complement could synergistically contribute to central nervous system demyelination in naive rats. A similar synergism would be an attractive hypothesis for demyelination in the peripheral nervous system.

Electrophysiologic studies in the Guillain-Barré syndrome: effects of plasma exchange and antibody rebound

Nerve conduction studies (NCS) and antiperipheral nerve myelin antibody (A-PNM Ab) titers were measured serially in 29 patients with Guillain-Barré syndrome (GBS), of whom 21 were treated with plasmapheresis. Data were obtained from 3 to 6 days until 1 to 2 years after onset of symptoms. Within 3 to 6 days, mean NCS were abnormal. They improved some by 1 week and became maximally abnormal by 4 to 8 weeks, during which time A-PNM Ab fell to low levels. In 5 patients plasmapheresed, A-PNM Ab fell and then increased at 4 to 8 weeks, followed by significant deterioration of NCS (P = 0.01) compared with those without antibody rebound at 18 weeks. These results suggest that, in monophasic GBS, there may be two mechanisms of conduction dysfunction such as early paranodal retraction and later demyelination. In some patients plasmapheresed, A-PNM Ab may rebound associated with further conduction dysfunction. These patients may benefit from further plasmapheresis.

Kinetics of anti-peripheral nerve myelin antibody in patients with Guillain-Barré syndrome treated and not treated with plasmapheresis

Serial anti-peripheral nerve myelin antibody titers were determined in 28 consecutive patients with Guillain-Barré syndrome during the course of their illness. Eighteen patients were treated with plasmapheresis and 10 were not. Anti-peripheral nerve myelin antibody titers in the group treated with plasmapheresis declined significantly more rapidly than in the group not treated with plasmapheresis. Five patients treated with plasmapheresis who showed initial clinical improvement, with a concurrent decline in anti-peripheral nerve myelin antibody titer, had one or two recurrences of clinical symptoms during a 2- to 8-week period associated with an increase in anti-peripheral nerve myelin antibody titer. Recurrent weakness was severe enough to prompt additional courses of plasmapheresis. The data suggest that serial determinations of antiperipheral nerve myelin antibody in patients with Guillain-Barré syndrome may identify patients with antibody rebound associated with recurrence of clinical symptoms and prolonged recovery in whom further plasmapheresis should be considered.

In vitro demyelination by serum antibody from patients with Guillain-Barré syndrome requires terminal complement complexes

Serum from 7 patients who had acute-phase Guillain-Barré syndrome with high anti-peripheral nerve myelin antibody activity (54 to 210 units/ml) was compared with serum from 3 patients in the recovery phase (0 to 17 units/ml) and serum from 7 disease control subjects (0 to 24 units/ml) and 7 normal control subjects (0 to 7 units/ml) for its ability to demyelinate rodent dorsal root ganglion cultures. The demyelinating capacity of each serum was quantitated by counting the percent of damaged internodal segments in each of four cultures. All sera from patients in the acute phase GBS caused 50 to 78% demyelination, in contrast with 6 to 19% by the sera from all 3 patients in the recovery phase and all other control subjects. The degree of demyelination correlated with anti-peripheral nerve myelin antibody activity of the sera and demyelination was complement-dependent. Further, cultures were treated with an immunoglobulin M (IgM) fraction of an acute-phase Guillain-Barré syndrome plasma plus normal human serum depleted of complement component C7. Only those cultures treated with IgM and C7-depleted human serum reconstituted with purified C7 resulted in 50.8% demyelination, which was significantly greater than the 14.2 to 16.2% demyelination observed in the presence of heat-inactivated, C7-depleted human serum plus purified C7 or in the absence of C7 or antibody. In summary, our work suggests that anti-peripheral nerve myelin antibody in Guillain-Barré syndrome mediated complement dependent-demyelination of rodent dorsal root ganglion cultures. Further, this in vitro demyelination required generation of activation complexes of the terminal complement cascade.

Characterization of complement-fixing antibodies to peripheral nerve myelin in Guillain-Barré syndrome

Complement-fixing antibodies to peripheral nerve myelin (anti-PNM Ab) can be detected in the serum of patients with Guillain-Barré syndrome (GBS). Kinetics of these antibodies can be correlated with the changing clinical course; the appearance of activation products of the terminal complement cascade in cerebrospinal fluid, serum, and peripheral nerve of patients with GBS; and the ability of GBS serum to mediate complement-dependent demyelination of myelinating cultures of rodent dorsal root ganglion. Some of the anti-PNM Ab in all GBS serum tested thus far bind a neutral glycolipid of human PNM and cross react with Forssman antigen, a cross-species antigen found in many infectious agents. Studies suggest that an IgM antibody in GBS patients that could be triggered by multiple infectious agents binds a surface determinant of a Forssman-like lipid of human PNM and participates in demyelination of peripheral nerve through the activation of complement.

Anti-peripheral nerve myelin antibodies in Guillain-Barre syndrome bind a neutral glycolipid of peripheral myelin and cross-react with Forssman antigen

During acute-phase illness, serum of patients with Guillain-Barre syndrome (GBS) contain complement-fixing antibodies (Ab) to peripheral nerve myelin (PNM). We investigated PNM lipids as putative antigens for these Ab since GBS serum retained significant reactivity to PNM treated with protease. Ab binding to specific lipids was studied with a C1 fixation and transfer (C1FT) assay using fractions of PNM lipid reincorporated into liposomes as antigen targets or to lipids on HPTLC plates with peroxidase-labeled goat Ab to human IgM. Reactivity was detected to a neutral glycolipid (NGL) of human PNM with a similar number of carbohydrates residues to that of Forssman hapten (Forss). Anti-NGL Ab titers in GBS patients (50-220 U/ml) were significantly elevated over disease and normal controls (0-5 and 0-6 U/ml). We studied possible antigenic cross-reactivity of these Ab with Forss by first quantitating Ab activity with C1FT assay and liposomes containing Forss. All 12 GBS sera tested showed titers (54-272 U/ml) significantly elevated over 11 disease controls (0-22 U/ml) and 25 normal controls (0-11 U/ml). GBS serum Ab reacted with Forss isolated from dog nerve or sheep erythrocytes on HPTLC plates. Further, absorption of 80-100% of anti-NGL Ab activity and 17-97% of anti-PNM Ab activity from eight GBS patient serums was accomplished with liposomes containing Forss but not with control liposomes. In seven GBS patients anti-NGL Ab activity represented only a portion of anti-PNM Ab activity. These results suggest that a glycolipid with antigenic cross-reactivity to Forssman hapten may be responsible for some of the anti-PNM Ab activity in GBS.

Autonomic dysfunction in Lambert-Eaton myasthenic syndrome

Autonomic symptoms were observed in 6 patients with clinically and electrophysiologically documented Lambert-Eaton myasthenic syndrome (LEMS). Of the 6 patients, 2 were extensively investigated in the laboratory. In contrast to previous reports which recognized only cholinergic dysautonomia, abnormalities of sympathetic as well as parasympathetic function were evident. Of the 6 patients, 4 had small cell lung cancer (SCLC). In one male patient, chemotherapy for SCLC resulted in an early improvement of autonomic dysfunction and the electrophysiological defect, documenting simultaneous regression of dysautonomia and LEMS. In addition, the patients with SCLC and LEMS had a survival thus far of 3-13 years suggesting that a subgroup of SCLC patients have a better prognosis.

Activation of terminal components of complement in patients with Guillain-Barré syndrome and other demyelinating neuropathies

In the present study, the role of antiperipheral nerve myelin antibody (anti-PNM Ab) in demyelination by generating the terminal attack complex (C5b-9) of complement was explored in patients with Guillain-Barré syndrome (GBS) and other demyelinating neuropathies. The presence in serum of SC5b-9, an inactive C5b-9 containing S protein, was assessed quantitatively by enzyme-linked immunosorbent assay using an antibody (Ab) to neoantigens expressed on C9 when complexed with C5b-8 or after tubular polymerization. SC5b-9 was detected in all 19 GBS, four patients with paraprotein-associated neuropathy and five of six patients with chronic recurrent polyneuritis. No SC5b-9 was detected in 10 normal controls. Kinetic studies from six GBS patients showed the highest values of SC5b-9 on the 3rd to 5th d of admission; in contrast, the anti-PNM Ab were highest on the day of admission. Anti-PNM Ab fell rapidly to very low levels by the 15th to 20th d. SC5b-9 declined with similar kinetics to undetectable levels by the 30th d. Levels of Ab and SC5b-9 did not quantitatively correlate with soluble immune complexes in these patients' serum. Membrane-bound C5b-9 was also detected by immunohistochemistry in the peripheral nerves from a GBS patient. These results, which show a relationship between levels of complement-fixing anti-PNM Ab and the tissue-damaging C5b-9 complex, suggest that peripheral nerve myelin may serve as the target for Ab-mediated complement attack.

Detection of activated terminal complement (C5b-9) in cerebrospinal fluid from patients with central nervous system involvement of primary Sjogren's syndrome or systemic lupus erythematosus

We have examined cerebrospinal fluid (CSF) and serum from patients with Sjogren's syndrome (SS) and systemic lupus erythematosus (SLE) for evidence of activation of the terminal pathway of complement. Fluid phase terminal complement complexes (SC5b-9), quantitated by ELISA, were detected in the CSF of 14 of 16 patients with SS and focal central nervous system (CNS) disease. Five of six SS patients without focal CNS disease but with psychiatric disease or cognitive dysfunction had detectable CSF SC5b-9, whereas two other SS patients without focal CNS or neuropsychiatric disease had no detectable CSF SC5b-9. Six of seven patients with SLE or SLE overlap syndrome with CNS involvement had CSF SC5b-9, whereas two patients with SLE without CNS involvement had no CSF SC5b-9. A subset of SS and SLE patients with CNS disease had SC5b-9 detected in CSF but not in serum. SC5b-9 was generally absent from the CSF of patients with noninflammatory CNS diseases. These findings demonstrate intrathecal activation of terminal complement in patients with CNS SS or CNS SLE, and suggest a role for terminal complement activation in the pathophysiology of CNS involvement in both SS and SLE.

Detection of activated terminal complement (C5b-9) in cerebrospinal fluid from patients with central nervous system involvement of primary Sjogren's syndrome or systemic lupus erythematosus

We have examined cerebrospinal fluid (CSF) and serum from patients with Sjogren's syndrome (SS) and systemic lupus erythematosus (SLE) for evidence of activation of the terminal pathway of complement. Fluid phase terminal complement complexes (SC5b-9), quantitated by ELISA, were detected in the CSF of 14 of 16 patients with SS and focal central nervous system (CNS) disease. Five of six SS patients without focal CNS disease but with psychiatric disease or cognitive dysfunction had detectable CSF SC5b-9, whereas two other SS patients without focal CNS or neuropsychiatric disease had no detectable CSF SC5b-9. Six of seven patients with SLE or SLE overlap syndrome with CNS involvement had CSF SC5b-9, whereas two patients with SLE without CNS involvement had no CSF SC5b-9. A subset of SS and SLE patients with CNS disease had SC5b-9 detected in CSF but not in serum. SC5b-9 was generally absent from the CSF of patients with noninflammatory CNS diseases. These findings demonstrate intrathecal activation of terminal complement in patients with CNS SS or CNS SLE, and suggest a role for terminal complement activation in the pathophysiology of CNS involvement in both SS and SLE.

Activated terminal complement in cerebrospinal fluid in Guillain-Barré syndrome and multiple sclerosis

A quantitative enzyme-linked immunosorbent assay was used to measure the concentration of fluid-phase complement C5b-9 complexes (SC5b-9) in the cerebrospinal fluid (CSF) of 14 patients with acute monophasic Guillain-Barré Syndrome (GBS), 21 patients with multiple sclerosis (MS), and 11 patients with noninflammatory central nervous system (CNS) diseases. SC5b-9 complexes were detected in the CSF of 13 of 14 patients with acute GBS (mean, 3.08 micrograms/ml; range, 0 to 7.1 micrograms/ml) and 16 of 21 patients with MS (mean, 1.83 micrograms/ml; range, 0 to 7.5 micrograms/ml). In the control group of patients with noninflammatory CNS diseases, SC5b-9 was not detected in eight of 11 and was present in low concentrations in the remaining three patients (mean, 0.28 micrograms/ml; range, 0 to 1.7 micrograms/ml). The finding of SC5b-9 complexes in the CSF of patients with GBS and MS suggests that terminal complement components may participate in the tissue-damaging processes in these diseases.

Activated terminal complement in cerebrospinal fluid in Guillain-Barré syndrome and multiple sclerosis

A quantitative enzyme-linked immunosorbent assay was used to measure the concentration of fluid-phase complement C5b-9 complexes (SC5b-9) in the cerebrospinal fluid (CSF) of 14 patients with acute monophasic Guillain-Barré Syndrome (GBS), 21 patients with multiple sclerosis (MS), and 11 patients with noninflammatory central nervous system (CNS) diseases. SC5b-9 complexes were detected in the CSF of 13 of 14 patients with acute GBS (mean, 3.08 micrograms/ml; range, 0 to 7.1 micrograms/ml) and 16 of 21 patients with MS (mean, 1.83 micrograms/ml; range, 0 to 7.5 micrograms/ml). In the control group of patients with noninflammatory CNS diseases, SC5b-9 was not detected in eight of 11 and was present in low concentrations in the remaining three patients (mean, 0.28 micrograms/ml; range, 0 to 1.7 micrograms/ml). The finding of SC5b-9 complexes in the CSF of patients with GBS and MS suggests that terminal complement components may participate in the tissue-damaging processes in these diseases.

Clinical correlation with anti-peripheral-nerve myelin antibodies in Guillain-Barré syndrome

Anti-peripheral-nerve myelin antibodies (anti-PNM Ab) can be detected in the serum of all patients with acute-phase Guillain-Barré syndrome (GBS) thus far tested. Correlation of the titer of this antibody with the clinical course would help to establish a role for the humoral immune system in the pathophysiology of GBS. In this study, anti-PNM Ab levels were measured in serial serum samples of 7 patients with GBS with an assay that detects antibodies bound to peripheral nerve myelin antigens by fixation of the first component of complement. Although the titers of anti-PNM Ab detected in these patients varied between 0 and 256 U/ml, the antibody titer was always highest on admission (35 to 256 U/ml) and rapidly declined during a one-to-three-week period. Disappearance of antibodies or very low levels of them correlated with cessation of progression and considerable clinical improvement as documented by increased pulmonary vital capacity and muscular strength. Low but measurable antibody titers (5 to 12 U/ml) were frequently found up to four months following the acute neurological deficit. The close temporal relationship between anti-PNM Ab titer and the clinical course in GBS suggests that antibody most likely participates through complement activation in peripheral nerve demyelination.

Elimination of terminal complement intermediates from the plasma membrane of nucleated cells: the rate of disappearance differs for cells carrying C5b-7 or C5b-8 or a mixture of C5b-8 with a limited number of C5b-9

We have previously shown that multiple complement (C) channels are required for lysis of a nucleated cell in contrast to the single channel requirement for erythrocytes. To further investigate this multichannel requirement for nucleated cells, we examined the stability of terminal C complexes in the plasma membrane of Ehrlich ascites tumor cells. Ehrlich cells bearing C5b-7 or C5b-8 with or without C9 were incubated at 37 degrees C or 0 degree C for various time intervals before converting the remaining complexes to lytic C5b-9 channels. C5b-7, C5b-8, and C5b-8 in the presence of a limited number of C5b-9 complexes disappeared functionally from the plasma membrane at 37 degrees C, with initial half-lives of 31, 20, and 10 min, respectively. Disappearance of these complexes did not occur at 0 degree C, nor did disappearance occur at 37 degrees C when formed on sheep erythrocytes. The fate of C5b-8 complexes on the surface of Ehrlich cells was traced with colloidal gold particles bound to C5 determinants on C5b-8 with the use of immunoelectron microscopy. Colloidal gold could be seen on the cell surface after specific binding to cells carrying C5b-8 sites at 0 degree C. After incubating these cells at 37 degrees C, gold particles were internalized into the cell continuously via endocytic vesicles. It is postulated that terminal C complexes may stimulate or accelerate the removal of these complexes from the cell surface.

Activation of the alternative pathway of complement by human peripheral nerve myelin

Destruction of peripheral nerve myelin (PNM) occurs as a consequence of a variety of pathologic conditions affecting the peripheral nervous system. In certain primary demyelinating neuropathies, several lines of evidence implicate complement in the pathogenesis of demyelination. In this study we demonstrate that human PNM consumes complement in vitro in the absence of specific antibody or C1 activation. Furthermore, activation of complement by PNM via the alternative pathway was shown by cleavage of C3 in normal human serum (NHS) and of B in C2-deficient serum (C2d-HS). Increasing consumption of hemolytic activity of C3 in Mg-EGTA-treated NHS was also noted with increasing amounts of PNM. Pronase treatment of PNM abolished C3 consumption, suggesting that a protein component exposed on the surface of myelin participated in the alternative pathway activation. When P0, the major amphiphilic glycoprotein of PNM, was incorporated into artificial lipid bilayers, the Po-liposomes consumed C3 activity in NHS containing Mg-EGTA. Pronase treatment of Po-liposomes abolished C3 consumption to the level of control liposomes, indicating that P0 was responsible for at least part of the activation seen with peripheral myelin.

Activation of the alternative pathway of complement by human peripheral nerve myelin

Destruction of peripheral nerve myelin (PNM) occurs as a consequence of a variety of pathologic conditions affecting the peripheral nervous system. In certain primary demyelinating neuropathies, several lines of evidence implicate complement in the pathogenesis of demyelination. In this study we demonstrate that human PNM consumes complement in vitro in the absence of specific antibody or C1 activation. Furthermore, activation of complement by PNM via the alternative pathway was shown by cleavage of C3 in normal human serum (NHS) and of B in C2-deficient serum (C2d-HS). Increasing consumption of hemolytic activity of C3 in Mg-EGTA-treated NHS was also noted with increasing amounts of PNM. Pronase treatment of PNM abolished C3 consumption, suggesting that a protein component exposed on the surface of myelin participated in the alternative pathway activation. When P0, the major amphiphilic glycoprotein of PNM, was incorporated into artificial lipid bilayers, the Po-liposomes consumed C3 activity in NHS containing Mg-EGTA. Pronase treatment of Po-liposomes abolished C3 consumption to the level of control liposomes, indicating that P0 was responsible for at least part of the activation seen with peripheral myelin.

Elimination of terminal complement intermediates from the plasma membrane of nucleated cells: the rate of disappearance differs for cells carrying C5b-7 or C5b-8 or a mixture of C5b-8 with a limited number of C5b-9

We have previously shown that multiple complement (C) channels are required for lysis of a nucleated cell in contrast to the single channel requirement for erythrocytes. To further investigate this multichannel requirement for nucleated cells, we examined the stability of terminal C complexes in the plasma membrane of Ehrlich ascites tumor cells. Ehrlich cells bearing C5b-7 or C5b-8 with or without C9 were incubated at 37 degrees C or 0 degree C for various time intervals before converting the remaining complexes to lytic C5b-9 channels. C5b-7, C5b-8, and C5b-8 in the presence of a limited number of C5b-9 complexes disappeared functionally from the plasma membrane at 37 degrees C, with initial half-lives of 31, 20, and 10 min, respectively. Disappearance of these complexes did not occur at 0 degree C, nor did disappearance occur at 37 degrees C when formed on sheep erythrocytes. The fate of C5b-8 complexes on the surface of Ehrlich cells was traced with colloidal gold particles bound to C5 determinants on C5b-8 with the use of immunoelectron microscopy. Colloidal gold could be seen on the cell surface after specific binding to cells carrying C5b-8 sites at 0 degree C. After incubating these cells at 37 degrees C, gold particles were internalized into the cell continuously via endocytic vesicles. It is postulated that terminal C complexes may stimulate or accelerate the removal of these complexes from the cell surface.

Anti-peripheral myelin antibody in patients with demyelinating neuropathy: quantitative and kinetic determination of serum antibody by complement component 1 fixation

The role of anti-peripheral nerve myelin antibody (anti-PNM Ab) in the pathogenesis of acquired demyelination of peripheral nerve is unclear, in part, due to the poor correlation between antibody and disease activity. Previous studies show that only 27-50% of patients with acute demyelinating neuropathy or Guillain-Barré syndrome (GBS) had serum Abs to peripheral nerve or PNM as demonstrated by consumption of hemolytic activity of serum complement 1 (C1) fixation and transfer assay, quantitative determinations of anti-PNM Ab showed significantly high titers in the serum of patients with GBS, chronic and recurrent polyneuritis, and paraproteinemia associated with peripheral neuropathy. All 11 patients with acute-phase GBS had Ab titers 6-56 times higher than controls. In 6 GBS patients, serial Ab determinations showed that titers were highest on admission, fell rapidly the first week, and became undetectable or barely detectable by the third week. Declining Ab titers coincided with cessation of clinical progression. In 3 GBS patients, depletion of serum IgM lowered anti-PNM Ab titers significantly, whereas IgG depletion failed to produce a similar effect. This study shows that the C1 fixation and transfer assay is a sensitive method to detect anti-PNM Ab in the serum of patients with a variety of demyelinating neuropathies and provides good correlation between Ab level and the clinical course of GBS patients. It may provide important information about the pathogenesis of the demyelinating neuropathies.