Immunofluorescence studies in a case of rheumatoid neuropathy.

Findings in a sural nerve biopsy from a patient with rheumatoid neuropathy are reported. Inflammatory changes in different stages were observed in epineurial arterioles. Arterioles with fibrinoid necrosis contained IgG, IgM, rheumatoid factor and complement. The same substances were found at the inner site of the perineurial sheaths. It is suggested that these proteins leaked out of endoneurial vessels and became trapped in the perineurial sheaths. With anti-herpes simplex virus serum fluorescence was seen in monuclear cells of infiltrated vessel walls. This virus could not be isolated in tissue culture.     

Direct immunofluoresence in vasculitic neuropathy: Specificity of vascular immune deposits

In suspected vasculitic neuropathy, vasculitis is demonstrated in only 30% of superficial peroneal nerve (SPN)/peroneus brevis muscle (PBM) specimens. Pathologic predictors of vasculitis are thus needed for non‐diagnostic cases. Immune deposits in epineurial vessels have an established sensitivity but unknown specificity. In this study we assessed specificity using direct immunofluorescence (DIF) in SPN/PBM biopsies for suspected vasculitic neuropathy. Biopsies from 13 patients with vasculitis, 13 without vasculitis, and 6 with diabetic radiculoplexus neuropathy (DRPN) were stained for immunoglobulin G (IgG), IgM, and complement 3 (C3), and analyzed in a blinded manner. Vascular immunoglobulin or C3 deposits occurred in 12 of 13 nerve or muscle biopsies (11 of 13 nerves, 5 of 13 muscles) in vasculitis vs. 1 of 13 (1 of 13 nerves, 0 of 13 muscles) in controls (P = 0.00003). Specificity was 92%. For DRPN, vascular immune deposits occurred in 5 of 6 nerves or muscles (4 of 6 nerves, 1 of 5 muscles), similar to vasculitis but significantly different from controls. Epineurial/perimysial vascular deposits of immunoglobulin/C3 by DIF are a specific marker of vasculitic neuropathy. Muscle Nerve 000:000–000, 2009     

Microvasculitis and ischemia in diabetic lumbosacral radiculoplexus neuropathy

OBJECTIVE: To determine whether microscopic vasculitis explains the clinical and pathologic features of diabetic lumbosacral radiculoplexus neuropathy (DLSRPN). BACKGROUND: DLSRPN is usually attributed to metabolic derangement or ischemic injury, but microscopic vasculitis as the sole cause needs consideration. METHODS: We prospectively studied the clinical, laboratory, and EMG features as well as the pathology of distal cutaneous nerve biopsy specimens of patients with DLSRPN. RESULTS: Study of DLSRPN nerve biopsy specimens (n = 33) compared with those from healthy controls (n = 14) and those with diabetic polyneuropathy (n = 21) provided strong evidence for ischemic injury (axonal degeneration, multifocal fiber loss, focal perineurial necrosis and thickening, injury neuroma, neovascularization, and swollen fibers with accumulated organelles), which we attribute to microscopic vasculitis (epineurial vascular and perivascular inflammation, vessel wall necrosis, and evidence of previous bleeding). Segmental demyelination was significantly associated with multifocal fiber loss. CONCLUSIONS: 1) This severe, debilitating neuropathy begins with symptoms unilaterally and focally in the leg, thigh, or buttock and spreads to involve the other regions of the same and then opposite side and is due to multifocal involvement of lumbosacral roots, plexus, and peripheral nerve (i.e., diabetic lumbosacral radiculoplexus neuropathy). 2) Motor, sensory, and autonomic fibers are all involved. 3) Ischemic injury explains the clinical features and pathologic abnormalities of nerve. 4) The proximate cause of the ischemic injury appears to be microscopic vasculitis. 5) The segmental demyelination is probably secondary to ischemic axonal dystrophy, thus providing a unifying hypothesis for both axonal degeneration and segmental demyelination.     

Epineurial microvasculitis in proximal diabetic neuropathy

Amongst the focal and multifocal neuropathies that are associated with diabetes mellitus one of the most common is a proximal predominantly motor lower limb neuropathy. Recent evidence has indicated that, at least in a proportion of cases, this may have an inflammatory basis. We have examined a consecutive series of 15 cases of proximal diabetic neuropathy (diabetic amyotrophy). These were characterized by proximal pain and asymmetric proximal or generalized lower limb muscle weakness, associated in some cases with radicular sensory involvement. Two-thirds of the patients had an accompanying distal symmetric sensory polyneuropathy. Biopsy of the intermediate cutaneous nerve of the thigh, a sensory branch of the femoral nerve, showed epineurial microvasculitis in 3 patients and nonvasculitic epineurial inflammatory infiltrates in another case. In a further case, microvasculitis was found in both in the sural nerve and a quadriceps muscle biopsy specimen. The detection of inflammatory changes appeared to be correlated with the occurrence of sensory radicular involvement. Whether similar changes are present in muscle nerves in this predominantly motor syndrome requires further study. Nevertheless, the present observations confirm the view that secondary vasculitic or other inflammatory reactions may contribute to some forms of diabetic neuropathy.

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Received: 16 June 1997 Received in revised form: 29 October 1997 Accepted: 6 November 1997     

Nerve biopsy findings in different patterns of proximal diabetic neuropathy

Besides distal symmetrical sensory polyneuropathy (DSSP), middle-aged diabetic patients may present with focal or multifocal neuropathies, including proximal neuropathy of the lower limbs, the pathophysiological features of which are uncertain. We studied 10 non–insulin-dependent diabetic patients, 45 to 72 years of age, who developed a painful proximal neuropathy of the lower limbs for which other causes of neuropathy were carefully excluded. The proximal neuropathy was asymmetrical in all patients, sensory in 4, motor and sensory in the others. Signs of DSSP were present in all. A sample of the intermediate cutaneous nerve of the thigh, a sensory branch of the femoral nerve, was taken by biopsy and examined by light and electron microscopy. Examination of the nerve specimens revealed ischemic nerve lesions in 3 patients. Nerve ischemia was associated with vasculitis and inflammatory infiltration in 2 of them. In the other patients the lesions of the cutaneous nerve of the thigh included a varying incidence of axonal and demyelinative lesions similar to those observed in DSSP, with mild inflammatory infiltration in 4 of them. The density of myelinated and of unmyelinated was variably decreased. This study shows that axonal and demyelinative lesions similar to those found in diabetic DSSP are present in proximal nerves in mild forms of proximal diabetic neuropathy; while nerve ischemia, inflammatory infiltration, and vasculitis are encountered in the most severe forms of proximal diabetic neuropathy.     

Chronic progressive sensory ataxic neuropathy with polyclonal gammopathy and disseminated focal perivascular cellular infiltrations

One autopsied case of chronic progressive sensory-ataxic neuropathy with polyclonal elevation of serum and CSF IgG and IgA and without malignancy is reported. A marked loss of large myelinated fibers was universal in both the central and peripheral rami of primary sensory neurons. Fiber loss showed a multifocal patchy pattern in the proximal nerve trunks. The posterior root ganglion cell bodies were moderately atrophic and loss of large cells was observed. Unmyelinated axons were well preserved. The ventral spinal roots, ventral spinal horn cells, and muscles showed minimal involvement. There were focal perivascular mononuclear inflammatory cells without necrotizing vasculitis around the endoneurial and epineurial vessels. Similar perivascular cellular invasions were observed in the visceral organs, occasionally forming germinal follicle centers. This case suggested that this neuropathy has a unique background with a possible immune-mediated basis.     

Symptomatic diabetic and non-diabetic neuropathies in a series of 100 diabetic patients

We have reviewed the clinical and pathological data of a series of 100 consecutive diabetic patients with symptomatic neuropathy in order to learn more about the causes of neuropathy in this population and on the signs and symptoms that could suggest another cause than diabetes in this setting. After diagnostic procedures, patients were assigned one (at most two) of a final total of 18 different causes of neuropathy. Diabetes accounted for 74 % of the neuropathies in the whole group of patients and for 79 % of those with a fiber length dependent pattern of neuropathy. One third of patients had a neuropathy unrelated to diabetes. As a group, 71 % of the patients presented either a length dependent diabetic polyneuropathy (LDDP) or a proximal diabetic neuropathy (PDN). The LDDP group was biased towards more severely affected patients owing to our specialization. Conversely, most patients with proximal diabetic neuropathy had usual features. Chronic inflammatory demyelinating neuropathy that was diagnosed in 9 % of the patients was the most common non-diabetic cause of neuropathy in this population. We conclude that a short interval between diagnosis of diabetes and the onset of the neuropathy, early motor deficit, markedly asymmetrical deficit and generalized areflexia, which are all uncommon in the LDDP, argue in favor of a non diabetic origin of the neuropathy and should lead to further investigation. Received: 19 June 2001, Received in revised form: 21 September 2001, Accepted: 8 October 2001     

Correlation between the number of epineurial and endoneurial blood vessels in diseased human sural nerves

In a preceding study it was shown that changes in the number of epineurial blood vessels may be a prominent feature in angiopathic and other peripheral neuropathies, for instance in vasculitis, diabetes mellitus, or cerebral autosomal dominant angiopathy with multiple infarcts and leukoencephalopathy (CADASIL). Endoneurial blood vessels usually may also show significant structural alterations in a broad spectrum of neuropathic conditions, although these are not as prominent as in the epineurium. However, the relationship between changes in the number of epineurial and endoneurial blood vessels in diseased human sural nerves, and the impact of the loss of myelinated nerve fibers on the number of endoneurial blood vessels has thus far not been determined. Therefore, we investigated and compared the number of epineurial and endoneurial blood vessels in 50 human sural nerve biopsy specimens, representing a variety of peripheral neuropathies. We found that despite a significant increase of the number of epineurial blood vessels in cases with vasculitic neuropathy (P<0.05) and neuropathy with other types of microangiopathy (P<0.01), the number and density of the endoneurial blood vessels remained remarkably constant. In cases with an axonal type of neuropathy, severe neuropathic changes were associated with a decreased epineurial blood vessel number and a simultaneous, relative increase in the endoneurial blood vessel density. No significant correlation was found between (1) the number of epineurial and endoneurial blood vessels, and (2) the severity of the neuropathy and the number or density of epineurial and endoneurial blood vessels.     

Combined nerve and muscle biopsy in the diagnosis of vasculitic neuropathy. A 16-year retrospective study of 202 cases

We reviewed 202 biopsies performed on patients with suspected vasculitic neuropathy, of which 24 Churg-Strauss cases are studied separately. Specimens from the superficial peroneal nerve and peroneus brevis muscle were taken simultaneously by one incision. Without taking into account constitutional signs, systemic involvement was present in 131 patients, whereas the remaining 47 corresponded to non-systemic patients with lesions limited to peripheral nervous system and adjoining muscles. Diagnosis of panarteritis nodosa or microscopic polyangiitis, according to the size of involved vessels, was attested by an infiltration of vessel walls by inflammatory cells associated with fibrinoid necrosis or sclerosis. Microvasculitis was diagnosed when inflammatory infiltration concerned small vessels with few or no smooth-muscle fibers and without any necrosis. Microvasculitis was present in 11 of 46 non-systemic cases, and this predominance is statistically significant. Isolated perivascular cell infiltrates in the epineurium were considered not significant but allowed the diagnosis of 'probable vasculitis' if associated with at least one of the following features: regenerating small vessels, endoneurial purpura, asymmetric nerve fiber loss, and/or asymmetric acute axonal degeneration. Necrotizing vasculitis was visible in 60 cases: in nerve (16 cases), in muscle (19 cases), and both (25 cases). Microvasculitis was present in 25 cases: in nerve (19 cases), muscle (four cases), or both (two cases). Moreover, granulomatous vasculitis was found in the nerve of one non-systemic patient presenting also sarcoid granulomas in muscle. There were 24 'probable vasculitis' and 68 negative cases. Muscle biopsy improved the yield of definite vasculitis by 27%.     

Painful diabetic neuropathy (pdn): a morphological study of capsaicin receptor distribution

Capsaicin receptor TRPV1 is a non‐selective ligand‐gated channel activated by different noxious stimuli. Previous studies suggested that an increased density of TRPV1 positive axons in the skin could be involved in the pathogenesis of neuropathic pain. To investigate the expression of TRPV1 in PDN patients, skin biopsies from 6 patients with PDN and 10 controls, and sural nerve biopsies from 2 patients with PDN and 2 controls were studied using the polyclonal anti‐human TRPV1 antibody. Skin nerve fibers widely expressed TRPV1 immunoreactivity. The density of TRPV1 positive dermal and intra‐epidermal nerve fibers (IENF) did not differ from that obtained using the PGP 9.5 antibody (the standard marker for IEFN recognition). Confocal analysis demonstrated that TRPV1 and anti unique‐tubulin‐1 antibody (TuJ1) co‐localized in all axons. In PDN patients IENF density was significantly reduced, but no difference in immunostaining was detectable using TRPV1, PGP 9.5 and TuJ1 antibodies. Sural nerve unmyelinated fibers and few small‐myelinated fibers were intensely stained by TRPV1. DPN patients disclosed a severe reduction in unmyelinated fiber density, but residual fibers were recognized by TRPV1. These data suggest that TRPV1 is widely expressed in skin and sural nerve unmyelinated axons, but its expression is not increased in PDN. Other mechanisms, such as changes in proximal axon or neuron excitability, are more likely involved in the pathogenesis of neuropathic pain in diabetic neuropathy.     

IgM deposits on skin nerves in anti-myelin-associated glycoprotein neuropathy

Anti-myelin-associated glycoprotein (anti-MAG) neuropathy is a chronic demyelinating neuropathy with predominant involvement of large sensory fibers and deposits of IgM and complement on sural nerve myelinated fibers. We assessed the presence of IgM deposits on skin myelinated nerve fibers and the involvement of unmyelinated axons in anti-MAG neuropathy. Skin biopsies were performed in 14 patients with anti-MAG neuropathy, in 8 patients with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), and in 2 patients with IgM paraproteinemic neuropathy. Biopsies were taken at the proximal thigh in 20 patients, at the distal leg in 21 patients, at the proximal arm in 13 patients, and at the hand or fingertip in 10 patients. We found IgM deposits on dermal myelinated fibers in all anti-MAG neuropathy patients, with a greater prevalence at the distal site of the extremities. Deposits were located throughout the length of the fibers and at the paranodal loops. CIDP and IgM paraproteinemic neuropathies did not show any deposit of IgM. Anti-MAG neuropathy and CIPD patients showed a decrease in epidermal nerve fiber density reflecting an associated axonal loss. In anti-MAG neuropathy, both large- and small-diameter nerve fibers are affected, and specific deposits of IgM are found on skin myelinated nerve fibers.     

Painful lumbosacral plexopathy with elevated erythrocyte sedimentation rate: a treatable inflammatory syndrome

Six patients had a syndrome of painful lumbosacral plexopathy and elevated erythrocyte sedimentation rate. Sural nerve biopsy in each case showed axonal degeneration and epineurial arterioles surrounded by mononuclear inflammatory cells. Differential fascicular involvement suggested an ischemic cause in three nerves, but no patient had a necrotizing vasculitis. None of the six patients had vasculitis or cancer. Three of the six were diabetic and were initially thought to have diabetic plexopathy, but deterioration continued despite control of the diabetes. These six patients appeared to have an ischemic neuropathy with an immunological basis. Five were treated with immunosuppressant drugs, and in four the plexopathy improved or was arrested. The pathogenesis is unclear, but postmortem findings in one case suggest that the syndrome does not stem from an underlying vasculitis.     

Painful proximal diabetic neuropathy: Inflammatory nerve lesions and spontaneous favorable outcome

Proximal diabetic neuropathy is a disabling neuropathy that occurs predominantly in non-insulin-dependent diabetic patients over the age of 50. Inflammatory lesions have been found in nerve biopsy specimens of diabetic patients with severe proximal neuropathy or with other patterns of multifocal neuropathy. Some of these patients respond dramatically to treatment with corticosteroids or with other immunomodulators. In this article we report on our findings in 4 additional patients with painful proximal diabetic neuropathy and different patterns of inflammatory nerve lesions whose condition improved spontaneously shortly after performance of a nerve biopsy, without additional treatment.     

Multifocal neuropathy with vasculitis in hypereosinophilic syndrome

Summary A 56-year-old male with a 2-year history of bronchial asthma, together with pulmonary infiltration and marked eosinophilia, developed a subacute multifocal sensorimotor neuropathy. Electrodiagnostic studies demonstrated both multifocal and generalized nerve involvement. Sural nerve and muscle biopsies revealed axonal degeneration with almost complete loss of myelinated fibres, lymphomononuclear vasculitis of interstitial vasa nervorum without eosinophils, and neurogenic atrophy of muscle without angiitis. Although eosinophilia decreased drastically with corticosteroid treatment, neuropathy rapidly progressed to total disability. The patient died from pulmonary embolism 4 months after the onset of neurological signs. Autopsy disclosed vasculitis of epineurial vessels of peripheral nerves and severe axonal neuropathy, particularly of the lower limbs, without vasculitis or other inflammatory lesions in any other organ system, including the lungs. Retrospective analysis revealed that the onset of pulmonary infiltration and eosinophilia coincided with the administration of cromolyn sodium (Intal), which is known to produce PIE syndrome (pulmonary infiltration and eosinophilia), vasculitis and allergic granulomatosis, while multifocal neuropathy with vasculitis appears not to have been reported in connection with this substance.     

Hepatitis B virus-related vasculitis manifesting as severe peripheral neuropathy following influenza vaccination

We report the case of a 68-year-old man who developed hepatitis B virus (HBV)-related vasculitis, manifesting as mononeuritis multiplex, 8 days after influenza vaccination. The patient was a carrier of wild-type HBV, and had never received influenza vaccination. Histologic examination of the left sural nerve revealed necrotising vasculitis predominantly involving small blood vessels. HbsAg deposits were observed at a high density around the epineurial blood vessels of the sural nerve. He was treated with prednisone and Lamivudine. His condition improved gradually. However, seroconversion of HBs and HBe Ag was not detected. At the last follow-up 2 years later, his vascilitis did not recur. On the basis of the time of onset of vasculitis, the presumptive immune-mediated pathology of this disorder suggests a possible etiologic link with influenza vaccine. To our knowledge, our case is the first to show vasculitis of peripheral nerves proven pathologically after influenza vaccination.     

Detection of Borrelia burgdorferi DNA and complement membrane attack complex deposits in the sural nerve of a patient with chronic polyneuropathy and tertiary lyme disease

We report a patient who developed a chronic sensory motor polyneuropathy and a progressive myelopathy 4 years after a tick bite. An increased serum antibody titer to Borrelia burgdorferi suggested a diagnosis of Lyme neuroborreliosis, although a concomitant cervical spondylosis probably contributed to spinal cord damage. Treatment with ceftriaxone resulted in a marked improvement of neuropathic symptoms, providing indirect evidence of spirochetal infection. Search for B. burgdorferi DNA by polymerase chain reaction amplification on sural nerve confirmed the diagnosis, demonstrating that the spirochete localized in the peripheral nervous system. The presence of complement membrane attack complex deposits and macrophage infiltrates around epineurial vessels and within the endoneurium suggests that the neuropathy in our patient was immune-mediated. © 1997 John Wiley & Sons, Inc. Muscle Nerve 20: 969–975, 1997     

Innervation of the vasa nervorum: changes in human diabetics.

Transperineurial and epineurial vessels are innervated by plexuses of unmyelinated axons. Human sural nerve biopsies were examined ultrastructurally and immunocytochemically with an antibody which recognizes a neuronal and neuroendocrine protein, PGP 9.5, to characterize perivascular axons of these plexuses. Diabetics exhibited a greater degree of abnormal innervation of the vasa nervorum than nondiabetics with and without neuropathy. Abnormal innervation included: a reduction in the percentage of vessels exhibiting perivascular axons and a concomitant increase in the percentage of vessels having denervated Schwann cell units, particularly around vessels confined to perineurial compartments, and remaining axons in nerves from diabetics exhibited fewer varicosities. Denervated arterioles of diabetics also displayed structural changes indicating injury. The arteriolar structural defects and loss of neurogenic control of neural blood flow may lead to or aggravate endoneurial ischemia or hypoxia. The patchy, focal endoneurial fiber loss that is prominent in proximal nerves and associated with the distal myelinated fiber loss of some diabetic patients may be due in part to perivascular denervation of the vasa nervorum.     

Local activation of the complement system in endoneurial microvessels of diabetic neuropathy

Quantitative immunocytochemical analysis of complement proteins (CP) was performed on sural nerve biopsies from 15 patients with diabetic neuropathy (DN) and 18 nondiabetic patients with other forms of chronic neuropathy (ON). The mean age of the patients and the pathological severity of the neuropathy were similar in both groups. The percentage of patients that expressed strongly immunoreactive CP in the walls of endoneurial microvessels was significantly greater in DN than in ON for all proteins tested. C3d neoantigen was expressed in 100% of DN cases compared with 17% of ON; and membrane attack complex (MAC), C5b-9 neoantigen, in 93% of DN and 17% of ON. In the cases with DN, 81% of endoneurial microvessels, as identified by the endothelial marker, Ulex europaeus, contained C5b-9 neoantigen deposits, compared with 22% in those of ON, and the staining in DN was significantly more intense. Expression of the neoantigens of C3d and C5b-9 in nerve implies local activation of the complement system. In DN, activation of the complement pathway and formation of the MAC could injure blood vessels and adversely affect the circulation in the endoneurium. Received: 27 November 1998 / Revised, accepted: 16 April 1999     

Immunohistochemical findings in vasculitic neuropathies

Fifteen sural nerve biopsies of vasculitic neuropathies have been compared with 11 cases of different non-vasculitic neuropathies and normal nerves from brain-dead organ donors. The APAAP (alkaline phosphatase monoclonal anti-alkaline phosphatase) immunostaining method was applied to cryostat sections from unfixed snap-frozen tissue samples. Immunoglobulins IgG, IgM, IgA, complement factors and light chains were reactive in biopsies of normal nerves as well as of vasculitic and nonvasculitic neuropathies. A strong reaction against IgE in the epineurial vessel walls was only seen in cases of Churg-Strauss-vasculitis. Antibodies against MHC class II (HLA DR) were positive in most of vasculitic infiltrates. Vascular endothelial cells were positive with anti MHC class I in all biopsies. A typical finding in all vasculitic neuropathies was the infiltration of epineurial vessels with CD4 positive and, to a lesser extent, CD8 positive lymphocytes. CD22 positive lymphocytes (B cells) have only been seen in about one third of vasculitic neuropathies. CD16 positive cells (NK-cells or neutrophils) could be demonstrated only in two biopsies. CD68 positive cells (macrophages) are frequently seen in most cases of neuropathy regardless of their etiology. The results support the concept of a primary T-cell mediated process against epineurial vessels as the most important mechanism in the pathogenesis of vasculitic neuropathies. In some cases with small epineurial infiltrates the vasculitic process can only be recognized with antiobodies against CD4 or CD8. Therefore, the immunohistochemical evaluation of sural nerve biopsies may be helpful for identifying cases with microvasculitis     

Primary and secondary vasculitic neuropathy

Necrotizing vasculitis occurs as a primary phenomenon in connective tissue disorders and cognate fields, including polyarteritis nodosa and the Churg and Strauss syndrome variant, rheumatoid arthritis, systemic lupus and Wegener’s granulomatosis. In all these conditions focal and multifocal neuropathy occur as a consequence of destruction of the arterial wall and occlusion of the lumen of small epineurial arteries. Vasculitis may also complicate the course of other conditions ranging from infection with the HIV and with the B and C hepatitis viruses to diabetes and sarcoidosis. Pathologically polymorphonuclear cells are present in the infiltrates of the vessel wall in primary necrotizing vasculitis, while in secondary vasculitis the inflammatory infiltrate is mainly composed of mononuclear cells. In all instances symptomatic vasculitis requires corticosteroid to control the inflammatory process and prevent further ischemic nerve lesions.