S. Sivieri

Cytokine pattern in the cerebrospinal fluid from patients with GBS and CIDP

Macrophage-colony stimulating factor (M-CSF) and, less frequently, IL-1 beta and IL-6 were detected in the cerebrospinal fluid (SF) from Guillain-Barré syndrome (GBS) patients. IL-1 alpha, IL-2, IL-10, TNF alpha, and IFN gamma were not found. Detectable cytokine levels were not observed in chronic inflammatory demyelinating polyneuropathy (CIDP) SF nor in any of the sera studied. These findings suggest a prominent intrathecal activation of cells of the monocyte/macrophage lineage (Mø) in GBS, and further support the hypothesis of a crucial role for Mø in GBS immunopathology.

Cerebrospinal fluid analysis in HIV-1-infected children: immunological and virological findings before and after AZT therapy.

Immunological and viral studies were conducted on cerebrospinal fluid from 31 HIV‐1‐infected children, of whom 23 were neurologically asymptomatic and 8 had progressive encephalopathy. After AZT treatment, a second cerebrospinal fluid specimen was obtained from 15 children, 11 of whom were neurologically asymptomatic and 4 had progressive encephalopathy. Virus isolation and p24Ag detection were more frequent in children with progressive encephalopathy than in asymptomatic children (66% versus 12%) and were inversely correlated with intrathecal HIV‐1‐antibody detection (anti‐gag AB: 25% versus 70%). High concentrations of interleukin‐10 (IL‐1p) and IL‐6 were found in children with progressive encephalopathy (50% and 37%, respectively), but low levels were also detected in some asymptomatic children (13% and 9%, respectively). Tumour necrosis factor‐a (TNFa) was not found. AZT treatment induced disappearance of p24Ag in cerebrospinal fluid, as well as a marked reduction in cytokine levels. Cytokine determination may be useful in monitoring AZT treatment in children with progressive encephalopathy.

M-CSF production by HIV-1-infected monocytes and its intrathecal synthesis implications for neurological HIV-1-related disease

Macrophage-colony stimulating factor (M-CSF) is detectable in the cerebrospinal fluid (SF) of HIV-1-infected patients, and may be produced intrathecally by both reactive astrocytes and cells of the monocyte/macrophage (MO) lineage, microglial cells included. Since MO constitute the target cells for HIV-1 in the central nervous system (CNS), the culture conditions that induce M-CSF production by HIV-1-infected MO were studied. MO cultures infected with supernatants (SN) of HIV-1-infected peripheral blood lymphocyte (PBL) cultures produced only trace or undetectable amounts of M-CSF. Co-cultures of MO with normal PBL released high amounts of M-CSF, suggesting that viable cell-to-cell interactions are required to induce cytokine production by MO and/or PBL. M-CSF production was markedly increased in the MO co-cultured with HIV-1-infected PBL, thus implying that HIV-1 induces increased cytokine synthesis/release by MO and/or PBL only when cell membrane-associated messages are operating. Intracerebrally synthesized M-CSF by HIV-1-infected MO may play a role in promoting viral replication/spread within the CNS, and inducing brain damage by stimulating microglia proliferation, and neurotoxic factor release by these cells.

Cerebrovascular and neurological disorders associated with antiphospolipid antibodies in CSF and serum

Paired serum and cerebrospinal fluid (CSF) samples from 70 patients with inflammatory and non-inflammatory neurological diseases, as well as 10 sera from patients with primary antiphospholipid syndrome (PAS), six of which presented with cerebrovascular ischemic syndromes, were studied for the presence of anticardiolipin antibodies (ACA) of the G and M classes. PAS sera and some selected paired CSF and serum specimens, were also analyzed for the presence of anti-phosphatidylserine (PS) and anti-phosphatidylethanolamine (PE) antibodies. High levels of IgG and IgM ACA were synthesized intrathecally only in patients with neurosyphilis. Patients with other infectious or inflammatory neurological diseases very rarely showed detectable levels of ACA in serum and/or CSF. ACA were found not only in patients with untreated PAS but also in the serum of 3/7 patients with migraine, thus confirming a relationship between ACA and vascular disorders. The search for PS and PE antibodies disclosed that in PAS patients the serum titers of these antibodies mirrored ACA IgG and IgM titers, while they were never found in the CSF.

Multiple sclerosis: IL-2 and sIL-2R levels in cerebrospinal fluid and serum. Review of literature and critical analysis of ELISA pitfalls.

The presence of interleukin-2 (IL-2) and soluble IL-2 receptors (sIL-2R) in the serum and cerebrospinal fluid (CSF) of patients suffering from multiple sclerosis (MS) has been extensively investigated. These studies, however, have produced conflicting results. The only significant finding concerns the frequent detection of increased sIL-2R levels in the serum in patients with relapsing-remitting MS (RRMS), especially after a short interval of time from the last relapse. Whether this finding can be used for clinical purposes requires further investigation. A standardization of the ELISA methods used to detect cytokines in biological fluids is urgently needed. Increased serum and/or CSF levels of IL-2 and sIL-2R strongly confirm a CD4+Th1 activation.

Protection from experimental autoimmune encephalomyelitis (EAE): non-depleting anti-CD4 mAb treatment induces peripheral T-cell tolerance to MBP in PL/J mice

Following pre-treatment with a non-depleting anti-CD4 mAb (H129.19) that produces long-lasting receptor saturation, PL/J mice were fully protected from experimental auto-immune encephalomyelitis (EAE) induced by injection of myelin basic protein (MBP). These mice did not develop EAE following MBP re-challenge 5-10 weeks later when the CD4+ cells were no longer coated by the mAb and their lymph node cells were specifically unresponsive to MBP stimulation in vitro. Moreover, superantigen staphylococcal enterotoxin B (SEB) inoculation, which re-induces EAE in MBP immunized mice, failed to activate encephalitogenic T-cells in anti-CD4 + MBP treated mice, even after MBP re-challenge, indicating that tolerance in the peripheral T-cell compartment was achieved. However, MBP re-challenge 16 weeks later, but not SEB, produced an acute episode of EAE in these mice, while it failed to induce disease in a parallel group of adult thymectomized mice. These results indicate that no memory of the first priming exists at this time and that new MBP-specific T-cell precursors are peripheralized and produce EAE after MBP recognition.

Time-course of interleukin-2 receptor expression in interferon beta-treated multiple sclerosis patients

The time-course of CD25 (the 55-kD/alpha subunit of the interleukin-2 (IL-2) receptor) expression on CD4+ T lymphocytes, and serum levels of soluble IL-2 receptors (sIL-2R) and IL-2 were evaluated in relapsing-remitting multiple sclerosis (RRMS) patients treated with interferon beta-1b (IFNbeta1b). Peripheral blood samples were collected before therapy (T0), and 1 (T1), 2 (T2), 3 (T3), 6 (T4), and 12 (T5) months after therapy initiation. While at T1 and T2, half the patients showed an increased number of circulating CD4+ CD25+ lymphocytes and an up-regulation of CD25 expression, at T3 this T-cell subset was significantly reduced in all the patients. From T4 to T5, however, the progressive return to pretreatment values was observed. Serum sIL-2R levels were not significantly affected by IFNbeta1b at any time point. IL-2 was detected in only a few patients at T0, and never at T1 to T5. The transient up-regulation of CD25+ expression that occurred in about 50% of the patients may explain the unchanged relapse rate observed during the first 2 to 3 months after starting IFNbeta1b therapy. Our study demonstrates that IFNbeta1b down-regulates CD25 expression in vivo. This effect, however, was observed only after 3 months of therapy, and was followed by the return to pretreatment values after 6 to 12 months. Taken all together, our findings suggest that IFNbeta1b only transiently affects CD25 expression in vivo, and that this effect cannot account for the reported long-lasting beneficial action of IFNbeta1b on RRMS.

Induction of peripheral T cell tolerance to MBP in pl/j mice by a non depleting anti-CD4 mAb treatment *

Following pre-treatment with a non dspleting antlCD4 mAb (Hl29.18), which induces long-lasting receptor saturation, PUJ mice were fully proGcad from experimental autoimmune encephalomyelitir (EAE) induced by injection of myelin basic protein (MBP). Lymph node cells from antiCM+ YBP-treated mice were specffically unreqonsive to YBP stimulation in vitro and these mice did not develop EAE following MBP re-challange 5 weeks later when the CD4+ cells were no longer coated by the mAb. Moreover, superantigen staphylococcal enterotoxin 6 (SEB) inoculation which rolnduces EAE in MBP kmtunixed mice, failed to activate encephalitogenic T ceils in antiCD4+ MBPtreated mice indkzatlng that 1 IymphocyW tolerance was established. However, MBP m-challenge 16 waeks later, but not SEB treatment, could produce acute EAE in these mice. This obse~~atlon indicates that no memory of the first priming existed at this time, and that new MBP-specific peripheralizad T cell preclNsors had roached the threshold to produce disease after MBP recognition. On the whole, our findings suggest that tre8tment of PUJ mice with non depleting antlCD4 mAb befors MBP challanga Induces MBPspecific hoies in the peripheral CM call repettoire.

IL-10 is intrathecally synthesized in HIV-induced/related CNS diseases, but it is not produced by HIV-infected mononuclear cells

INTRODUCTION: Intracembrst transplantation of lymphocytes from patients with MS into severe combined immunodeflcienoy (SCID) mice has been reported to reproduce demyelinating lesions typical of MS. The validity of these studies has been disputed. MATERIALS AND METHODS: PBLs from 7 patients with MS were transplanted by I.P. injection into 28 SCID mice (MSSCID). Seven animals transplanted with PBLs from 2 healthy subjects (huSCID) were used as controls. Animals were sacnficed between 2 and 8 weeks alter transplantation. RESULTS: PCR analysis aimed to the HLA-DQ region showed presence of human cells in neural tissues of MS-SCID mice. Immunocytochemical analysis showed that the majority of cells present in the brain of MS-SCID were T-cells and resided in the meningeal spaces or choroid plexuses. Isolated human cells were tound in the immediate submeningeal cerebral parenchyma. However, human lymphocytes were also found in brains of 2/7 hu-SCID mice. No signs or symptoms of neurological impairment were observed in MS-SCID. CONCLUSIONS: Our results indicate that T-calls from MS patients can reach the central nervous system of SCID mice when I.P. injected. However, no immuno-pathological signs of neurological impairment can be observed in this model. In our hands the I.P. MS-SCID mouse is not a valid tool for studies on MS immunopathology.