Decreased expression of HLA-DR antigens on monocytes in patients with multiple sclerosis

Cytokine serum levels, autologous mixed lymphocyte reaction and surface marker analysis in never medicated and chronically medicated schizophrenic patients

A number of immunological parameters were studied in 82 DSM-III-R diagnosed schizophrenic patients (53 first drug-naive and 29 medicated chronic patients) as well as 62 healthy blood donors. The serum levels of interleukin-2 (IL-2), interleukin-1 beta (IL-1beta) and tumour necrosis factor-alpha (TNF-alpha) were measured and correlated with cellular immunity, as assessed by the autologous mixed lymphocyte reaction (AMLR). T lymphocyte subsets were also examined. The above immune parameters were reassessed in a subgroup of 11 first-episode, drug-naive patients 1month after neuroleptic medication. IL-2 serum levels were significantly lower, and IL-1beta and TNF-alpha were significantly higher in schizophrenic patients compared with healthy donors (P<0.001); no significant difference was observed between the two patient groups (medicated and not medicated). Abnormal cytokine serum levels were associated with decreased AMLR responses in vitro. Increased percentages of activated CD4+ and CD16+ natural killer cells, as well as cells expressing ICAM-1 adhesion molecules and IL-2 specific receptors, were detected in the patients. Immunophenotype studies revealed a higher percentage of cells expressing IL-2 receptors in medicated chronic schizophrenic patients compared with drug-naive patients. The abnormal cytokine production in vivo, along with the low AMLR responses in vitro, and the high percentage of activated CD4+ lymphocytes presented in this study suggest alterations in the immune system of schizophrenic patients (medicated or not medicated) consistent with immune activation.

Effects of an anti-IL-10 monoclonal antibody on rIFNbeta-1b-mediated immune modulation. Relevance to multiple sclerosis

The mechanism of action of recombinant IFNbeta1b (IFNbeta-1b), as a therapy for multiple sclerosis (MS), is still unknown but may result from the enhancement of ConA-induced suppressor cell function and the inhibition of IFNgamma secretion by lymphocytes. We previously demonstrated that IFNbeta-1b stimulated modest amounts of IL-10 secretion by monocytes and IL-10 activity, as cytokine synthesis inhibitory factor, was normal in MS. To determine whether IL-10 plays a role in IFNbeta-1b modulation of immune function in MS, we studied ConA-induced suppressor cell function and IFNgamma production in presence of IFNbeta-1b and an anti-IL-10 monoclonal antibody (mAb). Anti-IL-10 mAb significantly reduced the effect of IFNbeta-1b on ConA-induced suppressor cell function and IFNgamma production in healthy subjects; MS patients showed a trend of inhibition. We hypothesized that IL-10 may play a role in mediating the effects of IFNbeta-1b on suppressor cell function and IFNgamma production but suppressor molecules other than IL-10 could be also involved.

IFN-beta 1b treatment of relapsing multiple sclerosis has no effect on CD3-induced inflammatory or counterregulatory anti-inflammatory cytokine secretion ex vivo after nine months

Multiple sclerosis (MS) is presumed to be a T-cell mediated chronic inflammatory disease of the central nervous system. We have previously reported that IFN-beta 1b (Betaseron) decreases CD3-mediated TNF-alpha secretion but increases another inflammatory cytokine, IL-6 after three months of treatment. We have now examined cytokine secretion of peripheral blood mononuclear (PMNC) cells after stimulation with OKT3 (anti-CD3) monoclonal antibody (mAb) or Con A in subjects with clinically stable relapsing MS before and three, six and nine months after initiating IFN-beta 1b treatment. At nine months Con A-induced TNF-alpha secretion decreased significantly below baseline but IFN-gamma secretion increased above baseline. There were no significant changes in Con A-induced IL-4 over the six month period and no changes in IL-10 and IL-2 over the nine month period. After nine months on treatment the CD3-induced TNF-alpha and IFN-gamma secretion was not significantly different from the original baseline values. Increased CD3-mediated IL-6 secretion in on-treatment compared to pre-treatment samples at three months gradually declined to baseline values by nine months on-treatment. There was no significant changes from baseline compared to nine months on-treatment in CD3-mediated IL-2, IL-4, IL-10. IFN-beta 1b (Betaseron) treatment has no clear persistent effect on CD3-induced inflammatory or counterregulatory anti-inflammatory cytokine secretion.

Methylprednisolone attenuates interferon-beta induced expression of HLA-DR on monocytes

The effect of methylprednisolone on constitutive and interferon-beta (IFN-beta) induced HLA-DR expression on monocytes from multiple sclerosis (MS) patients was investigated. Constitutive HLA-DR expression was reduced by 50% following a single dose (500 mg) of intravenous methylprednisolone (IVMP). Stimulation with natural IFN-beta, in vitro, resulted in a 20 fold increase in HLA-DR expression. Following IVMP, IFN-beta inducible HLA-DR levels were reduced (non-significantly) by 20-30%. Experiments in which monocytes from normal subjects and MS patients were pre-treated in vitro with methylprednisolone prior to IFN-beta stimulation revealed that induction of HLA-DR was significantly inhibited; in contrast, IFN-beta induced HLA-DR expression was not down-regulated following subsequent in vitro treatment with methylprednisolone. These findings suggest that the immunomodulatory effects of IVMP could be attenuated in MS patients receiving regular IFN-beta therapy.

Transient immunomodulation by intravenous methylprednisolone treatment of multiple sclerosis

The extent and duration of immunomodulation induced by high-dose corticosteroid treatment of clinical relapse of multiple sclerosis was investigated. Ten patients treated with a 5 day course of intravenous methylprednisolone (IVMP) (500 mg daily) were studied. Circulating lymphocyte subpopulations and mitogen-induced interleukin 2 (IL-2) and gamma-interferon (gamma-IFN) production were determined immediately before initiation of therapy (day 1), during therapy (24 h after first dose, day 2) and at 24 h and 1 week post therapy (days 6 and 12 respectively). T-cell subpopulation (CD3, CD4, CD8, CD4CD45RA, CD4CD45RO) levels fell within 24 h of initiation of therapy, rebounded above pretreatment levels at day 6 and normalised 1 week post therapy. Despite a reduction in total T-cell numbers during treatment, the gamma delta T-cell subpopulation was not significantly altered. HLA-DR expression on B cells and monocytes declined transiently on day 2 to approximately 50% of pretherapy levels. IL-2 and gamma-IFN production were reduced during therapy but returned to baseline levels by 24 h post therapy. The effects of IVMP on lymphocyte distribution and function appear to be short-lived and, therefore, may not be responsible for the rapid improvement associated with this form of treatment.

Parkinson's disease and immunological abnormalities: increase of HLA-DR expression on monocytes in cerebrospinal fluid and of CD45RO+ T cells in peripheral blood

The etiology of Parkinson's disease is mainly unknown. Immune abnormalities have been described, but the cause of such abnormalities has not been resolved. We examined by two-colour flow cytometry HLA-DR antigen expression on monocytes from cerebrospinal fluid (CSF) and blood and, moreover, lymphocyte subpopulations (CD4+ CD45RO+, CD4+ CD45RA+, CD8+ CD11b+high) in peripheral blood from patients with Parkinson's disease compared with age-matched patients with other neurological diseases (OND) and tension headache. We found higher HLA-DR expression on CSF monocytes compared with blood monocytes. This difference was restricted to Parkinson's disease patients. T helper cell analysis revealed a decreased percentage of CD45RA+ "naive" and an increased percentage of CD45RO+ "memory" T cell subset from CD4+ T cells in peripheral blood of patients with Parkinson's disease compared with patients with tension headache. The proportions of CD8+ CD11b+high "suppressor" T cells remained unchanged, among the three patient groups compared. A selective loss of CD4+ CD45RA+ cells, previously observed in diseases like multiple sclerosis and Down's syndrome as compared with healthy controls suggests a common immunological abnormality in neurological disorders.

Functional defects in peripheral blood T cells of multiple sclerosis patients. Diminished in vitro responsiveness in accessory cell dependent activation systems

Function and phenotype of peripheral blood (PB) T cells in multiple sclerosis (MS) patients were analyzed. In whole blood cultures, T cell proliferation of multiple sclerosis (MS) patients, using soluble CD3 mAb and CD2 mAb as stimulants, was reduced in comparison to healthy controls. A similar difference was seen when isolated PBMC were tested after stimulation with soluble CD3 mAb. However, in accessory cell-independent activation systems, i.e. after stimulation of PBMC with immobilized CD3 mAb or after co-stimulation with CD28 mAb, both patients and controls responded equally well. Phenotypical analysis of the circulating T cell population showed that there were no differences in the percentage of CD26+, 'memory' (CD45R0+) or 'effector' (CD4+CD45R0+CD27-) cells between MS patients and healthy controls. Finally, although MS patients did show an enhanced proportion of 'naive' (CD4+CD45RA+) T cells, this did not correlate with the observed functional defects.

On the role of monokines in the generation of nonspecific suppressor T cell activity in vitro

We examined the role of endogenously produced interleukin 1 beta (IL-1 beta) and tumor necrosis factor-alpha (TNF-alpha) in lectin-induced nonspecific suppressor activity in vitro. The cultures consisted of highly purified T lymphocytes, autologous monocytes and phytohemagglutinin (PHA). Kinetic studies revealed peak levels for both TNF-alpha and IL-1 beta production 4 hr after initiation of cultures which then declined and reached minimal levels on day 3. At this time point maximal levels of interleukin-2 (IL-2) were detected which declined sharply 24 hr later. The decline in cytokine levels in culture supernatants was most probably due to their consumption by the mononuclear cells which were found to express specific receptors for IL-1 beta, (IL-1 beta R), TNF-alpha (TNF-alpha R) and IL-2 (IL-2R) after 3- and 6-days of culture. After their first cycle of production and consumption both monokines were reproduced and the events followed the same patterns as for the first cycle: both monokines were first produced and at the time point of their consumption, IL-2 production reached maximal levels. The requirement for IL-1 beta and TNF-alpha in both IL-2 production and generation of suppressor activity was shown by three different approaches which included (a) blocking of HLA-DR molecules on monocytes which prevented monokine consumption during the early stages of culture, (b) blocking of HLA-A,B,C molecules on monocytes which prevented monokine consumption and IL-2 production late in culture, and (c) neutralization of monokine activity late in culture which resulted in highly reduced IL-2 production. T lymphocytes harvested from such cultures exhibited diminished suppressor activity. Our data suggest that the generation of nonspecific suppressor cell activity in vitro represents a complex system that requires cell interactions via self-major histocompatibility complex (MHC) antigen recognition and two cycles of cytokine production, where IL-1 beta and TNF-alpha production and consumption is a prerequisite for IL-2 production. Since lectin-induced nonspecific suppressor activity in vitro is deficient in certain autoimmune disorders the data presented herein might help in understanding the cellular basis for this immunodeficiency.

Monocyte phenotype in blood and cerebrospinal fluid: compartment-specific pattern is unrelated to neurological disease

An immunocytochemical study of surface and cytoplasmic markers of the monocyte/macrophage lineage was undertaken on peripheral blood (PB) and cerebrospinal fluid (CSF) cells in patients with multiple sclerosis (MS) or other neurological diseases (OND) and in three healthy controls. Size and granularity were assessed by means of cytofluorimetric analysis. Fewer monocytes were positive for complement receptors 1 and 3, myeloperoxidase, KiM6, IOM-3 and CD14 in CSF than in PB. Only DR-positive monocytes were present with the same frequency in the two compartments. There was no difference in the monocyte phenotype between patients and healthy controls. Furthermore, there was no difference between patients with MS or OND. Cytofluorimetric analysis showed that in CSF, regardless of clinical status, few cells displayed the physical features of blood monocytes. A population of granular and large granular cells that was not normally present among PB mononuclear cells was recognized in the CSF. A large proportion of these cells was able to adhere to plastic and--when sorted--displayed the morphology and surface markers of monocyte lineage. The results of our study demonstrate compartment-specific differences in the monocyte phenotype between CSF and PB but suggest that these changes may be unrelated to the investigated neurological diseases.

Phenotype analysis of unstimulated lymphocytes and anti-CD3-stimulated proliferating T-cells from cerebrospinal fluid and peripheral blood in patients with multiple sclerosis and other neurological diseases

In 15 patients with multiple sclerosis (MS) and in 11 patients with other neurological diseases (OND), the phenotype of fresh unstimulated CSF and PB mononuclear cells and of "in vitro" expanded T-cells was studied by monoclonal antibody stain and cytofluorimeter analysis. A compartment-specific decrease of CD8+Leu8+ and CD8+Leu8- cells in CSF was detected; moreover, lower levels of CD8+Leu8- cells were seen in MS than in OND patients, both in CSF and in PB. Although the percentages of unstimulated CSF CD4+ cells did not differ between MS and OND, a higher proportion of "in vitro" expanded CD4+ T-cells was obtained from MS patients than from OND. Among MS patients, T-cell growth was very scarce or absent in those sampled during relapses. The results suggest alterations both within the CD4+ "helper" and the CD8+ "suppressor-cytotoxic" populations in the CSF of MS patients, and stress the relevance of functional analysis in conjunction with phenotype studies.

Defective HLA class II expression in monocytes of type 1 diabetic patients. The Childhood Diabetes in Finland Study Group

Activation of T-helper cells is modulated by the intensity of HLA class II expression on antigen-presenting cells. We evaluated whether any abnormalities could be found in the expression of HLA-DR and -DQ molecules on monocytes in type 1 diabetic subjects. DR and DQ molecules were induced by human recombinant interferon-gamma on cultured peripheral blood monocytes obtained from children with type 1 diabetes (N = 28), their siblings (N = 18) and unrelated healthy controls (N = 21). The response in DQ induction varied considerably between different individuals, but the average responsiveness was significantly lower in patients compared to siblings and unrelated controls. In addition to the diabetic subjects deficient DQ induction was also observed in three siblings. One of them had high levels of islet cell antibodies and presented with diabetes 6 months later, and another had active rheumatoid arthritis. The response in DR induction was also slightly lower in patients than in siblings, but did not differ from that in unrelated controls. The results suggest abnormalities in the regulation of HLA class II expression in type 1 diabetic subjects possibly reflecting the ongoing autoimmune process.

Interleukin-2 receptor expression on blood monocytes of patients with multiple sclerosis

We studied the expression of class II MHC product (HLA DR) and IL-2 receptor on circulating monocytes (M phi) in MS patients, neurological and healthy controls, by double color flow cytometry. In all groups most M phi were DR+ without significant differences. More interesting, low percentages of IL-2+ M phi were detectable in healthy and neurological controls, whilst a few MS patients with active disease showed higher levels. This finding is in agreement with similar studies in other T-cell mediated diseases and with the report of rare IL-2+ macrophages in MS plaques. Although the actual role of IL-2+ M phi in the immune response still needs elucidation, our findings suggest their relevance to the pathological process of demyelinating disease.

Monocytes in active multiple sclerosis: intact regulation of HLA-DR density in vitro despite decreased HLA-DR density in vivo

HLA-DR expression on circulating monocytes varies as a function of disease activity in patients with multiple sclerosis (MS), a putative immunopathological demyelinating disorder. Specifically, monocytes isolated from subjects with active MS exhibit reduced HLA-DR antigen density, and immunoregulatory aberrations such as impaired T lymphocyte-mediated suppression correlate strongly with this quantitative defect. To address the mechanism underlying this phenomenon, we compared in vitro regulation of HLA-DR by interferon beta (IFN beta), interferon gamma (IFN gamma), and lipopolysaccharide (LPS) in monocytes from patients with stable and active MS and normal individuals. Interferon-gamma and LPS enhanced monocyte expression of HLA-DR equally in both MS patient groups, suggesting that underexpression of HLA-DR in active MS was not explained by impaired in vivo monocyte responsiveness. Furthermore, interferon regulation of HLA-DR in normals and stable MS subjects was indistinguishable, indicating that aberrant interferon-mediated regulation of class II major histocompatibility complex (MHC) on circulating monocytes does not appear to be a characteristic of the MS disease state.

Prothymosin-alpha enhances HLA-DR antigen expression on monocytes from patients with multiple sclerosis

Monocytes from patients with multiple sclerosis (MS) express decreased numbers of class II major histocompatibility complex (MHC) antigens in peripheral blood and are poor stimulators in the autologous mixed lymphocyte reaction (autoMLR). We assessed the effect of prothymosin-alpha (ProT alpha) on the expression of MHC class II antigens by monocytes. Immediately after isolation, monocytes were analyzed for MHC class II antigen expression using a radiolabelled monoclonal antibody specific for a monomorphic determinant on HLA-DR antigens. After incubation with ProT alpha we observed significant increases in HLA-DR antigens on MS monocytes (1.5- to 4-fold increase compared to freshly isolated monocytes). Kinetic analysis revealed that enhancement peaked after 2 days of incubation with ProT alpha. The increase in HLA-DR antigen on MS monocytes resulted in the restoration of the deficient autoMLR in MS patients. This is the first demonstration suggesting a link between HLA-DR antigen expression and cellular immune defects in MS. The significance of low autoMLR responses for T suppressor levels in MS patients is discussed.