Multiple sclerosis in Northern Ireland: a historical and global perspective

The uneven worldwide distribution of multiple sclerosis has been of interest to epidemiologists, neurologists and statisticians for over a century, prevalence rates for the disease apparently being determined by variations in age, gender, geography, race and ethnic group. Northern Ireland has been recognised as an area of high MS prevalence since the truly seminal work of Allison and Millar almost 50 years ago. The most recent study in Northern Ireland was undertaken in 1996 and involved the neighbouring districts of Coleraine, Ballymena, Ballymoney and Moyle (population, 151,000). Overall, 254 definite and probable cases were identified (prevalence: 168.2/100,000) with a further 34 suspected cases (overall prevalence: 190.7/100,000). Females predominated (ratio, 2.1:1) and the average age at onset was 31.6 years. The highest age specific prevalence rate for females was in the 35-44 years old age group (519.6/100,000) and for males was in those aged 55-64 (292.3/100,000). The spectrum of disability was broad and 20% could be considered to have relatively "benign" disease. These figures sadly confirm that Northern Ireland has one of the highest and rising MS prevalence rates in the world and implies an enormous potential for societary costs.

Maximal aerobic power, lactate threshold, and running performance in master athletes

PURPOSE

This study sought to determine how lactate threshold (LT) is related to running performance in older male and female runners, if LT changes significantly with age, and if gender alters the relationship between LT and performance in older runners.

METHODS

Subjects were 168 master runners (111 men, 57 women) selected from a longitudinal study, who ran at least 10 miles x wk(-1) for 5 yr or more. VO2max was measured on a treadmill and body composition by hydrostatic weighing. Blood samples taken each minute of exercise were analyzed for lactate concentration and LT determined as the breakpoint in lactate accumulation. Performance times and training histories were self-reported by questionnaire.

RESULTS

Men had significantly greater body mass, fat-free mass (FFM), and VO2max (L x min(-1); mL x kg(-1) x min(-1)) than women. FFM and VO2max (L x min(-1); mL x kg(-1) x min(-1)) declined with age in both men and women. Running performance was significantly different between men and women and declined with age in both. LT (L x min(-1); mL x kg(-1) x min(-1)) was significantly different between men and women, and declined significantly with age in men, whereas LT (%VO2max) did not differ between men and women and increased significantly with age in both. VO2max (mL x kg(-1) x min(-1)) was the most significant predictor of performance in both men and women, whereas LT (L x min(-1)) added to the prediction of 5-km and 10-km performance in women.

CONCLUSION

The results of this study demonstrate that VO2max (mL x kg(-1) x min(-1)) is a better predictor of performance than LT in older male and female runners. Additionally, LT as a percentage of VO2max increases significantly with age.

An evaluation of interleukin genes fails to identify clear susceptibility loci for multiple sclerosis

Differential expression of interleukins may influence susceptibility to inflammatory diseases such as MS. IL-1a production is increased in MS patients during acute relapse, IL-2 receptor (IL-2R) secretion correlates with disease activity in several inflammatory disorders and is variable in MS. Both IL-4 and IL-10 expression vary significantly with relapse/remission in MS and IL-9 is postulated to inhibit steroid-induced apoptosis. To examine the influence of interleukin (IL) genes on MS susceptibility and clinical course, gene association studies using separate polymorphic microsatellite markers for il-1 alpha, il-2, il-2r beta, il-4 il-9 and il-10 were performed, incorporating 150-177 relapsing-remitting or secondary progressive MS (RR/SPMS) patients, 100-110 primary progressive (PPMS) patients and 152-210 controls. No significant differences existed in allele frequencies between either MS group and controls for any of the interleukin microsatellite markers studied, nor were statistically significant differences observed in PPMS vs. RR/SPMS for any marker. These data indicate that the IL-1 alpha, IL-2, IL-2R beta, IL-4, IL-9 and IL-10 genes are unlikely to be susceptibility loci for MS in this population.

Effect of platelet-derived growth factor receptor-alpha and -beta blockade on flow-induced neointimal formation in endothelialized baboon vascular grafts

The growth of neointima and neointimal smooth muscle cells in baboon polytetrafluoroethylene grafts is regulated by blood flow. Because neointimal smooth muscle cells express both platelet-derived growth factor receptor-alpha and -beta (PDGFR-alpha and -beta), we designed this study to test the hypothesis that inhibiting either PDGFR-alpha or PDGFR-beta with a specific mouse/human chimeric antibody will modulate flow-induced neointimal formation. Bilateral aortoiliac grafts and distal femoral arteriovenous fistulae were placed in 17 baboons. After 8 weeks, 1 arteriovenous fistulae was ligated, normalizing flow through the ipsilateral graft while maintaining high flow in the contralateral graft. The experimental groups received a blocking antibody to PDGFR-alpha (Ab-PDGFR-alpha; 10 mg/kg; n=5) or PDGFR-beta (Ab-PDGFR-beta; 10 mg/kg; n=6) by pulsed intravenous administration 30 minutes before ligation and at 4, 8, 15, and 22 days after ligation. Controls received carrier medium alone (n=8). Serum antibody concentrations were followed. Grafts were harvested after 28 days and analyzed by videomorphometry. Serum Ab-PDGFR-alpha concentrations fell rapidly after day 7 to 0, whereas serum Ab-PDGFR-beta concentrations were maintained at the target levels (>50 microg/mL). Compared with controls (3.7+/-0.3), the ratio of the intimal areas (normalized flow/high flow) was significantly reduced in Ab-PDGFR-beta (1.2+/-0.2, P<0.01) but not in Ab-PDGFR-alpha (2.2+/-0.4). Ab-PDGFR-alpha decreased significantly the overall smooth muscle cell nuclear density of the neointima (P<0.01) compared with either the control or Ab-PDGFR-beta treated groups. PDGFR-beta is necessary for flow-induced neointimal formation in prosthetic grafts. Targeting PDGFR-beta may be an effective pharmacological strategy for suppressing graft neointimal development.

Evaluation of the clinical utility of cerebrospinal fluid (CSF) indices of inflammatory markers in multiple sclerosis

OBJECTIVES

Accumulating evidence indicates significant heterogeneity in MS and soluble (s) adhesion molecules are postulated as markers of disease activity. We sought to evaluate intrathecal production of these and other molecules across the clinical spectrum of MS.

METHODS

CSF indices of IgG, sICAM-1, sVCAM-1, sE-selectin and sCD30 were calculated in 17 primary progressive (PPMS) patients, 15 secondary progressive patients (SPMS), 28 relapsing-remitting patients in relapse (RRMSR) and 14 RRMS patients in remission (RRMSNR) using commercially available ELISA kits. Patients had not received any immunomodulating therapy within the previous 6 months. MS patients were compared with 44 patients with non-inflammatory neurological diseases (NINDs).

RESULTS

The most sensitive CSF index at a 90% level of specificity was for IgG which had 93% sensitivity in RRMSR and 92% sensitivity in RRMSNR. Corresponding sensitivity in PPMS and SPMS was 71% and 73% respectively. None of the other indices had sensitivity >50% apart from sVCAM-1 (64% in RRMSR and 52% RRMSNR) and sCD30 (53% in PPMS).

CONCLUSIONS

Unsurprisingly the strongest association in MS was with the intrathecal production of IgG. Similar results in PPMS and SPMS may reflect comparable rates of progression in these 2 groups. Of the other molecules only intrathecal sVCAM-1 production is significantly associated with MS and only in relapsing-remitting disease.

The neuropathology of experimental bovine spongiform encephalopathy in the pig

In an experimental study of the transmissibility of BSE to the pig, seven of 10 pigs, infected at 1-2 weeks of age by multiple-route parenteral inoculation with a homogenate of bovine brain from natural BSE cases developed lesions typical of spongiform encephalopathy. The lesions consisted principally of severe neuropil vacuolation affecting most areas of the brain, but mainly the forebrain. In addition, some vacuolar change was identified in the rostral colliculi and hypothalamic areas of normal control pigs. PrP accumulations were detected immunocytochemically in the brains of BSE-infected animals. PrP accumulation was sparse in many areas and its density was not obviously related to the degree of vacuolation. The patterns of PrP immunolabelling in control pigs differed strikingly from those in the infected animals.

Genetic association studies of tumour necrosis factor alpha and beta and tumour necrosis factor receptor 1 and 2 polymorphisms across the clinical spectrum of multiple sclerosis

Allelic association studies with microsatellite markers around the tumour-necrosis factor (TNF) genes have demonstrated significantly different allele distributions of TNF markers (a and b) between relapsing-remitting/secondary progressive multiple sclerosis (MS) (RR/SPMS) patients and normal controls. Considering the suspected genetic and immunological heterogeneity in MS, we tested this association in primary progressive MS (PPMS) patients. Elevated levels of serum soluble TNF receptors (sTNF-R) are reported in patients with gadolinium enhancing lesions, and animal models suggest a possible therapeutic role of sTNF-RI in MS. Thus we performed similar association studies using markers for the TNF-R genes. Gene association studies were carried out on 199-216 normal controls, 174 RR/SPMS patients and 102 PPMS patients using polymorphic dinucleotide repeat TNF markers (a, b and d), and separate markers for TNF-RI and TNF-RII. Forward primers were fluorescently labelled, polymerase chain reaction (PCR) products were analysed on a fluorescent fragment analyser, and Genescan 672 software was used for allele sizing. Samples were typed for HLA-DR antigens using PCR technology and sequence-specific oligonucleotide probes. TNFa marker allele distributions differed significantly between PPMS patients and controls (P = 0.028), largely attributable to an increase in the 118-bp TNFa allele in PPMS patients (P = 0.00024). Allele distributions were similar in PPMS and RR/SPMS patients (P = 0.91). Logistic regression analysis, however, indicated that these associations were not independent of that with HLA-DRB1*15. For the TNFb marker, the 127-bp allele showed association with both patient categories (PPMS vs. controls, P = 0.010; RR/SPMS vs. controls, P = 0.027), whilst the 128-bp allele occurred more frequently in controls (PPMS vs. controls, P = 0.036: RR/SPMS vs. controls, P = 0.0009). As with the TNFa 118 bp allele, the association with TNFb was not independent of the HLA association. No association occurred with the TNFd marker, and there were also no significant differences in allele frequencies between MS groups and controls regarding the marker for TNF-RI or TNF-RII. In Northern Irish patients the TNF contribution to MS genetic susceptibility is therefore similar across the clinical spectrum of the disease but is not independent of the association with HLA-DRB1*15.

Changes in plasma cytokines induced by interferon-beta1a treatment in patients with multiple sclerosis

It has been postulated that the efficacy of interferon-beta1a in multiple sclerosis may be due to the induction of type 2 cytokines. In this report we demonstrate that after 3 months of therapy, there is no sustained alteration in the plasma levels of type 1 (IL-12, IL-1beta and TNF-alpha) or type 2 (IL-6, IL-10) cytokines, but rather repeated induction of both with each injection. Little alteration is seen in the profile of cytokines induced with time, despite a decline in side effects. This suggests that IFN-beta1a causes repeated transient modulation of cytokine expression, but no sustained deviation in the type 1/type 2 balance.

The inability of hormone replacement therapy or chronic running to maintain bone mass in master athletes

BACKGROUND

Previous studies have demonstrated equivocal findings on the effect of chronic running on bone mass in post-menopausal women. The purpose of this study was to determine the effect of chronic running alone and in conjunction with hormone replacement therapy (HRT) on bone mineral density (BMD) in postmenopausal women.

METHODS

Forty-three women [15 premenopausal 48.1 +/- .4 yrs (Pre); 13 postmenopausal 57.3 +/- 2.3 yrs (Post); and 15 HRT-treated postmenopausal 56.8 +/- 1.5 yrs (PostE)] served as subjects. All were chronic runners (duration > 5 yrs, > 10 miles per week). BMD was determined by dual energy x-ray absorptiometry, VO2 max on a treadmill, body composition by hydrostatic weighing, knee strength by KinCom dynamometer, and training and menstrual history by questionnaire. Analysis of covariance with Tukey post hoc tests was utilized to compare the groups.

RESULTS

The groups were similar in body weight, VO2 max, years training, and miles run per week. Pre and PostE did not differ in total or spine BMD. However, Pre had greater hip BMD than PostE (.973 +/- .03 vs .876 +/- .03 g/cm2; p < .05). As well, Pre had greater BMD of the hip (.973 +/- .03 vs .805 +/- .03 g/cm2; p < .05), spine (1.047 +/- .04 vs .870 +/- .04 g/cm2; p < .05), and total body (1.115 +/- .02 vs .996 +/- .03 g/cm2; p < .05) than Post.

CONCLUSIONS

These results suggest that (a) chronic running + HRT is insufficient to protect hip BMD and (b) chronic running alone provides no protection for bone mass in postmenopausal women.

Eccentric muscle action increases site-specific osteogenic response

PURPOSE

Strain magnitude is known to be a primary determinant of the osteogenic response to loading. However, whether bone adaptation to muscle loading is determined primarily by load magnitude is unclear. The purpose of this study was to determine the contribution of load magnitude from muscle action on the site-specific osteogenic response.

METHODS

Twenty young women (12 exercise, 8 control) served as subjects. Bone mineral density (BMD) of the whole body and mid-femur segment and body composition were determined by dual-energy x-ray absorptiometry. Knee extension and flexion strengths were determined on a KinCom dynamometer, with surface electromyography of the vastus lateralis muscle. Exercise subjects trained three times weekly for 18 wk on a KinCom. One leg trained using eccentric knee extension and flexion, and the opposite leg trained using concentric knee extension and flexion.

RESULTS

Eccentric exercise demonstrated greater force production with lower integrated electromyographic signal (IEMG) compared with concentric exercise. Significant increases in muscle strength occurred in both exercised legs (P < 0.05), which were of similar relative change. However, only the eccentric trained leg significantly increased mid-femur segment BMD (+3.9%, P < 0.05) and mid-thigh segment lean mass (+5.2%, P < 0.05).

CONCLUSIONS

These results suggest that eccentric muscle training is more osteogenic than concentric muscle training and that eccentric training is more efficient by attaining higher force production with lower IEMG.

CD80 (B7-1) and CD86 (B7-2) expression in multiple sclerosis patients: clinical subtype specific variation in peripheral monocytes and B cells and lack of modulation by high dose methylprednisolone

Autoimmune activation of T cells by central nervous system (CNS)-derived antigens is hypothesised to underlie neural damage in multiple sclerosis (MS) patients. The role of coreceptor mediated signalling is currently under investigation in order to further elucidate the immunopathogenic mechanisms implicated and to determine possible targets for immune modulation. We have investigated whether differential coreceptor (B7-1/CD80; B7-2/CD86; CD28) expression on circulating lymphocytes and monocytes is (i) a feature of distinctive clinical subtypes of MS (relapsing-remitting in remission/stable-RRMS; relapsing-remitting in relapse/relapsing-RRMS; primary progressive/PPMS), (ii) related to disease activity, and (iii) altered by high dose corticocosteroid treatment. CD80(+) B cells were significantly reduced (P<0.05) in PPMS (4.0+/-0.8%) compared with normal subjects (CON) (9.1+/-1.1%), stable-RRMS (6.7+/-0.7%) and relapsing-RRMS (7.8+/-0.9%) patients. Comparatively fewer monocytes from relapsing-RRMS patients expressed CD86 (relapsing-RRMS 50+/-4.9% vs. stable-RRMS 75.1+/-3.4%, PPMS 77. 7+/-3.2%, CON 72.1+/-3.6%/P<0.05). Otherwise expression of coreceptors did not vary significantly between the groups. A 3-day course of methylprednisolone therapy did not alter coreceptor expression, but did suppress monocyte and B cell HLA-DR expression. There is evidence for differential coreceptor expression on circulating B cells and monocytes in MS disease subtypes. The biological significance of these findings is discussed in relation to alternative theories regarding coreceptor functioning.

Benign multiple sclerosis? Clinical course, long term follow up, and assessment of prognostic factors

OBJECTIVE

To establish the characteristics of patients following a benign course of multiple sclerosis and evaluate the importance of potential prognostic factors. Also, an assessment of the value of the Kurtzke EDSS as a prognostic indicator has been undertaken in patients previously determined to have benign multiple sclerosis, after 10 years of follow up.

METHODS

A prevalence study in the Coleraine, Ballymena, Ballymoney, and Moyle districts of Northern Ireland used the Kurtzke expanded disability scale score (EDSS) in 259 patients with multiple sclerosis. Of these, 181 had had multiple sclerosis for>/=10 years, 36 having benign disease (EDSS</=3.0) >/=10 years after onset. Clinical and demographic details of the various patient groups, including the minimal record of disability, were compared. The 1987 study in Northern Ireland identified 33 patients with benign multiple sclerosis. Twenty eight were available for follow up in 1996 along with 42 contemporary non-benign patients.

RESULTS

Patients with benign multiple sclerosis were predominantly women (ratio 4.1:1 v 2.1:1) and younger at onset (25.8 v 31.2 years). Commonest symptoms at onset were sensory and optic neuritis (33.3% each). Patients with late onset (older than 40 years) were less likely to have a benign course, more likely to have a progressive course from onset, significantly more likely to have motor disturbance at presentation, and had a lesser female predominance. Optic neuritis was significantly more common in those with a younger age at onset. In the follow up study, patients with benign multiple sclerosis continued to have a more favourable course than non-benign counterparts but progression of disability and to the secondary progressive phase remained significant.

CONCLUSIONS

The association of female sex, early onset, and presentation with optic neuritis and sensory symptoms with a favourable course is confirmed. However, although the EDSS does provide a useful indicator of prognosis, the label "benign multiple sclerosis" is often temporary as apparently benign disease often becomes disabling.

Oral arginine does not stimulate basal or augment exercise-induced GH secretion in either young or old adults

BACKGROUND

Growth hormone (GH) helps maintain body composition and metabolism in adults. However, basal and peak GH decline with age. Exercise produces a physiologic GH response that is subnormal in elderly people. Arginine (Arg) infusion can augment GH secretion, but the efficacy of oral Arg to improve GH response to exercise has not been explored. We investigated whether oral Arg increases GH secretion in young and old people at rest and during exercise.

METHODS

Twenty young (Y: 22.1 +/- 0.9 y; SEM) and 8 old (O: 68.5 +/- 2.1 y) male and female subjects underwent three different trials following determination of their one-repetition maximum strength (1-RM); exercise only (EO; 3 sets, 8-10 reps at 85% of 1-RM; on 12 separate resistive lifts), Arg only (5.0 g), or Arg + exercise. Blood samples were collected between successive lifts, and GH (ng x ml(-1)) was determined via RIA.

RESULTS

In Y vs O: Basal GH secreted (area under the curve) was 543.6 +/- 84.0 vs 211.5 +/- 63.0. During EO, values were 986.6 +/- 156.6 and 517.8 +/- 85.5. Both were significantly lower in the older individuals (p < .05). Oral Arg alone did not result in any increase in GH secretion at rest (310.8 +/- 73.2 vs 262.9 +/- 141.2). When Arg was coadministered during exercise, GH release was not affected in either the young or old and appeared to be blunted in the young compared to the exercise only trial in the young.

CONCLUSION

Based upon these findings, we concluded that oral Arg does not stimulate GH secretion and may impair GH release during resistive exercise.

Relationship between tumour necrosis factor-alpha (TNFalpha) production and a specific multiple sclerosis (MS) associated TNF gene haplotype

OBJECTIVE

To determine if monocyte TNFalpha production from patients homozygous for a specific MS associated TNF gene haplotype is different from that produced in patients either heterozygous for, or without this haplotype.

BACKGROUND

The balance between pro- and anti-inflammatory cytokines is important in the clinical outcome of inflammatory reactions. Levels of TNFalpha, a pro-inflammatory cytokine, is raised in MS as well as being found in acute and chronic MS lesions. A previous population based study in Northern Ireland with polymorphisms spanning the TNF gene region identified a conserved MS associated haplotype in relation to three markers (130: 118: 127 TNF d:a:b) for which 19 MS patients were homozygous.

METHODS

Venous blood collected in EDTA to give a concentration of 10(-3) M was drawn from 16 patients with the conserved MS associated haplotype, 19 patients heterozygous for the haplotype and 17 patients without the haplotype. Mononuclear cells were separated and cultured by standard techniques and levels of TNFalpha and of TNF binding proteins I and II were determined by commercial enzyme-linked immunosorbent assays.

RESULTS

There were no significant differences in TNFalpha production in the 3 h (P = 0.28) or 24 h cultures (P = 0.18) or following stimulation with interferon-gamma (P = 0.17) between the group positive for the conserved haplotype and the group negative for this haplotype. There was also no significant difference when compared to the heterozygote group. No association was found between the MS associated haplotype and levels of either TNF binding protein. A greater proportion of patients with the conserved haplotype had a benign clinical course (P = 0.06).

CONCLUSION

We conclude that whilst a trend exists, we have found no significant association between peripheral TNFalpha production and a specific MS associated TNF haplotype in this population. Paradoxically this haplotype may also predict a more favourable clinical course.

Age-related blunting of growth hormone secretion during exercise may not be soley due to increased somatostatin tone

Age-related declines in growth hormone (GH) secretion may result from augmented somatostatin (SRIH) tone and/or diminished GH-releasing hormone (GHRH) secretion. We assessed GH release during exercise without and with pyridostigmine (PYR), which indirectly suppresses SRIH. GH levels were measured throughout exercise and recovery in 12 young men (mean +/- SEM, 20.8 +/- 0.4 years) and seven old men (66.1 +/- 1.9). The area under the GH curve (GH-AUC) was greater in young versus old men during a short-term maximal exercise test (12.9 +/- 2.8 v 1.5 +/- 0.2 ng x min(-1) x mL(-1), P = .002) and a 1-hour 60% maximal (submaximal, 10.0 +/- 1.5 v 3.0 +/- 1.0 ng x min(-1) x mL(-1), P = .001) cycle exercise bout. PYR increased the GH-AUC in young and old men during maximal (20.9 +/- 5.2 v 4.9 +/- 1.8) and submaximal (12.3 +/- 1.6 v 4.7 +/- 1.5) exercise (P < .05). The greater GH response to maximal versus submaximal exercise suggests a role for adrenergic modulation of GHRH during exercise. However, the failure of PYR to restore the responses of the old to those of the young suggests that increased SRIH tone does not completely explain the age difference in GH secretion during exercise.

A study of the HLA-DR region in clinical subgroups of multiple sclerosis and its influence on prognosis

OBJECTIVE

To investigate the HLA-DR associations in relapsing-remitting/secondary progressive multiple sclerosis (RR/SPMS) and primary progressive MS (PPMS). The HLA-DR2 allele (or its split, HLA-DRB1*15) is felt to be a risk factor for MS, rather than a genetic marker for the population of origin. Some studies have indicated a different HLA-DR antigen profile in PPMS patients compared with those having an initially relapsing-remitting course, only those with relapsing disease showing an increase in HLA-DR2. Association of PPMS with DR4 has been suggested. Several DR alleles have also been felt to influence the prognosis in MS.

METHODS

Genomic DNA was prepared from peripheral blood of 202 RR/SPMS patients identified in a population-based prevalence study, 102 PPMS patients identified throughout Northern Ireland and 398 normal controls (Nor) matched for the postcode areas of those identified in the prevalence study. Samples were typed for the HLA-DR antigens using polymerase chain reaction (PCR) technology and sequence specific oligonucleotide probes (SSOP).

RESULTS

A high incidence of HLA-DRB1*15 was found in each MS group - PPMS (63.73%), RR/SPMS (66.83%) - compared with normals (32.41%), (PPMS vs. Nor, P<0.0001: RR/SPMS vs. Nor, P<0.0001). HLA-DRB1*04 occurred at a lower incidence in both MS groups compared with controls - RR/SPMS (22%), PPMS (30%), Nor (35%). Overall, highly significant differences existed across the full HLA-DR allele distribution (RR/SPMS vs. Nor, P<0.0001, df=12: PPMS vs. Nor, P=0.0007, df=12). No significant differences existed between PPMS and RR/SPMS (P=0.47, df=12), and the allele distributions in benign and aggressive MS were similar.

CONCLUSIONS

These data suggest that in this population, HLA-DRB1*15 is indeed associated with PPMS and that PPMS has a HLA-DR profile distinct from the normal population but not from those with an initially relapsing-remitting course. No single allele is associated with either a good or poor prognosis.

Lack of association of transforming growth factor (TGF)-beta 1 and beta 2 gene polymorphisms with multiple sclerosis (MS) in Northern Ireland

OBJECTIVE

To examine the influence of TGF-beta genes on MS susceptibility.

BACKGROUND

TGF-beta, of which three homologous isoforms exist (1, 2 and 3), is a strongly immunosuppressive cytokine-inhibiting expression of pro-inflammatory cytokines and blocking cytokine induction of adhesion molecules. TGF-beta delays onset of EAE and TGF-beta 1 gene knockout mice develop fatal multifocal inflammatory disease. High TGF-beta levels exist during MS remission whilst E-selectin, whose expression is inhibited by TGF-beta, is found at higher levels in primary progressive disease (PPMS) and it is postulated that the unremitting course of PPMS may be due to low levels of TGF-beta.

METHODS

Gene association studies using separate polymorphic microsatellite markers for TGF-beta 1 and TGF-beta 2 were performed, incorporating 151 relapsing-remitting or secondary progressive MS (RR/SPMS) patients, 104 PPMS patients and 159 normal controls (Nor). Forward primers were 5' end-labelled with 6-Fam, PCR products were analysed on an Applied Biosystems 373A fluorescent fragment analyser and Genescan 672 software was used for allele sizing.

RESULTS

No significant differences existed in allele frequencies between either MS group and controls regarding the TGF-beta 1 marker: RR/SPMS vs Nor (P = 0.48, df = 8); PPMS vs Nor (P = 0.34, df = 8). Similarly there were no associations demonstrated with the TGF-beta 2 marker: RR/SPMS vs Nor (P = 0.24, df = 2); PPMS vs Nor (P = 0.53, df = 2).

CONCLUSION

These data indicate that TGF-beta 1 and beta 2 genes are not loci influencing MS susceptibility, either RR/SPMS or PPMS, in this population.

Serum soluble adhesion molecules in multiple sclerosis: raised sVCAM-1, sICAM-1 and sE-selectin in primary progressive disease

Leucocyte invasion into the central nervous system in multiple sclerosis (MS) is complex, involving T-cell/endothelium interaction dependent upon initial adhesion mediated by molecules such as E-selectin, L-selectin, intracellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-(VCAM-1). Circulating levels of these can be measured by sensitive enzyme-linked immunoassay (ELISA) techniques. To assess whether serum concentrations of soluble adhesion molecules vary across the spectrum of patients with relapsing-remitting (RR), secondary progressive (SP) and primary progressive (PP) MS, we measured circulating levels of soluble (s)E-selectin, sL-selectin, sICAM-1 and sVCAM-1 in serum obtained from 78 PPMS patients, 71 patients with RRMS, 65 patients with SPMS and 66 patients with other neurological disease using commercially available ELISA systems. Levels of serum sVCAM-1 were significantly elevated in PPMS compared with RRMS in remission (P = 0.0001) and in relapse (P = 0.0001), whilst sICAM-1 was significantly elevated in PPMS compared with all other MS groups (vs SPMS, P = 0.006; vs RRMS in relapse, P = 0.003; vs RRMS in remission, P = 0.0001). Serum sE-selectin levels were significantly higher in PPMS compared with all other groups except inflammatory neurological disease (IND) [vs SPMS, P = 0.029; vs RRMS in relapse, P = 0.002; vs RRMS in remission, P = 0.001; vs non-inflammatory neurological disease (NIND), P = 0.002; vs IND, P = 0.076]. In PPMS there was no correlation between levels of any adhesion molecule and disability or disease duration. These results provide evidence for significant immunological heterogeneity in MS and suggest that different leucocyte/endothelial cell interactions may be active in various MS subgroups. It also challenges the hypothesis that PPMS is a less inflammatory form of the disease.