Journal of Clinical Neuroscience 17 (2010) 1009–1013

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Journal of Clinical Neuroscience

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Clinical Study

Clinical profile and HLA-DRB1 genotype of late onset multiple sclerosisin Western Australia

Wei Qiu a,c, Jing-Shan Wu a, Alison Castley d, Ian James e, Joyce Joseph a, Frank T. Christiansen d,f,William M. Carroll a, Frank L. Mastaglia a, Allan G. Kermode a,b,*

a Centre for Neuromuscular and Neurological Disorders, University of Western Australia, Nedlands, Western Australia, Australiab Australian Neuromuscular Research Institute, Department of Neurology, Sir Charles Gairdner Hospital, Queen Elizabeth II Medical Centre, Hospital Avenue, Nedlands 6009,Western Australia, Australiac Department of Neurology, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, Chinad Department of Clinical Immunology and Immunogenetics, Royal Perth Hospital, Perth, Western Australia, Australiae Centre for Clinical Immunology and Biomedical Statistics, Murdoch University and Royal Perth Hospital, Perth, Western Australia, Australiaf School of Pathology and Laboratory Medicine, University of Western Australia, Nedlands, Western Australia, Australia

a r t i c l e i n f o

Article history:Received 4 October 2009Accepted 16 December 2009

Keywords:Clinical profileHLA-DRB1 allelesLate onset multiple sclerosisMultiple sclerosis

0967-5868/$ - see front matter � 2010 Elsevier Ltd. Adoi:10.1016/j.jocn.2009.12.011

* Corresponding author. Tel.: +61 8 93881865; fax:E-mail address: kermode@me.com (A.G. Kermode)

a b s t r a c t

We aimed to characterize the clinical profile and human leukocyte antigen (HLA)-DRB1 genotype ofpatients with late onset multiple sclerosis (LOMS) in Western Australia. The clinical features, laboratorystudies and HLA-DRB1 alleles were analysed in patients with multiple sclerosis (MS) with onset over50 years of age and compared with 100 patients with early onset MS (EOMS). Of a cohort of 829 patientswith MS, 73 (8.8%) presented at over 50 years of age, including 14 (1.7%) over 60 years. Patients withLOMS had a lower female to male ratio, more frequent initial motor dysfunction, less frequent sensorysymptoms and optic neuritis, a more frequent primary-progressive course and shorter time to reachExtended Disability Status Scale (EDSS) scores of 3.0 and 6.0. More LOMS patients were initially misdiag-nosed compared to patients with EOMS. HLA-DRB1*1501 was strongly associated with both LOMS andEOMS compared to the Control subjects, while HLA-DRB1*0801 was over-represented in patients withLOMS. We concluded that patients with LOMS have a different clinical profile when compared to thosewith EOMS. Carriers of HLA-DRB1*0801 may be more prone to develop MS at a later age.

� 2010 Elsevier Ltd. All rights reserved.

1. Introduction

Multiple sclerosis (MS) is typically a heterogeneous demyelinat-ing disease of the central nervous system with a peak incidencefrom the second to fourth decades.1 It is characterized by a broadrange of clinical and laboratory manifestations and is notable fora variable course, prognosis, and response to treatment.

Traditionally MS has been regarded as a disease of young adults.Thus, most studies have arbitrarily defined MS as of late onset ifthe first clinical features presented after the age of 50 years.2–5 Insome studies a cut-off age of 60 years has also been proposed forvery late onset MS (VLOMS).6,7 It remains uncertain whether pa-tients with late onset MS (LOMS) constitute a distinct subset ofMS with regard to clinical presentation and course. Some studiesin Caucasian populations in the northern hemisphere reported thatpatients with LOMS were more likely to have motor and cerebellarpresentations, a more progressive course and a worse prognosis

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than patients with earlier onset disease.2,8 However other studiesreported conflicting results.3,4

Multiple factors, including genetic and environmental influ-ences, could determine the age at which the clinical manifestationsof MS first develop. The association between the human leukocyteantigen (HLA) class II allele DRB1*1501 (DR2) and MS has beenextensively studied in Caucasian populations.9 Although somestudies reported an association between HLA-DR2 and youngerage at onset,10–12 others did not find such an association.13 It re-mains unclear whether genetic factors predispose to a later onsetof MS.

In this study we looked for differences in the clinical profile,laboratory findings and HLA-DRB1 genotype in patients withLOMS and early onset MS (EOMS) from the Perth DemyelinatingDisease Database (PDDD). The major questions addressed werewhether: (i) LOMS constitutes a distinct subpopulation in termsof clinical and laboratory characteristics; and (ii) any HLA-DRB1alleles are associated with later onset of MS. To our knowledge,this is the first comprehensive study on LOMS from the southernhemisphere.

1010 W. Qiu et al. / Journal of Clinical Neuroscience 17 (2010) 1009–1013

2. Methods

2.1. Patients

The PDDD comprises a total of 1004 patients with demyelinat-ing diseases (829 with conventional MS) who were diagnosed andmanaged by the same two MS neurologists (AGK and WMC) from1990 to 2008. The patients in the PDDD represent about two-thirdsof the total MS population of Western Australia. They are derivedfrom various metropolitan areas and are representative of the MSpopulation at large.14 The cut-off age for LOMS was chosen as50 years, which has also been used in most previous studies.2–5

Ninety-three patients with onset age at 50 years or older were ini-tially identified, of whom LOMS was diagnosed in 73; the other pa-tients were classified as having neuromyelits optica (four patients),clinically isolated syndromes (13 patients) and atypical pheno-types (three patients). Of the 73 patients with LOMS, 14 hadVLOMS (onset age P 60 years). The last 100 consecutive patientswith EOMS (onset age 16–49 years) seen in the MS clinic and en-tered in the database were enrolled as controls. All patients withLOMS and EOMS met the criteria for clinically definite MS.15 Dis-ease course was defined as relapsing-remitting MS (RRMS) (includ-ing secondary-progressive) or primary-progressive MS (PPMS)(including progressive-relapsing).16

2.2. Data recorded

The following data were recorded: gender, family history of MS,age at clinical onset and first examination, initial symptoms anddiagnosis, disease duration, clinical course, relapse rate (total num-ber of relapses/disease duration), Extended Disability Status Scale(EDSS) score at last visit, presence of cerebrospinal fluid (CSF) oli-goclonal bands (OCB), frequency of abnormal pattern visual evokedpotentials (VEP) and abnormalities on the most recent MRI studies,and details of disease-modifying therapies.

The MRI were performed on 1.5 Tesla Sonata scanners (Sie-mens; Berlin, Germany) between 2006 and 2009. ConventionalMRI protocols were used in all patients: T1-weighted (400–700/8.4–19 ms, TR/TE); T2-weighted (2975–4560/90–115 ms, TR/TE);proton density (2975–3600/11–34 ms, TR/TE); sagittal and/orcoronal fluid-attenuated inversion recovery (FLAIR) (7500–9999/87–147/2500 ms, TR/TE/IR). The MRI were evaluated by a trainedneuroradiologist and an MS neurologist with MRI expertise (AGK)and abnormalities were diagnosed using the Barkhof criteria.15

Brain lesions were analysed for their distribution (cerebral hemi-spheres, brainstem and cerebellum) and gadolinium enhancement.Spinal lesions were analyzed for their anatomical location in theaxial and sagittal planes, length of focal lesions and the presenceof confluent or diffuse lesions.

Fig. 1. Distribution of age at onset in the whole multiple sclerosis (MS) populationfrom the Perth Demyelinating Disease Database (n = 829 patients) showing thatthere were more females than males and that males had a later overall distributionof onset age than females in the whole MS cohort.

2.3. Human leukocyte antigen typing

High-resolution 4-digit genotyping of HLA-DRB1 alleles wasperformed in 57/73 (78.1%) patients with LOMS from whomDNA samples were available (five were deceased and samplescould not be obtained from the other 11) and 92 EOMS patients(two non-Caucasians were excluded, and six declined to donateblood). The control group comprised 189 healthy Caucasian indi-viduals from the Busselton Community Health Study.17 The HLA-DRB1 typing of the patients and controls was performed using asequencing-based method.18 Automated sequencing was carriedout on an ABI Prism 3730 and 3730xl Genetic Analysers (AppliedBiosystems; Foster City, CA, USA) and HLA-DRB1 analysis was car-ried out using ASSIGNV4.0.1.36 (Conexio Genomics; Applecross,WA, Australia).

2.4. Statistical analysis

The Mann–Whitney U-test was used to compare disease dura-tion, relapse rate and EDSS scores. Differences in the gender fre-quency, clinical course (RRMS/PPMS), onset symptoms andfrequency of OCB were tested using Fisher’s exact test. Comparisonof time to reach an EDSS score 3.0 or 6.0 from onset was carried outvia Kaplan–Meier plots and associated log-rank tests betweenLOMS and EOMS. In comparing the spinal lesion distribution onMRI, the frequency of patients with lesions on the correspondingsegments was compared by Fisher’s exact test, and a corrected pvalue (pcorr) was obtained using the Bonferroni correction. The fre-quencies of HLA-DRB1 alleles between LOMS, EOMS and healthycontrols were compared by logistic regression analysis afteradjusting for gender. Statistical analysis was performed using theStatistical Package for the Social Sciences (version 16.0 for Mac)statistical software (SPSS Inc.; Chicago, IL, USA). A p < 0.05 was con-sidered to be statistically significant.

This study was approved by the Sir Charles Gairdner HospitalHuman Research Ethics Committee and informed consent was ob-tained from all participants.

3. Results

3.1. Demographic and clinical features

The distribution by gender and age of onset in our whole popula-tion of 829 patients with MS is shown in Fig. 1. Patients with LOMScomprised 8.8% of the whole MS cohort. Most (80.8%) were in the50-year to 59-year age bracket, while 14 (19.2%) had onset of symp-toms on or after age 60 years (VLOMS), including seven over65 years. The female to male ratio was lower in the LOMS group thanin EOMS (1.8:1 versus [vs.] 3.3:1, p = 0.045) and was even lower in theVLOMS group (0.8:1). Males had a later overall distribution of onsetage than females in the whole MS cohort (Fig. 1).

As shown in Table 1, patients with LOMS were more likely tohave a primary progressive course than patients with EOMS

Table 1Comparison of clinical findings in patient groups with LOMS and EOMS

LOMS(n = 73)

EOMS(n = 100)

p value

Female to male ratio 1.8 3.3 0.045Family history of MS, % (n) 8.2 (6) 11.0 (11) NSAge at onset, years 55.8 ± 5.3 32.7 ± 7.7 –Age at assessment, years 65.9 ± 8.1 45.5 ± 10.4 –RR to PP ratio 2.3 19.0 <0.0001Disease duration, years 10.2 ± 6.7 12.8 ± 9.5 NSRelapse ratea 0.3 ± 0.3 0.4 ± 0.4 NS

Onset features, % (n)Motor 41.1 (30) 19.0 (19) 0.001Sensory 19.4 (14) 37.0 (37) 0.008Cerebellum/Brainstem 12.3 (9) 11.0 (11) NSOptic neuritis 11.0 (8) 19.0 (19) NSBladder 2.7 (2) 1.0 (1) NSOther 6.8 (5) 3.0 (3) NS

Optic neuropathy duringentire courseb, % (n)

17.8 (13) 39.0 (39) 0.003

EO = early onset, LO = late onset, MS = multiple sclerosis, NS = not significant,PP = primary-progressive, RR = relapsing-remitting, VEP = visual evoked potential.

a In patients with RRMS.b Clinical diagnosis and/or subclinical diagnosis by VEP.

Fig. 2. The number of years from symptom onset for a patient with late onsetmultiple sclerosis (LOMS) compared to a patient with early onset multiple sclerosis(EOMS) to reach an Extended Disability Status Scale (EDSS) score of (A) 3.0 and (B)6.0. Cum = cumulative.

W. Qiu et al. / Journal of Clinical Neuroscience 17 (2010) 1009–1013 1011

(p < 0.0001). The relapse rate (in RRMS) and disease duration weresimilar in the LOMS and EOMS groups. The LOMS group had a high-er frequency of initial motor disturbances (41.1% vs. 19.0%,p = 0.001) and lower frequency of sensory symptoms (19.4% vs.37.0%, p = 0.008). Although the frequency of acute optic neuritisas the presenting manifestation was similar in both groups, theoverall frequency of optic neuropathy (diagnosed clinically or onthe basis of abnormal VEP) was lower in the LOMS group than inEOMS (17.8% vs. 39.0%, p = 0.003). When patients with PPMS wereexcluded, comparative analysis of RRMS patients in the LOMS andEOMS groups showed a lower female to male ratio (1.8 vs. 4.0,p = 0.043) and a slightly lower relapse rate in the LOMS group thanin the EOMS group (0.3 ± 0.3 vs. 0.4 ± 0.4, p = 0.036).

The frequency of initial misdiagnosis was higher in the LOMS(14/73) than the EOMS (4/100) group (19.2% vs. 4.0%, p = 0.001).The most frequent initial diagnoses in the LOMS group were stroke(four patients), cerebral tumour (three patients) and peripheralneuropathy (three patients). Two patients presented with tumefac-tive lesions and required a brain biopsy to exclude a tumour.

3.2. Disease progression

A survival analysis was undertaken to compare progression ofdisability in the two groups of patients with MS. As shown inFig. 2A, the time to reach EDSS 3.0 (moderate disability with fullambulation) was shorter in LOMS (median 10 vs. 13 years in EOMS;p = 0.006, log-rank test). The time to reach EDSS 6.0 (use of walkingaids) was also shorter in the LOMS group but the difference be-tween the groups was not significant due to the smaller numbers(median 20 vs. 31 years in EOMS; p = 0.067, log-rank test)(Fig. 2B). A direct comparison of RRMS patients only in the LOMSand EOMS groups showed that differences in time to reach EDSS3.0 (median 11.0 vs. 13.0 years) or EDSS 6.0 (median 20.0 vs.29.6 years) in the two groups were not significant.

There was no significant difference in the use of disease-modi-fying therapies in the two groups: 47.1% (24/51) in LOMS and50.5% (48/95) in the EOMS group.

3.3. MRI findings

The frequency of abnormal brain MRI was similar in patientswith LOMS and EOMS: 86.6% (58/67) in LOMS compared to 89.0%(89/100) in EOMS (p = not significant). The distribution of lesions

in the cerebral hemispheres (periventricular and/or subcorticalwhite matter), brainstem and cerebellum (cerebellar hemisphereand/or peduncles) was also similar in the two groups: 98.5 vs.99.0%, 41.8 vs. 45.0%, 22.4 vs. 30.0%, respectively, as was the fre-quency of scans with gadolinium enhancement (31.2 vs. 36.5%).Two patients with LOMS had tumefactive lesions on brain MRI.

Spinal MRI were available in 63 patients with LOMS and 100 pa-tients with EOMS. One or more cord lesions with high T2 signalintensity were detected in 54/63 (85.7%) patients with LOMS and87/100 (87%) patients with EOMS. Confluent or diffuse lesionswere found in 14.8% of LOMS and 6.9% of EOMS patients (p = notsignificant). Most patients with LOMS and EOMS had focal lesionsin the upper cervical area (C2–C3) and in the posterior or lateralcord. However, in the LOMS group, lesions were less frequent atthe T7 level (5.6 vs. 20.7%, p = 0.014) and in the anterior cord(11.1 vs. 26.4%, p = 0.029), but both differences disappeared aftercorrection (pcorr = 0.294, pcorr = 0.116, respectively). On comparison

1012 W. Qiu et al. / Journal of Clinical Neuroscience 17 (2010) 1009–1013

of patients with RRMS only between the LOMS and EOMS groups,there was no significant difference in the lesion distribution onspinal MRI, either on axial or sagittal sections (data not shown).The length of focal lesions was similar in the two groups(1.7 ± 0.5 vs. 1.8 ± 1.0 segments, p = not significant).

3.4. CSF abnormalities

The frequency of positive OCB was similar in the LOMS andEOMS groups (57.6 vs. 43.8%, p = not significant).

3.5. Correlations with HLA-DRB1 alleles

As shown in Supplementary Table 1, 34 different HLA-DRB1 al-leles were identified in the MS and control groups. Carriage fre-quencies of the HLA-DRB1*1501 and DRB1*0801 alleles in thepatients with LOMS, EOMS and controls are presented in Table 2.The carriage frequency of DRB1*1501 was significantly higher inboth the LOMS and EOMS groups than in controls (p < 0.0001)but the difference between LOMS and EOMS was not significant.DRB1*1501 homozygosity was significantly higher in LOMS thanin controls (p = 0.006 uncorrected), but was not significantly differ-ent from EOMS. The carriage frequency of DRB1*0801 was higherin the LOMS group than in controls (15.8 vs. 3.7%; p = 0.003 uncor-rected) and EOMS (15.8 vs. 5.4%, p = 0.035) and was still higherafter excluding DRB1*1501 carriers (Table 2), although the lattercomparisons would not survive correction for multiple compari-sons. The comparison of DRB1*0801 carriage in LOMS and controlpatients just fails significance when Bonferroni corrected over the22 alleles for which the frequencies were sufficient to achieve anuncorrected 5% significance level (corrected p = 0.06). Of theDRB1*0801 carriers in the LOMS group 8 out of 9 had RRMS andthere was no association between DRB1*0801 and PPMS. Therewas also no significant difference in carriage frequency ofDRB1*0801 allele between PPMS (5.0%, 1/20) and RRMS (10.1%,13/129) (p = 0.694). The frequency of DRB1*1501/*0801 heterozy-gotes was higher in the LOMS group than in controls (7.0 vs.0.0%, p = 0.003) but was also higher in the EOMS group (3.3% vs.0.0%, p = 0.034). Frequencies of other DRB1 alleles did not differsignificantly among LOMS, EOMS and control groups.

4. Discussion

The 8.8% frequency of LOMS in the PDDD is similar to the rates of6% to 13% reported in other populations19–22 but is slightly higherthan the figure of 5% of patients with MS over the age 50 years foundin a previous prevalence study in Western Australia in 1988.23 Thisincrease is probably due to more reliable diagnosis of MS in the olderage groups since the advent of MRI scanning rather than to a changein MS phenotype towards a later onset. However, in spite of this,there was still a higher rate of initial misdiagnosis in the LOMS groupof patients. As previously suggested this may be due to a greater like-lihood of unusual presentations and associated co-morbidities in pa-tients presenting after the age of 50 years.2,5,24,25 All the

Table 2Carriage frequencies of HLA-DRB1*1501 and DRB1*0801 alleles in the LOMS, EOMS and a

HLA-DRB1* LOMS (n = 57), % (n) EOMS (n = 92), % (n)

1501 54.4 (31) 45.7 (42)1501/1501 10.5 (6) 5.4 (5)0801 15.8 (9) 5.4 (5)1501/0801 7.0 (4) 3.3 (3)0801 in non-1501 carriers 19.2 (5/26) 4.0 (2/50)

EO = early onset, LO = late onset, MS = multiple sclerosis, NS = not significant, OR = odds

aforementioned prevalence rates were from studies of Caucasianpopulations, and data from non-Caucasian populations are scarce.26

The clinical phenotype in the LOMS group was similar to previousstudies from Europe and North America, with a greater preponder-ance of males and a higher frequency of PPMS and motor manifesta-tions at presentation, although the more common presentingfeatures of EOMS, such as optic neuritis and myelopathy, were alsoobserved in LOMS and in VLOMS. Although LOMS was more oftenprogressive from the outset, RRMS also occurred and the relapse ratewas slightly lower that in the EOMS group. Some previous studieshave found that patients with LOMS have a poorer prognosis andmore rapid progression of disability.2,8 Although our findings weresimilar, this may be due to greater numbers of patients with PPMSin the LOMS group.

Numerous studies have demonstrated the primary and inde-pendent effect of HLA-DRB1*1501 on susceptibility to MS9,13

and in some studies HLA-DRB1*1501 was also associated with anearlier age of onset.10–12 Our data demonstrated that HLA-DRB1*1501 was strongly associated with both LOMS and EOMS.An association was found between DRB1*0801 and LOMS but wecannot exclude the possibility that this may have arisen by chanceand the observation requires confirmation in a larger patient co-hort. The DRB1*0801 allele was reported to be associated withPPMS in Israel27 but this did not occur in the present LOMS cohort.The frequency of the HLA-DRB1*1501/*0801 allele combinationwhich has been associated with increased disease risk in largeMS family studies13,28 was higher in both the LOMS and EOMSgroups than in controls in this study (Table 2). However, the num-bers were small and it is unlikely to make a significant contributionin this population. Other alleles may be more relevant in patientswith onset over 60 years, especially if they are not HLA-DRB1*1501 carriers, but this could not be investigated in the pres-ent study because of the numbers of patients with VLOMS.

Other factors may also influence the age of onset of MS and theclinical course.29 These include aging-related changes in immunefunction such as increased oligoclonal expansion of T cells due toa defect in activation-induced cell death, defects in T cell apoptosis,and changes in cytokine profiles, which could all have modifyingeffects on the pathogenesis of LOMS and could also allow more ra-pid progression of the disease once it has been initiated.30,31 Failureof remyelination could also have a role.32

The preponderance of males in LOMS contrasts with the femalepreponderance in EOMS and of other autoimmune diseases in fe-males. While there is some evidence that oestrogen and prolactinmetabolism is abnormal in women with autoimmune diseases,the role of sex hormones remains inconclusive.33 An alternativeexplanation for which there is now increasing evidence is that hap-loinsufficiency of X-linked genes involved in immune function maybe a critical factor in predisposing females to the development ofautoimmune diseases34 and could also determine an earlier ageof disease onset in females.

In summary, the clinical profile of LOMS in our cohort was dif-ferent to that of EOMS and was similar to cohorts of patients withMS in the northern hemisphere. HLA-DRB1*1501 was a strong risk

healthy control group

Control (n = 189), % (n) LOMS vs. control LOMS vs. EOMS

OR p value OR p value

19.6 (37) 4.89 <0.0001 – NS1.6 (3) 7.29 0.006 – NS3.7 (7) 4.88 0.003 3.26 0.0350.0 (0) 0.93 0.003 – NS4.6 (7/152) 5.45 0.023 – NS

ratio.

W. Qiu et al. / Journal of Clinical Neuroscience 17 (2010) 1009–1013 1013

allele for both LOMS and EOMS while HLA-DRB1*0801 was weaklyassociated with LOMS. Our study showed an increased frequencyof LOMS compared with a previous West Australian survey in thelate 1980s, which is probably due to improved diagnosis and caseascertainment.

Acknowledgements

Steve Pummer and the staff at the Department of ClinicalImmunology and Immunogenetics Royal Perth Hospital, PathWest,kindly assisted with sample processing and data collection.

Dr Wei Qiu was supported by Endeavour International Post-graduate Research Scholarships (EIPRS) of Australia and Postgrad-uate Award from University of Western Australia. Dr Jing Shan Wuwas supported by Medical Postgraduate Scholarship from MultipleSclerosis Research Australia and the National Health and MedicalResearch Council of Australia.

Appendix A. Supplementary material

Supplementary data associated with this article can be found, inthe online version, at doi:10.1016/j.jocn.2009.12.011.

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