BRIEF C O M M U N I C A T I O N

No Associat ion of Multiple Sclerosis to Alleles at the TAP2 Locus

Anne Spurkland, Ingebj0rg Knutsen, Dag E. Undlien, and Frode Vartdal

ABSTRACT MS is associated with genes in the HLA complex We have previously proposed that the primary HLA-assocmted susceptibility may be conferred by par- tIcular DQ alleles Furthermore, we have previously found that there is no association of MS to DP alleles This study shows that MS is not associated to alleles of the

TAP2 locus, which IS located close to DQ on ~ts centro- merlc side This observation provides further support to the notion that HLA-assoclated susceptlblhty to MS maps telomerIc to the TAP2 locus Human Immunology 39,299- 301 (1994)

ABBREVIATION MS multiple sclerosis

I N T R O D U C T I O N

Multiple sclerosis (MS) is a disease of unknown etiology [1] Some of the genetic susceptibility maps to the HLA region on chromosome 6 [2] MS is most consistently shown to be assoclated with HLA-DR2 in the class II region [3, 4] However, the gene(s) primarily involved m the HLA-assoclated genetic susceptlblhty to multlple sclerosis remains unknown We have previously pro- posed that MS is primarily associated to HLA-DQ alleles sharing polymorphlc residues [5, 6], however, this no- tion is controversml [7] The posslblhty still exlsts that other genes within the HLA class II region may represent the disease susceptiblhty gene or eventually may modify the expresslon of disease-associated HLA alleles

Recently, genes located m the HLA class II region, TAP1 and TAP2, have been characterized The protein encoded by these genes is probably responsible for trans- port of peptldes into the endoplasmlc retlculum [8] In rats TAP2 polymorph,sm influences the spectrum of peptldes presented by the malor hlstocompatlblhty corn-

From the Instttute of Transplantatmn Immunology, Natmnal Hospital, Oslo, Norway

Address reprmt requests to Dr A Spurkland The Instttute of Trans- plantatton Immunology Nattonal Hospital, Oslo, Norway

Recewed (E) July 5, i993, accepted September 29, 1993

Human Immunology 39, 299-~01 (1994) © American Sooety for Hlstocompatlblhty and Immunogenetlcs, 1994

plex (MHC) class I molecules [9] In humans five dif- ferent TAP2 alleles have been identified [10]

To evaluate the role of TAP2 polymorphlsms m HLA- determined susceptlblhty to MS, we determined the dis- trlbutlon of the three most frequent TAP2 alleles (A, B, and C) among 69 MS patients (this report) and compared this distribution with that found among 173 Norwegian healthy blood donors [ 11] The dlstnbutlon of HLA class II alleles of these patients and controls has previously been reported [6, 12]

MATERIALS A N D M E T H O D S

DNA extracted from peripheral blood of the 69 MS pa- tients [6] was in vitro amplified using TAP2-speclfic prlmers as previously described [11, 13] The resulting amphficatlon products were subsequently slot-blotted onto nylon membranes and hybridized with 32p-labeled ohgonucleotldes specific for the TAP2 polymorphlsms at amino acid positions 665 and 687 [11] and position 379 [13] The nomenclature of the alleles detected corre- sponds to that used by Carrlngton et al [13] Signifi- cance of associations was tested using the ch~-squared analysis, and p values were corrected for number of com- parisons

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300 A Spurkland et al

T A B L E 1 Dlstnbut~on (%) of T A P 2 alleles and genotypes among Norwegmn MS patients and controls

D R 2 - D Q B 1"0602 pos*tlve DR2-DQB 1"0602 negative

MS Control MS Control MS Control n = 69 n = 173 X 2 n = 49 n = 56 X 2 n = 20 n = 117 X 2

TAP2 alleles A 91 B 3O C 2O

TAP2 genotypes AA 52 AB 23 AC 16 BB 4 BC 3 CC 1

Sum genotypes 99

84 2 1 94 91 0 2 89 81 0 8 39 1 4 31 29 0 1 32 44 1 2 21 0 0 27 20 0 7 5 21 2 7

43 1 8 47 54 0 5 65 38 5 1 ~ 27 0 4 27 21 0 4 15 31 1 9 13 0 5 20 16 0 :5 5 12 0 6 8 09 0 5 27 15 9 10 3 0 0 4 2 05 0 4 04 4 01 2 2 01 0 5 06

98 100 100 100 99

a p . . . . . . . . . . . d < 0 05, and p . . . . . . . . d NS

R E S U L T S A N D D I S C U S S I O N

The results are presented m Table 1 It can be seen that there is no dlfference m the dls tr lbut ion of TAP2 alleles or TAP2 genotypes among MS patients and controls

MS shows the strongest and most consistent associa- t ion to the D R 2 - D Q B 1"0602 haplotype [6, 7] To eval- uate whether T A P 2 polymorphlsms may influence dis- ease susceptlblhty among D R 2 - D Q B 1*0602-posit ive or D R 2 - D Q B l * 0 6 0 2 - n e g a t l v e mdlwduals , we analyzed the dis tr ibut ion of the T A P 2 alleles m these two groups separately There was an increase of the T A P 2 AA ge- notype among D R 2 - D Q B 1*0602-negat ive MS patients compared with controls, whlch dld not reach statistical slgmficance when corrected for number of comparisons, however This dewat lon may be due to the hnkage dls- e q m h b r m m observed between the T A P 2 A allele and the D R 4 - D Q B I * 0 3 0 2 haplotype [11], since there is a slg- mficant increase of D R 4 - D Q B 1"0302 among the D R 2 - DQB 1*0602-negat ive MS patients [6] N o difference m the d l s t n b u u o n of the T A P 2 alleles was found among the D R 2 - D Q B l * 0 6 0 2 - p o s l t l v e individuals, which is consistent wlth another recent observation [14]

The T A P 2 gene is located close to the DQB 1 locus on the centromerlc side [ 15] N o assocmtlon between TAP2 alleles and alleles at the more cen t romenc D P iocl was observed among Norwegmn controls [ 11] Furthermore, no association of MS to DP alleles have been observed [6, 7, 16] Recombinat ion between the D Q and DP loci may or may not revolve the T A P 2 gene [10], indicating that a recombinational hot spot ~s located between the D Q and the T A P 2 locl Genes located centromerlc to the T A P 2 gene may thus not be expected to confer HLA- assocmted susceptzblhty to MS The lack of assocmtlon between T A P 2 alleles and MS lends further support to

the notlon that D Q alleles confer the pr lmary HLA- associated susceptlblhty to develop MS [6]

N o t e A d d e d xn P r o o f

A recent report by Kel lar-Wood et al [17] reaches the same conclusion as the present report

ACKNOWLEDGMENTS

This work was supported by Medmnova and Inger and Fritz Nlelsen's legacy Bodvar Vandvik, Department of Neurology, Ullev~il Hospital, Oslo, kindly provided blood samples from the MS patients

R E F E R E N C E S

1 Matthew WB (ed) McAlpIne's Multiple Sclerosis Edin- burgh, Churchill Livingstone, 1991

2 Splelman RS, Nathanson N The genetics of susceptibil- ity to multiple sclerosis Epidemiol Rev 4 45, 1982

3 Jerslld C, Hansen GS, Svelgaard A, Fog T, Thomsen M, Dupont B HastocompatIbIhty determinants in multiple sclerosis with special reference to clinical course Lancet 2 1222, 1973

4 Tiwaris JL, Terasaki PI HLA and Disease Associations New York, Springer-Verlag, 1985

5 Vartdal F, Solhd LM, Vandvlk B, Markussen G, Thorsby E Patients with multiple sclerosis carry DQB1 genes which encode shared polymorphic amino acid sequences Hum Immunol 25 103, 1989

6 Spurkland A, RCnningen KS, Vandvlk B, Thorsby E, Vartdal F HLA-DQA1 and HLA-DQB1 genes may jointly determine susceptibility to develop muttlple scle- rosis Hum Immunol 30 69, 1991

7 Olerup O, Hlllert J HLA associated susceptiblhty In multiple sclerosis a critical evaluation Tissue Antigens 38 115, 1991

No Association of MS to Alleles at TAP2 Locus 301

8 Monaco JJ Genes in the MHC that may affect antigen processing Curr Opm Immunol 4 70, 1992

9 Powls SJ, Deverson EV, Coadwell WJ, Gruela A, Hlsklsson NS, Smith H, Butcher GW, Howard JC Ef- fect of polymorphism of an MHC linked transporter on the peptides assembled m a class I molecule Nature 357 211, 1992

10 Powis SH, Tonks S, Mockridge I, Kelly AP, BodmerJG, Trowsdale J Alleles and haplotypes of the MHC-encoded ABC transporters TAP1 and TAP2 ImmunogenetIcs 37 373, 1993

11 RCnnlngen KS, Undhen DE, Ploskl R, Maoum N, Kon- rad RJ, Jensen E, Homes E, Reilonen H, Colonna M, Monos DS, Strominger JL, Thorsby E Lmkage dlsequI- hbrium between TAP2 and HLA class II alleles no pri- mary association between TAP2 variants and msuhn- dependent dmbetes melhtus Eur J Immunol 23 1050, 1993

12 RCnnmgen KS, Spurkland A, Markussen G, Iwe T, Vart- dal F, Thorsby E The distribution of HLA class II alleles

among Norwegian Caucasians Hum Immunol 29 275, 1990

13 Carrlngton M, Colonna M, Spies T, Stephens JC, Mann DL HaplotypIc variation of the transporter associated with antigen processmg (TAP) genes and their extension of HLA class II region haplotypes Immunogenetlcs 37 266, 1993

14 Liblau R, van Endert PM, Sandberg-Wollhexm M, Patel SD, Lopez MT, Land S, Fugger L, McDevxtt HO Anti- gen processing gene polymorphlsms m HLA-DR2 mul- tiple sclerosis Neurology 43 1192, 1993

15 Trowsdale J, RagoussIs J, Campell RD Map of the hu- man MHC Immunol Today 12 443, 1992

16 Roth M-P, Coppm H, Descolns P, Ruidavets J-B, Com- bon-Thomson A, Clanet M HLA-DPB1 gene polymor- ph,sm and mult,ple sclerosis a large case-control study m the southwest of France J Neurolmmunol 34 215, 1991

17 Kellar-Wood HF, Powxs SH, Gray J, Compston DAS MHC-encoded TAP1 and TAP2 dimorphasms in multi- ple sclerosis Tissue Antigens 43 129, 1994