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HLA antigens in multiple sclerosis in coloured South Africans
Journal of the Neurological Sciences, 1984, 66:175-181
175
Elsevier
HLA Antigens in Multiple Sclerosis in Coloured South Africans M o n a E. Fewster and Bryan Kies Neurology Department, Groote Schuur Hospital, Observatory 7925, Cape Town (South Ajrica) (Received 10 May, 1984) (Revised, received 15 June, 1984) (Accepted 18 June, 1984)
SUMMARY
HLA-A and HLA-B antigens were determined in 24 Coloured patients with multiple sclerosis (MS) and HLA-DR antigens in 16 of these patients. There was a trend for an increased frequency of HLA-DR2 in the MS group (0.25 > P > 0.1).
Key words: Coloured South Africans - H L A antigens - Multiple sclerosis
INTRODUCTION
Among Caucasians in North Europe and the United States, an association between multiple sclerosis (MS) and the HLA antigens HLA-A3 (Naito et al. 1972) and HLA-B7 (Jersild et al. 1972) was described fh'st. Subsequently the association was found to be much stronger with HLA-Dw2 (Jersild et al. 1973) and with HLA-DR2 (Winchester et al. 1975). The Seventh International Histocompatibility Workshop confirmed findings by individual workers that MS Caucasian patients originating from North Europe show an association primarily with HLA-Dw2 and with HLA-DR2, a less strong association with HLA-B7 and an even less strong association with HLA-A3 (Bodmer et al. 1978). In South Europe, in Italy, MS patients lacked an association with HLA-A3 or with HLA-B7 (Menicucci et al. 1977, Tiwari et al. 1980) but had a significant association with HLA-DR2 (Tiwari et al. 1980). Black American MS patients had a frequency of HLA-B7 that was only slightly increased while HLA-Dw2 was significantly associated with MS (Dupont et al. 1977). No significant association between MS and HLA-A3, HLA-B7 or HLA-DR2 was found in Jordan (Kurdi et al. 1977), Japan (Saito et al. 1976; Naito et al. 1978) and Israel (European or Afro-Asian origin) (Brautbar et al. 1977a,b, 1982). In addition, in Japan and Israel there was no association between MS and HLA-Dw2. 0~22-510X,84,'$03.00 (~;, 1984 Elsevier Science Publishers B.V.
176 If the genetic locus at which the allele responsible for susceptibility to MS is HLA-A, HLA-B, HLA-D or HLA-DR, the gene in the HLA region which shows the highest association with MS shoukt be present in MS patients out of different ethnic origin such as Coloured South Africans. The present study was undertaken to determine if an association was present with those HLA antigens which are associated with MS among Caucasians in North Europe and the United States, especially HLA-DR2 which has seemed to have a strong association with MS among Caucasians. METHODS
Subjects Twenty four unrelated MS patients, members of the Cape Coloured Community who were born in South Africa, were HLA typed. Hospital records were examined from 1951 at this hospital and from 1970 at Tygerberg, the other major hospital to which Coloured patients are referred. All patients had been admitted at least once previously and were assessed by members of the Neurology Department. Patients previously diagnosed as having MS were included in the study provided their diagnosis was confirmed, when they were reassessed for this study, by using the diagnostic criteria of Poser et al. (1983). All patients previously identified tentatively as having MS were interviewed and examined and those who fulfiUed the diagnostic criteria for MS were included in the study. A diagnosis of MS was made according to the criteria of Poser et al. (1983). Eight MS patients previously typed for HLA-A and HLA-B antigens were not retyped as 6 had died and 2 resided over 800 km away. Thus HLA-A and HLA-B antigens were determined in 24 Coloured MS patients and HLA-DR antigens in 16 of these patients. Those 18 ofthe 24 patients currently alive provided the data for Table 1. To our knowledge there are no other Coloured MS patients alive at this time in South Africa, therefore the number of MS patients cannot be increased. 1042 healthy, unrelated, randomly sdected Cape Colouredindividuats were typed for HLA-A and HLA-B antiggns, and of these individuals, 190 were typed for HLA-DR antigens. These subjects served as the controls.
Lymphocyte typing Fifty ml of thrombolytic blood from each subject were delivered to the Provincial Laboratory for Tissue Immunology. The lymphocytes were isolated by the Ficoll-Hypaque method (B~yum 1968) and segarated by nylon wool into T andB lymphocytes (Danilovs et al. 1980). The T lymlalaoeytes were typed for HLA-A and HLA-B antigens by the micro-lymphocytotoxic test (NAIAD 1966-1967), and the B lymphoc~es were typed for HLA-DR antigens (Faucet et al. 1980).
Statistical methods The classical 7`2test for homog~eity was used for tables larger than two-by-two tables. The 7.2 test for association with Yat~' correction factor for continuity was used for two-by-two tables. When any of the cells of a two-by-two table had a value less than 5, Fisher's exact test was used.
177 RESULTS
Table 1 shows the number and ages of the Coloured MS patients compared with White South African born MS patients previously typed for HLA antigens (Fewster et al. 1979) and who are currently alive. In each group there were more females than males, the proportion being greater, especially in the 30-60 year age group, than the approximate proportion of three to two generally reported (Kurtzke 1983). Tables 2 and 3 show the tissue typing results. There was no significant difference between the MS patients and controls for HLA-A and HLA-B antigens. Three of the 16 (19% ) MS patients typed for HLA-DR antigens were homozygous for HLA-DR2. The classical Z 2 t e s t for homogeneity showed no significant difference between the MS patients and controls for HLA-DR antigens but HLA-DR2 and HLA-DRw8 contributed the most to the overall Z2 value. There was no significant difference between the frequency of HLA-DR2 in the MS group compared with the controls, but there was a trend for an increased frequency of HLA-DR2 in the MS group (0.25 > P > 0.1). The distribution of the phenotypes HLA-A3, HLA-B7 and HLA-DR2 in Coloured South African patients with MS showed that 69~o had either one or two of these antigens (Table 4). DISCUSSION
Coloured South Africans are the descendants during the past 300 years from a mixture of Caucasian immigrants from North Europe (Dutch, German, French and later English), Blacks, Malay and Xhoisan (Bushman and Hottentot) people. On Census Day 1980 their population was 2 612 780, 85 yo (2 226 160) of whom lived in the Cape Province, in which the two teaching hospitals provided neurological service. The 14 known diagnosed MS cases on Census Day 1980 give a prevalence rate for MS of 0.6 per 100 000 for the Cape Province which is probably a close approximation to the prevalence rate for the whole country. This is extremely low compared with the prevalence rates of 30 and above per 100000 in the high risk zone of North Europe (Kurtzke 1983). Moreover, out of 16 924000 Black South Africans on Census Day and prior and subsequent to that day, no case of MS confirmed at autopsy has ever been reported, including cases reported by the well staffed Neurology Department of
TABLE ! SEX A N D MEAN AGE FOR THE MULTIPLE SCLEROSIS PATIENTS Group
Total No.
Males
Females
Mean age (yr)
Range
Multiple sclerosis - Coloured Multiple sclerosis - White South African born
18
4
14
39
19-54
37
6
31
49
24-72
TABLE 2 F R E Q U E N C Y O F H L A A N T I G E N S IN PATIENTS W I T H M U L T I P L E SCLEROSIS HLA antigen a
MS (n = 24) Controls (n = 1(142) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +
A1 A2 A3 All A~w23 (9) Aw24 (9) Aw26 10) A28 A29 Aw30 Aw31 Aw32 Aw33 Aw43 B7 B8 B27 Bw35 Bw42 Bw44 (12) Bw45 (12) Bw51 (5) Bw57 (17) Bw58 (17) Bw60 (40) Bw62 (15) Bw63 (15) B15B
5 11 2 6 2 5 2 1 2 1 2 3 1 1 4 4 2 3 3 3 1 1 1 6 1 3 2 2
_
19 13 22 18 22 19 22 23 22 23 22 21 23 23 20 20 22 21 21 21 23 23 16 1t 15 15 16 14
o, %
+
20.8 45.8 8.3 25.0 8.3 20.8 8.3 4.2 8.2 4.2 8.3 12.5 4.2 4.2 16.7 16.7 8.3 12.5 12.5 12.5 4.2 4.2 5.9 35.3 6.3 16.7 11.1 12.5
+
182 313 175 109 119 205 91 160 102 184 19 60 78 55 217 100 47 122 59 179 62 50 105 149 43 94 28 154
_
859 729 867 933 923 837 951 882 940 858 1023 982 964 987 825 942 995 920 983 863 980 796 928 884 999 939 1005 888
t), 'o
+
17.5 30.0 16.8 10.5 11.4 19.7 8.7 15.4 9.8 17.7 1.8 5.8 7.5 5.3 20.8 9.6 4.5 11.7 5.7 17.2 6.0 5.9 10.2 14.4 4. I 9.2 2.7 14.8
Antigens tested for but absent in the MS c a s e s , HLA-B13, B14, B18, B37, Bw38, Bw39, Bw41, Bw46, Bw47, Bw48, Bw50, Bw52, Bw53, Bw54, Bw55, Bw56, Bw59, Bw61, Bu, Sv. TABLE 3 F R E Q U E N C Y O F H L A A N T I G E N S IN P A T I E N T S W I T H M U L T I P L E SCLEROSIS HLA antigen ~
MS (n = 16)
Controls (n = 190
+ DR1 DR2 DR3 DR4 DR5 DRw6 DR7 DRwl0
a
1 9 4 2 3 3 4 2
15 7 12 14 13 13 12 14
~,~ +
+
6.3 56.3 25.0 12.5 18.8 18.8 25.0 12.5
28 62 41 49 56 18 43 4
Antigens tested for but absent in the MS cases - HLA-DRw8, DRw9.
~o 162 128 149 141 134 172 147 186
14,7 32.6 21.6 25.8 29.5 9.5 22.6 2.1
179 TABLE 4 DISTRIBUTION MULTIPLE
O F A3, B7 A N D
SCLEROSIS
DR2 PHENOTYPES
IN COLOURED
PATIENTS
WITH
(MS)
HLA-A3
HLA-B7
HLA-DR2
M S (n = 16)
+
+
+
0
+ +
+
+
0
+
-
-
I
-
+
+
2
-
+
-
1
-
+
6
--
--
5
Baragwanath Hospital for Blacks near Johannesburg. However, Cosnett (1981) reported 6 cases of demyelinating disease in South African Blacks. When the data in their report are examined, three of these cases fulfil the criteria of Poser et al. (1983) for the diagnosis of MS or its variant neuromyelitis optica. The sex ratio in ethnic groups among South African born MS cases varies inexplicably. Thus Dean (1967) reported that the ratio of females to males among 57 Afrikaans-speaking White MS patients (1.8:1) was not significantly different from the expected ratio of 1.4 : 1 whereas the ratio was higher (2.7 : 1) than expected among 101 English-speaking White MS patients. This difference is not exclusive to Englishspeaking White MS patients as the ratio for 18 Coloured MS patients in the present study, 14 : 4 (3.5 : 1) is also higher than the generally expected 3 : 2 female to male ratio in MS patients (Kurtzke 1983). Despite the very small number of known Coloured MS patients alive (20) or deceased (7) at the time of the current study, it was felt that a study of the HLA types in Coloured MS patients should be undertaken as it might provide clues regarding the relative contribution of genetic factors to the disease. The association between HLA antigens and MS, especially HLA-DR2, seems to indicate the presence of a genetic contribution by an MS susceptibility gene to the etiology of the disease. One would anticipate that such a gene would show an association with MS patients not only of different ethnic origins but also in MS patients in countries where the disease is extremely uncommon, such as Coloured South African MS patients. The antigens which have been suggested to be associated with an MS haplotype include HLA-A3, B7, BtTM,DR2 and Dw2 (Terasaki and Mickey 1976). The frequencies of HLA-A3 and B7 in White South African born MS patients and their White controls have been reported previously (Fewster et al. 1979). In the present study the frequency of HLA-A3 in South African born Coloured patients with MS (8~o) was surprisingly low and was significantly lower than in White South African born patients with MS (28 .%) (P = 0.05) or than their White controls without MS (28 °/o) (P = 0.04). Thus at
180
any rate in White (Fewster et al. 1979) and Coloured South Africans there appears to be no association of HLA-A3 with MS. The frequency of HLA-B7 in Coloured South African patients with MS (17%) is significantly lower (P < 0.05) than for White South African born patients with MS (40 %). However it is not significantly different from the frequency in the White South African born controls (31%) ofthe White MS patients reported by Fewster et al. (1979), so that the difference between the Coloured and ~ t e MS patients is not meaningful. Although there was no significant association between HLA-DR2 and MS in the Coloured MS patients, there was a trend towards such an association (0,25 > P > 0.1). If one assumed that the distribution of HLA-DR antigens remained the same in the MS group and the healthy controls with a Type 1 error of 0.05 and Type 2 error of 0.2 for the null hypothesis, 65 Coloured MS patients would be required. This far exceeds the number of known MS patients alive in this country. The frequency of HLA-DR2 in Coloured MS patients (569/o) contrasts with the low frequency (12%) of HLA-DR2 in Israeli Jews of European origin with MS (Brautbar et al. 1982). However the frequency (56 % ) is similar to, and is not statistically different from the frequency of HLA-DR2 in North European Caucasian MS patients (41%) (Bodmer et al. 1978), This in a population of mixed ethnic ancest~, the frequency of HLA-DR2 among MS patients seems to reflect the frequency in MS patients among an ethnic group, namely North: European Caucasians from whom they are partially descended. However, HLA-DR2 is always statistically increased in European Caucasian MS patients, whereas in the unavoidably limited sample size of Coloured South African MS patients, the trend for an increased fr~aency of HLA.DR2 antigens compared with Coloured South African healthy indi~uals is not enough of a difference to enable any conclusions to be made. ACKNOWLEDGEMENTS
The authors acknowledge the technical assistance of the staff of the Provincial Laboratory for Tissue Immunology, Observatory 7925, Cape. The antigen frequencies for HLA-A, HLA-B and HLA-DR among the unrelated, randomly selected healthy Cape Coloured individuals used as controls are preliminary analyses of unpublished data of Dr. E. Du Toit, Provincial Laboratory for Tissue Immunology. The medical superintendent and Professor A. S, De Grartf, Nearology Department, kindly gave us access to ~ records of Tygerberg Hospital. REFERENCES Bodmer, W.F., J.R. Batchelor, J.G. Bodmer, H: Festenstein and P.J. Morris (1978).Histocompatibility Testing 1977, Report of the Seventh International Histocompatibility Workshop and Conference, Oxford, Munksgaard, Copenhagen. B/Syum,A. (1968) Separation of leucocytes from blood and bone-marrow, Scand. J. Clin, Lab. Invest., 21 (Suppl. 97): 77-89. Brautbar, C., E. Kahana, M. Alter, F. Jergansen and L. Lamm (1977a) Histocompatibilitydeterminants in Israeli Jewish patients with multiple sclerosis, Tissue Antigens, 10: 291-302. Brautbar, C., E. Kahana, M. Alter, FI Jergensen and L. Lamm (1977b) Lack of association between HLA-Dw2 and multiple sclerosis in Israeli Jewish patients, N. Engl. J. Med., 296: 1537-1538.
18J Brautbar, C., A. Avraham, I. Cohen, E. Kahana, T. Cohen, D. Bloch, H. Grosse-Wilde and M. Alter (1982) Histocompatibility (HLA) antigens and multiple sclerosis in Israelis, Israel J. Med. Sci., 18:631-634. Cosnett, J. (1981) Multiple sclerosis and neuromyelitis optica, S. Air. Med. J., 60: 249-251. Danilovs, J. A., G. Ayoub and P.I. Terasaki (1980) Joint report: B lymphocyte isolation by thrombin-nylon wool. In: P. I. Terasaki (Ed.), Histocompatibility Testing, UCLA Tissue Typing Laboratory, Los Angeles, CA, pp. 287-288. Dean, G. (1967) Annual incidence, prevalence, and mortality of multiple sclerosis in white South-Africanborn and in white immigrants to South Africa, Brit, Med. J., 2: 724-730. Dupont, B., R.P. Lisak, C. Jersild, C. Hansen, J.A. Silberberg, D.H. Whitsett, B. Zweiman and A. K, Ciongoli (1977) HLA antigens in black patients with multiple sclerosis, Transplant. Proc., 9 (Suppl. 1): 181-185. Faucet, R., O. Bouhallier and B. Genetet (1980) Joint report: B cell typing by rosetting with AET-treated sheep red blood cells. In: P.I. Terasaki (Ed.), Histocompatibility Testing, UCLA Tissue Typing Laboratory, Los Angeles, CA, p. 289. Fewster, M.E., F.R. Ames and M.C. Botha (1979) Measles antibodies and histocompatibility types iu multiple sclerosis, J. Neurol. Sci., 43: 19-26. Jersild, C., A. Svejgaard and T. Fog (1972) HLA antigens and multiple sclerosis, Lancet, i: 1240-1241. Jersild, C., T. Fog, G.S. Hansen, M. Thomsen, A. Svejgaard and B. Dupont (1973) Histocompatibility determinants in multiple sclerosis with special reference to clinical course, Lancet, ii: 1221-1225. Kurdi, A,, Ayesh, A. Abdallat, U, Maayta, W.I. McDonald, D. A. S. Compston and J.R. Batchelor (1977) Different B lymphocyte alloantigens associated with multiple sclerosis in Arabs and North Europeans, Lancet, i: 1123-1125. Kurtzke, J.F. (1983) In: J.F. Hallpike, C. W. M, Adams and W.W. Tourtellotte (Eds.), Multiple Sclerosis, Chapman and Hall, London, pp. 66, 70. Menicucci, A., O. Baricordio, C. Conighi, L. Amaducci and P.L. Mattiuz (1977) HLA and B-lymphocyte in multiple sclerosis in Italy, Tissue Antigens, 10: 193. NA1AID Manual of Tissue Typing Techniques, 1966-1967, p. 22. Naito, S., N. Namerow, M. R. Mickey and P. I. Terasaki (1972) Multiple sclerosis: association with HL-A3, Tissue Antigens, 2: 1-4. Naito, S., Y. Kuroiwa, T. Itoyama, T. Tsubaki, A. Horikawa, T. Sasazuki, S. Noguchi, S. Ohtsuki, H. Tokuomi, T. Miyatake, N. Takahata, S. Kawanami and A.J. McMichael (1978) HLA and Japanese MS, Tissue Antigens, 12: 19-24. Poser, C.M., D.W. Paty, L. Scheinberg, W. I. McDonald, F.A. Davis, G.W. Ebers, K.P. Johnson, W.A. Sibley, D. H. Silberberg and W.W. Tourtellotte (1983) New diagnostic criteria for multiple sclerosis - - Guidelines for research protocols, Ann. Neurol., 13: 227-231. Saito, S., S. Naito, S. Kawanami and Y. Kuroiwa (1976) HLA studies on multiple sclerosis in Japan, Neurology, 26:49. Ferasaki, P. 1. and M. R. Mickey (1976) A single mutation hypothesis for multiple sclerosis based on the HL-A system, Neurology, 26 (No. 6, Part 2): 56-58. Tiwari, J. L., N.E. Morton, J.M. Lalouel, P.I. Terasaki, H. Zander, B.R. Hawkins and Y.W. Cho (1980) Joint report: Multiple sclerosis. In: P. I. Terasaki (Ed.), Histocompatibility Testing, UCLA Tissue Typing Laboratory, Los Angeles, CA., pp. 687-692. Winchester, R.J., G. Ebers, S.M. Fu, L. Espinosa, J. Zabriskie and H.G. Kunkel (1975) B cell alloantigeq Ag7a in multiple sclerosis, Lancet, ii: 814 (Letter).
175
Elsevier
HLA Antigens in Multiple Sclerosis in Coloured South Africans M o n a E. Fewster and Bryan Kies Neurology Department, Groote Schuur Hospital, Observatory 7925, Cape Town (South Ajrica) (Received 10 May, 1984) (Revised, received 15 June, 1984) (Accepted 18 June, 1984)
SUMMARY
HLA-A and HLA-B antigens were determined in 24 Coloured patients with multiple sclerosis (MS) and HLA-DR antigens in 16 of these patients. There was a trend for an increased frequency of HLA-DR2 in the MS group (0.25 > P > 0.1).
Key words: Coloured South Africans - H L A antigens - Multiple sclerosis
INTRODUCTION
Among Caucasians in North Europe and the United States, an association between multiple sclerosis (MS) and the HLA antigens HLA-A3 (Naito et al. 1972) and HLA-B7 (Jersild et al. 1972) was described fh'st. Subsequently the association was found to be much stronger with HLA-Dw2 (Jersild et al. 1973) and with HLA-DR2 (Winchester et al. 1975). The Seventh International Histocompatibility Workshop confirmed findings by individual workers that MS Caucasian patients originating from North Europe show an association primarily with HLA-Dw2 and with HLA-DR2, a less strong association with HLA-B7 and an even less strong association with HLA-A3 (Bodmer et al. 1978). In South Europe, in Italy, MS patients lacked an association with HLA-A3 or with HLA-B7 (Menicucci et al. 1977, Tiwari et al. 1980) but had a significant association with HLA-DR2 (Tiwari et al. 1980). Black American MS patients had a frequency of HLA-B7 that was only slightly increased while HLA-Dw2 was significantly associated with MS (Dupont et al. 1977). No significant association between MS and HLA-A3, HLA-B7 or HLA-DR2 was found in Jordan (Kurdi et al. 1977), Japan (Saito et al. 1976; Naito et al. 1978) and Israel (European or Afro-Asian origin) (Brautbar et al. 1977a,b, 1982). In addition, in Japan and Israel there was no association between MS and HLA-Dw2. 0~22-510X,84,'$03.00 (~;, 1984 Elsevier Science Publishers B.V.
176 If the genetic locus at which the allele responsible for susceptibility to MS is HLA-A, HLA-B, HLA-D or HLA-DR, the gene in the HLA region which shows the highest association with MS shoukt be present in MS patients out of different ethnic origin such as Coloured South Africans. The present study was undertaken to determine if an association was present with those HLA antigens which are associated with MS among Caucasians in North Europe and the United States, especially HLA-DR2 which has seemed to have a strong association with MS among Caucasians. METHODS
Subjects Twenty four unrelated MS patients, members of the Cape Coloured Community who were born in South Africa, were HLA typed. Hospital records were examined from 1951 at this hospital and from 1970 at Tygerberg, the other major hospital to which Coloured patients are referred. All patients had been admitted at least once previously and were assessed by members of the Neurology Department. Patients previously diagnosed as having MS were included in the study provided their diagnosis was confirmed, when they were reassessed for this study, by using the diagnostic criteria of Poser et al. (1983). All patients previously identified tentatively as having MS were interviewed and examined and those who fulfiUed the diagnostic criteria for MS were included in the study. A diagnosis of MS was made according to the criteria of Poser et al. (1983). Eight MS patients previously typed for HLA-A and HLA-B antigens were not retyped as 6 had died and 2 resided over 800 km away. Thus HLA-A and HLA-B antigens were determined in 24 Coloured MS patients and HLA-DR antigens in 16 of these patients. Those 18 ofthe 24 patients currently alive provided the data for Table 1. To our knowledge there are no other Coloured MS patients alive at this time in South Africa, therefore the number of MS patients cannot be increased. 1042 healthy, unrelated, randomly sdected Cape Colouredindividuats were typed for HLA-A and HLA-B antiggns, and of these individuals, 190 were typed for HLA-DR antigens. These subjects served as the controls.
Lymphocyte typing Fifty ml of thrombolytic blood from each subject were delivered to the Provincial Laboratory for Tissue Immunology. The lymphocytes were isolated by the Ficoll-Hypaque method (B~yum 1968) and segarated by nylon wool into T andB lymphocytes (Danilovs et al. 1980). The T lymlalaoeytes were typed for HLA-A and HLA-B antigens by the micro-lymphocytotoxic test (NAIAD 1966-1967), and the B lymphoc~es were typed for HLA-DR antigens (Faucet et al. 1980).
Statistical methods The classical 7`2test for homog~eity was used for tables larger than two-by-two tables. The 7.2 test for association with Yat~' correction factor for continuity was used for two-by-two tables. When any of the cells of a two-by-two table had a value less than 5, Fisher's exact test was used.
177 RESULTS
Table 1 shows the number and ages of the Coloured MS patients compared with White South African born MS patients previously typed for HLA antigens (Fewster et al. 1979) and who are currently alive. In each group there were more females than males, the proportion being greater, especially in the 30-60 year age group, than the approximate proportion of three to two generally reported (Kurtzke 1983). Tables 2 and 3 show the tissue typing results. There was no significant difference between the MS patients and controls for HLA-A and HLA-B antigens. Three of the 16 (19% ) MS patients typed for HLA-DR antigens were homozygous for HLA-DR2. The classical Z 2 t e s t for homogeneity showed no significant difference between the MS patients and controls for HLA-DR antigens but HLA-DR2 and HLA-DRw8 contributed the most to the overall Z2 value. There was no significant difference between the frequency of HLA-DR2 in the MS group compared with the controls, but there was a trend for an increased frequency of HLA-DR2 in the MS group (0.25 > P > 0.1). The distribution of the phenotypes HLA-A3, HLA-B7 and HLA-DR2 in Coloured South African patients with MS showed that 69~o had either one or two of these antigens (Table 4). DISCUSSION
Coloured South Africans are the descendants during the past 300 years from a mixture of Caucasian immigrants from North Europe (Dutch, German, French and later English), Blacks, Malay and Xhoisan (Bushman and Hottentot) people. On Census Day 1980 their population was 2 612 780, 85 yo (2 226 160) of whom lived in the Cape Province, in which the two teaching hospitals provided neurological service. The 14 known diagnosed MS cases on Census Day 1980 give a prevalence rate for MS of 0.6 per 100 000 for the Cape Province which is probably a close approximation to the prevalence rate for the whole country. This is extremely low compared with the prevalence rates of 30 and above per 100000 in the high risk zone of North Europe (Kurtzke 1983). Moreover, out of 16 924000 Black South Africans on Census Day and prior and subsequent to that day, no case of MS confirmed at autopsy has ever been reported, including cases reported by the well staffed Neurology Department of
TABLE ! SEX A N D MEAN AGE FOR THE MULTIPLE SCLEROSIS PATIENTS Group
Total No.
Males
Females
Mean age (yr)
Range
Multiple sclerosis - Coloured Multiple sclerosis - White South African born
18
4
14
39
19-54
37
6
31
49
24-72
TABLE 2 F R E Q U E N C Y O F H L A A N T I G E N S IN PATIENTS W I T H M U L T I P L E SCLEROSIS HLA antigen a
MS (n = 24) Controls (n = 1(142) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +
A1 A2 A3 All A~w23 (9) Aw24 (9) Aw26 10) A28 A29 Aw30 Aw31 Aw32 Aw33 Aw43 B7 B8 B27 Bw35 Bw42 Bw44 (12) Bw45 (12) Bw51 (5) Bw57 (17) Bw58 (17) Bw60 (40) Bw62 (15) Bw63 (15) B15B
5 11 2 6 2 5 2 1 2 1 2 3 1 1 4 4 2 3 3 3 1 1 1 6 1 3 2 2
_
19 13 22 18 22 19 22 23 22 23 22 21 23 23 20 20 22 21 21 21 23 23 16 1t 15 15 16 14
o, %
+
20.8 45.8 8.3 25.0 8.3 20.8 8.3 4.2 8.2 4.2 8.3 12.5 4.2 4.2 16.7 16.7 8.3 12.5 12.5 12.5 4.2 4.2 5.9 35.3 6.3 16.7 11.1 12.5
+
182 313 175 109 119 205 91 160 102 184 19 60 78 55 217 100 47 122 59 179 62 50 105 149 43 94 28 154
_
859 729 867 933 923 837 951 882 940 858 1023 982 964 987 825 942 995 920 983 863 980 796 928 884 999 939 1005 888
t), 'o
+
17.5 30.0 16.8 10.5 11.4 19.7 8.7 15.4 9.8 17.7 1.8 5.8 7.5 5.3 20.8 9.6 4.5 11.7 5.7 17.2 6.0 5.9 10.2 14.4 4. I 9.2 2.7 14.8
Antigens tested for but absent in the MS c a s e s , HLA-B13, B14, B18, B37, Bw38, Bw39, Bw41, Bw46, Bw47, Bw48, Bw50, Bw52, Bw53, Bw54, Bw55, Bw56, Bw59, Bw61, Bu, Sv. TABLE 3 F R E Q U E N C Y O F H L A A N T I G E N S IN P A T I E N T S W I T H M U L T I P L E SCLEROSIS HLA antigen ~
MS (n = 16)
Controls (n = 190
+ DR1 DR2 DR3 DR4 DR5 DRw6 DR7 DRwl0
a
1 9 4 2 3 3 4 2
15 7 12 14 13 13 12 14
~,~ +
+
6.3 56.3 25.0 12.5 18.8 18.8 25.0 12.5
28 62 41 49 56 18 43 4
Antigens tested for but absent in the MS cases - HLA-DRw8, DRw9.
~o 162 128 149 141 134 172 147 186
14,7 32.6 21.6 25.8 29.5 9.5 22.6 2.1
179 TABLE 4 DISTRIBUTION MULTIPLE
O F A3, B7 A N D
SCLEROSIS
DR2 PHENOTYPES
IN COLOURED
PATIENTS
WITH
(MS)
HLA-A3
HLA-B7
HLA-DR2
M S (n = 16)
+
+
+
0
+ +
+
+
0
+
-
-
I
-
+
+
2
-
+
-
1
-
+
6
--
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Baragwanath Hospital for Blacks near Johannesburg. However, Cosnett (1981) reported 6 cases of demyelinating disease in South African Blacks. When the data in their report are examined, three of these cases fulfil the criteria of Poser et al. (1983) for the diagnosis of MS or its variant neuromyelitis optica. The sex ratio in ethnic groups among South African born MS cases varies inexplicably. Thus Dean (1967) reported that the ratio of females to males among 57 Afrikaans-speaking White MS patients (1.8:1) was not significantly different from the expected ratio of 1.4 : 1 whereas the ratio was higher (2.7 : 1) than expected among 101 English-speaking White MS patients. This difference is not exclusive to Englishspeaking White MS patients as the ratio for 18 Coloured MS patients in the present study, 14 : 4 (3.5 : 1) is also higher than the generally expected 3 : 2 female to male ratio in MS patients (Kurtzke 1983). Despite the very small number of known Coloured MS patients alive (20) or deceased (7) at the time of the current study, it was felt that a study of the HLA types in Coloured MS patients should be undertaken as it might provide clues regarding the relative contribution of genetic factors to the disease. The association between HLA antigens and MS, especially HLA-DR2, seems to indicate the presence of a genetic contribution by an MS susceptibility gene to the etiology of the disease. One would anticipate that such a gene would show an association with MS patients not only of different ethnic origins but also in MS patients in countries where the disease is extremely uncommon, such as Coloured South African MS patients. The antigens which have been suggested to be associated with an MS haplotype include HLA-A3, B7, BtTM,DR2 and Dw2 (Terasaki and Mickey 1976). The frequencies of HLA-A3 and B7 in White South African born MS patients and their White controls have been reported previously (Fewster et al. 1979). In the present study the frequency of HLA-A3 in South African born Coloured patients with MS (8~o) was surprisingly low and was significantly lower than in White South African born patients with MS (28 .%) (P = 0.05) or than their White controls without MS (28 °/o) (P = 0.04). Thus at
180
any rate in White (Fewster et al. 1979) and Coloured South Africans there appears to be no association of HLA-A3 with MS. The frequency of HLA-B7 in Coloured South African patients with MS (17%) is significantly lower (P < 0.05) than for White South African born patients with MS (40 %). However it is not significantly different from the frequency in the White South African born controls (31%) ofthe White MS patients reported by Fewster et al. (1979), so that the difference between the Coloured and ~ t e MS patients is not meaningful. Although there was no significant association between HLA-DR2 and MS in the Coloured MS patients, there was a trend towards such an association (0,25 > P > 0.1). If one assumed that the distribution of HLA-DR antigens remained the same in the MS group and the healthy controls with a Type 1 error of 0.05 and Type 2 error of 0.2 for the null hypothesis, 65 Coloured MS patients would be required. This far exceeds the number of known MS patients alive in this country. The frequency of HLA-DR2 in Coloured MS patients (569/o) contrasts with the low frequency (12%) of HLA-DR2 in Israeli Jews of European origin with MS (Brautbar et al. 1982). However the frequency (56 % ) is similar to, and is not statistically different from the frequency of HLA-DR2 in North European Caucasian MS patients (41%) (Bodmer et al. 1978), This in a population of mixed ethnic ancest~, the frequency of HLA-DR2 among MS patients seems to reflect the frequency in MS patients among an ethnic group, namely North: European Caucasians from whom they are partially descended. However, HLA-DR2 is always statistically increased in European Caucasian MS patients, whereas in the unavoidably limited sample size of Coloured South African MS patients, the trend for an increased fr~aency of HLA.DR2 antigens compared with Coloured South African healthy indi~uals is not enough of a difference to enable any conclusions to be made. ACKNOWLEDGEMENTS
The authors acknowledge the technical assistance of the staff of the Provincial Laboratory for Tissue Immunology, Observatory 7925, Cape. The antigen frequencies for HLA-A, HLA-B and HLA-DR among the unrelated, randomly selected healthy Cape Coloured individuals used as controls are preliminary analyses of unpublished data of Dr. E. Du Toit, Provincial Laboratory for Tissue Immunology. The medical superintendent and Professor A. S, De Grartf, Nearology Department, kindly gave us access to ~ records of Tygerberg Hospital. REFERENCES Bodmer, W.F., J.R. Batchelor, J.G. Bodmer, H: Festenstein and P.J. Morris (1978).Histocompatibility Testing 1977, Report of the Seventh International Histocompatibility Workshop and Conference, Oxford, Munksgaard, Copenhagen. B/Syum,A. (1968) Separation of leucocytes from blood and bone-marrow, Scand. J. Clin, Lab. Invest., 21 (Suppl. 97): 77-89. Brautbar, C., E. Kahana, M. Alter, F. Jergansen and L. Lamm (1977a) Histocompatibilitydeterminants in Israeli Jewish patients with multiple sclerosis, Tissue Antigens, 10: 291-302. Brautbar, C., E. Kahana, M. Alter, FI Jergensen and L. Lamm (1977b) Lack of association between HLA-Dw2 and multiple sclerosis in Israeli Jewish patients, N. Engl. J. Med., 296: 1537-1538.
18J Brautbar, C., A. Avraham, I. Cohen, E. Kahana, T. Cohen, D. Bloch, H. Grosse-Wilde and M. Alter (1982) Histocompatibility (HLA) antigens and multiple sclerosis in Israelis, Israel J. Med. Sci., 18:631-634. Cosnett, J. (1981) Multiple sclerosis and neuromyelitis optica, S. Air. Med. J., 60: 249-251. Danilovs, J. A., G. Ayoub and P.I. Terasaki (1980) Joint report: B lymphocyte isolation by thrombin-nylon wool. In: P. I. Terasaki (Ed.), Histocompatibility Testing, UCLA Tissue Typing Laboratory, Los Angeles, CA, pp. 287-288. Dean, G. (1967) Annual incidence, prevalence, and mortality of multiple sclerosis in white South-Africanborn and in white immigrants to South Africa, Brit, Med. J., 2: 724-730. Dupont, B., R.P. Lisak, C. Jersild, C. Hansen, J.A. Silberberg, D.H. Whitsett, B. Zweiman and A. K, Ciongoli (1977) HLA antigens in black patients with multiple sclerosis, Transplant. Proc., 9 (Suppl. 1): 181-185. Faucet, R., O. Bouhallier and B. Genetet (1980) Joint report: B cell typing by rosetting with AET-treated sheep red blood cells. In: P.I. Terasaki (Ed.), Histocompatibility Testing, UCLA Tissue Typing Laboratory, Los Angeles, CA, p. 289. Fewster, M.E., F.R. Ames and M.C. Botha (1979) Measles antibodies and histocompatibility types iu multiple sclerosis, J. Neurol. Sci., 43: 19-26. Jersild, C., A. Svejgaard and T. Fog (1972) HLA antigens and multiple sclerosis, Lancet, i: 1240-1241. Jersild, C., T. Fog, G.S. Hansen, M. Thomsen, A. Svejgaard and B. Dupont (1973) Histocompatibility determinants in multiple sclerosis with special reference to clinical course, Lancet, ii: 1221-1225. Kurdi, A,, Ayesh, A. Abdallat, U, Maayta, W.I. McDonald, D. A. S. Compston and J.R. Batchelor (1977) Different B lymphocyte alloantigens associated with multiple sclerosis in Arabs and North Europeans, Lancet, i: 1123-1125. Kurtzke, J.F. (1983) In: J.F. Hallpike, C. W. M, Adams and W.W. Tourtellotte (Eds.), Multiple Sclerosis, Chapman and Hall, London, pp. 66, 70. Menicucci, A., O. Baricordio, C. Conighi, L. Amaducci and P.L. Mattiuz (1977) HLA and B-lymphocyte in multiple sclerosis in Italy, Tissue Antigens, 10: 193. NA1AID Manual of Tissue Typing Techniques, 1966-1967, p. 22. Naito, S., N. Namerow, M. R. Mickey and P. I. Terasaki (1972) Multiple sclerosis: association with HL-A3, Tissue Antigens, 2: 1-4. Naito, S., Y. Kuroiwa, T. Itoyama, T. Tsubaki, A. Horikawa, T. Sasazuki, S. Noguchi, S. Ohtsuki, H. Tokuomi, T. Miyatake, N. Takahata, S. Kawanami and A.J. McMichael (1978) HLA and Japanese MS, Tissue Antigens, 12: 19-24. Poser, C.M., D.W. Paty, L. Scheinberg, W. I. McDonald, F.A. Davis, G.W. Ebers, K.P. Johnson, W.A. Sibley, D. H. Silberberg and W.W. Tourtellotte (1983) New diagnostic criteria for multiple sclerosis - - Guidelines for research protocols, Ann. Neurol., 13: 227-231. Saito, S., S. Naito, S. Kawanami and Y. Kuroiwa (1976) HLA studies on multiple sclerosis in Japan, Neurology, 26:49. Ferasaki, P. 1. and M. R. Mickey (1976) A single mutation hypothesis for multiple sclerosis based on the HL-A system, Neurology, 26 (No. 6, Part 2): 56-58. Tiwari, J. L., N.E. Morton, J.M. Lalouel, P.I. Terasaki, H. Zander, B.R. Hawkins and Y.W. Cho (1980) Joint report: Multiple sclerosis. In: P. I. Terasaki (Ed.), Histocompatibility Testing, UCLA Tissue Typing Laboratory, Los Angeles, CA., pp. 687-692. Winchester, R.J., G. Ebers, S.M. Fu, L. Espinosa, J. Zabriskie and H.G. Kunkel (1975) B cell alloantigeq Ag7a in multiple sclerosis, Lancet, ii: 814 (Letter).