HLA-Dw 'RSH': a new HLA-Dw specificity associated with HLA-DRw18(3)

The present study describes a new HLA-Dw specificity, Dw'RSH'. HLA-Dw'RSH' is associated with DRw18(3) and is clearly different to the DRw17(3) associated specificity Dw3. Dw'RSH' was shown to be the most common Dw specificity found in the South African (SA) Negroes (gf = 0.10) and was less common in Cape Coloureds (gf = 0.01). The specificity was absent in the SA Caucasoids tested. Dw'RSH' is part of the common Negro haplotype Bw42, DRw18, DQw4 which is seen as commonly in the SA Negroes as the B8, DRw17, DQw2, Dw3 haplotype is seen in the Caucasoids.

HLA-A,B,C, and DR antigens, GLO I and Bf marker profiles in 75 Cape coloured patients with systemic lupus erythematosus (SLE)

HLA-A,B,C and DR antigens were tested in 75 Cape Coloured systemic lupus erythematosus (SLE) patients, and the GLO I and Bf markers in 51. The patients with HLA-DR2 had a relative risk significantly greater than one (p=0.0005). Twenty-two (29%) patients had only one detectable DR antigen. Of these, 11 (50%) were found to have DR2 only. The HLA-DR7 antigen was associated with severe disease (p less than 0.02). Bf and GLO I markers were not associated with SLE.

HLA-A, B, C, DR and DQ polymorphisms in three South African population groups: South African Negroes, Cape Coloureds and South African Caucasoids

The HLA class I and II phenotypes of the three population groups in the Cape Province of South Africa were determined. The HLA-A,B, and C antigens were tested in 1027 South African Negroes (Xhosa), 3716 Cape Coloureds and 1059 South African Caucasoids. This is the first study which has also included the class II antigens in the Southern African Negroes (Xhosa). The numbers tested for the DR and DQ antigens were smaller, as only typings done after the 8th Histocompatibility Workshop were included. A comparison was made between the frequencies in the Xhosa, the Cape Coloureds and the South African Caucasoids as well as the Nigerians, another group who also belong to the Bantu-speaking division of African Negroes and who were recently studied. The antigen, gene and haplotype frequencies were estimated in all three groups, and the genetic distances calculated. Striking differences in gene and haplotype frequencies between the various populations were seen. For example, Bw42 had a phenotype frequency of 0.062 in the Cape Coloureds, 0.213 in the Xhosa and 0.004 in the South African Caucasoids. The Xhosa showed marked differences in HLA distribution compared to the other Negro group (Nigerians), which can be attributed to a Khoisan admixture, e.g. HLA-DR4 had a phenotype frequency of 0.134 in the Xhosa and only 0.010 in the Nigerians. The haplotype B8,DR3, seen in association with many autoimmune diseases, had a significant delta value in all three populations.

A study of the HLA-Dw determinants and their relationship to DR and DQ antigens in three South African population groups: South African Caucasoids, South African Negroes, and Cape coloureds

The HLA-Dw specificities of a group of 177 unrelated randomly selected healthy individuals consisting of 67 South African Negroes (Xhosa), 57 Cape Coloureds, and 53 South African Caucasoids were determined. HLA-Dw specificities were determined in a mixed lymphocyte culture test using HTCs. Antigen and gene frequencies as well as the association between HLA-DR, DQ, and Dw were established in three populations. HLA-Dw gene frequencies in the South African Caucasoids agreed with these frequencies in other Caucasoid groups. The HLA-Dw1 frequency was decreased in the Cape Coloureds and South African Negroes compared to the Caucasoids. The gene frequency of Dw3 was low in the South African Negroes in spite of the fact that DR3 is a common DR antigen in this group. A high frequency of Dw 'blank' was observed in the South African Negroes and Cape Coloureds, suggesting the existence of undefined HLA-Dw specificities in these populations. Data concerning the HLA-Dw, DR, and DQ relationships showed that once a certain Dw specificity was associated with a particular DR and DQ antigen, this association remained a fixed entity in the different population groups.