Soluble HLA-II expression in African-Americans.
OBJECTIVE
In this study we evaluated the contribution of major histocompatibility complex (MHC) genes to soluble histocompatibility antigen class II (sHLA-II) secretion in African American patients with rheumatoid arthritis (RA).


METHODS
A sensitive enzyme-linked immunoassay was used to quantitate sHLA-II in the serum of 7 patients with RA, as well as 28 of their kinships and 49 HLA typed normal African American individuals.


RESULTS
Mean sHLA-II values were higher in patients with RA than those in healthy African American individuals (p < 0.05). There were variations in concentrations in individual patients but these were unrelated to any apparent clinical event. The proportion of unaffected family members with detectable levels of sHLA-II was not significantly different than those in normal controls. Neither specific HLA-haplotype, or HLA-allele(s) correlated with high or low sHLA-II secretion.


CONCLUSIONS
Our data suggest that sHLA-II molecules are not regulated by MHC linked genes but may be regulated by non-MHC linked genes and racial background may reflect genetic heterogeneity of the expression of this soluble HLA material. These observations contrast with previous observations concerning soluble HLA class I (sHLA-I) molecules in a described population sample which were almost the precise reverse.
Adamashvili
I
I
Department of Surgery, Louisiana State University Health Sciences Center, Shreveport 71130-3932, USA. iadama@lsumc.edu
Fraser
P A
PA
Milford
E L
EL
Sittig
K
K
Gebel
H
H
Zibari
G
G
Pressly
T
T
McDonald
J C
JC
D001172:Arthritis, Rheumatoid / Q000276:immunology; D044383:Black People; D015395:Histocompatibility Antigens Class I / Q000097:blood; D000949:Histocompatibility Antigens Class II / Q000097:blood* / Q000502:physiology; D006801:Humans; D008285:Major Histocompatibility Complex; D001741:Black or African American
D015395:Histocompatibility Antigens Class I; D000949:Histocompatibility Antigens Class II