Antibody-reactive class I epitopes defined by pairs of mismatched eplets and self-eplets.

The identification of human leukocyte antigen (HLA) antibodies in the sera of candidates awaiting organ transplantation has evolved over time. This has been possible because of the introduction of more sensitive techniques and to the increasing focus on the structural aspects of the HLA epitopes. The use of the HLAMatchmaker algorithm in the analysis of positive sera and the verification of HLA ABC epitopes in the HLA Epitope Registry website provide new stimuli on the interpretation of antibody reactivity. The epitopes defined by eplet pairs often involve a nonself-eplet and a self-eplet (nonself-self paradigm), suggesting that the antibody response to an HLA mismatch must have an auto-reactive component. Here, we report an application of the nonself-self paradigm that provides a basis for better knowledge and interpretation of HLA-antibody reactivity in Luminex assays with single alleles.

Antinuclear antibodies in first-degree relatives of patients with polymyositis-dermatomyositis: analysis of the relationship with HLA haplotypes.

Antinuclear antibodies (ANA), as detected by indirect immunofluorescence on HEp-2 cells, have been investigated in five spouses and 41 first-degree relatives of nine probands with polymyositis-dermatomyositis (PM-DM) and in 41 sex- and age-matched controls. ANA were detected in 12 out of the 41 first-degree relatives and in two controls (chi 2 = 6.97; P less than 0.01). HLA typing was done in four out of the nine families; in two of them only, ANA segregated with a haplotype. ANA positivity was not correlated either to sex or to age or to household contact. Our results show that ANA occur in a significant percentage of first-degree relatives of patients with PM-DM. The finding seems to be genetically conditioned.