DNA typing of maternal HLA in congenital complete heart block - Comparisonwith systemic lupus erythematosus and primary Sjogren's syndrome

Objective, To investigate which maternal HLA allele or haplotype is primari ly associated with isolated congenital complete heart block (CCHB) in offsp ring. Methods. HLA class II typings were assessed by line probe assay and polymer ase chain reaction-sequence-specific oligonucleotide probe methods, and HLA class I by the microlymphocytotoxicity test, in 13 Italian anti-Ro-positiv e mothers of children with CCHB and 41 anti-Re-positive mothers with health y children (20 mothers with systemic lupus erythematosus [SLE] and 21 with Sjogren's syndrome [SS]), Anti-Re antibodies were studied by immunoblot. Results. HLA-DRB1*03011 and DRB1*03011; DQA1*0501;DQB1*0201 were more frequ ent in mothers of infants with CCHB than in mothers who had SLE, but not in mothers who had SS and whose children were healthy. Mothers of infants wit h CCHB were either HLA-B5/35, B17, or B44 positive and had a higher prevale nce of B44;DRB11;DQA1*0501;DQB1*0301 and isolated anti-52-kd antibodies, wh ich were absent in SS and SLE controls. Conclusion. Mothers of infants with CCHB presented a strong genetic similar ity to mothers who had SS, except for HLA class I phenotype, HLA-DRB1*03011 ;DQA1*0501;DQB1*0201 seemed not to be primary CCHB-associated genes, but we re involved in an SS-like anti-Ro/La response. The combined presence of HLA -DRB1*03011 and anti-52-kd SSA/Ro antibodies conveyed the highest risk of g iving birth to an affected child.