HLA-B5 and Behçet's disease.

Correspondence HLA B5 and Behget's disease SIR, May we draw your attention again to the inheritance of the HLA B5 antigen and its association with Behcet's disease? The association of the HLA B5 and especially its Bw5l split' 2 with Behcet's disease was established in Japan'`3 and Turkey.4'5 There is also a weak association of B5 and Beh,et's disease in British male patients.5'6 There has been a further suggestion by Japanese workers in the field7 that the B5 of Japanese patients is inherited selectively from the mother. We want to present evidence that this is not the case, at least for patients of occidental and Middle Eastern origins. From a family study of patients with the disease classified according to Japanese criteria8 patients were selected who carried the HLA B5 antigen. We found 8 such Turk-ish patients and 3 English patients (in all cases except one the antigen carried was Bw5l). Tissue typings of these patients and their first-degree relatives were performed in Leiden with a set of 120 typing sera recognising 19 HLA A, 41 HLA B, and 6 HLA C specifications by standard microlymphocytotoxicity tests. The results are shown in the tables. In Table 1 the HLA typing results on the parents of 8 Turkish probands are given (the mother of case 6 could not be typed, but her HLA genotype was derived from the typing of 6 additional siblings). Of the 3 British probands 2 mothers and 3 fathers could be HLA typed. The HLA B5 antigen was inherited from the mother alone in 2 Turkish patients, from the father alone in 5, and from both parents in one instance. One British patient inherited the allele from the father, one from the mother, and one from both parents (Table 2). Ohno et al.7 found that the haplotype carrying the B5 was inherited from the mother alone in 5 patients and from both father and mother in one patient (6 patients and 5 families were studied). We have looked at 11 families of patients carrying the B5 antigen and found no selective inheritance from the mother. In our series 3 subjects inherited the B5 antigen from the mother, 2 inherited it from both parents, and 6 exclusively from the father. We would submit that inheritance is random.