HLA-B51

Bw51 was associated with Behçet's disease,^[5] in endemic (versus epidemic) mucocutaneous lymph node syndrome,^[6] susceptibility to the virus that causes German measles infection.^[7]

Behçet's disease is an inflammation of the wall of blood vessels that can involve the eyes, skin, and the rest of the body.^[8] Several alleles of B51 (B*5101, B*5108, B*5105, and B*5104) are found in disease, and linkage to markers, D6S285, in the HLA locus was strong (P<0.005).^[9] Homozygotes of B51 showed considerably high risk for disease indicating a possible gene-dose effect. B51 is capable of distinguishing several varieties of disease. HLA-B51 is found more frequently in disease that has an eye involvement.^[10] However it is less common in some regions when there is increased neurological involvement.^[11] The MICA*009 allele has been found to also associated with ABD when B51 is also present,^[12] IL-8 and other cytokines may also be involved.^[13][14] Sister chromatid exchange has also been observed more frequently in B51(+) ABD.^[15]

However, B51 tends not to be found in ABD when a certain SUMO4 gene variant is involved,^[16] and symptoms appear to be milder when HLA-B27 is present.^[17]