HLA-DQ9

HLA-DQ9 (DQ9) is a human leukocyte antigen serotype within the HLA-DQ (DQ) serotype group. DQ9 is a split antigen of the DQ3 broad antigen. DQ9 is determined by the antibody recognition of β⁹ and this generally detects the gene product of DQB1*0303.

HLA-DQ9

Illustration of HLA-DQ with bound peptide.
Polymer type	MHC Class II, DQ cell surface antigen
Cis-haplotype Haplotype isoform subtype DQA1 DQB1 DQ α2β9 DQ9.2 *0201 *0303 DQ α3β9 DQ9.3 *0302 *0303

Serology

DQ2, DQ3, DQ7, DQ8, and DQ9 recognition of DRB1*0303 product^[1]

	DQ9	DQ3	DQ2	DQ7	DQ8	sample
	%	%	%	%	%	(N)
*0303	67	12	11	1	1	2563
Red indicates the level of 'false' reaction in non-DQ9 serotypes
Alleles link-out to IMGT/HLA Databease at EBI

The serotyping efficiency of DQ9 is poor. The recognition of DQB1*0303 by DQ9 and or DQ3 is poorest, DQ2 which recognizes a different DQB1 subgroup recognizes DQB1*0303 as efficiently as DQ3. For this reason DQ9 serotyping is a poor method of typing for transplantation or disease association prediction or study.

DQB1*0303

(DQ9) is associated with nasal polyps,^[2] gestational diabetes,^[3] microscopic polyangiitis (Japanese). Primary linkage is with DRB1*0901-DQB1*0303 ^[4]

Haplotypes and disease

DQ9.2

DQA1*0201:DQB1*0303 is associated with type I psoriasis (vulgaris),^[5][6]

DQ9.3

DQA1*0302:DQB1*0303 maybe associated with juvenile diabetes in the orient.^[7][8] (Chinese) Primary linkage of vitiligo is with DQA1*03-DQB1*0303.^[9]