HLA B27

Keywords: HLA typing

Specimen:

10 mL blood in ACD. Sample must be processed within 48 hours of collection.

Method:

PCR amplification with identification by allele specific oligonucleotide probes and other molecular genetic methods/sequencing.

HLA-B27 by flow cytometry.

Application:

Histocompatibility testing for transplantation: HLA-A, B, C, DR and DQ antigens for renal and bone marrow transplantation.

Family studies required for selection of appropriate related bone marrow donors. Search of the bone marrow donor registries is indicated when no suitable related donor has been identified.

HLA associations have been described in a number of diseases but are not diagnostic. HLA typing is used as a prognostic indicator in rheumatoid arthritis.

HLA typing is not appropriate as a diagnostic test for ankylosing spondylitis, coeliac disease or narcolepsy but can be used to assist exclusion of these disorders.

It is no longer used in the diagnosis of haemochromatosis or in the assessment of risk for family members.

See Hereditary haemochromatosis.

Interpretation:

Near perfect matching is necessary for bone marrow transplantation.

A greater degree of mismatch is acceptable for renal and other organ transplantation.

Lack of HLA-B27 virtually excludes ankylosing spondylitis and the lack of HLA-DR2 excludes narcolepsy.

The presence of HLA-DR4 serves to delineate a subgroup of patients with rheumatoid arthritis with a poorer prognosis.

Lack of DQ2 or DQ8 excludes coeliac disease.

Reference:

Klein J and Sato A. N Engl J Med. 2000; 343: 702-709.