Human Leukocyte Antigen B27

General

Synonym/Acronym:
HLA-B27.

Rationale
To assist in diagnosing juvenile rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis, and Reiter syndrome.

Patient Preparation
There are no food, fluid, activity, or medication restrictions unless by medical direction.

Normal Findings
(Method: Flow cytometry) Negative (indicating absence of HLA B27).

Critical Findings and Potential Interventions
N/A

Overview

(Study type: Blood collected in a green-top [heparin] or a yellow-top [acid-citrate-dextrose (ACD)] tube; related body system: Immune system.)

The human leukocyte antigens (HLAs) are gene products of the major histocompatibility complex, derived from their respective loci on the short arm of chromosome 6. There are three general groups: HLA-A, HLA-B, and HLA-DR. Each group contains many different proteins. HLA-B27 is an allele (one of two or more genes for an inheritable trait that occupy the same location on each chromosome, paternal and maternal) of the HLA-B locus. There are a number of HLA-B27 subtypes, not all of which are associated with disease. The antigens are present on the surface of nucleated tissue cells as well as on white blood cells. HLA testing is used in determining histocompatibility for organ and tissue transplantation. Another application for HLA testing is in paternity investigations. The presence of HLA-B27 is associated with several specific autoimmune conditions, including ankylosing spondylitis, rheumatoid arthritis, psoriatic arthritis, undifferentiated oligoarthritis, uveitis, and inflammatory bowel disease. Although less than 10% of the population are carriers of HLA B-27, 20% of carriers will develop an autoimmune condition.

Indications

  • Assist in diagnosing ankylosing spondylitis and Reiter syndrome (reactive arthritis).
  • Determine compatibility for organ and tissue transplantation.

Interfering Factors


Other Considerations:

  • The specimen should be stored at room temperature and should be received by the laboratory performing the assay within 24 hr of collection. It is highly recommended that the laboratory be contacted before specimen collection to avoid specimen rejection.

Potential Medical Diagnosis: Clinical Significance of Results

Positive Findings In:

  • Ankylosing spondylitis
  • Inflammatory bowel disease
  • Juvenile rheumatoid arthritis
  • Psoriatic arthritis
  • Reiter syndrome
  • Sacroiliitis
  • Uveitis

Nursing Implications, Nursing Process, Clinical Judgement

Before the Study: Planning and Implementation


Teaching the Patient What to Expect

  • Explain that a blood sample is needed for the test.
  • Discuss how this test can assist with investigation of specific leukocyte disorders and determine compatibility for organ and tissue transplantation.

After the Study: Implementation & Evaluation Potential Nursing Actions


Treatment Considerations

  • Recognize the fear of shortened life expectancy, as these diseases can be moderately to severely debilitating. Discuss symptoms and treatment options associated with the specific disease diagnosed.

Clinical Judgement

  • Consider who can provide the best support in managing social interactions in conjunction with disease process.

Followup Evaluation and Desired Outcomes

  • Acknowledges the clinical implications of the test results and the lifestyle changes that will need to be made.

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