Reference Interval:
Reports include age appropriate reference intervals and interpretation.
| Components
| Reference Interval
| % CD2
Absolute CD2
| By report
| % CD3 (Total T-cells)
Absolute CD3
| By report
| % HLA-DR
Absolute HLA-DR
| By report
| % CD4 (Helper T-cells)
Absolute CD4
| By report
| % CD45RA (Naive helper T-cells)
Absolute CD45RA
| By report
| % CD45RO (Memory helper T-cells)
Absolute CD45RO
| By report
| % CD8 (Suppressor T-cells)
Absolute CD8
| By report
| | CD4:CD8 ratio
| By report
| % CD19 (B-cells )
Absolute CD19
| By report
| % NK-cells
Absolute NK-cells
| By report
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| Interpretive Data: |
This profile screens for inherited immunodeficiencies. T-cell subsets (include naive and memory T-cells), B-cells, and NK-cells are evaluated. Primary immune deficiencies that show phenotypic abnormalities include X-linked hypogammaglobulinemia, DiGeorge syndrome, bare lymphocyte syndrome, and severe combined immunodeficiency disease (SCID).
X-linked hypogammaglobulinemia (X-linked agammaglobulinemia, Bruton's agammaglobulinemia) is caused by defective B-cell maturation secondary to mutations in the btk (Bruton's/B-cell tyrosine kinase) gene. T-cells (CD2, CD3) are normal or increased in number, and the CD4:CD8 ratio is normal or decreased. Most of the CD4 cells express the CD45RA antigen characteristic of naive rather than memory cells. B-cells (CD19, HLA-DR) are severely decreased or absent in the peripheral blood.
X-linked hypogammaglobulinemia can be distinguished form transient hypogammaglobulinemia of infancy by the absence of B-cells. Transient hypogammaglobulinemia of infancy results from delayed capacity for immunoglobulin synthesis and spontaneously resolves with age.
Thymic aplasia (congenital thymic aplasia, DiGeorge syndrome) results in impaired T-cell maturation and function. B-cells (CD19, HLA-DR) and NK-cells (CD16/CD56) are normal but T-cells (CD2, CD3) are usually decreased with an elevated CD4:CD8 ratio. The clinical course is variable, ranging from "partial DiGeorge syndrome" to cases that resemble SCID.
SCID has multiple genetic causes, including mutations in the gamma chain of the interleukin 2 receptor and the purine degradation enzymes, adenosine deaminase, and nucleoside phosphorylase. In adenosine deaminase deficiency, both B-cells (CD19, HLA-DR) and T-cells (CD2, CD3) are decreased in the peripheral blood. In other forms of SCID, the lymphopenia is not as severe, but the lymphocyte count is usually less than 1,000/µL even though B-cells (CD19, HLA-DR) may be normal or increased. In contrast to thymic aplasia, any T-cells present may have an immature phenotype.
Major histocompatibility complex class II deficiency, bare lymphocyte syndrome, is caused by defective transcription of HLA class II genes; B-cells (CD19) and T-cells (CD2, CD3) are present in normal numbers, but HLA-DR is absent. The CD4+ cells are usually CD45RA+.
Common variable immunodeficiency (CVID) describes a heterogeneous group of disorders with defective antibody formation. B-cells (CD19, HLA-DR) and T-cells (CD2, CD3) are usually normal in number, although B-cells may be decreased when CVID occurs concurrently with systemic lupus erythematosus. The CD4:CD8 ratio may be normal or decreased.
Wiskott-Aldrich syndrome includes immunodeficiency with thrombocytopenia and eczema. Lymphopenia is usually present with a progressive decline in T-cells numbers. The CD4:CD8 ratio is normal. The gene is X-linked and encodes the Wiskott-Aldrich syndrome protein.
Immunophenotyping is generally not useful in characterizing selective IgA deficiency, IgG subclass deficiencies, the hyper IgG syndrome, or hyperimmunoglobulin E syndrome (Job's syndrome).
Refer to Statement A under Testing Information at http://www.aruplab.com.
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| Note: |
This assay is designed for enumerating the percents and absolute cell counts of lymphocyte subsets in lysed whole blood. Whole blood is added to fluorochrome-labeled antibodies that bind specifically to cell surface antigens on lymphocytes. After incubation, lysing, and fixation, percents and absolute counts are enumerated utilizing an internal quantitation standard. Additional CBC data is not required.
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| CPT Code(s): |
86355 B-Cells, Total count; 86357 NK cells, Total count; 86359 T-Cells, Total count; 86360 Absolute CD4 and CD8 counts with ratio; 86356 CD4; 86356 CD45RA; 86356 CD45RO; 86356 CD2; 86356 HLA-DR
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Cross References: |
Congential T and B Cell Immunodeficiencies (Lymphocyte Subset Panel 7 - Congenital Immunodeficiencies)
, Primary Immunodeficiency Profile (Lymphocyte Subset Panel 7 - Congenital Immunodeficiencies) |
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