Test ID: ALPS
Alpha Beta Double-Negative T Cells for Autoimmune Lymphoproliferative Syndrome
Secondary ID 
A test code used for billing and in test definitions created prior to November 2011
NY State Approved Indicates the status of NY State approval and if the test is orderable for NY State clients.
Useful For Suggests clinical disorders or settings where the test may be helpful
Diagnosing autoimmune lymphoproliferative syndrome, primarily in patients <45 years of age
Method Name A short description of the method used to perform the test
Flow Cytometry
Reporting Name A shorter/abbreviated version of the Published Name for a test; an abbreviated test name
Aliases Lists additional common names for a test, as an aid in searching
Canale-Smith syndrome
CD4/CD8 negative
DNT (Double Negative T-Cells)
Double negative T cells (DNT)
Specimen Type Describes the specimen type needed for testing
Specimen Required Defines the optimal specimen. This field describes the type of specimen required to perform the test and the preferred volume to complete testing. The volume allows automated processing, fastest throughput and, when indicated, repeat or reflex testing.
Send specimen Monday through Thursday only. Draw and package specimen as close to shipping time as possible. Ship specimen overnight.
Container/Tube: Lavender top (EDTA)
Specimen Volume: 3 mL
Additional Information:
1. Ordering physician name and phone number are required.
2. For serial monitoring, we recommend that specimen draws be performed at the same time of day.
Specimen Minimum Volume Defines the amount of specimen required to perform an assay once, including instrument and container dead space. Submitting the minimum specimen volume makes it impossible to repeat the test or perform confirmatory or perform reflex testing. In some situations, a minimum specimen volume may result in a QNS (quantity not sufficient) result, requiring a second specimen to be collected.
Reject Due To Identifies specimen types and conditions that may cause the specimen to be rejected
| Hemolysis | Mild OK; Gross reject |
| Lipemia | Mild OK; Gross reject |
| Icterus | NA |
| Other | NA |
Specimen Stability Information Provides a description of the temperatures required to transport a specimen to the laboratory. Alternate acceptable temperature(s) are also included.
| Specimen Type | Temperature | Time |
|---|---|---|
| Whole Blood EDTA | Ambient (preferred) | 72 hours |
| Refrigerated | 72 hours |
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
Autoimmune lymphoproliferative syndrome (ALPS) (also known as Canale-Smith syndrome) is a complex clinical disorder of dysregulated lymphocyte homeostasis that is characterized by lymphoproliferative disease, autoimmune cytopenias, splenomegaly, and lymphadenopathy with an increased susceptibility to malignancy.(1) Typically, ALPS is diagnosed by childhood or young adulthood.
Genetic defects in the apoptosis (programmed cell death) pathway have been determined for most cases of ALPS. Apoptosis plays a role in normal immune homeostasis by limiting lymphocyte accumulation and autoimmune reactivity. The interaction of the surface receptor CD95 (FAS) and its ligand (CD95L;FASL) triggers the apoptotic pathway in lymphocytes.
The following molecular ALPS classification has been established:
| ALPS Classification |
Molecular/Genetic Defect in Apoptosis |
| Type Ia | CD95 (FAS) mutations(1) |
| Type Ib | Heterozygous CD95L (FASLG) mutations(1) |
| Type Ic | Homozygous CD95L (FASLG) mutation(2) |
| Type II | CASP8 or CASP10 mutations(1,3) |
| Type III | Unknown(1,3) |
Patients with ALPS have an increase in a normally rare population of T cells (typically <1%) that are alpha beta T-cell receptor (TCR)-positive, as well as negative for both CD4 and CD8 coreceptors (double-negative T cells: DNT).(1) The alpha beta TCR+DNT cells from ALPS patients also express an unusual B-cell-specific CD45R isoform, called B220.(4,5) B220 expression on alpha beta TCR+DNT cells has been demonstrated to be a sensitive and specific marker for ALPS and is associated with FAS mutations.(4)
Several other diseases can present with an ALPS-like phenotype, including independent conditions like Evans syndrome (a combination of autoimmune hemolytic anemia and autoimmune thrombocytopenic purpura), Rosai-Dorfman disease (massive painless cervical lymphadenopathy that may be accompanied by leukocytosis, elevated erythrocyte sedimentation rate, and hypergammaglobulinemia), and nodular lymphocyte-predominant Hodgkin disease.(1)
Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
Alpha beta TCR+DNT cells
2-18 years: <2% CD3 T cells
19-70+ years: <3% CD3 T cells
Reference values have not been established for patients that are less than 24 months of age.
Alpha beta TCR+DNT cells
2-18 years: <35 cells/mcL
19-70+ years: <35 cells/mcL
Reference values have not been established for patients that are less than 24 months of age.
Alpha beta TCR+DNT B220+ cells
2-18 years: <0.4% CD3 T cells
19-70+ years: <0.3% CD3 T cells
Reference values have not been established for patients that are less than 24 months of age.
Alpha beta TCR+DNT B220+ cells
2-18 years: <7 cells/mcL
19-70+ years: <6 cells/mcL
Reference values have not been established for patients that are less than 24 months of age.
Interpretation Provides information to assist in interpretation of the test results
The presence of increased circulating T cells (CD3+) that are negative for CD4 and CD8 (double-negative T cells: DNT) and positive for the alpha/beta T-cell receptor (TCR) is required for the diagnosis of autoimmune lymphoproliferative syndrome (ALPS).
The laboratory finding of increased alpha beta TCR+DNT cells is consistent with ALPS only with the appropriate clinical picture (nonmalignant lymphadenopathy, splenomegaly, and autoimmune cytopenias). Conversely, there are other immunological disorders, including common variable immunodeficiency (CVID), which have subsets for patients with this clinical picture, but no increase in alpha beta TCR+DNT cells.
If the percent of the absolute count of either the alpha beta TCR+DNT cells or alpha beta TCR+DNT B220+ cells is abnormal, additional testing is indicated. All abnormal alpha beta TCR+DNT cell results should be confirmed (for ALPS) with additional testing for defective in vitro lymphocyte apoptosis, followed by confirmatory genetic testing for FAS mutations (contact Mayo Medical Laboratories for test forwarding information).
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
This test is typically not indicated in older adults. For questions about appropriate test selection, contact Mayo Medical Laboratories.
The sole presence of increased alpha beta TCR+DNT B220+ cells is not sufficient for a diagnosis of autoimmune lymphoproliferative syndrome (ALPS); additional testing is required to confirm a diagnosis of ALPS.
Clinical Reference Provides recommendations for further in-depth reading of a clinical nature
1. Worth A, Thrasher AJ, Gaspar HB: Autoimmune lymphoproliferative syndrome: molecular basis of disease and clinical phenotype. Brit J Hematol 2006;133:124-140
2. Del-Rey M, Ruiz-Contreras J, Bosque A, et al: A homozygous Fas ligand gene mutation in a patient causes a new type of autoimmune lymphoproliferative syndrome. Blood 2006;108:1306-1312
3. Salmena L, Hakem R: Caspase-8 deficiency in T-cells leads to a lethal lymphinfiltrative immune disorder. J Exp Med 2005;202:727-732
4. Blessing JJH, Brown MR, Dale JK, et al: TCR alpha beta+ CD4-CD8-T-cells in humans with the autoimmune lymphoproliferative syndrome express a novel CD45 isoform that is analogous to urine B220 and represents a marker of altered O-glycan biosynthesis. Clin Immunol 2001;100(3):314-324
5. Bleesing JJH, Janik JE, Fleisher TA: Common expression of an unusual CD45 isoform on T-cells from patients with large granular lymphocyte leukemia and autoimmune lymphoproliferative syndrome. Brit J Hematol 2003;120:93-96
Method Description Describes how the test is performed and provides a method-specific reference
This assay uses a 5-color, single-platform method with a 2-tube panel stained for the following antibodies: CD3, CD4, CD8, CD45, alpha beta TCR, and B220. The sample is stained with the antibody cocktail and incubated in the dark at room temperature for 20 minutes. Following incubation, the samples are treated with BD lysing solution to lyse the RBCs, followed with a wash step using BD FACS wash buffer. The cells are resuspended in 1% paraformaldehyde and analyzed by flow cytometry. The different subsets are expressed as a percent of CD3 T cells, and the absolute counts of all subsets are expressed as cells/mcL. (Unpublished Mayo method; Bleesing JJH, Brown MR, Dale JK, et al: TCR alpha beta + CD4-CD8- T-cells in humans with the autoimmune lymphoproliferative syndrome express a novel CD45 isoform that is analogous to murine B220 and represents a marker of altered O-glycan biosynthesis. Clin Immunol 2001;100[3]:314-324)
Day(s) and Time(s) Test Performed Outlines the days and times the test is performed. This field reflects the day and time the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time required before the test is performed. Some tests are listed as continuously performed, which means assays are performed several times during the day.
Monday through Friday
Do not send specimen after Thursday.
Specimen must be received by 10 a.m. Friday.
Analytic Time Defines the amount of time it takes the laboratory to setup and perform the test. This is defined in number of days. The shortest interval of time expressed is "same day/1 day," which means the results may be available the same day that the sample is received in the testing laboratory. One day means results are available 1 day after the sample is received in the laboratory.
Maximum Laboratory Time Defines the maximum time from specimen receipt at Mayo Medical Laboratories until the release of the test result
Specimen Retention Time Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded
Performing Laboratory Location The location of the laboratory that performs the test
Test Classification Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer's instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR), Investigation Use Only (IUO) product, or a Research Use Only (RUO) product.
CPT Code Information Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Medical Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.
88184-Flow cytometry, cell surface, cytoplasmic; first marker
88185 x 4-Each additional marker
LOINC® Code Information Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the result codes returned for this test or profile.
| Result ID | Reporting Name | LOINC Code |
|---|---|---|
| 23973 | %alpha/beta-TCR DNT | 34962-1 |
| 23974 | alpha/beta-TCR DNT | 34963-9 |
| 28904 | % TCR+DNT B220+ | In Process |
| 28905 | Absolute TCR+DNT B220+ | In Process |
| 23975 | Interpretation | 69052-9 |
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