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HelpTest Code LRBA Lipopolysaccharide-Responsive Beige-Like Anchor Protein (LRBA) Deficiency, Blood
Test Down Notes
LRBA is temporarily test down due to reagent issues.
Ordering Guidance
This flow cytometry test is complementary to genetic testing.
Shipping Instructions
Testing is performed Monday through Friday. Specimens not received by 4 p.m. (CST) on Friday may be cancelled.
Collect and package specimen as close to shipping time as possible. It is recommended that specimens arrive within 24 hours of collection.
Samples arriving on the weekend and observed holidays may be canceled.
Necessary Information
Ordering healthcare professional name and phone number are required.
Specimen Required
Container/Tube: Lavender top (EDTA)
Specimen Volume: 3 mL
Collection Instructions: Send whole blood specimen in original tube. Do not aliquot.
Secondary ID
608113Useful For
Aiding in the diagnosis of lipopolysaccharide-responsive beige-like anchor protein (LRBA) deficiency
This test is not useful for identifying a carrier status for LRBA deficiency.
Genetics Test Information
The human lipopolysaccharide-responsive beige-like anchor protein (LRBA) gene is on chromosome 4.
Assessment of 109 patients with LRBA deficiency has shown 93 homozygous and 16 compound heterozygous alterations in the gene.
Alterations in the LRBA gene have been observed throughout the length of the gene and include the following main categories: Nonsense; missense; insertions, deletions, indels, and splice site alterations.
Highlights
The test determines the percentage and intensity of expression of lipopolysaccharide-responsive beige-like anchor (LRBA) protein on T cells and B cells in peripheral blood.
It can be used as a screening step prior to genetic testing for LRBA; to confirm the finding of an established disease-causing alteration in LRBA at the protein level; and to examine the effect of reported genetic variants of undetermined significance on LRBA protein expression.
It can help distinguish LRBA deficiency from conditions with overlapping clinical manifestations, including immune dysregulation and autoimmunity, such as immune dysregulation, polyendocrinopathy, enteropathy, X-linked (IPEX)-like syndromes; early onset hypogammaglobulinemia; common variable immune deficiency; inflammatory bowel disease; and autoimmune lymphoproliferative syndrome.
Method Name
Flow Cytometry
Reporting Name
LRBA Deficiency, BSpecimen Type
Whole Blood EDTASpecimen Minimum Volume
1 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Whole Blood EDTA | Ambient | 48 hours | PURPLE OR PINK TOP/EDTA |
Reject Due To
| Gross hemolysis | Reject |
| Gross lipemia | Reject |
| Gross icterus | OK |
Clinical Information
Lipopolysaccharide-responsive beige-like anchor protein (LRBA) deficiency is a rare autosomal recessive primary immunodeficiency disease (also known as inborn errors of immunity) caused by homozygous or compound heterozygous loss-of-function variants in the LRBA gene. It has a wide spectrum of clinical manifestations, including immune dysregulation and autoimmunity, inflammatory bowel disease, early-onset hypogammaglobulinemia, recurrent infections and organomegaly.
Reference Values
The appropriate reference values will be provided on the report.
Interpretation
The results are reported as the percentage and MFI (mean fluorescence intensity) of lipopolysaccharide-responsive beige-like anchor protein (LRBA) expression in T cells and B cells.
The majority of genetically confirmed cases of LRBA deficiency lead to the absence of LRBA expression. Therefore, the lack of LRBA expression in T and B cells is consistent with LRBA deficiency. In this case, genetic analysis of LRBA to confirm the diagnosis and to identify the underlying variant will be recommended.
In addition, there are reported cases of LRBA deficiency where the protein is expressed but at lower intensity. Therefore, the expression of LRBA at diminished intensity could be due to a disease-causing LRBA variant, which would have to be confirmed or ruled out by genetic and functional analysis.
Cautions
No significant cautionary statementsClinical Reference
1. Lopez-Herrera G, Tampella G, Pan-Hammarstrom Q, et al. Deleterious mutations in LRBA are associated with a syndrome of immune deficiency and autoimmunity. Am J Hum Genet. 2012;90(6):986-1001
2. Gamez-Diaz L, August D, Stepensky P, et al. The extended phenotype of LPS-responsive beige-like anchor protein (LRBA) deficiency. J Allergy Clin Immunol. 2016;137(1):223-230
3. Habibi S, Zaki-Dizaji M, Rafiemanesh H, et al. Clinical, Immunologic, and Molecular Spectrum of Patients with LPS-Responsive Beige-Like Anchor Protein Deficiency: A Systematic Review. J Allergy Clin Immunol Pract. 2019;7(7):2379-86.e5
4. Serwas NK, Kansu A, Santos-Valente E, et al. Atypical manifestation of LRBA deficiency with predominant IBD-like phenotype. Inflamm Bowel Dis. 2015;21(1):40-47
5. Revel-Vilk S, Fischer U, Keller B, et al. Autoimmune lymphoproliferative syndrome-like disease in patients with LRBA mutation. Clin Immunol. 2015;159(1):84-92
6. Kiykim A, Ogulur I, Dursun E, et al. Abatacept as a Long-Term Targeted Therapy for LRBA Deficiency. J Allergy Clin Immunol Pract. 2019;7(8):2790-2800.e15
7. Tesch VK, Abolhassani H, Shadur B, et al. Long-term outcome of LRBA deficiency in 76 patients after various treatment modalities as evaluated by the immune deficiency and dysregulation activity (IDDA) score. J Allergy Clin Immunol. 2020;145(5):1452-1463
Method Description
The lipopolysaccharide-responsive beige-like anchor (LRBA) protein expression assay is performed on EDTA whole blood. Samples are fixed, permeabilized and stained with antibodies specific for CD45, CD14, CD19, CD3, and CD56 along with either the LRBA antibody (unconjugated) or isotype control (unconjugated). A secondary reporter antibody is added to allow the assessment of LRBA and isotype control expression. Samples are then analyzed on a flow cytometer. LRBA expression is evaluated on the following populations: T-cells: (CD45+CD14negCD3+) and B-cells: (CD45+CD14negCD3negCD19+).(Unpublished Mayo method)
Specimen Retention Time
4 daysPerforming Laboratory
Mayo Clinic Laboratories in Rochester
Test Classification
This test was developed using an analyte specific reagent. Its performance characteristics were determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.CPT Code Information
86356 x 2
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| LRBA | LRBA Deficiency, B | In Process |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 608960 | %CD3+LRBA+ | In Process |
| 608964 | MFI CD3+LRBA+ | In Process |
| 608961 | %CD19+LRBA+ | In Process |
| 608965 | MFI CD19+LRBA+ | In Process |
| 608968 | LRBA Interpretation | 69052-9 |
Day(s) Performed
Monday through Friday