NEW!
Tests for Immune
Deficiency

T-B-NK Immunophenotyping
Test Code 403106

T, B, and NK lymphocytes play central roles in immune system function. T-B-NK Immunopheno-
typing is useful when evaluating patients with recurrent infections for immunodeficiency. Lymphocyte immunophenotyping is also vital when following HIV and bone marrow transplant patients.

Immunoglobulin A (IgA) Low Range
Test Code 6

Anti-IgA
Test Code 2107

IgA Deficiency Panel
Test Code 403017 (includes both tests)

IgA deficiency is the most common immune deficiency occurring in an estimated 1 in 600 individuals (Clin Exp Immunol. 2000;120:225-231). A patient is considered deficient if their serum IgA level is below 5 mg/dL for adults, but many regular IgA assays do not have the sensitivity to detect IgA at this level. The Immunoglobulin A (IgA) Low Range test has a lower limit of quantitation of 0.04 mg/dL. Most individuals with IgA deficiency appear healthy and are asymptomatic. Others, however, may have frequent recurrent respiratory infections, allergies, chronic diarrhea, and/or other autoimmune diseases.

The potential for anti-IgA antibodies to develop arises when there is an absence of normal IgA. The Anti-IgA test detects these IgG antibodies. Patients with IgG antibodies against IgA may suffer from anaphylactoid reactions when given IVIG. In one study (Clin Immunol. 2007;122:156) five out of eight patients with IgG anti-IgA antibodies developed anaphylactoid reactions when IVIG was administered.

T cell Receptor Excisiion Circles (TREC)
Test Code 403108

The ability to generate new naïve T cells is vital during infancy, following bone marrow transplant and when undergoing Highly Active Antiretroviral Therapy (HAART). The T cell Receptor Excision Circles (TREC) test quantifies T cell receptor excision circles (TREC) present in peripheral blood mononuclear cells (PBMC) or CD3 T cells by real-time PCR as a measure of newly produced naïve T cells (thymopoiesis). In one study (Blood. 2006;108:763) the number of TREC in patients with severe combined immunodeficiency receiving hematopoietic stem cell transplantation was a good predictor for long term T cell reconstitution.

Natural Killer Cell Function Assay
Test Code 2108

The NK cell function assay evaluates the ability of NK cells present in PBMC to lyse K562 cells. Natural killer cells mediate killing of virally infected cells and tumor cells. Decreased natural killer cell function has been observed in patients with recurrent viral infections and cancer patients.

In the News

Filaggrin Mutations and Asthma:
Dr. Ingo Marenholz and colleagues (J Allergy Clin Immunol. 2009;123:911) evaluated the utility of using filaggrin (FLG) mutations to predict the future development of asthma. They evaluated 871 patients in the German Multicenter Allergy Study for three FLG mutations (R501X, 2282del4, and R2447X). The authors concluded that “genotyping the FLG mutations allow the prediction of asthma before the onset of symptoms.” IBT offers the ProGenotyper™ Filaggrin Mutation Detection Test (403100) that detects 6 loss of function mutations including the three described in this study.

IVIG for subclass and/or antibody deficiency: Dr. Abdou and colleagues (Int Arch Allergy Immunol. 2009;149:267) evaluated the response of patients with either antibody deficiency or subclass deficiency when treated with IVIG. They monitored antibody levels to tetanus and pneumococcal as well as Toll Like Receptor (TLR) and Mannon Binding Lectin (MBL) analysis. They concluded that IVIG was beneficial in this patient population. IBT offers a wide range of tests for evaluating and monitoring patients with immune deficiencies.