Immunoglobulin Disorders

Diagnosis

Indications for Testing

  • Recurrent infections (eg, sinusitis, otitis media, pneumonia) and/or chronic diarrhea

Laboratory Testing

  • Initial screening
    • General immunodeficiency screening
      • CBC with differential 
      • Comprehensive metabolic profile 
      • Quantitative serum immunoglobulins (IgA, IgG, IgM)
        • IgG normal but suspicion for deficiency – perform IgG subclass testing
        • Elevated immunoglobulins may require further evaluation including mutation testing to confirm uncommon disorders (eg, hyper-IgM syndrome)
      • Lymphocyte subset analyses – depending on clinical presentation
      • Pre- and post-vaccination titers – if presentation is solely recurrent sinopulmonary disease, or normal quantitative immunoglobulins
    • Rule out other diseases associated with immunodeficiency
    • Rule out diseases associated with protein losses (eg, protein-losing enteropathy, nephropathy)
  • More specific screening – based on initial screening results
    • Clinical presentation may require multiple immune system investigations (see Immunodeficiency Evaluation algorithms)
    • Definitive diagnosis, prognostication,  genetic counseling, and treatment  may require genetic testing

Clinical Background

Immunoglobulin deficiencies are the most common primary immunodeficiency.

Epidemiology

  • Incidence – 1/2,000 live births for primary immunodeficiency

Specific Immunoglobulins

  • Structure – 2 heavy chains, 2 light chains
    • Isotype (G, M, A, D, E) – determined by type of heavy chain
  • IgG

    Characteristics

    • Constitutes 75-85% of total serum immunoglobulins
    • Produced in response to antigens of most bacteria and viruses and to small soluble protein antigens
    • Only class of immunoglobulins in humans actively transported through placenta
      • Responsible for newborn protection during the first 4-6 months of life
    • Capable of fixing complement

    Subclasses

    • Subclasses 1, 2, 3, 4
      • IgG1 – highest concentration
      • IgG3 and 4 – lowest concentrations
      • Concentrations change with age
      • Subclasses fix complement in the following order of descending efficiency – IgG3, IgG1, IgG2, IgG4
    • Subclass deficiency may go undetected because total IgG level can be normal
      • IgG2 and 3 – most common deficiencies
      • May be associated with recurrent infections even in the presence of normal IgG concentrations

    Increased IgG concentrations  

    • Serum
      • Malignancy
      • Autoimmune disorders (eg, autoimmune hepatitis, multiple sclerosis [MS])
      • Chronic infections – present as polyclonal
      • Monoclonal gammopathy of undetermined significance (MGUS), multiple myeloma – present as monoclonal
      • Chronic lymphocytic leukemia (CLL)
    • Central nervous system (CNS) samples
      • Infections
      • Inflammation (eg, MS and neoplastic conditions of the CNS)

    IgG deficiency

    • Etiologies
      • Excessive protein loss (eg, protein-losing enteropathy, nephropathy)
      • Inherited defects in synthesis
      • Acquired defects in production
      • Immunosuppressive drugs or toxins
      • In association with primary immunodeficiencies
        • Hypogammaglobulinemia of infancy
          • Usually transient – most have normal concentration by 3 years
        • Agammaglobulinemia
          • Complete or near complete lack of mature B cells and immunoglobulins
          • X-linked (Bruton type for males) or autosomal inheritance (males and females)
        • Hyper-IgM syndrome
        • Common variable immunodeficiency (CVID)
        • Other immunodeficiency syndromes with IgG deficiency (eg, warts, hypogammaglobulinemia, infections, and myelokathexis (WHIM) syndrome)
    • Clinical presentation
      • Recurrent upper/lower respiratory infections
        • Severe infections uncommon in subclass deficiencies
      • Chronic diarrhea
    • Laboratory
      • Low to undetectable IgG concentrations – deficiency may be solely in subclass
      • Other abnormalities possible – particularly in association with primary immunodeficiencies
    IgA

    Characteristics

    • Predominant class of immunoglobulins in respiratory and gastrointestinal secretions
      • 10-15% of total serum immunoglobulins
    • Secretory IgA found in tears, sweat, saliva, milk, colostrum, gastrointestinal, and bronchial secretions
      • Synthesized by plasma cells in gut, bronchi, and ductules of lactating breast
      • More resistant to enzymes and able to protect mucosa from bacteria and viruses
    • Affects development of allergic (IgE) reactions to various ingested antigens
      • Binds antigens and prevents IgE responses (immune exclusion)

    Subclasses

    • Two subclasses
      • IgA1 – predominant in serum
      • IgA2 – predominant in secretions

    Increased serum IgA concentrations

    • Infections
      • Skin, gut, respiratory, and renal
      • AIDS
    • CNS involvement in autoimmune diseases (eg, systemic lupus erythematosus [SLE])
    • Portal cirrhosis and other liver disease
      • Concomitant IgG increases are common
    • Multiple myeloma, monoclonal gammopathy of undetermined significance (MGUS)

    IgA deficiency

    • Etiologies
    • Selective IgA deficiency
      • Epidemiology
        • One of the most common primary deficiencies
        • European, African, Middle Eastern descent – 1/150-900
        • Asian populations – uncommon
      • Clinical presentation
        • Often asymptomatic
        • Recurrent respiratory and GI tract infections (Giardia duodenalis – most common)
        • Autoimmune disease (eg, CD, SLE, rheumatoid arthritis)
        • May be associated with atopic disease
        • Circulating anti-IgA often present
          • May mediate fatal anaphylactoid reactions if IgA is infused (eg, in blood component therapy, plasma or intravenous immunoglobulin)
      • Laboratory
        • Very low to undetectable IgA concentration
        • IgG2 or IgG4 may also have very low concentrations
        • Normal B-cell and T-cell testing
    IgM

    Characteristics

    • Circulates mainly in the bloodstream – 5-10% of total serum immunoglobulins
    • Primary immune response antibody – first to appear in infections
    • Predominates in primary viral and blood stream infections for first 2-3 months postinfection and may persist for as long as 1 year

    Increased IgM concentrations

    • Polyclonal increases – most common
      • Infections
      • Autoimmune disease (eg, rheumatoid arthritis, primary biliary cirrhosis)
      • Fetal elevations when intrauterine infection has occurred
        • Cord blood may have IgM specific to offending pathogen
    • Monoclonal increases – most common in Waldenström macroglobulinemia and monoclonal cryoglobulinemias
    • CNS fluid increases
    • Hyper-IgM syndrome
      • Pathophysiology – altered in immunoglobulin class switch recombination due to defect or deficiency in T- and B-cell interactions, B-cell development, or DNA repair  
        • B cells cannot switch from IgM production to IgA, IgE, and IgG
      • Clinical presentation
        • Onset in infancy and early childhood
        •  Recurrent bacterial and/or opportunistic infections (eg, Pneumocystis jirovecii, Histoplasma capsulatum, aspergillus, Cryptosporidium spp., Cryptococcus neoformans)
        • Protracted and severe diarrhea common
        • Autoimmune diseases common (eg, sclerosing cholangitis)
        • Significant risk for liver disease if survival to adolescence
        • Increased risk for malignancy – particularly liver and GI tract
      • Laboratory
        • Low IgG, IgA, and IgE concentrations
        • Normal to elevated IgM concentrations – also may include IgD
        • Anemia, thrombocytopenia, neutropenia common
        • Normal B- and T-cell numbers – function often impaired
        • Mutations in CD40LG, IKBKG, CD40, UNG, AICDA, PMS2 genes
          • X-linked inheritance (almost exclusively males) – defects in CD40LG or, rarely, in IKBKG (NEMO) genes
          • Autosomal inheritance (males and females) – CD40, UNG, AICDA, PMS2 genes

    IgM deficiency

    • Primary
      • Inherited defects
      • Selective IgM deficiency
      • Toxins/drugs
    • Secondary
    • Clinical presentation
      • May be asymptomatic
      • May present with recurrent severe bacterial infections
    IgE

    Characteristics

    • Small percent of total immunoglobulins (<1%)
    • Binds to mast cells and basophils
      • Involved in immediate hypersensitivity and atopic disease
      • Causes allergic or anaphylactic reactions
    • Strong correlation between total serum plasma IgE levels and allergic disease
      • Increased cord blood and infant IgE is predictive of early-onset allergic disease
    • Parasitic immunity immunoglobulin

    Increased IgE concentrations

    • Allergic disease
      • Allergic rhinitis
      • Extrinsic asthma
      • Urticaria
      • Atopic eczema
    • Infections
    • Drug allergies
    • Hyper-IgE syndrome (Job syndrome)
      • Pathophysiology
        • Defective intracellular signaling (caused by STAT3 or DOCK8 gene mutations)
      • Clinical presentation
        • Two forms
          • Type I – autosomal dominant (AD)
          • Type II – autosomal recessive (AR)
        • Recurrent infections and abscesses
        • Early-onset eczema
        • Sinopulmonary disease
        • Classic facial abnormalities in type I disease
        • AR disease distinguished from AD disease by severe viral infections, higher rate of CNS disease, and autoimmune disease
      • Laboratory
        • Elevated IgE concentrations
        • Eosinophilia
        • Other immunoglobulins and blood counts usually normal
          • AR disease – low IgM concentrations, decreased blood T-cell count
        • Gene mutations
          • STAT3 – AD disease
          • DOCK8 – AR disease
    • Immune dysregulation, polyendocrinopathy, enteropathy, X-linked inheritance syndrome (IPEX)
      • Pathophysiology
        • Regulatory T-cell defect (CD4+CD25+ regulatory)
      • Clinical presentation
        • Immune – hemolytic anemia, autoimmune thrombocytopenia, neutropenia
        • Polyendocrine – diabetes mellitus (DM) type I, thyroiditis
        • Enteropathy – diarrhea (onset usually <6 months)
        • Other – eczema, other autoimmunity (eg, autoimmune hepatitis)
      • Laboratory
        • Elevated IgE concentrations
        • Normal IgA, IgG, IgM concentrations initially – eventually all immunoglobulins decrease as a result of enteropathy-induced protein loss
        • Complement studies normal
        • Metabolic abnormalities develop – DM type I, hypothyroidism
        • Gene mutations
          • FOXP3 – X-linked inheritance, males
          • IPEX-like diseases – AR inheritance, males and females
            • IL2RA (CD25)
            • STAT5B
            • STAT1
            • ITCH

    IgE deficiency

    • Does not indicate absence of allergic disease
    • Certain allergic individuals have low total IgE but high concentration of allergen-specific IgE
    • May suffer anaphylaxis with low to undetectable concentrations of IgE or allergen-specific IgE antibodies
    IgD

    Characteristics

    • Major receptor for antigen on B-cell surface – very small portion (<1%) of total immunoglobulins
    • Early B-cell antigen receptor
    • May help regulate B-cell function

    Increased IgD concentrations

    • Polyclonal increase in infections, autoimmunity, and many other conditions (eg, smoking)
    • Monoclonal increase in IgD multiple myeloma – rare (2%)
    • Often presents with high-risk features
    • Hyper-IgD with periodic fever syndrome
      • Pathophysiology
        • Hereditary periodic fever syndrome
        • Mutation causes decreased mevalonate kinase activity – involved in cholesterol biosynthesis
          • Results in interleukin1 and mevalonic acid accumulation
      • Clinical presentation
        • High-spiking fevers
        • Headache
        • Lymphadenopathy – usually cervical
        • Gastrointestinal – abdominal pain, diarrhea, emesis
        • Musculoskeletal – arthritis, arthralgia
        • Dermatologic – maculopapular rash, purpura, urticaria
      • Laboratory
        • Elevated IgD concentrations; IgA concentrations may be elevated
        • Elevated urine mevalonic acid during acute attacks
        • During attack – leukocytosis, elevated erythrocyte sedimentation rate (ESR)/C-reactive protein (CRP)
        • MVK  gene mutations

    IgD deficiency

    • Usually asymptomatic – discovered during testing for immunodeficiencies

Indications for Laboratory Testing

  • Tests generally appear in the order most useful for common clinical situations
  • Click on number for test-specific information in the ARUP Laboratory Test Directory
Test Name and Number Recommended Use Limitations Follow Up
Immunoglobulins (IgA, IgG, IgM), Quantitative 0050630
Method: Quantitative Nephelometry

General screen for suspected immunodeficiency

   
Immunoglobulin G Subclasses (1, 2, 3, 4) 0050577
Method: Quantitative Nephelometry
Order for suspected subclass immunodeficiency when IgG is low or if IgG normal and subclass deficiency suspected    
Lymphocyte Subset Panel 6 - Total Lymphocyte Enumeration with CD45RA and CD45RO 0095862
Method: Quantitative Flow Cytometry

Determine presence of T-cell deficiency

Measures percentage and absolute numbers of CD4  (helper T cells), CD45RA (naive helper T cells), CD45RO (memory helper T cells), CD8 (suppressor T cells), CD4: CD8 ratio, CD3 (total T cells), CD19 (B cells), NK cells

   
Lymphocyte Subset Panel 7 - Congenital Immunodeficiencies 0095899
Method: Quantitative Flow Cytometry

Determine presence of congenital deficiencies of lymphocytes

Measures percentage and absolute numbers of CD2, CD4  (helper T cells), CD45RA (naive helper T cells), CD45RO (memory helper T cells), CD8 (suppressor T cells), CD4: CD8 ratio, CD3 (total T cells), CD19 (B cells), NK cells

   
Regulatory T-Cell Panel 2010172
Method: Quantitative Flow Cytometry

May be useful when evaluating patients for a rare primary immune deficiency called IPEX (immune dysregulation, polyendocrinopathy, enteropathy, X-linked),  graft-vs-host disease in post-hematopoietic stem cell transplantation, some malignancies, or autoimmune disease

Panel includes percent CD4+CD25+CD127Low regulatory T cells (regulatory T cells [Tregs]); abs CD4+CD25+CD127Low (Tregs); percent CD4+CD25+CD127LowCD45RA+ natural naïve regulatory T cells (natural naïve [Nn] Tregs); abs CD4+CD25+CD127LowCD45RA+ (Nn Tregs); percent CD4+CD25+CD127LowCD45RO+ naturally occurring regulatory T cells (N Tregs); abs CD4+CD25+CD127LowCD45RO+ (N Tregs)

   
Streptococcus pneumoniae Antibodies, IgG (14 Serotypes) 0050725
Method: Quantitative Multiplex Bead Assay

Use to evaluate vaccine response

Evaluate suspected immunodeficiency

   
Diphtheria, Tetanus, and H. Influenzae b Antibodies, IgG 0050779
Method: Quantitative Multiplex Bead Assay

Use to evaluate vaccine response

Evaluate suspected immunodeficiency

   
Hyper IgM Syndrome Panel, Sequencing (12 Genes) and Deletion/Duplication (10 Genes) 2011154
Method: Massive Parallel Sequencing/Exonic Oligonucleotide-based CGH Microarray

Confirm suspected hyper-IgM syndrome in individual with clinical symptoms

Genes sequenced – AICDA, ATM, BTK, CD40, CD40LG, IKBKG, MRE11A, NBN/NBS1, NFKBIA, PIK3CD, RAG2, UNG

Genes analyzed for deletions/duplications – AICDA, ATM, BTK, CD40, CD40LG, MRE11A, NBN/NBS1, NFKBIA, RAG2, UNG

Not determined or evaluated – mutations in genes not included on the panel; deep intronic and regulatory region mutations; breakpoints for large deletions/duplications; translocations

Deletions/duplications will not be detected in IKBKG or PIK3CD

Small deletions or insertions may not be detected

Diagnostic errors can occur due to rare sequence variations

Lack of a detectable gene mutation does not exclude a diagnosis of hyper-IgM syndrome

 
Primary Antibody Deficiency Panel, Sequencing (35 Genes) and Deletion/Duplication (26 Genes)  2011156
Method: Massive Parallel Sequencing/Exonic Oligonucleotide-based CGH Microarray

Preferred test for individuals with clinical phenotype of antibody deficiency (eg, agammaglobulinemia, common variable immunodeficiency)

Genes sequenced –  ADA, AICDA, ATM, BLNK, BTK, CD19, CD40, CD40LG, CD79A, CD79B, CD81, CR2, ICOS, IGHM, IGLL1, IKBKG, LRBA, LRRC8A, MRE11A, MS4A1, NBN/NBS1, NFKB2, NFKBIA, PIK3CD, PIK3R1, PLCG2, PRKCD, PTPRC, RAG2, SH2D1A, TNFRSF13B, TNFRSF13C, UNG, VAV1, XIAP/BIRC4

Genes analyzed for deletions/duplications – ADA, AICDA, ATM, BLNK, BTK, CD19, CD40, CD40LG, CD79A, CD79B, CD81, CR2, ICOS, IGHM, IGLL1, MRE11A, MS4A1, NBN/NBS1, NFKB2, NFKBIA, PTPRC, RAG2, TNFRSF13B, TNFRSF13C, UNG, VAV1

Not determined or evaluated – mutations in genes not included on the panel; deep intronic and regulatory region mutations; breakpoints for large deletions/duplications; translocations

Deletions/duplications will not be detected in IKBKG, LRBA, LRRC8A, PIK3CD, PIK3R1, PLCG2, PRKCD, SH2D1A, or XIAP/BIRC4 genes

Small deletions or insertions may not be detected

Diagnostic errors can occur due to rare sequence variations

Lack of a detectable gene mutation does not exclude a diagnosis of primary antibody deficiency

 
Additional Tests Available
 
Click the plus sign to expand the table of additional tests.
Test Name and NumberComments
CBC with Platelet Count and Automated Differential 0040003
Method: Automated Cell Count/Differential

General screen for suspected immunodeficiency

Comprehensive Metabolic Panel 0020408
Method: Quantitative Ion-Selective Electrode/Quantitative Enzymatic/Quantitative Spectrophotometry

General screen for suspected immunodeficiency

Monoclonal Protein Detection Quantitation and Characterization, SPEP, IFE, IgA, IgG, IgM, Serum 0050615
Method: Qualitative Immunofixation Electrophoresis/Quantitative Capillary Electrophoresis/Quantitative Nephelometry

Evaluation for plasma cell dyscrasias

Kappa and Lambda Free Light Chains (Bence Jones Protein), Quantitative, Urine 0050618
Method: Qualitative Immunofixation Electrophoresis/Quantitative Nephelometry

Evaluation for plasma cell dyscrasias

Alpha-1-Antitrypsin, Quantitative by ELISA, Random Stool 2011041
Method: Quantitative Enzyme-Linked Immunosorbent Assay

Useful in evaluation of  protein-losing enteropathy

Alpha-1-Antitrypsin Clearance, Quantitative by ELISA, Timed Stool 2011043
Method: Enzyme-Linked Immunosorbent Assay/Quantitative Immunoturbidimetry

Useful in evaluation of protein-losing enteropathy

Human Immunodeficiency Virus Types 1 and 2 (HIV-1, HIV-2) Antibodies by CIA with Reflex to HIV-1 Antibody Confirmation by Western Blot 2005377
Method: Qualitative Chemiluminescent Immunoassay/Qualitative Western Blot

Initial evaluation for HIV

Immunoglobulin A, Saliva 0050525
Method: Quantitative Nephelometry

Quantify salivary IgA in patients with recurrent upper respiratory infections

Immunoglobulin G 0050350
Method: Quantitative Nephelometry
Immunoglobulin M 0050355
Method: Quantitative Nephelometry
Immunoglobulin D, Serum 0099200
Method: Quantitative Nephelometry
Immunoglobulin E 0050345
Method: Quantitative ImmunoCAP® Fluorescent Enzyme Immunoassay
Immunoglobulin G Subclass 1 0050571
Method: Quantitative Nephelometry
Immunoglobulin G Subclass 2 0050572
Method: Quantitative Nephelometry
Immunoglobulin G Subclass 3 0050573
Method: Quantitative Nephelometry
Immunoglobulin G Subclass 4 0050576
Method: Quantitative Nephelometry
Immunoglobulin G4 by Immunohistochemistry 2005844
Method: Immunohistochemistry
Immunoglobulins, CSF Quantitative 0050631
Method: Quantitative Nephelometry
Immunoglobulin A, CSF 0050341
Method: Quantitative Nephelometry
Immunoglobulin G, CSF 0050670
Method: Quantitative Nephelometry
Immunoglobulin G/Albumin Ratio, CSF 0050680
Method: Nephelometry
Immunoglobulin G, CSF Index 0050676
Method: Quantitative Nephelometry
Immunoglobulin M, CSF 0050356
Method: Quantitative Nephelometry
Humoral Immunity Panel I 0050980
Method: Quantitative Nephelometry/Semi-Quantitative Multiplex Bead Assay
Immunoglobulin A Subclasses (1&2) 0093149
Method: Quantitative Nephelometry
Humoral Immunity Panel II 0050981
Method: Semi-Quantitative Multiplex Bead Assay
Anti-IgA Antibody by ELISA 2003126
Method: Quantitative Enzyme-Linked Immunosorbent Assay

Test for antibodies to IgA in patients with IgA deficiency and blood transfusion reaction