See-Tarn Woon

New diagnostic criteria for common variable immune deficiency (CVID), which may assist with decisions to treat with intravenous or subcutaneous immunoglobulin

Common variable immune deficiency (CVID) is the most frequent symptomatic primary immune deficiency in adults. The standard of care is intravenous immunoglobulin (IVIG) or subcutaneous immunoglobulin (scIG) therapy. The cause of CVID is currently unknown, and there is no universally accepted definition of CVID. This creates problems in determining which patients will benefit from IVIG/scIG treatment. In this paper, we review the difficulties with the commonly used European Society of Immune Deficiencies (ESID) and the Pan American Group for Immune Deficiency (PAGID) definition of CVID. We propose new criteria for the diagnosis of CVID, which are based on recent scientific discoveries. Improved diagnostic precision will assist with treatment decisions including IVIG/scIG replacement. We suggest that asymptomatic patients with mild hypogammaglobulinaemia are termed hypogammaglobulinaemia of uncertain significance (HGUS). These patients require long‐term follow‐up, as some will evolve into CVID.

Haploinsufficiency of the NF-κB1 Subunit p50 in Common Variable Immunodeficiency

Common variable immunodeficiency (CVID), characterized by recurrent infections, is the most prevalent symptomatic antibody deficiency. In ∼90% of CVID-affected individuals, no genetic cause of the disease has been identified. In a Dutch-Australian CVID-affected family, we identified a NFKB1 heterozygous splice-donor-site mutation (c.730+4A>G), causing in-frame skipping of exon 8. NFKB1 encodes the transcription-factor precursor p105, which is processed to p50 (canonical NF-κB pathway). The altered protein bearing an internal deletion (p.Asp191_Lys244delinsGlu; p105ΔEx8) is degraded, but is not processed to p50ΔEx8. Altered NF-κB1 proteins were also undetectable in a German CVID-affected family with a heterozygous in-frame exon 9 skipping mutation (c.835+2T>G) and in a CVID-affected family from New Zealand with a heterozygous frameshift mutation (c.465dupA) in exon 7. Given that residual p105 and p50—translated from the non-mutated alleles—were normal, and altered p50 proteins were absent, we conclude that the CVID phenotype in these families is caused by NF-κB1 p50 haploinsufficiency.

Comparison of Diagnostic Criteria for Common Variable Immunodeficiency Disorder

Common variable immunodeficiency disorders (CVIDs) are the most frequent symptomatic primary immune deficiency condition in adults. The genetic basis for the condition is not known and no single clinical feature or laboratory test can establish the diagnosis; it has been a diagnosis of exclusion. In areas of uncertainty, diagnostic criteria can provide valuable clinical information. Here, we compare the revised European society of immune deficiencies (ESID) registry (2014) criteria with the diagnostic criteria of Ameratunga et al. (2013) and the original ESID/pan American group for immune deficiency (ESID/PAGID 1999) criteria. The ESID/PAGID (1999) criteria either require absent isohemagglutinins or impaired vaccine responses to establish the diagnosis in patients with primary hypogammaglobulinemia. Although commonly encountered, infective and autoimmune sequelae of CVID were not part of the original ESID/PAGID (1999) criteria. Also excluded were a series of characteristic laboratory and histological abnormalities, which are useful when making the diagnosis. The diagnostic criteria of Ameratunga et al. (2013) for CVID are based on these markers. The revised ESID registry (2014) criteria for CVID require the presence of symptoms as well as laboratory abnormalities to establish the diagnosis. Once validated, criteria for CVID will improve diagnostic precision and will result in more equitable and judicious use of intravenous or subcutaneous immunoglobulin therapy.

New diagnostic criteria for CVID

Response to: Kumar R, Bhatia A. Common variable immunodeficiency in adults: current diagnostic protocol and laboratory measures. Expert Rev. Clin. Immunol. 10(2), 000–000 (2014).

Fulminant Mulch Pneumonitis in Undiagnosed Chronic Granulomatous Disease: A Medical Emergency

Chronic granulomatous disease (CGD) was first recognized in the 1950s and was termed fatal granulomatous disease of childhood. CGD is a rare primary immune deficiency disorder with a minimum estimated prevalence of 1:250 000 in the general population. CGD is caused by mutations of the components of the phagocyte NADPH oxidase. The NADPH oxidase comprises catalytic membrane bound and regulatory cytosolic proteins. During phagocytosis, the cytosolic proteins translocate to the membrane to assemble the NADPH oxidase. Its function is to reduce molecular oxygen in order to kill ingested microorganisms. Failure of the NADPH oxidase as a result of mutations of any of its components results in CGD. Five genotypic disorders have been recognized, based on the affected component. The commonest mutation affects membrane-bound gp91phox (NOX2, CYBB) and is inherited as an X-linked recessive disorder. Given that mutations of gp91phox cause 60% to 70% CGD cases, the majority of affected patients are male. More recently, autosomal recessive presentations of CGD have been recognized. These variants are caused by mutations of p47phox (NCF1), p22phox (CYBA), and p67phox (NCF2), and very recently, p40phox (NCF4) of the NADPH oxidase has also been implicated. Mutations of these 4 genes can affect males and females equally. Careful study of large series of patients has shown there are significant phenotypic variations in the clinical profiles of CGD patients. Specifically, patients with p47phox appear to have a milder phenotype and can present later in life. Often infections are milder and respond to antibiotics. In this article, we describe the case of a 16-year-old girl with a mutation of p47phox, who died following exposure to mulch. She suffered overwhelming Aspergillus fumigatus infection and died in spite of intense antifungal treatment and supportive therapy including extracorporeal membrane oxygenation (ECMO).

The clinical utility of molecular diagnostic testing for primary immune deficiency disorders: a case based review

Primary immune deficiency disorders (PIDs) are a group of diseases associated with a genetic predisposition to recurrent infections, malignancy, autoimmunity and allergy. The molecular basis of many of these disorders has been identified in the last two decades. Most are inherited as single gene defects. Identifying the underlying genetic defect plays a critical role in patient management including diagnosis, family studies, prognostic information, prenatal diagnosis and is useful in defining new diseases. In this review we outline the clinical utility of molecular testing for these disorders using clinical cases referred to Auckland Hospital. It is written from the perspective of a laboratory offering a wide range of tests for a small developed country.

Primary immune deficiency disorders in the South Pacific: the clinical utility of a customized genetic testing program in New Zealand

Primary immune deficiency disorders (PIDs) are a group of diseases associated with a genetic susceptibility to recurrent infections, malignancy, autoimmunity, and allergy. The molecular basis of many of these disorders has been identified in the last two decades. Most are inherited as single gene defects. As discussed in this paper, identifying the underlying genetic defect plays a critical role in many areas—including patient management, diagnosis, identifying atypical presentations, family studies, providing prognostic information, prenatal diagnosis, and defining new diseases. New Zealand is a geographically isolated, developed country in the South Pacific. We have introduced a dedicated customized genetic testing service for PID patients in New Zealand. This accredited diagnostic program offers rapid turnaround times for genetic tests and minimizes the risk of laboratory errors. Here we review the clinical indications for genetic testing for PIDs based on cases referred to the molecular immunology diagnostic service at Auckland City Hospital.

Epistatic interactions between mutations of TACI (TNFRSF13B) and TCF3 result in a severe primary immunodeficiency disorder and systemic lupus erythematosus

Common variable immunodeficiency disorders (CVID) are a group of primary immunodeficiencies where monogenetic causes account for only a fraction of cases. On this evidence, CVID is potentially polygenic and epistatic although there are, as yet, no examples to support this hypothesis. We have identified a non‐consanguineous family, who carry the C104R (c.310T>C) mutation of the Transmembrane Activator Calcium‐modulator and cyclophilin ligand Interactor (TACI, TNFRSF13B) gene. Variants in TNFRSF13B/TACI are identified in up to 10% of CVID patients, and are associated with, but not solely causative of CVID. The proband is heterozygous for the TNFRSF13B/TACI C104R mutation and meets the Ameratunga et al. diagnostic criteria for CVID and the American College of Rheumatology criteria for systemic lupus erythematosus (SLE). Her son has type 1 diabetes, arthritis, reduced IgG levels and IgA deficiency, but has not inherited the TNFRSF13B/TACI mutation. Her brother, homozygous for the TNFRSF13B/TACI mutation, is in good health despite profound hypogammaglobulinemia and mild cytopenias. We hypothesised that a second unidentified mutation contributed to the symptomatic phenotype of the proband and her son. Whole‐exome sequencing of the family revealed a de novo nonsense mutation (T168fsX191) in the Transcription Factor 3 (TCF3) gene encoding the E2A transcription factors, present only in the proband and her son. We demonstrate mutations of TNFRSF13B/TACI impair immunoglobulin isotype switching and antibody production predominantly via T‐cell‐independent signalling, while mutations of TCF3 impair both T‐cell‐dependent and ‐independent pathways of B‐cell activation and differentiation. We conclude that epistatic interactions between mutations of the TNFRSF13B/TACI and TCF3 signalling networks lead to the severe CVID‐like disorder and SLE in the proband.

Application of diagnostic and treatment criteria for common variable immunodeficiency disorder

ABSTRACT Common variable immunodeficiency disorder (CVID) is the most frequent symptomatic primary immune deficiency disorder in adults. It probably comprises a spectrum of polygenic disorders, with hypogammaglobulinemia being the overarching feature. While the majority of patients with CVID can be identified with relative ease, a significant proportion can present with minimal symptoms in spite of profound laboratory abnormalities. Here we discuss three patients who were presented to the Auckland Hospital immunoglobulin treatment committee to determine if they qualified for immunoglobulin replacement. Two were asymptomatic with profound laboratory abnormalities while the third patient was severely ill with extensive bronchiectasis. The third patient had less severe laboratory abnormalities compared with the two asymptomatic patients. We have applied four sets of published diagnostic and treatment criteria to these patients to compare their clinical utility. We have chosen these patients from the broad phenotypic spectrum of CVID, as this often illustrates differences in diagnostic and treatment criteria.

IgE-type multiple myeloma with the late development of IgA2 kappa and plasma cell leukaemia

Sir, IgE-type myeloma is a rare haematological condition. Previously only around 40 cases have been described. Two recent cases were reported from Australia and China. Here we report what is believed to be the first published case of IgE-type myeloma from New Zealand. Our patient was a 76-year-old woman who presented with several months of lethargy and bilateral rib pain. There were no symptoms suggestive of underlying allergy or hyperviscosity. Clinical examination revealed significant pallor and right lower rib tenderness. Initial laboratory investigations showedhaemoglobin (Hb) 102g/L (reference range 115–154), mean corpuscular volume (MCV) 100 fl (82–99), mean corpuscular haemoglobin (MCH) 33 pg (27–33), white blood cell count (WBC) 5.76 10/L (4.1–11.7) and platelet 2336 10/L (110–400); plasma creatinine 90 mmol/L (40–100), corrected calcium 2.47 mmol/L (2.10–2.55); plasma total protein 111 g/L (64–83), albumin 44 g/L (35–47); immunoglobulin G (IgG) 6.4 g/L (6–15), IgA 0.7 g/L (0.8–4), IgM 0.6 g/L (0.4–2.4); serum b2-microglobulin 3.4 mg/L (52.4). Serum protein electrophoresis and immunofixation (Sebia Hydrasys system; Sebia, France) revealed a large, diffusemid gamma IgE kappa band, measured at 29.6 g/L by densitometry. Electrophoresis of concentrated urine revealed two far gamma free kappa light chain bands, their combinedquantity measured at 12 mg/mmol creatinine. A full skeletal survey demonstrated asymptomatic radiolucencies in the skull and left distal humerus. A bone scintiscan revealed foci of increased tracer uptake in the ribs bilaterally. Sestamibi whole body scan revealed moderate diffuse uptake in the vertebral column, sternum and clavicles. Myeloma staging confirmedaDurie-Salmon stage IIIA (frombone lesions) and International Staging System stage I. Bone marrow examination revealed extensive infiltration by mostly well differentiated plasma cells (55% of bone marrow cellularity). Occasional binucleate plasma cells were identified. The three haematopoietic lineages were mildly depressed. Interphase nuclear in situ hybridisation (FISH) studies on bone marrow aspirate material revealed no 13q14 deletion at the D13S319 and RB-1 loci (Abbott Molecular, USA). FISH at 14q32 IGH@ (Abbott Molecular), specifically looking at t(11:14) CCND1 and t(4:14) FGFR3 loci demonstrated a signal pattern consistent with no gene rearrangement. After two cycles of monthly treatment with melphalan and prednisone together with intravenous Zoledronic acid, the patient’s rib pain resolved, the total globulin fell to 38 g/L and the IgE band reduced to 9.7 g/L. M-band quantitation remained at 9.2 g/L after four cycles of chemotherapy. Treatment was changed to 2-weekly intravenous cyclophosphamide, which did not achieve any further reduction in the M-band level. The patient maintained a good quality of life for more than 14 months (European Cooperative Oncology Group performance score 0). Renal function and calcium remained normal throughout this period. Some 17 months from diagnosis she developed secondary plasma cell leukaemia (peripheral blood plasma cell count 0.316 10/L). At the time, the IgE band declined further to 3.2 g/L but a new far gamma free kappa and a new mid gamma IgA kappa band emerged (Fig. 1). She was then treated with oral thalidomide and pulsed oral dexamethasone to which she responded briefly before deteriorating further. She died from disseminated infection some 23 months from diagnosis. The new IgA kappa M-band was subsequently identified as predominantly of IgA2 subtype (IgA subclass quantification radial immunodiffusion kit; Binding Site Ltd, UK). A dramatic rise of serum IgA2 from the early phase of the patient’s condition when the level was 125 mg/L (reference interval 60–610 mg/L) to a level of 44165 mg/L occurred during the later part of her illness. IgA1 production was suppressed from the time of diagnosis and became further suppressed as the disease progressed [270 mg/L falling to 184 mg/L (600–2940 mg/L)]. The m-e switch region in this patient was examined at the DNA level midway in her clinical course, when the plasma cell leukaemia and the new IgA2 band were detected. Polymerase chain reaction (PCR) was performed to amplify the m-e switch region with subsequent DNA sequencing being performed. We then carried out PCR using oligomers flanking the m-a2 switch site, cloned the product into a DNA vector and performed DNA sequencing on the cloned vector. A ‘residual’ molecular footprint of the e switch region was not found at the m-a2 switch site. Molecular studies on the light chain region were not performed. IgE-type multiple myeloma prevalence is estimated at 50.1% of all plasmacytomas. It usually presents late (mean age 62 years) with a slight male predominance. Features noted in higher frequency when compared to other myeloma subtypes include anaemia, Bence Jones proteinuria, osteoblastic bony lesions and progression to secondary plasma cell leukaemia. Protein electrophoresis usually detects the IgE type M-band in the g region but sometimes the M-band is found at the b or a2 regions. With the raised IgE level, hyperviscosity syndrome and mast cell activation reactions have been rarely reported. IgE-type myeloma generally runs a more malignant course than non-IgE myeloma with a mean survival 12.5 months or 19 months in those without renal failure. Hypodiploidy, chromosome 13 abnormalities and IGH@ gene rearrangement (chromosome 14q32) have been described in multiple myeloma patients and are typically associated with a poorer prognosis. From a small series of patients with myeloma variants, including IgM, IgD, non-secretory myeloma and two IgE subtype patients, a much higher (83%) incidence of the t(11:14) was found compared with the more common IgG and IgA subtypes. However, our patient’s bone marrow did not reveal chromosome 14 IGH@ loci (11:14) rearrangement or chromosome 13 deletion. Pathology (January 2010) 42(1), pp. 82–104