Chinese patients with defective IL-12/23-interferon-gamma circuit in Taiwan: partial dominant interferon-gamma receptor 1 mutation presenting as cutaneous granuloma and IL-12 receptor beta1 mutation as pneumatocele

Distinct Lymphocyte Immunophenotyping and Quantitative Anti-Interferon Gamma Autoantibodies in Taiwanese HIV-Negative Patients with Non-Tuberculous Mycobacterial Infections

PURPOSE

The presence of anti-interferon-γ autoantibodies (AutoAbs-IFN-γ) is not rare in patients suffering from persistent non-tuberculous mycobacterial (NTM) infections that are characteristic of adult-onset immunodeficiency syndrome. The immune disturbances in this distinct disorder remain to be elucidated.

METHODS

Patients with NTM infections but without effective response over 3 months' treatment were referred to our institute to quantify their level of AutoAbs-IFN-γ after excluding defective IL12/23-IFN-γ circuit and reactive oxygen species production. The AutoAbs-IFN-γ and percentage of lymphocyte subpopulations most relevant to T and B cell pools were assessed and compared with age-matched healthy controls.

RESULTS

A total of 31 patients were enrolled during the 15-year study period (2008-2022), 20 patients with > 50% suppression of IFN-γ detection at 1:100 serum dilution were classified into the Auto-NTM group. The remaining 11 with negligible suppression were assigned to the No Auto-NTM group. Mycobacterium chimaera-intracellulare group (MAC), M. kansasii, and M. abscessus were the most common pathogens. Pneumonia (19 vs 7), lymphadenitis (11 vs 5), Salmonella sepsis (6 vs 2), osteomyelitis (5 vs 1), and cutaneous herpes zoster (4 vs 4) were the main manifestations in both the Auto-NTM and No Auto-NTM groups who had similar onset-age (55.3 vs 53.6 years; p = 0.73) and follow-up duration (71.9 vs 54.6 months; p = 0.45). The Auto-NTM group had significantly higher transitional (IgM +  + CD38 + +), CD19 + CD21-low, and plasmablast (IgM-CD38 + +) in the B cell pool, with higher effector memory (CD4 + /CD8 + CD45RO + CCR7 -), senescent CD8 + CD57 + , and Th17 cells, but lower naïve (CD4 + /CD8 + CD45RO - CCR7 +) and Treg cells in the T cell pool when compared to the No Auto-NTM and healthy groups. NTM patients with/without AutoAbs-IFN-γ had lower Th1-like Tfh (CD4 + CXCR5 + CXCR3 + CCR6 -) cells. All Auto-NTM patients still had non-remitted mycobacterial infections and higher AutoAbs-IFN-γ despite anti-CD20 therapy in 3 patients.

CONCLUSION

In patients with suspected adult-onset immunodeficiency syndrome, two thirds (20/31) were recognized as having significantly inhibitory AutoAbs-IFN-γ with higher antibody-enhancing transitional, CD19 + CD21-low and plasmablast B cells; as well as higher effector memory, senescent CD8 + CD57 + and Th17 cells, but lower naïve T and Treg cells in contrast to those with negligible AutoAbs-IFN-γ. Such immunophenotyping disturbances might correlate with the presence of AutoAbs-IFN-γ. However, the mutual mechanisms need to be further clarified.

Genetic and Functional Identifying of Novel STAT1 Loss-of-Function Mutations in Patients with Diverse Clinical Phenotypes

PURPOSE

Mutations in signal transducer and activator of transcription 1 (STAT1) cause a broad spectrum of disease phenotypes. Heterozygous STAT1 loss-of-function (LOF) mutations cause Mendelian susceptibility to mycobacterial diseases (MSMD) infection, which is attributable to impaired IFN-γ signaling. The identification of novel mutations may extend the phenotypes associated with autosomal dominant (AD) STAT1 deficiency.

METHODS

Five patients with heterozygous STAT1 variations were recruited and their clinical and immunologic phenotypes were analyzed, with particular reference to JAK-STAT1 signaling pathways.

RESULTS

Four, heterozygous STAT1 deficiency mutations were identified, three of which were novel mutations. Two of the mutations were previously unreported mRNA splicing mutations in AD STAT1-deficient patients. Patients with heterozygous STAT1 deficiency suffered not only mycobacterial infection, but also intracellular non-mycobacterial bacterial infection and congenital multiple malformations. AD-LOF mutation impaired IFN-γ-mediated STAT1 phosphorylation, gamma-activated sequence (GAS), and IFN-stimulated response element (ISRE) transcription activity and IFN-induced gene expression to different extents, which might account for the diverse clinical manifestations observed in these patients.

CONCLUSION

The infectious disease susceptibility and phenotypic spectrum of patients with AD STAT1-LOF are broader than simply MSMD. The susceptibility to infections and immunological deficiency phenotypes, observed in AD-LOF patients, confirms the importance of STAT1 in host-pathogen interaction and immunity. However, variability in the nature and extent of these phenotypes suggests that functional analysis is required to identify accurately novel, heterozygous STAT1 mutations, associated with pathogenicity. Aberrant splice of STAT1 RNA could result in AD-LOF for STAT1 signaling which need more cases for confirmation.

An Updated Review on MSMD Research Globally and A Literature Review on the Molecular Findings, Clinical Manifestations, and Treatment Approaches in China

Mendelian susceptibility to mycobacterial disease (MSMD) arises from a group of rare inherited errors of immunity that result in selective susceptibility of otherwise healthy people to clinical disease caused by low virulence strains of mycobacteria, such as Mycobacterium bovis Bacille Calmette-Guérin (BCG) and environmental mycobacteria. Patients have normal resistance to other pathogens and no overt abnormalities in routine immunological and hematological evaluations for primary immunodeficiencies. At least 19 genes and 34 clinical phenotypes have been identified in MSMD. However, there have been no systematic reports on the clinical characteristics and genetic backgrounds of MSMD in China. In this review, on the one hand, we summarize an update findings on molecular defects and immunological mechanisms in the field of MSMD research globally. On the other hand, we undertook a systematic review of PubMed (MEDLINE), the Cochrane Central Register of Controlled Trials (CENTRAL), Web of Science, EMBASE, CNKI, and Wanfang to identify articles published before Jan 23, 2022, to summarize the clinical characteristics, diagnosis, treatment, and prognosis of MSMD in China. All the English and Chinese publications were searched without any restriction on article types.

Enhanced osteoclastogenesis in patients with MSMD due to impaired response to IFN-γ

BACKGROUND

Patients with Mendelian susceptibility to mycobacterial disease (MSMD) experience recurrent and/or persistent infectious diseases associated with poorly virulent mycobacteria. Multifocal osteomyelitis is among the representative manifestations of MSMD. The frequency of multifocal osteomyelitis is especially high in patients with MSMD etiologies that impair cellular response to IFN-γ, such as IFN-γR1, IFN-γR2, or STAT1 deficiency.

OBJECTIVES

This study sought to characterize the mechanism underlying multifocal osteomyelitis in MSMD.

METHODS

GM colonies prepared from bone marrow mononuclear cells from patients with autosomal dominant (AD) IFN-γR1 deficiency, AD STAT1 deficiency, or STAT1 gain of function (GOF) and from healthy controls were differentiated into osteoclasts in the presence or absence of IFN-γ. The inhibitory effect of IFN-γ on osteoclastogenesis was investigated by quantitative PCR, immunoblotting, tartrate-resistant acid phosphatase staining, and pit formation assays.

RESULTS

Increased osteoclast numbers were identified by examining the histopathology of osteomyelitis in patients with AD IFN-γR1 deficiency or AD STAT1 deficiency. In the presence of receptor activator of nuclear factor kappa-B ligand and M-CSF, GM colonies from patients with AD IFN-γR1 deficiency, AD STAT1 deficiency, or STAT1 GOF differentiated into osteoclasts, similar to GM colonies from healthy volunteers. IFN-γ concentration-dependent inhibition of osteoclast formation was impaired in GM colonies from patients with AD IFN-γR1 deficiency or AD STAT1 deficiency, whereas it was enhanced in GM colonies from patients with STAT1 GOF.

CONCLUSIONS

Osteoclast differentiation is increased in AD IFN-γR1 deficiency and AD STAT1 deficiency due to an impaired response to IFN-γ, leading to excessive osteoclast proliferation and, by inference, increased bone resorption in infected foci, which may underlie multifocal osteomyelitis.

Spectrum of Inborn errors of immunity in a cohort of 90 patients presenting with complications to BCG vaccination in India

World Health Organisation recommends the practice of BCG vaccination at birth in countries which have a high incidence of tuberculosis and/or high leprosy burden. The BCG vaccination is considered safe for a competent immune system. However, in children with weakened immune systems cause of which can be primary or secondary, the vaccine may lead to side effects which can be localized or disseminated. In this study, we report a spectrum of inborn errors of immunity (IEI) commonly referred to as primary immunodeficiency disorders (PIDs) diagnosed in a large cohort of patients presenting with complications to BCG vaccination from India. Retrospective data analysis of patients referred to ICMR- National Institute of Immunohematology (ICMR-NIIH) for IEI workup between 2007 and 2019 was done. IEI was identified in n = 52/90 (57.7%) patients presenting with BCG complications. Of these, n = 13(14.4%) patients were diagnosed with severe combined immune deficiency, n = 15(16.7%) with chronic granulomatous disease, n = 19(21.1%) with Inborn errors of IFN-γ immunity, n = 4(4.4%) with Combined immunodeficiency and n = 1(1.1%) with Leucocyte Adhesion Deficiency type1. Majority of cases with BCGosis (88%) had an underlying IEI. This study strongly highlights the need for evaluation of patients with BCG complications for underlying IEI. While disseminated BCGosis strongly predicts underlying IEI, even localized persistent adenitis may be a warning sign of underlying IEI. It is also strongly recommended to record a family history of previous sibling death prior to administration of this live vaccine and deferring live vaccine till the diagnosis of IEI is ruled out in cases with a positive family history.

Primary Immunodeficiency Diseases and Bacillus Calmette-Guérin (BCG)-Vaccine-Derived Complications: A Systematic Review

BACKGROUND

Bacillus Calmette-Guérin (BCG) vaccine is a live attenuated bacterial vaccine derived from Mycobacterium bovis, which is mostly administered to neonates in regions where tuberculosis is endemic. Adverse reactions after BCG vaccination are rare; however, immunocompromised individuals and in particular patients with primary immunodeficiencies (PIDs) are prone to develop vaccine-derived complications.

OBJECTIVE

To systematically review demographic, clinical, immunologic, and genetic data of PIDs that present with BCG vaccine complications. Moreover, we performed a meta-analysis aiming to determine the BCG-vaccine complications rate for patients with PID.

METHODS

We conducted electronic searches on Embase, Web of Science, PubMed, and Scopus (1966 to September 2018) introducing terms related to PIDs, BCG vaccination, and BCG vaccine complications. Studies with human subjects with confirmed PID, BCG vaccination history, and vaccine-associated complications (VACs) were included.

RESULTS

A total of 46 PIDs associated with BCG-VAC were identified. Severe combined immunodeficiency was the most common (466 cases) and also showed the highest BCG-related mortality. Most BCG infection cases in patients with PID were reported from Iran (n = 219 [18.8%]). The overall frequency of BCG-VAC in the included 1691 PID cases was 41.5% (95% CI, 29.9-53.2; I² = 98.3%), based on the results of the random-effect method used in this meta-analysis. Patients with Mendelian susceptibility to mycobacterial diseases had the highest frequency of BCG-VACs with a pooled frequency of 90.6% (95% CI, 79.7-1.0; I² = 81.1%).

CONCLUSIONS

Several PID entities are susceptible to BCG-VACs. Systemic neonatal PID screening programs may help to prevent a substantial amount of BCG vaccination complications.

Three novel compound heterozygous IL12RB1 mutations in Chinese patients with Mendelian susceptibility to mycobacterial disease

Mendelian Susceptibility to Mycobacterial Diseases (MSMD) is a primary immunodeficiency disease (PID) characterized by variable susceptibility to weakly virulent mycobacteria (Bacille Calmette-Guerin, BCG) and various intramacrophagic bacteria, fungi, parasites. Mycobacterial disease generally begins in childhood, more rarely during adolescence and adulthood. The pathogenesis of MSMD is the inherited impaired production of interferon gamma (IFN-γ) or inadequate response to it. Autosomal recessive IL12RB1 deficiency is the most common genetic etiology of MSMD. Here we identified three novel compound heterozygous mutations in IL12RB1 gene (c.635G>A, c.765delG; c.632G>C, c.847C>T; c.64G>A, c.1673insGAGCTTCCTGAG) in three Chinese families with MSMD.

Molecular, Immunological, and Clinical Features of 16 Iranian Patients with Mendelian Susceptibility to Mycobacterial Disease

PURPOSE

Mendelian susceptibility to mycobacterial disease (MSMD) is a rare primary immunodeficiency, triggered by non-tuberculous mycobacteria or Bacillus Calmette-Guérin (BCG) vaccines and characterized by severe diseases. All known genetic etiologies are inborn errors of IFN-γ-mediated immunity. Here, we report the molecular, cellular, and clinical features of patients from 15 Iranian families with disseminated disease without vaccination (2 patients) or following live BCG vaccination (14 patients).

METHODS

We used whole blood samples from 16 patients and 12 age-matched healthy controls. To measure IL-12 and IFN-γ, samples were activated by BCG plus recombinant human IFN-γ or recombinant human IL-12. Immunological assessments and genetic analysis were also done for the patients.

RESULTS

Eight patients affected as a result of parental first-cousin marriages. Seven patients originated from multiplex kindred with positive history of death because of tuberculosis or finding the MSMD-related gene mutations. Two patients died due to mycobacterial disease at the ages of 8 months and 3.7 years. The remaining patients were alive at the last follow-up and were aged between 2 and 13 years. Patients suffered from infections including chronic mucocutaneous candidiasis (n = 10), salmonellosis (n = 2), and Leishmania (responsible for visceral form) (n = 2). Thirteen patients presented with autosomal recessive (AR) IL-12Rβ1 deficiency, meaning their cells produced low levels of IFN-γ. Bi-allelic IL12RB1 mutations were detected in nine of patients. Three patients with AR IL-12p40 deficiency (bi-allelic IL12B mutations) produced low levels of both IL-12 and IFN-γ. Overall, we found five mutations in the IL12RB1 gene and three mutations in the IL12B gene. Except one mutation in exon 5 (c.510C>A) of IL12B, all others were previously reported to be loss-of-function mutations.

CONCLUSIONS

We found low levels of IFN-γ production and failure to respond to IL12 in 13 Iranian MSMD patients. Due to complicated clinical manifestations in affected children, early cellular and molecular diagnostics is crucial in susceptible patients.

Impaired IL-12- and IL-23-Mediated Immunity Due to IL-12Rβ1 Deficiency in Iranian Patients with Mendelian Susceptibility to Mycobacterial Disease

PURPOSE

Inborn errors of IFN-γ-mediated immunity underlie Mendelian Susceptibility to Mycobacterial Disease (MSMD), which is characterized by an increased susceptibility to severe and recurrent infections caused by weakly virulent mycobacteria, such as Bacillus Calmette-Guérin (BCG) vaccines and environmental, nontuberculous mycobacteria (NTM).

METHODS

In this study, we investigated four patients from four unrelated consanguineous families from Isfahan, Iran, with disseminated BCG disease. We evaluated the patients' whole blood cell response to IL-12 and IFN-γ, IL-12Rβ1 expression on T cell blasts, and sequenced candidate genes.

RESULTS

We report four patients from Isfahan, Iran, ranging from 3 months to 26 years old, with impaired IL-12 signaling. All patients suffered from BCG disease. One of them presented mycobacterial osteomyelitis. By Sanger sequencing, we identified three different types of homozygous mutations in IL12RB1. Expression of IL-12Rβ1 was completely abolished in the four patients with IL12RB1 mutations.

CONCLUSIONS

IL-12Rβ1 deficiency was found in the four MSMD Iranian families tested. It is the first report of an Iranian case with S321* mutant IL-12Rβ1 protein. Mycobacterial osteomyelitis is another type of location of BCG infection in an IL-12Rβ1-deficient patient, notified for the first time in this study.

Mendelian susceptibility to mycobacterial disease: genetic, immunological, and clinical features of inborn errors of IFN-γ immunity

Mendelian susceptibility to mycobacterial disease (MSMD) is a rare condition characterized by predisposition to clinical disease caused by weakly virulent mycobacteria, such as BCG vaccines and environmental mycobacteria, in otherwise healthy individuals with no overt abnormalities in routine hematological and immunological tests. MSMD designation does not recapitulate all the clinical features, as patients are also prone to salmonellosis, candidiasis and tuberculosis, and more rarely to infections with other intramacrophagic bacteria, fungi, or parasites, and even, perhaps, a few viruses. Since 1996, nine MSMD-causing genes, including seven autosomal (IFNGR1, IFNGR2, STAT1, IL12B, IL12RB1, ISG15, and IRF8) and two X-linked (NEMO, and CYBB) genes have been discovered. The high level of allelic heterogeneity has already led to the definition of 18 different disorders. The nine gene products are physiologically related, as all are involved in IFN-γ-dependent immunity. These disorders impair the production of (IL12B, IL12RB1, IRF8, ISG15, NEMO) or the response to (IFNGR1, IFNGR2, STAT1, IRF8, CYBB) IFN-γ. These defects account for only about half the known MSMD cases. Patients with MSMD-causing genetic defects may display other infectious diseases, or even remain asymptomatic. Most of these inborn errors do not show complete clinical penetrance for the case-definition phenotype of MSMD. We review here the genetic, immunological, and clinical features of patients with inborn errors of IFN-γ-dependent immunity.

Phagocyte NADPH oxidase, chronic granulomatous disease and mycobacterial infections

Infection of humans with Mycobacterium tuberculosis remains frequent and may still lead to death. After primary infection, the immune system is often able to control M. tuberculosis infection over a prolonged latency period, but a decrease in immune function (from HIV to immunosenescence) leads to active disease. Available vaccines against tuberculosis are restricted to BCG, a live vaccine with an attenuated strain of M. bovis. Immunodeficiency may not only be associated with an increased risk of tuberculosis, but also with local or disseminated BCG infection. Genetic deficiency in the reactive oxygen species (ROS)-producing phagocyte NADPH oxidase NOX2 is called chronic granulomatous disease (CGD). CGD is among the most common primary immune deficiencies. Here we review our knowledge on the importance of NOX2-derived ROS in mycobacterial infection. A literature review suggests that human CGD patient frequently have an increased susceptibility to BCG and to M. tuberculosis. In vitro studies and experiments with CGD mice are incomplete and yielded - at least in part - contradictory results. Thus, although observations in human CGD patients leave little doubt about the role of NOX2 in the control of mycobacteria, further studies will be necessary to unequivocally define and understand the role of ROS.

Intact IFN-γR1 expression and function distinguishes Langerhans cell histiocytosis from mendelian susceptibility to mycobacterial disease

PURPOSE

Poly-ostotic Langerhans Cell Histiocytosis (LCH) can be difficult to distinguish clinically and histologically from disseminated infection in manifesting specific subtypes of Mendelian Susceptibility to Mycobacterial Disease (MSMD). In MSMD-patients, dominant negative germline mutations in the IFN-γR1 gene, in particular in exon 6, lead to autosomal dominant IFN-γ receptor 1 deficiency (ADIFNGR1) and can mimic LCH. We hypothesized that similar defects might underlie the pathogenesis of LCH.

METHODS

IFN-γR1 expression was immunohistochemically determined at disease onset in biopsies from 11 LCH-patients and four ADIFNGR1-patients. IFN-γR1 function was analyzed in 18 LCH-patients and 13 healthy controls by assessing the IFN-γ-induced upregulation of Fc-gamma-receptor I (FcγRI) expression on monocytes. Pro-inflammatory cytokine production was measured after stimulation of whole blood with LPS and IFN-γ. Exon 6 of the IFN-γR1 gene was sequenced in 67 LCH-patients to determine whether mutations were present.

RESULTS

IFN-γR1 expression was high in three LCH-affected biopsies, similar to ADIFNGR1-affected biopsies, but varied from negative to moderate in eight other LCH-affected biopsies. No functional differences in IFN-γ signaling were detected between LCH-patients with active or non-active disease and healthy controls. No germline mutations in exon 6 of the IFN-γR1 gene were detected in any of the 67 LCH-patients.

CONCLUSIONS

In contrast to ADIFNGR1-patients, IFN-γ signaling is fully functional in LCH-patients. Either performed before, during or after treatment, these non-invasive functional assays can distinguish LCH-patients from ADIFNGR1-patients and thereby facilitate correct therapy regimens for patients with recurrent osteolytic lesions.

IL-12Rβ1 deficiency: mutation update and description of the IL12RB1 variation database

IL-12Rβ1 deficiency is an autosomal recessive disorder characterized by predisposition to recurrent and/or severe infections caused by otherwise poorly pathogenic mycobacteria and salmonella. IL-12Rβ1 is a receptor chain of both the IL-12 and the IL-23 receptor and deficiency of IL-12Rβ1 thus abolishes both IL-12 and IL-23 signaling. IL-12Rβ1 deficiency is caused by bi-allelic mutations in the IL12RB1 gene. Mutations resulting in premature stop codons, such as nonsense, frame shift, and splice site mutations, represent the majority of IL-12Rβ1 deficiency causing mutations (66%; 46/70). Also every other morbid mutation completely inactivates the IL-12Rβ1 protein. In addition to disease-causing mutations, rare and common variations with unknown functional effect have been reported in IL12RB1. All these variants have been deposited in the online IL12RB1 variation database (www.LOVD.nl/IL12RB1). In this article, we review the function of IL-12Rβ1 and molecular genetics of human IL12RB1.

Heterozygosity for the Y701C STAT1 mutation in a multiplex kindred with multifocal osteomyelitis

Heterozygosity for dominant-negative STAT1 mutations underlies autosomal dominant Mendelian susceptibility to mycobacterial diseases. Mutations conferring Mendelian susceptibility to mycobacterial diseases have been identified in the regions of the STAT1 gene encoding the tail segment, DNA-binding domain and SH2 domain. We describe here a new heterozygous mutation, Y701C, in a Japanese two-generation multiplex kindred with autosomal dominant Mendelian susceptibility to mycobacterial diseases. This mutation affects precisely the canonical STAT1 tyrosine phosphorylation site. The Y701C STAT1 protein is produced normally, but its phosphorylation is abolished, resulting in a loss-of-function for STAT1-dependent cellular responses to interferon-γ or interferon-α. In the patients' cells, the allele is dominant-negative for γ-activated factor-mediated responses to interferon-γ, but not for interferon-stimulated gene factor-3-mediated responses to interferon-α/β, accounting for the clinical phenotype of Mendelian susceptibility to mycobacterial diseases without severe viral diseases. Interestingly, both patients displayed multifocal osteomyelitis, which is often seen in patients with Mendelian susceptibility to mycobacterial diseases with autosomal dominant partial IFN-γR1 deficiency. Multifocal osteomyelitis should thus prompt investigations of both STAT1 and IFN-γR1. This experiment of nature also confirms the essential role of tyrosine 701 in human STAT1 activity in natura.

Granulomatous skin lesions, severe scrotal and lower limb edema due to mycobacterial infections in a child with complete IFN-γ receptor-1 deficiency

Interferon-γ receptor-1 (IFNγR1) deficiency is caused by mutations in the IFNγR1 gene and is characterized mainly by susceptibility to mycobacterial disease. Herein, we report an 8-month-old boy with complete recessive IFNγR1 deficiency, afflicted by recurrent mycobacterial diseases with Mycobacterium bovis, Mycobacterium tuberculosis, Mycobacterium avium intracellulare and Mycobacterium fortuitum. Genetic analysis showed a homozygous mutation (106insT) in the IFNγR1 gene leading to complete IFNγR1 deficiency. In addition, he had atypical mycobacterial skin lesions caused by M. avium intracellulare and developed scrotal and lower limb lymphedema secondary to compression of large and fixed inguinal lymphadenopathies. Hematopoietic stem cell transplantation was performed from a matched unrelated donor at 5 years of age; however, he died at 9 months post-transplant. To our knowledge, the patient is the first case with IL-12/IFN-γ pathway defect and severe lymphedema. We have also reviewed and summarized the literature related with IFNγR1 deficiency.

Two cases of partial dominant interferon-γ receptor 1 deficiency that presented with different clinical courses of bacille Calmette-Guérin multiple osteomyelitis

We experienced two cases of unrelated Japanese children with bacille Calmette-Guérin (BCG) multiple osteomyelitis with partial interferon (IFN)-γ receptor 1 (IFNGR1) deficiency. Heterozygous small deletions with frame shift (811 del4 and 818 del4) were detected, which were consistent with the diagnosis of partial dominant IFNGR1 deficiency. Case 1: a 2-year-old boy visited us because of limb and neck pain. He had been vaccinated with BCG at 17 months of age. Multiple destructive lesions were observed in the skull, ribs, femur, and vertebral bones. Mycobacterium bovis (BCG Tokyo 172 strain by RFLP technique) was detected in the bone specimen. The BCG multiple osteomyelitis was treated successfully without recurrence. Case 2: an 18-month-old girl developed multiple osteomyelitis 9 months after BCG inoculation. Radiologic images showed multiple osteolytic lesions in the skull, ribs, femur, and vertebrae. M. bovis (BCG Tokyo 172 strain) was detected in the cultures from a bone biopsy. Her clinical course showed recurrent osteomyelitis and lymphadenitis with no pulmonary involvement. The effects of high-dose antimycobacterial drugs and IFN-γ administration were transient, and complete remission has since been achieved by combination antimycobacterial therapy, including levofloxacin. Partial dominant IFNGR1 deficiency is a rare disorder, but it should be considered when a patient presents with multiple osteomyelitis after BCG vaccination. The cases that are resistant to conventional regimens require additional second-line antituberculous drugs, such as levofloxacin.

Bacillus Calmette-Guérin (BCG) complications associated with primary immunodeficiency diseases

Primary immunodeficiency diseases (PIDs) are a group of inherited disorders, characterized by defects of the immune system predisposing individuals to variety of manifestations, including recurrent infections and unusual vaccine complications. There are a number of PIDs prone to Bacillus Calmette-Guérin (BCG) complications. This review presents an update on our understanding about the BCGosis-susceptible PIDs, including severe combined immunodeficiency, chronic granulomatous disease, and Mendelian susceptibility to mycobacterial diseases.

Immune defects in active mycobacterial diseases in patients with primary immunodeficiency diseases (PIDs)

Natural human immunity to the mycobacteria group, including Mycobacterium tuberculosis, Bacille Calmette-Guérin (BCG) or nontuberculous mycobacteria (NTM), and/or Salmonella species, relies on the functional IL-12/23-IFN-γ integrity of macrophages (monocyte/dendritic cell) connecting to T lymphocyte/NK cells. Patients with severe forms of primary immunodeficiency diseases (PIDs) have more profound immune defects involving this impaired circuit in patients with severe combined immunodeficiencies (SCID) including complete DiGeorge syndrome, X-linked hyper IgM syndrome (HIGM) (CD40L mutation), CD40 deficiency, immunodeficiency with or without anhidrotic ectodermal dysplasia (NEMO and IKBA mutations), chronic granulomatous disease (CGD) and hyper IgE recurrent infection syndromes (HIES). The patients with severe PIDs have broader diverse infections rather than mycobacterial infections. In contrast, patients with an isolated inborn error of the IL-12/23-IFN-γ pathway are exclusively prone to low-virulence mycobacterial infections and nontyphoid salmonella infections, known as Mendelian susceptibility to the mycobacterial disease (MSMD) phenotype. Restricted defective molecules in the circuit, including IFN-γR1, IFN-γR2, IL-12p40, IL-12R-β1, STAT-1, NEMO, IKBA and the recently discovered CYBB responsible for autophagocytic vacuole and proteolysis, and interferon regulatory factor 8 (IRF8) for dendritic cell immunodeficiency, have been identified in around 60% of patients with the MSMD phenotype. Among all of the patients with PIDs referred for investigation since 1985, we have identified four cases with the specific defect (IFNRG1 for three and IL12RB for one), presenting as both BCG-induced diseases and NTM infections, in addition to some patients with SCID, HIGM, CGD and HIES. Furthermore, manifestations in patients with autoantibodies to IFN-γ (autoAbs-IFN-γ), which is categorized as an anticytokine autoantibody syndrome, can resemble the relatively persistent MSMD phenotype lacking BCG-induced diseases.

Distribution, clinical features and treatment in Taiwanese patients with symptomatic primary immunodeficiency diseases (PIDs) in a nationwide population-based study during 1985-2010

Primary immunodeficiency diseases (PIDs) are a group of rare diseases with wide geographic and ethnic variations in incidence, prevalence, and distribution patterns. The aim of this study was to examine the distribution pattern and clinical spectrum of PIDs in Taiwan at a national referral institute. From 1985 to 2010, 215 patients from 183 families were diagnosed and grouped according to the updated classification of PIDs. Eighty-one (37.7%) patients had "other well-defined immunodeficiency syndromes", followed by "predominantly antibody deficiencies" (54 patients; 25.1%), "T- and B-cell immunodeficiencies" (34; 15.8%), "congenital defects of phagocytes" (25; 20.2%), "complement deficiencies" (15; 7.0%), and "disease in immune dysregulation" (5; 2.3%). The last category included two patients with Chediak-Higashi syndrome, and one each with familial hemophagocytosis, IPEX, and hypogammaglobulinemia and albinism. One female had cold-induced auto-inflammatory disease. There were no cases of "defects in innate immunity". Pseudomonas and Streptococcus pneumoniae were the two most identified microorganisms in septicemia (42.7%; 44/103 episodes). Stem cell transplantation was successful in 13 of 22 patients, while 34 patients (15.8%) died. Molecular defects were identified in 109 individuals (from 90 families). There were relatively fewer cases of "predominantly antibody deficiencies" due to there being only a few patients with adult-onset PIDs, implying certainty bias rather than ethnic variation. Awareness of under-diagnosis among physicians rather than pediatricians is vital for timely diagnosis and consequently adequate treatment.

Clinical and host genetic characteristics of Mendelian susceptibility to mycobacterial diseases in Japan

PURPOSE

The aim of this study is to investigate clinical characteristics and genetic backgrounds of Mendelian susceptibility to mycobacterial diseases (MSMD) in Japan.

METHODS

Forty-six patients diagnosed as having MSMD were enrolled in this study. All patients were analyzed for the IFNGR1, IFNGR2, IL12B, IL12RB1, STAT1, and NEMO gene mutations known to be associated with MSMD.

RESULTS

Six patients and one patient were diagnosed as having partial interferon-γ receptor 1 deficiency and nuclear factor-κB-essential modulator deficiency, respectively. Six of the seven patients had recurrent disseminated mycobacterial infections, while 93% of the patients without these mutations had only one episode of infection.

CONCLUSIONS

The patients with a genetic mutation were more susceptible to developing recurrent disseminated mycobacterial infections. Recurrent disseminated mycobacterial infections occurred in a small number of patients even without these mutations, suggesting the presence of as yet undetermined genetic factors underlying the development and progression of this disease.

Revisiting human IL-12Rβ1 deficiency: a survey of 141 patients from 30 countries

Interleukin-12 receptor β1 (IL-12Rβ1) deficiency is the most common form of Mendelian susceptibility to mycobacterial disease (MSMD). We undertook an international survey of 141 patients from 102 kindreds in 30 countries. Among 102 probands, the first infection occurred at a mean age of 2.4 years. In 78 patients, this infection was caused by Bacille Calmette-Guérin (BCG; n = 65), environmental mycobacteria (EM; also known as atypical or nontuberculous mycobacteria) (n = 9) or Mycobacterium tuberculosis (n = 4). Twenty-two of the remaining 24 probands initially presented with nontyphoidal, extraintestinal salmonellosis. Twenty of the 29 genetically affected sibs displayed clinical signs (69%); however 8 remained asymptomatic (27%). Nine nongenotyped sibs with symptoms died. Recurrent BCG infection was diagnosed in 15 cases, recurrent EM in 3 cases, recurrent salmonellosis in 22 patients. Ninety of the 132 symptomatic patients had infections with a single microorganism. Multiple infections were diagnosed in 40 cases, with combined mycobacteriosis and salmonellosis in 36 individuals. BCG disease strongly protected against subsequent EM disease (p = 0.00008). Various other infectious diseases occurred, albeit each rarely, yet candidiasis was reported in 33 of the patients (23%). Ninety-nine patients (70%) survived, with a mean age at last follow-up visit of 12.7 years ± 9.8 years (range, 0.5-46.4 yr). IL-12Rβ1 deficiency is characterized by childhood-onset mycobacteriosis and salmonellosis, rare recurrences of mycobacterial disease, and more frequent recurrence of salmonellosis. The condition has higher clinical penetrance, broader susceptibility to infections, and less favorable outcome than previously thought.

More than just infections: an update on primary immune deficiencies

PURPOSE OF REVIEW

The general pediatrician should be empowered to utilize continuity of care for the recognition of unusual or severe patterns of infection. With the burgeoning field of genetics, primary immune deficiencies (PIDs) can be diagnosed and treated earlier to provide better outcomes for patients and families. Improved treatment modalities have redefined expectations for many infants born with PIDs.

RECENT FINDINGS

The prevalence of PIDs increases as researchers discover novel immunodeficiency syndromes and as clinicians increasingly recognize and diagnose nuanced presentations of immunodeficiency. Novel immunodeficiency syndromes associated with mutations in DOCK8, CARD9, and PRKDC recently have been described. For the first time in the United States, newborns from an entire state were screened for lymphopenia, allowing potentially life-saving early diagnosis of the most severe forms of PID before the onset of symptoms. Hematopoietic stem cell transplantation (HSCT) and gene therapy continue to be evaluated as curative treatments with increasing success rates for some of the most severe PIDs.

SUMMARY

The field of PID continues to expand and advancements have been made in earlier diagnosis and screening. Comparative effectiveness research into treatment modalities offered to patients with PID is leading to a better understanding of optimal therapies for specific PIDs. In the meantime, the advocacy efforts of established and emerging PID networks promote excellence in clinical recognition and treatment of PIDs in children.

Paternal uniparental isodisomy of chromosome 6 causing a complex syndrome including complete IFN-gamma receptor 1 deficiency

Mendelian susceptibility to mycobacterial disease (MSMD) is a rare primary immunodeficiency associated with clinical disease caused by weakly virulent mycobacterial species. Interferon gamma receptor 1 (IFN-gammaR1) deficiency is a genetic etiology of MSMD. We describe the clinical and genetic features of a 7-year-old Italian boy suffering from MSMD associated with a complex phenotype, including neonatal hyperglycemia, neuromuscular disease, and dysmorphic features. The child also developed necrotizing pneumonia caused by Rhodococcus equi. The child is homozygous for a nonsense mutation in exon 3 of IFNGR1 as a result of paternal uniparental disomy (UPD) of the entire chromosome 6. This is the first reported case of uniparental disomy resulting in a complex phenotype including MSMD.

A novel form of cell type-specific partial IFN-gammaR1 deficiency caused by a germ line mutation of the IFNGR1 initiation codon

IFN-gammaR1 deficiency is a genetic etiology of Mendelian susceptibility to mycobacterial diseases, and includes two forms of complete recessive deficiency, with or without cell surface expression, and two forms of partial deficiency, dominant or recessive. We report here a novel form of partial and recessive Interferon gamma receptor 1 (IFN-gammaR1) deficiency, which is almost as severe as complete deficiency. The patient is homozygous for a mutation of the initiation codon (M1K). No detectable expression and function of IFN-gammaR1 were found in the patient's fibroblasts. However, IFN-gammaR1 expression was found to be impaired, but not abolished, on the EBV-transformed B cells, which could respond weakly to IFN-gamma. The mechanism underlying this weak expression involves leaky translation initiation at both non-AUG codons and the third AUG codon at position 19. It results in the residual expression of IFN-gammaR1 protein of normal molecular weight and function. The residual IFN-gamma signaling documented in this novel form of partial IFN-gammaR1 deficiency was not ubiquitous and was milder than that seen in other forms of partial IFN-gammaR1 deficiency, accounting for the more severe clinical phenotype of the patient, which was almost as severe as that of patients with complete deficiency.

Genetic deficiencies of innate immune signalling in human infectious disease

The type-1 cytokine (interleukin 12, interleukin 23, interferon gamma, interleukin 17) signalling pathway is triggered during infection by activation of phagocyte-expressed pattern-recognition receptors that recognise specific pathogen-associated molecular patterns. Triggering of this pathway results, among other things, in activation of microbicidal mechanisms in phagocytic cells. Individuals with a deficiency in one of the proteins in the pathway are unusually susceptible to otherwise poorly pathogenic, mostly environmental, mycobacteria and salmonellae. Individuals with deficiencies in other innate immune signalling proteins show unusual susceptibility to pathogens other than mycobacteria or salmonellae. We discuss recent insights into key molecules involved in type-1 cytokine signalling pathways and provide an update on the molecular genetic defects underlying mendelian susceptibility to mycobacterial disease. We also discuss deficiencies in the innate immune signalling proteins that lead to susceptibility to other pathogens. Knowledge of innate immune signalling has allowed the identification of defects in such patients. However, some patients have enhanced susceptibility to pathogens even though no mutations have been found in the candidate genes identified thus far. Whereas a few patients might have autoantibodies against type-1 cytokines, others might harbour mutations in new genes and pathways that still need to be identified.