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Tak AS, Satapathy J, Jana M, Sinha A, Jat KR, Bagri NK. Monogenic lupus with homozygous C4A deficiency presenting as bronchiectasis and immune-mediated thrombocytopenia. Rheumatol Int 2021; 42:1477-1482. [PMID: 34287686 DOI: 10.1007/s00296-021-04943-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2021] [Accepted: 07/01/2021] [Indexed: 02/05/2023]
Abstract
Monogenic lupus is a subset of lupus caused by single-gene disorders, integrating the paradoxical combination of autoimmunity and immunodeficiency. Pulmonary manifestations with recurrent pneumonia and bronchiectasis have rarely been described as the predominant presentation of juvenile lupus and may suggest an alternate differential like primary immunodeficiency, especially in early childhood. We describe a case of 10-year girl who presented with a history of recurrent pneumonia, arthritis, alopecia, and poor weight gain for the past 2 years. On examination, she had respiratory distress, bilateral diffuse crackles and arthritis of the small joints of hands. Lab investigations showed pancytopenia, low complement levels and high titers of ANA and anti-dsDNA antibodies. The patient was diagnosed with juvenile lupus. Imaging studies revealed evidence of multiple lobar collapse and consolidation with bronchiectasis. She was started on steroids, HCQ and supportive measures for bronchiectasis. The child reported relief in initial symptoms of lupus on follow-up but developed recurrent thrombocytopenia requiring IVIG and escalating the doses of oral steroids. The young age and atypical presentation prompted a screening for monogenic lupus, and clinical exome sequencing revealed a novel homozygous missense variation in exon 20 of the C4Agene with clinically reduced C4 levels, consistent with the diagnosis of C4A deficiency.
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Affiliation(s)
- Asma S Tak
- Department of Pediatrics, All India Institute of Medical Sciences, New Delhi, India
| | | | - Manisha Jana
- Department of Radio Diagnosis, All India Institute of Medical Sciences, New Delhi, India
| | - Aditi Sinha
- Division of Pediatric Nephrology, Department of Pediatrics, All India Institute of Medical Sciences, New Delhi, India
| | - Kana Ram Jat
- Division of Pediatric Pulmonology, Department of Pediatrics, All India Institute of Medical Sciences, New Delhi, India
| | - Narendra K Bagri
- Division of Pediatric Rheumatology, Department of Pediatrics, All India Institute of Medical Sciences, New Delhi, 110029, India.
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Wang H, Liu M. Complement C4, Infections, and Autoimmune Diseases. Front Immunol 2021; 12:694928. [PMID: 34335607 PMCID: PMC8317844 DOI: 10.3389/fimmu.2021.694928] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Accepted: 06/21/2021] [Indexed: 02/05/2023] Open
Abstract
Complement C4, a key molecule in the complement system that is one of chief constituents of innate immunity for immediate recognition and elimination of invading microbes, plays an essential role for the functions of both classical (CP) and lectin (LP) complement pathways. Complement C4 is the most polymorphic protein in complement system. A plethora of research data demonstrated that individuals with C4 deficiency are prone to microbial infections and autoimmune disorders. In this review, we will discuss the diversity of complement C4 proteins and its genetic structures. In addition, the current development of the regulation of complement C4 activation and its activation derivatives will be reviewed. Moreover, the review will provide the updates on the molecule interactions of complement C4 under the circumstances of bacterial and viral infections, as well as autoimmune diseases. Lastly, more evidence will be presented to support the paradigm that links microbial infections and autoimmune disorders under the condition of the deficiency of complement C4. We provide such an updated overview that would shed light on current research of complement C4. The newly identified targets of molecular interaction will not only lead to novel hypotheses on the study of complement C4 but also assist to propose new strategies for targeting microbial infections, as well as autoimmune disorders.
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Affiliation(s)
- Hongbin Wang
- Master Program of Pharmaceutical Sciences College of Graduate Studies, California Northstate University, Elk Grove, CA, United States.,Department of Pharmaceutical and Biomedical Sciences College of Pharmacy, California Northstate University, Elk Grove, CA, United States.,Department of Basic Science College of Medicine, California Northstate University, Elk Grove, CA, United States
| | - Mengyao Liu
- Master Program of Pharmaceutical Sciences College of Graduate Studies, California Northstate University, Elk Grove, CA, United States
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3
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Complement C4 Gene Copy Number Variation Genotyping by High Resolution Melting PCR. Int J Mol Sci 2020; 21:ijms21176309. [PMID: 32878183 PMCID: PMC7504122 DOI: 10.3390/ijms21176309] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 08/26/2020] [Accepted: 08/29/2020] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND Complement C4 gene copy number variation plays an important role as a determinant of genetic susceptibility to common diseases, such as systemic lupus erythematosus, schizophrenia, rheumatoid arthritis, and infectious diseases. This study aimed to develop an assay for the quantification of copy number variations in the C4 locus. METHODS the assay was based on a gene ratio analysis copy enumeration (GRACE) PCR combined with high resolution melting (HRM) PCR. The test was optimized using samples of a known genotype and validated with 72 DNA samples from healthy blood donors. RESULTS to validate the assay, standard curves were generated by plotting the C4/RP1 ratio values against copy number variation (CNV) for each gene, using genomic DNA with known C4 CNV. The range of copy numbers in control individuals was comparable to distributions observed in previous studies of European descent. CONCLUSIONS the method herein described significantly simplifies C4 CNV diagnosis to validate the assay.
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4
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Pereira KMC, Perazzio S, Faria AGA, Moreira ES, Santos VC, Grecco M, da Silva NP, Andrade LEC. Impact of C4, C4A and C4B gene copy number variation in the susceptibility, phenotype and progression of systemic lupus erythematosus. Adv Rheumatol 2019; 59:36. [PMID: 31387635 DOI: 10.1186/s42358-019-0076-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Accepted: 07/12/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Complement component 4 (C4) gene copy number (GCN) affects the susceptibility to systemic lupus erythematosus (SLE) in different populations, however the possible phenotype significance remains to be determined. This study aimed to associate C4A, C4B and total C4 GCN and SLE, focusing on the clinical phenotype and disease progression. METHODS C4, C4A and C4B GCN were determined by real-time PCR in 427 SLE patients and 301 healthy controls, which underwent a detailed clinical evaluation according to a pre-established protocol. RESULTS The risk of developing SLE was 2.62 times higher in subjects with low total C4 GCN (< 4 copies, OR = 2.62, CI = 1.77 to 3.87, p < 0.001) and 3.59 times higher in subjects with low C4A GCN (< 2 copies; OR = 3.59, CI = 2.15 to 5.99, p < 0.001) compared to those subjects with normal or high GCN of total C4 (≥4) and C4A (≥2), respectively. An increased risk was also observed regarding low C4B GCN, albeit to a lesser degree (OR = 1.46, CI = 1.03 to 2.08, p = 0.03). Furthermore, subjects with low C4A GCN had higher permanent disease damage as assessed by the Systemic Lupus International Collaborating Clinics - Damage Index (SLICC-DI; median = 1.5, 95% CI = 1.2-1.9) than patients with normal or high copy number of C4A (median = 1.0, 95% CI = 0.8-1.1; p = 0.004). There was a negative association between low C4A GCN and serositis (p = 0.02) as well as between low C4B GCN and arthritis (p = 0.02). CONCLUSIONS This study confirms the association between low C4 GCN and SLE susceptibility, and originally demonstrates an association between low C4A GCN and disease severity.
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Affiliation(s)
- Kaline Medeiros Costa Pereira
- Disciplina de Reumatologia, Universidade Federal de São Paulo, Rua Botucatu 740, 3o andar, São Paulo, SP, ZIP: 04023-062, Brazil
| | - Sandro Perazzio
- Disciplina de Reumatologia, Universidade Federal de São Paulo, Rua Botucatu 740, 3o andar, São Paulo, SP, ZIP: 04023-062, Brazil
| | - Atila Granado A Faria
- Disciplina de Reumatologia, Universidade Federal de São Paulo, Rua Botucatu 740, 3o andar, São Paulo, SP, ZIP: 04023-062, Brazil
| | - Eloisa Sa Moreira
- Departamento de Genética e Biologia Evolutiva, Centro de Estudos do Genoma Humano, Instituto de Biociências, Universidade de São Paulo, São Paulo, SP, Brazil
| | - Viviane C Santos
- Disciplina de Reumatologia, Universidade Federal de São Paulo, Rua Botucatu 740, 3o andar, São Paulo, SP, ZIP: 04023-062, Brazil
| | - Marcelle Grecco
- Disciplina de Reumatologia, Universidade Federal de São Paulo, Rua Botucatu 740, 3o andar, São Paulo, SP, ZIP: 04023-062, Brazil
| | - Neusa Pereira da Silva
- Disciplina de Reumatologia, Universidade Federal de São Paulo, Rua Botucatu 740, 3o andar, São Paulo, SP, ZIP: 04023-062, Brazil
| | - Luis Eduardo Coelho Andrade
- Disciplina de Reumatologia, Universidade Federal de São Paulo, Rua Botucatu 740, 3o andar, São Paulo, SP, ZIP: 04023-062, Brazil.
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Liesmaa I, Paakkanen R, Järvinen A, Valtonen V, Lokki ML. Clinical features of patients with homozygous complement C4A or C4B deficiency. PLoS One 2018; 13:e0199305. [PMID: 29928053 PMCID: PMC6013154 DOI: 10.1371/journal.pone.0199305] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Accepted: 06/05/2018] [Indexed: 12/28/2022] Open
Abstract
INTRODUCTION Homozygous deficiencies of complement C4A or C4B are detected in 1-10% of populations. In genome-wide association studies C4 deficiencies are missed because the genetic variation of C4 is complex. There are no studies where the clinical presentation of these patients is analyzed. This study was aimed to characterize the clinical features of patients with homozygous C4A or C4B deficiency. MATERIAL AND METHODS Thirty-two patients with no functional C4A, 87 patients with no C4B and 120 with normal amount of C4 genes were included. C4A and C4B numbers were assessed with genomic quantitative real-time PCR. Medical history was studied retrospectively from patients' files. RESULTS Novel associations between homozygous C4A deficiency and lymphoma, coeliac disease and sarcoidosis were detected. These conditions were present in 12.5%, (4/32 in patients vs. 0.8%, 1/120, in controls, OR = 17.00, 95%CI = 1.83-158.04, p = 0.007), 12.5% (4/32 in patients vs. 0%, 0/120 in controls, OR = 1.14, 95%CI = 1.00-1.30, p = 0.002) and 12.5%, respectively (4/32 in patients vs. 2.5%, 3/120 in controls, OR = 5.571, 95%CI = 1.79-2.32, p = 0.036). In addition, C4A and C4B deficiencies were both associated with adverse drug reactions leading to drug discontinuation (34.4%, 11/32 in C4A-deficient patients vs. 14.2%, 17/120 in controls, OR = 3.174, 95%CI = 1.30-7.74, p = 0.009 and 28.7%, 25/87 in C4B-deficient patients, OR = 2.44, 95%CI = 1.22-4.88, p = 0.010). CONCLUSION This reported cohort of homozygous deficiencies of C4A or C4B suggests that C4 deficiencies may have various unrecorded disease associations. C4 gene should be considered as a candidate gene in studying these selected disease associations.
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Affiliation(s)
- Inka Liesmaa
- Division of Infectious Diseases, Inflammation Center, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
- * E-mail:
| | - Riitta Paakkanen
- Transplantation Laboratory, Medicum, University of Helsinki, Helsinki, Finland
- Division of Cardiology, Department of Medicine, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Asko Järvinen
- Division of Infectious Diseases, Inflammation Center, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Ville Valtonen
- Division of Infectious Diseases, Inflammation Center, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Marja-Liisa Lokki
- Transplantation Laboratory, Medicum, University of Helsinki, Helsinki, Finland
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6
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Nissilä E, Korpela K, Lokki AI, Paakkanen R, Jokiranta S, de Vos WM, Lokki ML, Kolho KL, Meri S. C4B gene influences intestinal microbiota through complement activation in patients with paediatric-onset inflammatory bowel disease. Clin Exp Immunol 2017; 190:394-405. [PMID: 28832994 DOI: 10.1111/cei.13040] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/08/2017] [Indexed: 12/19/2022] Open
Abstract
Complement C4 genes are linked to paediatric inflammatory bowel disease (PIBD), but the mechanisms have remained unclear. We examined the influence of C4B gene number on intestinal microbiota and in-vitro serum complement activation by intestinal microbes in PIBD patients. Complement C4A and C4B gene numbers were determined by genomic reverse transcription-polymerase chain reaction (RT-PCR) from 64 patients with PIBD (Crohn's disease or ulcerative colitis). The severity of the disease course was determined from faecal calprotectin levels. Intestinal microbiota was assessed using the HITChip microarray. Complement reactivity in patients was analysed by incubating their sera with Yersinia pseudotuberculosis and Akkermansia muciniphila and determining the levels of C3a and soluble terminal complement complex (SC5b-9) using enzyme immunoassays. The microbiota diversity was wider in patients with no C4B genes than in those with one or two C4B genes, irrespective of intestinal inflammation. C4B and total C4 gene numbers correlated positively with soluble terminal complement complex (TCC, SC5b-9) levels when patient serum samples were stimulated with bacteria. Our results suggest that the C4B gene number associates positively with inflammation in patients with PIBD. Multiple copies of the C4B gene may thus aggravate the IBD-associated dysbiosis through escalated complement reactivity towards the microbiota.
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Affiliation(s)
- E Nissilä
- Immunobiology, Research Programs Unit, University of Helsinki, Helsinki, Finland.,Department of Bacteriology and Immunology, University of Helsinki, Helsinki, Finland
| | - K Korpela
- Immunobiology, Research Programs Unit, University of Helsinki, Helsinki, Finland
| | - A I Lokki
- Immunobiology, Research Programs Unit, University of Helsinki, Helsinki, Finland.,Department of Medical and Clinical Genetics, University of Helsinki, Helsinki, Finland
| | - R Paakkanen
- Transplantation Laboratory, Medicum, University of Helsinki, Helsinki, Finland
| | - S Jokiranta
- Immunobiology, Research Programs Unit, University of Helsinki, Helsinki, Finland.,Department of Bacteriology and Immunology, University of Helsinki, Helsinki, Finland
| | - W M de Vos
- Immunobiology, Research Programs Unit, University of Helsinki, Helsinki, Finland
| | - M-L Lokki
- Transplantation Laboratory, Medicum, University of Helsinki, Helsinki, Finland
| | - K-L Kolho
- Children's Hospital, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - S Meri
- Immunobiology, Research Programs Unit, University of Helsinki, Helsinki, Finland.,Department of Bacteriology and Immunology, University of Helsinki, Helsinki, Finland.,Helsinki University Hospital Laboratory (HUSLAB), Helsinki, Finland
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7
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Zhu B, Zhu CF, Lin Y, Perkovic V, Li XF, Yang R, Tang XL, Zhu XL, Cheng XX, Li Q, Chen HY, Sun Y, Chen QW, Wang YJ. Clinical characteristics of IgA nephropathy associated with low complement 4 levels. Ren Fail 2014; 37:424-32. [PMID: 25539484 DOI: 10.3109/0886022x.2014.994408] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
OBJECTIVE C4 deficiency is the most commonly inherited immune disorder in human. The present study investigated the characteristics of the IgAN patients with low serum C4 levels. METHODS We performed a prospective observational study. Clinical as well as histopathologic parameters were assessed. A Kaplan-Meier survival analysis was performed concerning the primary outcome defined as the serum creatinine increased 1.5-fold from baseline. The prognostic significances of clinical and histopathologic parameters were determined using Cox proportional hazards models. RESULTS Five-hundred twelve biopsy proven IgAN cases were available for analysis with a median follow-up of 38.4 months. Ninety-nine cases (19.34%) presented with low C4 levels (LowC4 group) and the other 413 cases did not (NlowC4 group). At the time of renal biopsy, renal injury was lighter in the LowC4 group compared with the NlowC4 group. Renal C4 deposition was significantly decreased while IgM deposition was increased in the LowC4 group. A correlation analysis shows that lower C4 levels were associated with better renal presentations at biopsy. However, the risk of developing the primary outcome was significantly greater in those with low C4 levels. Specifically, during the follow-up period, the risk of developing primary outcome was nearly ten folds higher in those with low C4, compared to those without low C4. CONCLUSION There is a high prevalence of low C4 levels in IgAN patients. These patients with low C4 levels exhibited better renal presentations at the time of renal biopsy, whereas might be associated with a poor prognosis.
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Affiliation(s)
- Bin Zhu
- Department of Nephrology, Hangzhou Hospital of Traditional Chinese Medicine (Guangxing Hospital), Zhejiang Chinese Medical University , Hangzhou, Zhejiang Province , China
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8
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Kotilainen H, Lokki ML, Paakkanen R, Seppänen M, Tukiainen P, Meri S, Poussa T, Eskola J, Valtonen V, Järvinen A. Complement C4 deficiency--a plausible risk factor for non-tuberculous mycobacteria (NTM) infection in apparently immunocompetent patients. PLoS One 2014; 9:e91450. [PMID: 24638111 PMCID: PMC3956671 DOI: 10.1371/journal.pone.0091450] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2013] [Accepted: 02/12/2014] [Indexed: 01/08/2023] Open
Abstract
Background Non-tuberculous mycobacteria (NTM) are ubiquitous in the environment and they infect mainly persons with underlying pulmonary diseases but also previously healthy elderly women. Defects in host resistance that lead to pulmonary infections by NTM are relatively unknown. A few genetic defects have been associated with both pulmonary and disseminated mycobacterial infections. Rare disseminated NTM infections have been associated with genetic defects in T-cell mediated immunity and in cytokine signaling in families. We investigated whether there was an association between NTM infections and deficiencies of complement components C4A or C4B that are encoded by major histocompatibility complex (MHC). Methods 50 adult patients with a positive NTM culture with symptoms and findings of a NTM disease were recruited. Patients' clinical history was collected and symptoms and clinical findings were categorized according to 2007 diagnostic criteria of The American Thoracic Society (ATS). To investigate the deficiencies of complement, C4A and C4B gene copy numbers and phenotype frequencies of the C4 allotypes were analyzed. Unselected, healthy, 149 Finnish adults were used as controls. Results NTM patients had more often C4 deficiencies (C4A or C4B) than controls (36/50 [72%] vs 83/149 [56%], OR = 2.05, 95%CI = 1.019–4.105, p = 0.042). C4 deficiencies for female NTM patients were more common than for controls (29/36 [81%] vs 55/100 [55%], OR = 3.39, 95% CI = 1.358–8.460, p = 0.007). C4 deficiences seemed not to be related to any specific underlying disease or C4 phenotype. Conclusions C4 deficiency may be a risk factor for NTM infection in especially elderly female patients.
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Affiliation(s)
- Hannele Kotilainen
- Division of Infectious Diseases, Department of Medicine, Helsinki University Central Hospital, Helsinki, Finland
- * E-mail:
| | - Marja-Liisa Lokki
- Transplantation Laboratory, Haartman Institute, University of Helsinki, Helsinki, Finland
| | - Riitta Paakkanen
- Transplantation Laboratory, Haartman Institute, University of Helsinki, Helsinki, Finland
- Division of Cardiology, Department of Medicine, Helsinki University Central Hospital, Helsinki, Finland
| | - Mikko Seppänen
- Division of Infectious Diseases, Department of Medicine, Helsinki University Central Hospital, Helsinki, Finland
| | - Pentti Tukiainen
- Division of Lung Diseases, Department of Medicine, Helsinki University Central Hospital, Helsinki, Finland
| | - Seppo Meri
- Department of Bacteriology and Immunology, Haartman Institute, University of Helsinki, Helsinki, Finland
| | | | - Jussi Eskola
- Mycobacteriology Unit, Helsinki University Central Hospital Laboratory, Helsinki, Finland
| | - Ville Valtonen
- Division of Infectious Diseases, Department of Medicine, Helsinki University Central Hospital, Helsinki, Finland
| | - Asko Järvinen
- Division of Infectious Diseases, Department of Medicine, Helsinki University Central Hospital, Helsinki, Finland
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9
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Wennerström A, Vlachopoulou E, Lahtela LE, Paakkanen R, Eronen KT, Seppänen M, Lokki ML. Diversity of extended HLA-DRB1 haplotypes in the Finnish population. PLoS One 2013; 8:e79690. [PMID: 24278156 PMCID: PMC3836878 DOI: 10.1371/journal.pone.0079690] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2013] [Accepted: 09/23/2013] [Indexed: 11/18/2022] Open
Abstract
The Major Histocompatibility Complex (MHC, 6p21) codes for traditional HLA and other host response related genes. The polymorphic HLA-DRB1 gene in MHC Class II has been associated with several complex diseases. In this study we focus on MHC haplotype structures in the Finnish population. We explore the variability of extended HLA-DRB1 haplotypes in relation to the other traditional HLA genes and a selected group of MHC class III genes. A total of 150 healthy Finnish individuals were included in the study. Subjects were genotyped for HLA alleles (HLA-A, -B, -DRB1, -DQB1, and -DPB1). The polymorphism of TNF, LTA, C4, BTNL2 and HLA-DRA genes was studied with 74 SNPs (single nucleotide polymorphism). The C4A and C4B gene copy numbers and a 2-bp silencing insertion at exon 29 in C4A gene were analysed with quantitative genomic realtime-PCR. The allele frequencies for each locus were calculated and haplotypes were constructed using both the traditional HLA alleles and SNP blocks. The most frequent Finnish A∼B∼DR -haplotype, uncommon in elsewhere in Europe, was A*03∼B*35∼DRB1*01∶01. The second most common haplotype was a common European ancestral haplotype AH 8.1 (A*01∼B*08∼DRB1*03∶01). Extended haplotypes containing HLA-B, TNF block, C4 and HLA-DPB1 strongly increased the number of HLA-DRB1 haplotypes showing variability in the extended HLA-DRB1 haplotype structures. On the contrary, BTNL2 block and HLA-DQB1 were more conserved showing linkage with the HLA-DRB1 alleles. We show that the use of HLA-DRB1 haplotypes rather than single HLA-DRB1 alleles is advantageous when studying the polymorphisms and LD patters of the MHC region. For disease association studies the HLA-DRB1 haplotypes with various MHC markers allows us to cluster haplotypes with functionally important gene variants such as C4 deficiency and cytokines TNF and LTA, and provides hypotheses for further assessment. Our study corroborates the importance of studying population-specific MHC haplotypes.
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Affiliation(s)
- Annika Wennerström
- Transplantation Laboratory, Haartman Institute, Helsinki, Finland
- * E-mail:
| | | | - L. Elisa Lahtela
- Transplantation Laboratory, Haartman Institute, Helsinki, Finland
| | - Riitta Paakkanen
- Transplantation Laboratory, Haartman Institute, Helsinki, Finland
| | - Katja T. Eronen
- Transplantation Laboratory, Haartman Institute, Helsinki, Finland
| | - Mikko Seppänen
- Division of Infectious Diseases, Department of Medicine, Helsinki University Central Hospital, Helsinki, Finland
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10
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Ruuskanen O, Nurkka A, Helminen M, Viljanen MK, Käyhty H, Kainulainen L. Specific antibody deficiency in children with recurrent respiratory infections: a controlled study with follow-up. Clin Exp Immunol 2013; 172:238-44. [PMID: 23574320 DOI: 10.1111/cei.12053] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/10/2012] [Indexed: 11/30/2022] Open
Abstract
Specific antibody deficiency (SAD) to unconjugated pneumococcal vaccine (PPV) is an established primary B cell immunodeficiency. The occurrence and natural history of SAD in children is unclear. We conducted an observational study to identify SAD in children with recurrent respiratory infections. Ninety-nine children, mean age 5·9 (range 2-16) years, with recurrent or severe infections were vaccinated with PPV; serum antibody concentrations for serotypes 4, 6B, 9V, 14, 18C, 19F and 23F were measured before and 2 weeks after vaccination with enzyme immunoassay. The retrospective control group consisted of 89 healthy children matched for age and gender. No children had received previous conjugated pneumococcal vaccine (PCV) or PPV. The structured history of infectious diseases of all participants was collected. Ten of 91 (11%) children (eight excluded due to immunoglobulin G subclass deficiency) with recurrent respiratory infections had SAD. In the control group, three children (3%) responded inadequately to PPV (P = 0·05). Most children with SAD also had many other minor immune defects. After 0·5-5 years (medium 3·8), eight children with SAD were revaccinated with PPV; five responded adequately and three inadequately. Two SAD children were revaccinated with PCV, one developed an adequate and one an inadequate response. Two children with SAD received treatment with intravenous immunoglobulin; the remaining eight children recovered without replacement therapy during the follow-up. SAD is common in young children with recurrent respiratory infections, but it is often transient and resolves itself within a few years without specific treatment.
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Affiliation(s)
- O Ruuskanen
- Department of Paediatrics, Turku University Hospital, PO Box 52, FI-20521 Turku, Finland.
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11
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Bay JT, Schejbel L, Madsen HO, Sørensen SS, Hansen JM, Garred P. Low C4 gene copy numbers are associated with superior graft survival in patients transplanted with a deceased donor kidney. Kidney Int 2013; 84:562-9. [PMID: 23715124 DOI: 10.1038/ki.2013.195] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2012] [Revised: 03/01/2013] [Accepted: 03/08/2013] [Indexed: 11/09/2022]
Abstract
Complement C4 is a central component of the classical and the lectin pathways of the complement system. The C4 protein exists as two isotypes C4A and C4B encoded by the C4A and C4B genes, both of which are found with varying copy numbers. Deposition of C4 has been implicated in kidney graft rejection, but a relationship between graft survival and serum C4 concentration as well as C4 genetic variation has not been established. We evaluated this using a prospective study design of 676 kidney transplant patients and 211 healthy individuals as controls. Increasing C4 gene copy numbers significantly correlated with the C4 serum concentration in both patients and controls. Patients with less than four total copies of C4 genes transplanted with a deceased donor kidney experienced a superior 5-year graft survival (hazard ratio 0.46, 95% confidence interval: 0.25-0.84). No significant association was observed in patients transplanted with a living donor. Thus, low C4 copy numbers are associated with increased kidney graft survival in patients receiving a kidney from a deceased donor. Hence, the degree of ischemia may influence the clinical impact of complement.
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Affiliation(s)
- Jakob T Bay
- Laboratory of Molecular Medicine, Department of Clinical Immunology, Rigshospitalet, Copenhagen, Denmark
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12
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Brudner M, Karpel M, Lear C, Chen L, Yantosca LM, Scully C, Sarraju A, Sokolovska A, Zariffard MR, Eisen DP, Mungall BA, Kotton DN, Omari A, Huang IC, Farzan M, Takahashi K, Stuart L, Stahl GL, Ezekowitz AB, Spear GT, Olinger GG, Schmidt EV, Michelow IC. Lectin-dependent enhancement of Ebola virus infection via soluble and transmembrane C-type lectin receptors. PLoS One 2013; 8:e60838. [PMID: 23573288 PMCID: PMC3614905 DOI: 10.1371/journal.pone.0060838] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2011] [Accepted: 03/05/2013] [Indexed: 01/19/2023] Open
Abstract
Mannose-binding lectin (MBL) is a key soluble effector of the innate immune system that recognizes pathogen-specific surface glycans. Surprisingly, low-producing MBL genetic variants that may predispose children and immunocompromised individuals to infectious diseases are more common than would be expected in human populations. Since certain immune defense molecules, such as immunoglobulins, can be exploited by invasive pathogens, we hypothesized that MBL might also enhance infections in some circumstances. Consequently, the low and intermediate MBL levels commonly found in human populations might be the result of balancing selection. Using model infection systems with pseudotyped and authentic glycosylated viruses, we demonstrated that MBL indeed enhances infection of Ebola, Hendra, Nipah and West Nile viruses in low complement conditions. Mechanistic studies with Ebola virus (EBOV) glycoprotein pseudotyped lentiviruses confirmed that MBL binds to N-linked glycan epitopes on viral surfaces in a specific manner via the MBL carbohydrate recognition domain, which is necessary for enhanced infection. MBL mediates lipid-raft-dependent macropinocytosis of EBOV via a pathway that appears to require less actin or early endosomal processing compared with the filovirus canonical endocytic pathway. Using a validated RNA interference screen, we identified C1QBP (gC1qR) as a candidate surface receptor that mediates MBL-dependent enhancement of EBOV infection. We also identified dectin-2 (CLEC6A) as a potentially novel candidate attachment factor for EBOV. Our findings support the concept of an innate immune haplotype that represents critical interactions between MBL and complement component C4 genes and that may modify susceptibility or resistance to certain glycosylated pathogens. Therefore, higher levels of native or exogenous MBL could be deleterious in the setting of relative hypocomplementemia which can occur genetically or because of immunodepletion during active infections. Our findings confirm our hypothesis that the pressure of infectious diseases may have contributed in part to evolutionary selection of MBL mutant haplotypes.
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Affiliation(s)
- Matthew Brudner
- Programs of Developmental Immunology, Department of Pediatrics, Massachusetts General Hospital, Boston, Massachusetts, United States of America
| | - Marshall Karpel
- Programs of Developmental Immunology, Department of Pediatrics, Massachusetts General Hospital, Boston, Massachusetts, United States of America
| | - Calli Lear
- Virology Division, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, Maryland, United States of America
| | - Li Chen
- Programs of Developmental Immunology, Department of Pediatrics, Massachusetts General Hospital, Boston, Massachusetts, United States of America
| | - L. Michael Yantosca
- Programs of Developmental Immunology, Department of Pediatrics, Massachusetts General Hospital, Boston, Massachusetts, United States of America
| | - Corinne Scully
- Virology Division, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, Maryland, United States of America
| | - Ashish Sarraju
- Programs of Developmental Immunology, Department of Pediatrics, Massachusetts General Hospital, Boston, Massachusetts, United States of America
| | - Anna Sokolovska
- Programs of Developmental Immunology, Department of Pediatrics, Massachusetts General Hospital, Boston, Massachusetts, United States of America
| | - M. Reza Zariffard
- Department of Immunology and Microbiology, Rush University Medical Center, Chicago, Illinois, United States of America
| | - Damon P. Eisen
- Victorian Infectious Diseases Service, Royal Melbourne Hospital, Parkville, Victoria, Australia
| | - Bruce A. Mungall
- Australian Animal Health Laboratory, Commonwealth Scientific and Industrial Research Organisation (CSIRO) Livestock Industries, Geelong, Victoria, Australia
| | - Darrell N. Kotton
- Department of Medicine, Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - Amel Omari
- Department of Medicine, Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - I-Chueh Huang
- New England Primate Research Center, Southborough, Massachusetts, United States of America
| | - Michael Farzan
- New England Primate Research Center, Southborough, Massachusetts, United States of America
- Harvard Medical School, Boston, Massachusetts, United States of America
| | - Kazue Takahashi
- Programs of Developmental Immunology, Department of Pediatrics, Massachusetts General Hospital, Boston, Massachusetts, United States of America
- Harvard Medical School, Boston, Massachusetts, United States of America
| | - Lynda Stuart
- Programs of Developmental Immunology, Department of Pediatrics, Massachusetts General Hospital, Boston, Massachusetts, United States of America
- Harvard Medical School, Boston, Massachusetts, United States of America
| | - Gregory L. Stahl
- CETRI, Brigham and Women's Hospital, Boston, Massachusetts, United States of America
- Harvard Medical School, Boston, Massachusetts, United States of America
| | - Alan B. Ezekowitz
- Programs of Developmental Immunology, Department of Pediatrics, Massachusetts General Hospital, Boston, Massachusetts, United States of America
| | - Gregory T. Spear
- Department of Immunology and Microbiology, Rush University Medical Center, Chicago, Illinois, United States of America
| | - Gene G. Olinger
- Virology Division, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, Maryland, United States of America
| | - Emmett V. Schmidt
- Programs of Developmental Immunology, Department of Pediatrics, Massachusetts General Hospital, Boston, Massachusetts, United States of America
- Harvard Medical School, Boston, Massachusetts, United States of America
- * E-mail: (EVS); (ICM)
| | - Ian C. Michelow
- Programs of Developmental Immunology, Department of Pediatrics, Massachusetts General Hospital, Boston, Massachusetts, United States of America
- Harvard Medical School, Boston, Massachusetts, United States of America
- * E-mail: (EVS); (ICM)
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Paakkanen R, Vauhkonen H, Eronen KT, Järvinen A, Seppänen M, Lokki ML. Copy number analysis of complement C4A, C4B and C4A silencing mutation by real-time quantitative polymerase chain reaction. PLoS One 2012; 7:e38813. [PMID: 22737222 PMCID: PMC3380926 DOI: 10.1371/journal.pone.0038813] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2011] [Accepted: 05/10/2012] [Indexed: 01/30/2023] Open
Abstract
Low protein levels and copy number variation (CNV) of the fourth component of human complement (C4A and C4B) have been associated with various diseases. High-throughput methods for analysing C4 CNV are available, but they commonly do not detect the most common C4A mutation, a silencing CT insertion (CTins) leading to low protein levels. We developed a SYBR® Green labelled real-time quantitative polymerase chain reaction (qPCR) with a novel concentration range approach to address C4 CNV and deficiencies due to CTins. This method was validated in three sample sets and applied to over 1600 patient samples. CTins caused C4A deficiency in more than 70% (76/105) of the carriers. Twenty per cent (76/381) of patients with a C4A deficiency would have been erroneously recorded as having none, if the CTins had not been assessed. C4A deficiency was more common in patients than a healthy reference population, (OR = 1.60, 95%CI = 1.02-2.52, p = 0.039). The number of functional C4 genes can be straightforwardly analyzed by real-time qPCR, also with SYBR® Green labelling. Determination of CTins increases the frequency of C4A deficiency and thus helps to elucidate the genotypic versus phenotypic disease associations.
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Affiliation(s)
- Riitta Paakkanen
- Transplantation Laboratory, Haartman Institute, University of Helsinki, Helsinki, Finland.
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