J Clin Immunol (2014) 34:138–141 DOI 10.1007/s10875-014-9989-3
ASTUTE CLINICIAN REPORT
Autosomal Recessive Agammaglobulinemia: A Novel Non-sense Mutation in CD79a Abbas Khalili & Alessandro Plebani & Massimiliano Vitali & Hassan Abolhassani & Vassilios Lougaris & Babak Mirminachi & Nima Rezaei & Asghar Aghamohammadi
Received: 24 December 2013 / Accepted: 5 January 2014 / Published online: 1 February 2014 # Springer Science+Business Media New York 2014
Abstract This study describes the fifth case worldwide of autosomal recessive agammaglobulinemia due to a novel nonsense mutation in CD79a gene with a severe unusual onset due to an invasive central nervous system infection.
Keywords pre-BCR . CD79a . Autosomal recessive agammaglobulinemia A. Khalili : H. Abolhassani : B. Mirminachi : N. Rezaei : A. Aghamohammadi Research Center for Immunodeficiencies, Pediatrics Center of Excellence, Children’s Medical Center, Tehran University of Medical Sciences, Tehran, Iran A. Khalili : A. Aghamohammadi Department of Allergy and Clinical Immunology, Pediatrics Center of Excellence, Children’s Medical Center, Tehran University of Medical Sciences, Tehran, Iran A. Plebani : M. Vitali : V. Lougaris Pediatrics Clinic and Institute for Molecular Medicine A. Nocivelli, Department of Clinical and Experimental Sciences, University of Brescia, Spedali Civili, Brescia, Italy H. Abolhassani Division of Clinical Immunology, Department of Laboratory Medicine, Karolinska Institute, Karolinska University Hospital, Stockholm, Sweden N. Rezaei Molecular Immunology Research Center; and Department of Immunology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran A. Aghamohammadi (*) Children’s Medical Center Hospital, 62 Qarib St., Keshavarz Blvd., Tehran 14194, Iran e-mail: [email protected]
Abbreviations pre-BCR CD79a Igα
pre-B cell receptor complex CD79a antigen Immunoglobulin-associated alpha
Pre-B cell receptor (Pre-BCR) assembly is an essential step for the progression of B cell development in the bone marrow. Mutations in components of the pre-BCR or in the downstream signaling cascade have been reported to result in the rare forms of autosomal recessive agammaglobulinemia (ARA). This rare condition is characterized by absent peripheral B cells and severe hypogammaglobulinemia due to a developmental arrest at the pro-B stage to pre-B stage. To date, mutations in the genes encoding for μ heavy chain, Igα, Igβ, λ5, BLNK and p85α (PI3K) have been identified as the responsible causes for ARA in humans. The autosomal recessive forms of agammaglobulinemia have been reported to present with a more severe and earlier onset disease than Xlinked agammaglobulinemia (XLA) [1, 2]. We report on the fifth patient worldwide with a novel null mutation in Igα and severe onset with invasive central nervous system complication. The patient was born to consanguineous parents with Turkish ethnicity and came to our center at 6 months of age because of febrile convulsion. Her sibling had expired with severe infection due to unknown etiology in third year of life (Fig. 1a). Her clinical conditions deteriorated rapidly with loss of consciousness and intractable seizure. Lumbar puncture was performed and cerebrospinal fluid (CSF) analysis showed elements suggestive of viral infection (White blood cells: 27 cells/μl, Neutrophil: 2 %; Lymphocyte: 98 %; Glucose: 57 mg/dl; Protein: 53 mg/dl). CSF cultures and polymerase
J Clin Immunol (2014) 34:138–141 Fig. 1 a Family pedigree of the affected patient. b Eletropherograms showing the novel Q53X mutation in the patient, her parents (healthy carriers) and a healthy control (wild type). c Distribution of the novel Igα mutation and the previously reported ones
139
a
Early death
Early death
Early death
Early death
b c caa>taa Q53X (novel)
a > g IVS3AS, A-G, -2 (5)
father
extracellular
mother
TM
cytoplasmic 226
1 gaa>taa E48X (1)
p.R68VfsX9 (1)
g > a IVS2DS, G-A, +1 (4)
patient
control
chain reaction resulted negative for herpes simplex virus; however, empirical treatment for viral encephalitis was initiated. Further worsening of the patient’s clinical conditions prompted us to further investigation of the CSF for other infectious agents. Echovirus and Coxsackie viruses were not detected, but positive results for human herpes virus 8 (HHV8) and John Cunningham (JC) viruses were obtained. Although these results only suggested that these opportunistic viruses might have been responsible for the encephalitis, immunological work-up was performed considering the severity of the clinical conditions. This investigation showed severe hypogammaglobulinemia and absence of peripheral B cells in the presence of normal absolute count of T and NK cells (Table I). Based on the unusual viral agents involved, the
patient was further investigated for cellular immunodeficiency but no defects in number and function of T-cells emerged (normal response to phytohemagglutinin in the lymphocyte transformation test). The patient was treated with broad spectrum antibiotics, acyclovir, and intravenous immunoglobulin replacement therapy, and clinical improvement was achieved after 4 weeks of hospitalization. The immunological phenotype, the female sex and the parental consanguinity of this patient prompted us to investigate the known genes responsible for ARA. The genetic analysis revealed a novel homozygous mutation in the CD79a gene changing a cytosine with a thymine (caa>taa) which leads to the substitution of Glutamine with a Stop codon: Q53X (Fig. 1b). The healthy parents resulted both
140 Table I Immunologic feature of patient with CD79a deficiency
J Clin Immunol (2014) 34:138–141
Parameters
Patient
Normal values for age
Immunoglubulins IgG (mg/dl) IgA (mg/dl) IgM (mg/dl) IgE (IU/dl)
30 Undetectable Undetectable Undetectable
222–846 6–60 28–39 0.9–28.0
0.9 2.6
>0.01 >0.01
9,800 3,100 (31.6 %) 6,700 (68.3 %)
6,000–17,000 1,500–9,000 3,000–9,500
4,920 (73.4 %) 3,070 (45.8 %) 1,850 (27.6 %) 10 (0.14 %) 18 (0.26 %) 1,020 (15.2 %)
4,500±520 2,700±600 1,500±550 540±180 600±300 900±420
Specific antibodies Anti-diphtheria antibody (IU/mL) Anti-tetanus antibody (IU/mL) Complete blood count White blood cells, cells/ml Neutrophils, cells/ml (% of WBC) Lymphocytes, cells/ml (% of WBC) Lymphocyte subsets CD3+ T cells, cells/ml (% of lymphocytes) CD3+CD4+ T cells, cells/ml (% of lymphocytes) CD3+CD8 T cells, cells/ml (% of lymphocytes) CD19+ B cells, cells/ml (% of lymphocytes) CD20+ B cells, cells/ml (% of lymphocytes) CD16/56+ NK cells, cells/ml (% of lymphocytes)
heterozygous for the same mutation. This defect in Igα protein is located in the extracellular domain similarly to previously reported patients. Figure 1c depicts the localization of the novel mutation in CD79a gene and the previously reported ones responsible for autosomal recessive agammaglobulinemia. It should be noted that all reported mutations, as is present in our case, placed upstream of the transmembrane domain [3, 4]. The correct assembly of the pre-BCR requires the co-presence of all components; this null-mutation therefore abrogates the expression of the pre-BCR on the cell surface leading to the B cell developmental block and agammaglobulinemia. As previously reported, the autosomal recessive forms of agammaglobulinemia tend to show a more severe and early onset comparing to X-linked form of the disease. Patients with null defects in Igα reported by Minegishi et al. [3, 5] showed a severe block at the pro-B stage in the bone marrow, resulting in the almost complete lack of B cells in the periphery, similarly to the patient reported here. Unfortunately, we were not able to perform bone marrow evaluation for this patient, since the patient’s family did not agree. Although as of few cases with Igα defects, we cannot compare immunologic data of previous patients with intradomain mutations with our case suffered from defect in extracellular domain, our patient was presented with severe clinical complication, lowest immunoglobulin levels and earlier diagnosis. The patient here reported with the novel defect in Igα presented with an unusual central nervous system infection that fortunately responded to treatment. The first reported
patient with Igα deficiency presented in a Turkish family with prolonged and recurrent diarrhea, failure to thrive, bronchitis and neutropenia, all within the first year of life [5]. The second reported patient also was Turkish and showed an early onset form of immunodeficiency with recurrent lower respiratory tract infections and otitis media at 8 months and at 13 months she developed dermatomyositis [4]. Two patients with defects in extracellular domain also were reported in 2009 [3]. Unfortunately, there is no clinical explanation for these cases to be comparable with our case. Our findings further strengthen the fact that ARA has an earlier and more severe onset when compared to the more frequent X-linked form of agammaglobulinemia. Furthermore, unusual invasive infections should always function as an alarm for clinicians and lead them to perform immunological work-up. Timely diagnosis is essential for primary immunodeficiencies in order to initiate appropriate treatment and limit possible complications [6, 7]. The patient here described is the fifth patient ever reported to be affected with Igα deficiency broadening the clinical and molecular variability of autosomal recessive form of congenital agammaglobulinemia. Funding The research leading to these results has received funding from the European Community’s Seventh Framework Programme FP7/ 2007–2013 under grant agreement no 201549 (EURO-PADnet HEALTH-F2-2008-201549) The research leading to these results also received funding from the “Fondazione C. Golgi”, Brescia. Conflict of interest The authors declare no conflict of interest.
J Clin Immunol (2014) 34:138–141
References 1. Lougaris V, Ferrari S, Cattalini M, Soresina A, Plebani A. Autosomal recessive agammaglobulinemia: novel insights from mutations in Igbeta. Curr Allergy Asthma Rep. 2008;8(5):404–8. 2. Winkelstein JA, Marino MC, Lederman HM, Jones SM, Sullivan K, Burks AW, et al. X-linked agammaglobulinemia: report on a United States registry of 201 patients. Medicine. 2006;85(4):193–202. doi:10. 1097/01.md.0000229482.27398.ad. 3. Conley ME, Dobbs AK, Farmer DM, Kilic S, Paris K, Grigoriadou S, et al. Primary B cell immunodeficiencies: comparisons and contrasts. Annu Rev Immunol. 2009;27:199–227. doi:10.1146/annurev. immunol.021908.132649. 4. Wang Y, Kanegane H, Sanal O, Tezcan I, Ersoy F, Futatani T, et al. Novel Igalpha (CD79a) gene mutation in a Turkish patient
141 with B cell-deficient agammaglobulinemia. Am J Med Genet. 2002;108(4):333–6. 5. Minegishi Y, Coustan-Smith E, Rapalus L, Ersoy F, Campana D, Conley ME. Mutations in Igalpha (CD79a) result in a complete block in B-cell development. J Clin Investig. 1999;104(8):1115–21. doi:10. 1172/JCI7696. 6. Bousfiha AA, Jeddane L, Ailal F, Al Herz W, Conley ME, Cunningham-Rundles C, et al. A phenotypic approach for IUIS PID classification and diagnosis: guidelines for clinicians at the bedside. J Clin Immunol. 2013;33(6):1078–87. doi:10.1007/ s10875-013-9901-6. 7. Aghamohammadi A, Bahrami A, Mamishi S, Mohammadi B, Abolhassani H, Parvaneh N, et al. Impact of delayed diagnosis in children with primary antibody deficiencies. J Microbiol Immunol Infect. 2011;44(3):229–34. doi:10.1016/j.jmii.2011. 01.026.
ASTUTE CLINICIAN REPORT
Autosomal Recessive Agammaglobulinemia: A Novel Non-sense Mutation in CD79a Abbas Khalili & Alessandro Plebani & Massimiliano Vitali & Hassan Abolhassani & Vassilios Lougaris & Babak Mirminachi & Nima Rezaei & Asghar Aghamohammadi
Received: 24 December 2013 / Accepted: 5 January 2014 / Published online: 1 February 2014 # Springer Science+Business Media New York 2014
Abstract This study describes the fifth case worldwide of autosomal recessive agammaglobulinemia due to a novel nonsense mutation in CD79a gene with a severe unusual onset due to an invasive central nervous system infection.
Keywords pre-BCR . CD79a . Autosomal recessive agammaglobulinemia A. Khalili : H. Abolhassani : B. Mirminachi : N. Rezaei : A. Aghamohammadi Research Center for Immunodeficiencies, Pediatrics Center of Excellence, Children’s Medical Center, Tehran University of Medical Sciences, Tehran, Iran A. Khalili : A. Aghamohammadi Department of Allergy and Clinical Immunology, Pediatrics Center of Excellence, Children’s Medical Center, Tehran University of Medical Sciences, Tehran, Iran A. Plebani : M. Vitali : V. Lougaris Pediatrics Clinic and Institute for Molecular Medicine A. Nocivelli, Department of Clinical and Experimental Sciences, University of Brescia, Spedali Civili, Brescia, Italy H. Abolhassani Division of Clinical Immunology, Department of Laboratory Medicine, Karolinska Institute, Karolinska University Hospital, Stockholm, Sweden N. Rezaei Molecular Immunology Research Center; and Department of Immunology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran A. Aghamohammadi (*) Children’s Medical Center Hospital, 62 Qarib St., Keshavarz Blvd., Tehran 14194, Iran e-mail: [email protected]
Abbreviations pre-BCR CD79a Igα
pre-B cell receptor complex CD79a antigen Immunoglobulin-associated alpha
Pre-B cell receptor (Pre-BCR) assembly is an essential step for the progression of B cell development in the bone marrow. Mutations in components of the pre-BCR or in the downstream signaling cascade have been reported to result in the rare forms of autosomal recessive agammaglobulinemia (ARA). This rare condition is characterized by absent peripheral B cells and severe hypogammaglobulinemia due to a developmental arrest at the pro-B stage to pre-B stage. To date, mutations in the genes encoding for μ heavy chain, Igα, Igβ, λ5, BLNK and p85α (PI3K) have been identified as the responsible causes for ARA in humans. The autosomal recessive forms of agammaglobulinemia have been reported to present with a more severe and earlier onset disease than Xlinked agammaglobulinemia (XLA) [1, 2]. We report on the fifth patient worldwide with a novel null mutation in Igα and severe onset with invasive central nervous system complication. The patient was born to consanguineous parents with Turkish ethnicity and came to our center at 6 months of age because of febrile convulsion. Her sibling had expired with severe infection due to unknown etiology in third year of life (Fig. 1a). Her clinical conditions deteriorated rapidly with loss of consciousness and intractable seizure. Lumbar puncture was performed and cerebrospinal fluid (CSF) analysis showed elements suggestive of viral infection (White blood cells: 27 cells/μl, Neutrophil: 2 %; Lymphocyte: 98 %; Glucose: 57 mg/dl; Protein: 53 mg/dl). CSF cultures and polymerase
J Clin Immunol (2014) 34:138–141 Fig. 1 a Family pedigree of the affected patient. b Eletropherograms showing the novel Q53X mutation in the patient, her parents (healthy carriers) and a healthy control (wild type). c Distribution of the novel Igα mutation and the previously reported ones
139
a
Early death
Early death
Early death
Early death
b c caa>taa Q53X (novel)
a > g IVS3AS, A-G, -2 (5)
father
extracellular
mother
TM
cytoplasmic 226
1 gaa>taa E48X (1)
p.R68VfsX9 (1)
g > a IVS2DS, G-A, +1 (4)
patient
control
chain reaction resulted negative for herpes simplex virus; however, empirical treatment for viral encephalitis was initiated. Further worsening of the patient’s clinical conditions prompted us to further investigation of the CSF for other infectious agents. Echovirus and Coxsackie viruses were not detected, but positive results for human herpes virus 8 (HHV8) and John Cunningham (JC) viruses were obtained. Although these results only suggested that these opportunistic viruses might have been responsible for the encephalitis, immunological work-up was performed considering the severity of the clinical conditions. This investigation showed severe hypogammaglobulinemia and absence of peripheral B cells in the presence of normal absolute count of T and NK cells (Table I). Based on the unusual viral agents involved, the
patient was further investigated for cellular immunodeficiency but no defects in number and function of T-cells emerged (normal response to phytohemagglutinin in the lymphocyte transformation test). The patient was treated with broad spectrum antibiotics, acyclovir, and intravenous immunoglobulin replacement therapy, and clinical improvement was achieved after 4 weeks of hospitalization. The immunological phenotype, the female sex and the parental consanguinity of this patient prompted us to investigate the known genes responsible for ARA. The genetic analysis revealed a novel homozygous mutation in the CD79a gene changing a cytosine with a thymine (caa>taa) which leads to the substitution of Glutamine with a Stop codon: Q53X (Fig. 1b). The healthy parents resulted both
140 Table I Immunologic feature of patient with CD79a deficiency
J Clin Immunol (2014) 34:138–141
Parameters
Patient
Normal values for age
Immunoglubulins IgG (mg/dl) IgA (mg/dl) IgM (mg/dl) IgE (IU/dl)
30 Undetectable Undetectable Undetectable
222–846 6–60 28–39 0.9–28.0
0.9 2.6
>0.01 >0.01
9,800 3,100 (31.6 %) 6,700 (68.3 %)
6,000–17,000 1,500–9,000 3,000–9,500
4,920 (73.4 %) 3,070 (45.8 %) 1,850 (27.6 %) 10 (0.14 %) 18 (0.26 %) 1,020 (15.2 %)
4,500±520 2,700±600 1,500±550 540±180 600±300 900±420
Specific antibodies Anti-diphtheria antibody (IU/mL) Anti-tetanus antibody (IU/mL) Complete blood count White blood cells, cells/ml Neutrophils, cells/ml (% of WBC) Lymphocytes, cells/ml (% of WBC) Lymphocyte subsets CD3+ T cells, cells/ml (% of lymphocytes) CD3+CD4+ T cells, cells/ml (% of lymphocytes) CD3+CD8 T cells, cells/ml (% of lymphocytes) CD19+ B cells, cells/ml (% of lymphocytes) CD20+ B cells, cells/ml (% of lymphocytes) CD16/56+ NK cells, cells/ml (% of lymphocytes)
heterozygous for the same mutation. This defect in Igα protein is located in the extracellular domain similarly to previously reported patients. Figure 1c depicts the localization of the novel mutation in CD79a gene and the previously reported ones responsible for autosomal recessive agammaglobulinemia. It should be noted that all reported mutations, as is present in our case, placed upstream of the transmembrane domain [3, 4]. The correct assembly of the pre-BCR requires the co-presence of all components; this null-mutation therefore abrogates the expression of the pre-BCR on the cell surface leading to the B cell developmental block and agammaglobulinemia. As previously reported, the autosomal recessive forms of agammaglobulinemia tend to show a more severe and early onset comparing to X-linked form of the disease. Patients with null defects in Igα reported by Minegishi et al. [3, 5] showed a severe block at the pro-B stage in the bone marrow, resulting in the almost complete lack of B cells in the periphery, similarly to the patient reported here. Unfortunately, we were not able to perform bone marrow evaluation for this patient, since the patient’s family did not agree. Although as of few cases with Igα defects, we cannot compare immunologic data of previous patients with intradomain mutations with our case suffered from defect in extracellular domain, our patient was presented with severe clinical complication, lowest immunoglobulin levels and earlier diagnosis. The patient here reported with the novel defect in Igα presented with an unusual central nervous system infection that fortunately responded to treatment. The first reported
patient with Igα deficiency presented in a Turkish family with prolonged and recurrent diarrhea, failure to thrive, bronchitis and neutropenia, all within the first year of life [5]. The second reported patient also was Turkish and showed an early onset form of immunodeficiency with recurrent lower respiratory tract infections and otitis media at 8 months and at 13 months she developed dermatomyositis [4]. Two patients with defects in extracellular domain also were reported in 2009 [3]. Unfortunately, there is no clinical explanation for these cases to be comparable with our case. Our findings further strengthen the fact that ARA has an earlier and more severe onset when compared to the more frequent X-linked form of agammaglobulinemia. Furthermore, unusual invasive infections should always function as an alarm for clinicians and lead them to perform immunological work-up. Timely diagnosis is essential for primary immunodeficiencies in order to initiate appropriate treatment and limit possible complications [6, 7]. The patient here described is the fifth patient ever reported to be affected with Igα deficiency broadening the clinical and molecular variability of autosomal recessive form of congenital agammaglobulinemia. Funding The research leading to these results has received funding from the European Community’s Seventh Framework Programme FP7/ 2007–2013 under grant agreement no 201549 (EURO-PADnet HEALTH-F2-2008-201549) The research leading to these results also received funding from the “Fondazione C. Golgi”, Brescia. Conflict of interest The authors declare no conflict of interest.
J Clin Immunol (2014) 34:138–141
References 1. Lougaris V, Ferrari S, Cattalini M, Soresina A, Plebani A. Autosomal recessive agammaglobulinemia: novel insights from mutations in Igbeta. Curr Allergy Asthma Rep. 2008;8(5):404–8. 2. Winkelstein JA, Marino MC, Lederman HM, Jones SM, Sullivan K, Burks AW, et al. X-linked agammaglobulinemia: report on a United States registry of 201 patients. Medicine. 2006;85(4):193–202. doi:10. 1097/01.md.0000229482.27398.ad. 3. Conley ME, Dobbs AK, Farmer DM, Kilic S, Paris K, Grigoriadou S, et al. Primary B cell immunodeficiencies: comparisons and contrasts. Annu Rev Immunol. 2009;27:199–227. doi:10.1146/annurev. immunol.021908.132649. 4. Wang Y, Kanegane H, Sanal O, Tezcan I, Ersoy F, Futatani T, et al. Novel Igalpha (CD79a) gene mutation in a Turkish patient
141 with B cell-deficient agammaglobulinemia. Am J Med Genet. 2002;108(4):333–6. 5. Minegishi Y, Coustan-Smith E, Rapalus L, Ersoy F, Campana D, Conley ME. Mutations in Igalpha (CD79a) result in a complete block in B-cell development. J Clin Investig. 1999;104(8):1115–21. doi:10. 1172/JCI7696. 6. Bousfiha AA, Jeddane L, Ailal F, Al Herz W, Conley ME, Cunningham-Rundles C, et al. A phenotypic approach for IUIS PID classification and diagnosis: guidelines for clinicians at the bedside. J Clin Immunol. 2013;33(6):1078–87. doi:10.1007/ s10875-013-9901-6. 7. Aghamohammadi A, Bahrami A, Mamishi S, Mohammadi B, Abolhassani H, Parvaneh N, et al. Impact of delayed diagnosis in children with primary antibody deficiencies. J Microbiol Immunol Infect. 2011;44(3):229–34. doi:10.1016/j.jmii.2011. 01.026.
