- Email: [email protected]
Adenosine deaminase deficiency can present with features of Omenn syndrome
1056 LETTERS TO THE EDITOR
FIP1L1-PDGFRA gene fusion respond to imatinib mesilate.2,5 However, FIP1L1-PDGFRA–positive patients with CEL may also respond to anti–IL-5 antibody treatment,6 perhaps because the FIP1L1-PDGFRA gene fusion alone is not sufficient and may require IL-5 to induce CEL.7 To understand whether the eosinophil differentiation process can be stopped by neutralizing IL-5, we administrated 4 intravenous injections of an anti–IL-5 antibody (mepolizumab, 750 mg each) with intervals of 2 weeks.8 The patient did not respond with a detectable decrease of his eosinophil count as a consequence of this treatment (Fig 1, B), suggesting that the neutralization of IL-5 by mepolizumab was not sufficient to stop the eosinophil differentiation process. The antibody treatment had also no influence on the relative distribution of T subpopulations and B cells or the expression of markers indicating their activation. Although single imatinib treatment had no effect (Fig 1, A), we thought a combination of mepolizumab and imatinib mesilate might be able to reduce eosinophil numbers. Therefore, we treated the patient with 400 mg imatinib daily, starting 2 weeks after the last mepolizumab infusion. At this time, mepolizumab still exhibits antieosinophil activity in hypereosinophilic patients.8 Again, no effect of imatinib on eosinophil numbers or symptoms was seen (Fig 1, B). The patient was subsequently substituted with 25 mg hydrocortisone. He died of heart failure in 2006. Because imatinib resistance might be caused by mutations, we analyzed the primary structure of the entire FIP1L1-PDGFRA fusion gene. To this end, the complete FIP1L1-PDGFRA cDNA was amplified by RT-PCR and sequenced. We identified 2 mutations in PDGFRA sequence (accession no. M22734: T1949C and T2034C), resulting in 2 amino acid changes within the kinase domain: S601P and L629P (Fig 1, C and D). No homologous mutations have been described in the BCR-ABL fusion oncoprotein causing imatinib resistance in chronic myeloid leukemia.9 Therefore, the exact molecular mechanisms through which these newly identified mutations likely cause imatinib resistance remain to be investigated. It should be noted that no mRNA was available before the patient received the drug for the first time. Therefore, the possibility exists that the imatinib treatment may have influenced the mutation. Nevertheless, mutations within the kinase domain of oncoproteins are common causes of drug resistance.10 Taken together, patients with CEL with the FIP1L1-PDGFRA gene fusion may be resistant to imatinib mesilate because of mutations within the tyrosine kinase domain of the chimeric protein, and increased IL-5 levels in blood do not predict an antieosinophil response to anti–IL-5 antibody therapy. The identification of novel drug-resistant variants may help to develop the next generation of target-directed compounds for CEL and other leukemias. We thank Ine`s Schmid for excellent technical assistance. Dagmar Simon, MDa Souzan Salemi, PhDb Shida Yousefi, PhDb Hans-Uwe Simon, MD, PhDb From athe Department of Dermatology, Inselspital, Bern, and bthe Institute of Pharmacology, University of Bern, Bern, Switzerland. E-mail: [email protected]. Supported by grants from the Swiss National Science Foundation (310000-107526) and the Stanley Thomas Johnson Foundation, Bern. Disclosure of potential conflict of interest: The authors have declared that they have no conflict of interest.
J ALLERGY CLIN IMMUNOL APRIL 2008
REFERENCES 1. Gleich GJ, Leiferman KM, Pardanasi A, Tefferi A, Butterfield JH. Treatment of hypereosinophilic syndrome with imatinib mesilate. Lancet 2002;359:1577-8. 2. Cools J, DeAngelo DJ, Gotlib J, Stover EH, Legare RD, Cortes J, et al. A novel tyrosine kinase created by the fusion of the PDGFRA and FIP1L1 genes is a therapeutic target of imatinib in idiopathic hypereosinophilic syndrome. N Engl J Med 2003;348:1201-4. 3. Simon HU, Plo¨tz SG, Dummer R, Blaser K. Abnormal clones of T cells producing interleukin-5 in idiopathic eosinophilia. N Engl J Med 1999;341:1112-20. 4. Simon HU, Plo¨tz SG, Simon D, Seitzer U, Braathen LR, Menz G, et al. Interleukin-2 primes eosinophil degranulation in hypereosinophilia and Wells’ syndrome. Eur J Immunol 2003;33:834-9. 5. Klion AD, Robyn J, Akin C, Noel P, Brown M, Law M, et al. Molecular remission and reversal of myelofibrosis in response to imatinib mesylate treatment in patients with the myeloproliferative variant of hypereosinophilic syndrome. Blood 2004; 103:473-8. 6. Klion AD, Law MA, Noel P, Kim YJ, Haverty TP, Nutman TB. Safety and efficacy of the monoclonal anti-interleukin-5 antibody SCH55700 in the treatment of patients with hypereosinophilic syndrome. Blood 2004;103:2939-41. 7. Yamada Y, Rothenberg ME, Lee AW, Akei HS, Brandt EB, Williams DA, et al. The FIP1L1-PDGFRA fusion gene cooperates with IL-5 to induce murine hypereosinophilic syndrome (HES)/chronic eosinophilic leukemia (CEL)-like disease. Blood 2006;107:4071-9. 8. Plo¨tz SG, Simon HU, Darsow U, Simon D, Vassina E, Yousefi S, et al. Use of an anti-interleukin-5 antibody in the hypereosinophilic syndrome with eosinophilic dermatitis. N Engl J Med 2003;349:2334-9. 9. Nardi V, Azam M, Daley GQ. Mechanisms and implications of imatinib resistance mutations in BCR-ABL. Curr Opin Hematol 2003;11:35-43. 10. Azam M, Latek RR, Daley GQ. Mechanisms of autoinhibition and STI-571/ imatinib resistance revealed by mutagenesis of Bcr-Abl. Cell 2003;112:831-43. Available online January 31, 2008. doi:10.1016/j.jaci.2007.11.027
Adenosine deaminase deficiency can present with features of Omenn syndrome To the Editor: The clinical and laboratory group of features including generalized scaly exudative erythroderma, enlarged lymphoid tissues, protracted diarrhea, failure to thrive, and eosinophilia is traditionally referred to as Omenn syndrome.1 This is a fatal variant of severe combined immunodeficiency (SCID) unless treated with bone marrow transplantation. Treatment with cyclosporine and/ or corticosteroids before bone marrow transplantation results in the amelioration of skin inflammation and is believed to improve engraftment.2 We report here, for the first time, 2 patients with adenosine deaminase (ADA) deficiency who had typical features of Omenn syndrome. Both presented with protracted diarrhea, pneumonitis, and universal erythroderma. Skin manifestations started at ages 6 months and 4 months for patient 1 and patient 2, respectively. They also had lymphadenopathy and hepatosplenomegaly. Eosinophil counts were increased to 0.85 3 1029/L and 1.73 3 1029/L for patient 1 and patient 2, respectively (normal range, 0.02-0.5 3 1029/L). IgE levels were also elevated to 385 IU/mL and 620 IU/mL in patient 1 and patient 2, respectively. They had a low number of circulating lymphocytes that responded poorly to mitogens and to vaccinations (Table I). Skin biopsy obtained from patient 1 was compatible with changes observed in other cases of Omenn syndrome.3 A thymus shadow was detected in both patients on a chest x-ray, suggesting an incomplete arrest of T-cell development. Indeed, similar to other cases of Omenn syndrome caused by mutations in recombination activating gene (rag)– 1/rag 2, a partial block of enzymatic activity may result in a leaky defect, which allows partial development of the thymus and
LETTERS TO THE EDITOR 1057
J ALLERGY CLIN IMMUNOL VOLUME 121, NUMBER 4
TABLE I. Humoral and cellular immunity
Serum immunoglobulins IgG (g/L) IgM (g/L) IgA (g/L) IgE (IU/mL) Specific antibodies Tetanus (IU/mL) Polio (neutralization titres) Lymphocyte markers (cells/mL) CD3 CD4 CD8 CD19 CD56 Mitogenic responses,* patient/control Phytohemagglutinin Anti-CD3
Patient 1
Patient 2
Normal range
<0.3 <0.07 <0.07 385
1.37 0.20 <0.13 620
0.8-6.5 0.19-0.96 0.04-0.4 <12
<0:01 <1:8
<0.01 <1:8
>0.04 >1:16
149 64 28 22 188
88 84 4 9 211
2000-6900 1400-5100 600-2200 700-2500 100-1000
2/78 Not done
1/242 1/27
*Stimulation index.
maturation of a very limited number of T cells.4,5 We demonstrate here that both patients had a skewed T-cell repertoire, with limited expression of T-cell receptor subfamilies and expansion of several clones in peripheral blood and skin.6 Remarkably, expansion of T-cell clones in these patients was similar to a pattern observed in cases of Omenn syndrome caused by rag 1 deficiency (Fig 1). However, sequence analysis of rag 1 and rag 2 was normal in both patients. Nevertheless, similar clones including Vb12 and Vb17 were commonly expanded in the patients with rag 1 and
ADA. The circulating T cells in our patients are likely autologous and not of maternal origin as determined by HLA analysis and karyotyping. Adenosine deaminase activity was markedly reduced to 2% of control and 1% of control for patients 1 and 2, respectively. Inherited defects in ADA activity result in the accumulation of enzyme substrates such as adenosine and 29-deoxy-adenosine, which are toxic to T and B lymphocytes, leading to a secondary immunodeficiency.7 Indeed, the level of deoxyadenosine nucleotides in the red cells of patient 1 was increased to 410 nmol/mL. This condition could be ideally predisposing for Omenn syndrome. The secondary immunodeficiency caused by ADA deficiency may be time-dependent, allowing a window of opportunity for maturation of some selective T-cell clones. These clones may expand in the periphery in spite of the harsh environment caused by the accumulation of adenosine metabolites, leading to inflammation in the skin and enlarged lymphoid tissues. The features in our patients may at least in part be explained by their genetic aberrations. Patient 1 was a compound heterozygote for 2 missense mutations, Ser 291 Leu and Arg 156 His. These mutations were previously described in combination with other mutations in patients with delayed presentation of ADA deficiency.8 Both mutations were associated with some residual ADA activity in T cells and a significant but low number of circulating T lymphocytes. Interestingly, the Ser 291 Leu mutation was previously found in a patient who had eosinophilia and elevated serum IgE, features typical of Omenn syndrome.8 Patient 2, who was a product of consanguinous Inuit parents, surprisingly had 2 different mutations that have not been previously reported in this community. The exon 10 D955-959 deletion found on one allele was previously identified in a patient who had a delayed presentation. He was diagnosed only at the age of
FIG 1. T-cell repertoire. Profile of expression of Vb families. Flow cytometry analysis of various Vb finding in PBMCs obtained from control (,), patient 2 (n), and a patient with Omenn syndrome caused by rag 1 deficiency (n).
1058 LETTERS TO THE EDITOR
J ALLERGY CLIN IMMUNOL APRIL 2008
3 years. This patient like ours had a significant number of circulating T cells, probably a result of residual ADA activity. The other allele in patient 2 carried the R142X mutation, which was previously reported in Canadian Mennonites.9 Treatment at an early stage made it difficult to assess the full effect on clinical presentation. Thus, the mutations in the ADA gene observed in our patients that permitted trace ADA activity may have allowed the development of a selective group of T-cell clones causing the systemic inflammation designated Omenn syndrome. This report supports the concept that Omenns syndrome is not a distinct form of SCID, nor is it caused by 1 defined genetic defect. Rather, it is an aberrant inflammatory condition that can be associated with a leaky SCID caused by various genetic abnormalities.
TABLE I. Results of intradermal testing Anesthetic agent
Mepivacaine Bupivacaine Lidocaine Prilocaine
1:100 dilution
12 12 8 0
mm mm mm mm
Result
1:10 dilution
Positive Positive Borderline Negative
ND ND 12 mm ND
Result
Positive
Chaim M. Roifman, MDa Junyan Zhang, BSca Adelle Atkinson, MDa Eyal Grunebaum, MDa Karen Mandel, MDb From athe Division of Immunology and Allergy, the Hospital for Sick Children and the University of Toronto; and bthe Division of Hematology/Oncology, Childrens Hospital of Eastern Ontario, Toronto, Ontario, Canada. E-mail: chaim.roifman@ sickkids.ca. Supported by the Canadian Center for Primary Immunodeficiency, the Canadian Immunodeficiency Society, and the Jeffrey Modell Foundation. C.M.R. is the Donald and Audrey Campbell Chair in Immunology. Disclosure of potential conflict of interest: The authors have declared that they have no conflict of interest. REFERENCES 1. Omenn GS. Familial reticuloendotheliosis with eosinophilia. N Engl J Med 1965; 273:427-32. 2. Wirt DP, Brooks EG, Vaidya S, Klimpel GR, Waldmann TA, Goldblum RM. Novel T-lymphocyte population in combined immunodeficiency with features of graft-versus-host disease. N Engl J Med 1989;321:370-4. 3. Roifman CM, Gu Y, Cohen A. Mutations in the RNA component of RNase mitochondrial RNA processing might cause Omenn syndrome. J Allergy Clin Immunol 2006;117:897-903. 4. Villa A, Santagata S, Bozzi F, Giliani S, Frattini A, Imberti L, et al. Partial V(D)J recombination activity leads to Omenn syndrome. Cell 1998;93:885-96. 5. Melamed I, Cohen A, Roifman CM. Expansion of CD31 CD42 CD82 T cell population expressing high levels of IL-5 in Omenn’s syndrome. Clin Exp Immunol 1994;95:14-21. 6. Zhang J, Quintal L, Atkinson A, Williams B, Grunebaum E, Roifman CM. Novel Rag1 mutation in a case of severe combined immunodeficiency. Pediatrics 2005; 116:e445-9. 7. Cohen A, Hirschhorn R, Horowitz SD, Rubinstein A, Polmar SH, Hong R, et al. Deoxyadenosine triphosphates as a potentially toxic metabolite in adenosine deaminase deficiency. Proc Natl Acad Sci U S A 1978;75:472-6. 8. Santisteban I, Arredondo-Vega FX, Kelly S, Mary A, Fischer A, Hummell DS, et al. Novel splicing, missense and deletion mutations in seven adenosine deaminase deficient patients with late/delayed onset of combined immunodeficiency disease. J Clin Invest 1993;92:2291-302. 9. Santisteban I, Arredondo-Vega FX, Kelly S, Loubser M, Meydan N, Roifman C, et al. Three new adenosine deaminase mutations that define a splicing enhancer and cause severe and partial phenotypes: implications for evolution of a CpG hotspot and expression of a transduced ADA cDNA. Hum Mol Genet 1995;4:2081-7. Available online February 13, 2008. doi:10.1016/j.jaci.2007.12.1148
IgE-mediated reaction to mepivacaine To the Editor: In August 2006, a 31-year-old woman received 2 cartridges (each cartridge, 66 mg in 2.2 mL) of mepivacaine (Scandonest, Septodont, Emu Plains, Australia) 3% for the relief of dental pain before a procedure. She also had exposure to lidocaine gel and
FIG 1. ImmunoCAP inhibition curves. The binding of IgE from the patient serum to the mepivacaine ImmunoCAP was inhibited by mepivacaine, bupivacaine, lidocaine, and prilocaine.
latex gloves. Within a few minutes, she experienced intense pruritus of the hands and feet accompanied by nausea and a need to go to the toilet. She rested for about 10 minutes but then attempted to walk to the toilet, vomited, and had a brief loss of consciousness. Erythema and swelling of the hands was noticed. She was taken to the hospital and treated with parenteral and oral antihistamines but not adrenaline. The patient had no history of allergy to medications or foods and no personal or family history of atopy. Her serum total IgE level was 178 KU/L, and results of allergenspecific IgE tests to latex were negative (ImmunoCAP, Phadia AB, Uppsala, Sweden). She had known previous exposure to lidocaine, but it is not known whether she had previous exposure to mepivacaine. We carried out intradermal testing before planned challenge, and the results are shown in Table I. Subsequently, the patient underwent a graded-dose challenge by means of subcutaneous injection of prilocaine 0.5% up to a maximum dose of 2 mL without any reaction and has had further dental procedures with this anesthetic. An IgE-mediated mechanism was further supported by a positive in vitro test result for specific IgE against mepivacaine. The patient’s serum showed a level of 1.4 kUA/L by using an experimental mepivacaine ImmunoCAP (a result 0.35 kUA/L was considered positive). In ImmunoCAP inhibition experiments, in vitro cross-reactivity between various local anesthetic (LA) drugs was demonstrated (Fig 1). Mepivacaine induced the strongest inhibition of IgE binding, followed by bupivacaine, lidocaine, and prilocaine, respectively. Inhibition correlated well with the intradermal test results and seemed to correlate with the structural similarity between mepivacaine
FIP1L1-PDGFRA gene fusion respond to imatinib mesilate.2,5 However, FIP1L1-PDGFRA–positive patients with CEL may also respond to anti–IL-5 antibody treatment,6 perhaps because the FIP1L1-PDGFRA gene fusion alone is not sufficient and may require IL-5 to induce CEL.7 To understand whether the eosinophil differentiation process can be stopped by neutralizing IL-5, we administrated 4 intravenous injections of an anti–IL-5 antibody (mepolizumab, 750 mg each) with intervals of 2 weeks.8 The patient did not respond with a detectable decrease of his eosinophil count as a consequence of this treatment (Fig 1, B), suggesting that the neutralization of IL-5 by mepolizumab was not sufficient to stop the eosinophil differentiation process. The antibody treatment had also no influence on the relative distribution of T subpopulations and B cells or the expression of markers indicating their activation. Although single imatinib treatment had no effect (Fig 1, A), we thought a combination of mepolizumab and imatinib mesilate might be able to reduce eosinophil numbers. Therefore, we treated the patient with 400 mg imatinib daily, starting 2 weeks after the last mepolizumab infusion. At this time, mepolizumab still exhibits antieosinophil activity in hypereosinophilic patients.8 Again, no effect of imatinib on eosinophil numbers or symptoms was seen (Fig 1, B). The patient was subsequently substituted with 25 mg hydrocortisone. He died of heart failure in 2006. Because imatinib resistance might be caused by mutations, we analyzed the primary structure of the entire FIP1L1-PDGFRA fusion gene. To this end, the complete FIP1L1-PDGFRA cDNA was amplified by RT-PCR and sequenced. We identified 2 mutations in PDGFRA sequence (accession no. M22734: T1949C and T2034C), resulting in 2 amino acid changes within the kinase domain: S601P and L629P (Fig 1, C and D). No homologous mutations have been described in the BCR-ABL fusion oncoprotein causing imatinib resistance in chronic myeloid leukemia.9 Therefore, the exact molecular mechanisms through which these newly identified mutations likely cause imatinib resistance remain to be investigated. It should be noted that no mRNA was available before the patient received the drug for the first time. Therefore, the possibility exists that the imatinib treatment may have influenced the mutation. Nevertheless, mutations within the kinase domain of oncoproteins are common causes of drug resistance.10 Taken together, patients with CEL with the FIP1L1-PDGFRA gene fusion may be resistant to imatinib mesilate because of mutations within the tyrosine kinase domain of the chimeric protein, and increased IL-5 levels in blood do not predict an antieosinophil response to anti–IL-5 antibody therapy. The identification of novel drug-resistant variants may help to develop the next generation of target-directed compounds for CEL and other leukemias. We thank Ine`s Schmid for excellent technical assistance. Dagmar Simon, MDa Souzan Salemi, PhDb Shida Yousefi, PhDb Hans-Uwe Simon, MD, PhDb From athe Department of Dermatology, Inselspital, Bern, and bthe Institute of Pharmacology, University of Bern, Bern, Switzerland. E-mail: [email protected]. Supported by grants from the Swiss National Science Foundation (310000-107526) and the Stanley Thomas Johnson Foundation, Bern. Disclosure of potential conflict of interest: The authors have declared that they have no conflict of interest.
J ALLERGY CLIN IMMUNOL APRIL 2008
REFERENCES 1. Gleich GJ, Leiferman KM, Pardanasi A, Tefferi A, Butterfield JH. Treatment of hypereosinophilic syndrome with imatinib mesilate. Lancet 2002;359:1577-8. 2. Cools J, DeAngelo DJ, Gotlib J, Stover EH, Legare RD, Cortes J, et al. A novel tyrosine kinase created by the fusion of the PDGFRA and FIP1L1 genes is a therapeutic target of imatinib in idiopathic hypereosinophilic syndrome. N Engl J Med 2003;348:1201-4. 3. Simon HU, Plo¨tz SG, Dummer R, Blaser K. Abnormal clones of T cells producing interleukin-5 in idiopathic eosinophilia. N Engl J Med 1999;341:1112-20. 4. Simon HU, Plo¨tz SG, Simon D, Seitzer U, Braathen LR, Menz G, et al. Interleukin-2 primes eosinophil degranulation in hypereosinophilia and Wells’ syndrome. Eur J Immunol 2003;33:834-9. 5. Klion AD, Robyn J, Akin C, Noel P, Brown M, Law M, et al. Molecular remission and reversal of myelofibrosis in response to imatinib mesylate treatment in patients with the myeloproliferative variant of hypereosinophilic syndrome. Blood 2004; 103:473-8. 6. Klion AD, Law MA, Noel P, Kim YJ, Haverty TP, Nutman TB. Safety and efficacy of the monoclonal anti-interleukin-5 antibody SCH55700 in the treatment of patients with hypereosinophilic syndrome. Blood 2004;103:2939-41. 7. Yamada Y, Rothenberg ME, Lee AW, Akei HS, Brandt EB, Williams DA, et al. The FIP1L1-PDGFRA fusion gene cooperates with IL-5 to induce murine hypereosinophilic syndrome (HES)/chronic eosinophilic leukemia (CEL)-like disease. Blood 2006;107:4071-9. 8. Plo¨tz SG, Simon HU, Darsow U, Simon D, Vassina E, Yousefi S, et al. Use of an anti-interleukin-5 antibody in the hypereosinophilic syndrome with eosinophilic dermatitis. N Engl J Med 2003;349:2334-9. 9. Nardi V, Azam M, Daley GQ. Mechanisms and implications of imatinib resistance mutations in BCR-ABL. Curr Opin Hematol 2003;11:35-43. 10. Azam M, Latek RR, Daley GQ. Mechanisms of autoinhibition and STI-571/ imatinib resistance revealed by mutagenesis of Bcr-Abl. Cell 2003;112:831-43. Available online January 31, 2008. doi:10.1016/j.jaci.2007.11.027
Adenosine deaminase deficiency can present with features of Omenn syndrome To the Editor: The clinical and laboratory group of features including generalized scaly exudative erythroderma, enlarged lymphoid tissues, protracted diarrhea, failure to thrive, and eosinophilia is traditionally referred to as Omenn syndrome.1 This is a fatal variant of severe combined immunodeficiency (SCID) unless treated with bone marrow transplantation. Treatment with cyclosporine and/ or corticosteroids before bone marrow transplantation results in the amelioration of skin inflammation and is believed to improve engraftment.2 We report here, for the first time, 2 patients with adenosine deaminase (ADA) deficiency who had typical features of Omenn syndrome. Both presented with protracted diarrhea, pneumonitis, and universal erythroderma. Skin manifestations started at ages 6 months and 4 months for patient 1 and patient 2, respectively. They also had lymphadenopathy and hepatosplenomegaly. Eosinophil counts were increased to 0.85 3 1029/L and 1.73 3 1029/L for patient 1 and patient 2, respectively (normal range, 0.02-0.5 3 1029/L). IgE levels were also elevated to 385 IU/mL and 620 IU/mL in patient 1 and patient 2, respectively. They had a low number of circulating lymphocytes that responded poorly to mitogens and to vaccinations (Table I). Skin biopsy obtained from patient 1 was compatible with changes observed in other cases of Omenn syndrome.3 A thymus shadow was detected in both patients on a chest x-ray, suggesting an incomplete arrest of T-cell development. Indeed, similar to other cases of Omenn syndrome caused by mutations in recombination activating gene (rag)– 1/rag 2, a partial block of enzymatic activity may result in a leaky defect, which allows partial development of the thymus and
LETTERS TO THE EDITOR 1057
J ALLERGY CLIN IMMUNOL VOLUME 121, NUMBER 4
TABLE I. Humoral and cellular immunity
Serum immunoglobulins IgG (g/L) IgM (g/L) IgA (g/L) IgE (IU/mL) Specific antibodies Tetanus (IU/mL) Polio (neutralization titres) Lymphocyte markers (cells/mL) CD3 CD4 CD8 CD19 CD56 Mitogenic responses,* patient/control Phytohemagglutinin Anti-CD3
Patient 1
Patient 2
Normal range
<0.3 <0.07 <0.07 385
1.37 0.20 <0.13 620
0.8-6.5 0.19-0.96 0.04-0.4 <12
<0:01 <1:8
<0.01 <1:8
>0.04 >1:16
149 64 28 22 188
88 84 4 9 211
2000-6900 1400-5100 600-2200 700-2500 100-1000
2/78 Not done
1/242 1/27
*Stimulation index.
maturation of a very limited number of T cells.4,5 We demonstrate here that both patients had a skewed T-cell repertoire, with limited expression of T-cell receptor subfamilies and expansion of several clones in peripheral blood and skin.6 Remarkably, expansion of T-cell clones in these patients was similar to a pattern observed in cases of Omenn syndrome caused by rag 1 deficiency (Fig 1). However, sequence analysis of rag 1 and rag 2 was normal in both patients. Nevertheless, similar clones including Vb12 and Vb17 were commonly expanded in the patients with rag 1 and
ADA. The circulating T cells in our patients are likely autologous and not of maternal origin as determined by HLA analysis and karyotyping. Adenosine deaminase activity was markedly reduced to 2% of control and 1% of control for patients 1 and 2, respectively. Inherited defects in ADA activity result in the accumulation of enzyme substrates such as adenosine and 29-deoxy-adenosine, which are toxic to T and B lymphocytes, leading to a secondary immunodeficiency.7 Indeed, the level of deoxyadenosine nucleotides in the red cells of patient 1 was increased to 410 nmol/mL. This condition could be ideally predisposing for Omenn syndrome. The secondary immunodeficiency caused by ADA deficiency may be time-dependent, allowing a window of opportunity for maturation of some selective T-cell clones. These clones may expand in the periphery in spite of the harsh environment caused by the accumulation of adenosine metabolites, leading to inflammation in the skin and enlarged lymphoid tissues. The features in our patients may at least in part be explained by their genetic aberrations. Patient 1 was a compound heterozygote for 2 missense mutations, Ser 291 Leu and Arg 156 His. These mutations were previously described in combination with other mutations in patients with delayed presentation of ADA deficiency.8 Both mutations were associated with some residual ADA activity in T cells and a significant but low number of circulating T lymphocytes. Interestingly, the Ser 291 Leu mutation was previously found in a patient who had eosinophilia and elevated serum IgE, features typical of Omenn syndrome.8 Patient 2, who was a product of consanguinous Inuit parents, surprisingly had 2 different mutations that have not been previously reported in this community. The exon 10 D955-959 deletion found on one allele was previously identified in a patient who had a delayed presentation. He was diagnosed only at the age of
FIG 1. T-cell repertoire. Profile of expression of Vb families. Flow cytometry analysis of various Vb finding in PBMCs obtained from control (,), patient 2 (n), and a patient with Omenn syndrome caused by rag 1 deficiency (n).
1058 LETTERS TO THE EDITOR
J ALLERGY CLIN IMMUNOL APRIL 2008
3 years. This patient like ours had a significant number of circulating T cells, probably a result of residual ADA activity. The other allele in patient 2 carried the R142X mutation, which was previously reported in Canadian Mennonites.9 Treatment at an early stage made it difficult to assess the full effect on clinical presentation. Thus, the mutations in the ADA gene observed in our patients that permitted trace ADA activity may have allowed the development of a selective group of T-cell clones causing the systemic inflammation designated Omenn syndrome. This report supports the concept that Omenns syndrome is not a distinct form of SCID, nor is it caused by 1 defined genetic defect. Rather, it is an aberrant inflammatory condition that can be associated with a leaky SCID caused by various genetic abnormalities.
TABLE I. Results of intradermal testing Anesthetic agent
Mepivacaine Bupivacaine Lidocaine Prilocaine
1:100 dilution
12 12 8 0
mm mm mm mm
Result
1:10 dilution
Positive Positive Borderline Negative
ND ND 12 mm ND
Result
Positive
Chaim M. Roifman, MDa Junyan Zhang, BSca Adelle Atkinson, MDa Eyal Grunebaum, MDa Karen Mandel, MDb From athe Division of Immunology and Allergy, the Hospital for Sick Children and the University of Toronto; and bthe Division of Hematology/Oncology, Childrens Hospital of Eastern Ontario, Toronto, Ontario, Canada. E-mail: chaim.roifman@ sickkids.ca. Supported by the Canadian Center for Primary Immunodeficiency, the Canadian Immunodeficiency Society, and the Jeffrey Modell Foundation. C.M.R. is the Donald and Audrey Campbell Chair in Immunology. Disclosure of potential conflict of interest: The authors have declared that they have no conflict of interest. REFERENCES 1. Omenn GS. Familial reticuloendotheliosis with eosinophilia. N Engl J Med 1965; 273:427-32. 2. Wirt DP, Brooks EG, Vaidya S, Klimpel GR, Waldmann TA, Goldblum RM. Novel T-lymphocyte population in combined immunodeficiency with features of graft-versus-host disease. N Engl J Med 1989;321:370-4. 3. Roifman CM, Gu Y, Cohen A. Mutations in the RNA component of RNase mitochondrial RNA processing might cause Omenn syndrome. J Allergy Clin Immunol 2006;117:897-903. 4. Villa A, Santagata S, Bozzi F, Giliani S, Frattini A, Imberti L, et al. Partial V(D)J recombination activity leads to Omenn syndrome. Cell 1998;93:885-96. 5. Melamed I, Cohen A, Roifman CM. Expansion of CD31 CD42 CD82 T cell population expressing high levels of IL-5 in Omenn’s syndrome. Clin Exp Immunol 1994;95:14-21. 6. Zhang J, Quintal L, Atkinson A, Williams B, Grunebaum E, Roifman CM. Novel Rag1 mutation in a case of severe combined immunodeficiency. Pediatrics 2005; 116:e445-9. 7. Cohen A, Hirschhorn R, Horowitz SD, Rubinstein A, Polmar SH, Hong R, et al. Deoxyadenosine triphosphates as a potentially toxic metabolite in adenosine deaminase deficiency. Proc Natl Acad Sci U S A 1978;75:472-6. 8. Santisteban I, Arredondo-Vega FX, Kelly S, Mary A, Fischer A, Hummell DS, et al. Novel splicing, missense and deletion mutations in seven adenosine deaminase deficient patients with late/delayed onset of combined immunodeficiency disease. J Clin Invest 1993;92:2291-302. 9. Santisteban I, Arredondo-Vega FX, Kelly S, Loubser M, Meydan N, Roifman C, et al. Three new adenosine deaminase mutations that define a splicing enhancer and cause severe and partial phenotypes: implications for evolution of a CpG hotspot and expression of a transduced ADA cDNA. Hum Mol Genet 1995;4:2081-7. Available online February 13, 2008. doi:10.1016/j.jaci.2007.12.1148
IgE-mediated reaction to mepivacaine To the Editor: In August 2006, a 31-year-old woman received 2 cartridges (each cartridge, 66 mg in 2.2 mL) of mepivacaine (Scandonest, Septodont, Emu Plains, Australia) 3% for the relief of dental pain before a procedure. She also had exposure to lidocaine gel and
FIG 1. ImmunoCAP inhibition curves. The binding of IgE from the patient serum to the mepivacaine ImmunoCAP was inhibited by mepivacaine, bupivacaine, lidocaine, and prilocaine.
latex gloves. Within a few minutes, she experienced intense pruritus of the hands and feet accompanied by nausea and a need to go to the toilet. She rested for about 10 minutes but then attempted to walk to the toilet, vomited, and had a brief loss of consciousness. Erythema and swelling of the hands was noticed. She was taken to the hospital and treated with parenteral and oral antihistamines but not adrenaline. The patient had no history of allergy to medications or foods and no personal or family history of atopy. Her serum total IgE level was 178 KU/L, and results of allergenspecific IgE tests to latex were negative (ImmunoCAP, Phadia AB, Uppsala, Sweden). She had known previous exposure to lidocaine, but it is not known whether she had previous exposure to mepivacaine. We carried out intradermal testing before planned challenge, and the results are shown in Table I. Subsequently, the patient underwent a graded-dose challenge by means of subcutaneous injection of prilocaine 0.5% up to a maximum dose of 2 mL without any reaction and has had further dental procedures with this anesthetic. An IgE-mediated mechanism was further supported by a positive in vitro test result for specific IgE against mepivacaine. The patient’s serum showed a level of 1.4 kUA/L by using an experimental mepivacaine ImmunoCAP (a result 0.35 kUA/L was considered positive). In ImmunoCAP inhibition experiments, in vitro cross-reactivity between various local anesthetic (LA) drugs was demonstrated (Fig 1). Mepivacaine induced the strongest inhibition of IgE binding, followed by bupivacaine, lidocaine, and prilocaine, respectively. Inhibition correlated well with the intradermal test results and seemed to correlate with the structural similarity between mepivacaine