- Email: [email protected]
Identical Phenotype in Patients with Somatic and Germline CD95 Mutations Requires a New Diagnostic Approach to Autoimmune Lymphoproliferative Syndrome
CLINICAL AND LABORATORY OBSERVATIONS
IDENTICAL PHENOTYPE IN PATIENTS WITH SOMATIC AND GERMLINE CD95 MUTATIONS REQUIRES A NEW DIAGNOSTIC APPROACH TO AUTOIMMUNE LYMPHOPROLIFERATIVE SYNDROME JOCHEN RO¨SSLER, MD, ANSELM ENDERS, MD, GEORGIA LAHR, PHD, ANDREAS HEITGER, MD, KARL WINKLER, MD, HANS FUCHS, MD, MATTHIAS KOPP, MD, CHARLOTTE NIEMEYER, MD, AND STEPHAN EHL, MD
In a patient with a somatic mutation in the CD95 gene, the long-term evolution of the clinical phenotype was indistinguishable from that of patients with autoimmune lymphoproliferative syndrome caused by germline CD95 mutations. A new diagnostic algorithm for autoimmune lymphoproliferative syndrome is suggested incorporating studies on sorted TCRa/b+CD3+CD82 CD42 T cells. (J Pediatr 2005;147:691-4)
he wide differential diagnosis of lymphoproliferative disease with autoimmunity includes malignant, infectious, and immunologic diseases. Autoimmune lymphoproliferative syndrome (ALPS) is a genetic disorder of lymphocyte homeostasis,1 in which impaired CD95-mediated apoptosis has been identified as the main pathogenic factor. An increase in the percentage of circulating TCRa/b1CD31 T cells expressing neither CD4 nor CD8 (double negative or DNT cells), hypergammaglobulinemia, elevated serum interleukin-10 (IL-10) and mutations in one of the genes of the CD95L-CD95 pathway may support the diagnosis. The key diagnostic test is, however, the evaluation of T-cell apoptosis on CD95 ligation, which is generally impaired in patients with ALPS. Recently, 6 patients with lymphoproliferation, autoimmunity, and elevated DNT cells, but normal apoptosis and none of the known genetic defects in DNA isolated from peripheral blood mononuclear cells (PBMC) were found to carry somatic mutations in the CD95 gene. The mutations could only be detected in sorted DNT cells.2 Here we describe the long-term clinical evolution of ALPS in another patient with a somatic CD95 mutation and propose a change in the diagnostic approach to patients with suspected ALPS.
T
CASE REPORT The patient is the second child of non-consanguineous parents. Mild splenomegaly was first detected during a hospitalization for pneumonia at age 7 months. The patient subsequently had development of extensive lymphoproliferation and mild cytopenia with antiplatelet antibodies. Lipid metabolism was disturbed (Table). A bone marrow biopsy specimen was normal, and a liver biopsy specimen showed mild portal fibrosis and dense portal lymphocytic infiltrates. A lymph node biopsy specimen revealed reactive lymphadenopathy with T-cell predominance without evidence for monoclonality. No mutations were found in the Apo A1 gene. Immunologic studies at 9 years of age revealed 15% TCRa/b1 DNT cells. Serum IL-10 levels were elevated. There was no increase in Human leukocyte antigen (HLADR) expressing T cells or in CD51 B cells. Sequencing of the CD95 gene from PBMC revealed no mutations. CD95 ligand induced apoptosis in 70% of cultured patient’s Phytohemagglutinin (PHA) blasts, which was comparable to healthy control cells. For the last 2 years there was no change in the degree of cytopenia, hypergammaglobulinemia, and the percentage of DNT cells. By contrast, lipid abnormalities improved in parallel to the
ALPS IL-10 PBMC
Autoimmune lymphoproliferative syndrome Interleukin-10 Peripheral blood mononuclear cells
PCR SPT
Polymerase chain reaction Single positive T
From the Departments of Pediatrics and Adolescent Medicine and Clinical Chemistry, University of Freiburg, Freiburg, Germany, and University Children’s Hospital, University of Ulm, St.Anna-Kinderspital, Vienna, Austria. Submitted for publication Mar 23, 2005; last revision received Jun 22, 2005; accepted Jul 19, 2005. Reprint requests: Stephan Ehl, MD, Department of Pediatrics and Adolescent Medicine, University of Freiburg, Mathildenstrasse 1, 79106 Freiburg, Germany. E-mail: [email protected]. 0022-3476/$ - see front matter Copyright ª 2005 Elsevier Inc. All rights reserved. 10.1016/j.jpeds.2005.07.027
691
Table. Evolution of the clinical and immunologic phenotype
Hepatomegaly Splenomegaly Lymphadenopathy Hemoglobin (g/dl) Leukocytes (31000/ml) Thrombocytes (31000/ml) IgG (mg/dl) IL-10 (pg/ml) Triglyceride (mg/dl) HDL-Chol (mg/dl) Apo A1 (mg/dl) a-Lipoprotein (%)
7 mo
14 mo
5y
8y
11 y
Normal
2 1 2 10.5 8.1 280 n.d. n.d. n.d. n.d. n.d. n.d.
11 111 11 9.6 5.4 96 1570 n.d. 204 n.d. n.d. n.d.
11 111 1 9.6 3.9 105 1650 n.d. 289 15 56 6
1 111 1 11 2.3 72 1640 n.d. 136 13 67 12
2 11 2 9.6 3.3 93 1530 152 95 25 87 22
2 2 2 11 to 15 5 to 14 100-436 -1530 -10 30-150 45-90 100-180 45-100
Figure 1. Identification of CD95 mutation in sorted doublenegative T cells. A, Direct sequencing revealed a single nucleotide deletion in DNA extracted from TCRa/b1 DNT cells, but not from SPT cells or unsorted PBMC. Available in color online at www. jpeds.com. B, TCR Vb chain repertoire of TCR a/b1 DNT and SPT cells.
692
Ro¨ssler et al
regressing lymphoproliferation with decreasing size of lymph nodes, spleen, and liver (Table). The recent report on ALPS associated with somatic CD95 mutations2 prompted us to look for mutations in sorted double-negative T cells. Genomic DNA was extracted from DNT or CD4 or CD8 single positive T (SPT) cells purified using a MoFlo (Dako Cytomation Hamburg, Germany) high-speed cell sorter. A pre-amplification step with the GenomiPhi DNA Amplification Kit (AmershamBiosciences Little Chalfont, UK) was performed before polymerase chain reaction (PCR)–amplification. Exon-specific DNA primers were designed according to the published GenBank sequence NT_030059 (available upon request). Cycle-sequencing was performed directly on purified PCR products (MinElute PCR Purification-Kit; Qiagen Hilden, Germany) with the use of the Big Dye DNA Sequencing Kit (Perkin–Elmer Wellesley, MA) and the ABIPRISM 310 genetic analyzer automated sequencing system (Applied Biosystems Darmstadt, Germany). For verification of the mutation found in DNT cells, we repeated PCR and sequencing of the appropriate exon starting from unamplified genomic DNA. The patient had a hitherto undescribed deletion of an A nucleotide in exon 8 (999-1001 delA; NM_000043) (Figure 1, A). This leads to a premature stop codon at position 206 in the intracellular death domain [fs Glu202, stop 206] of the processed mature peptide, because the amino-terminal 16 amino acid signal peptide is cleaved and absent from the mature CD95.3 Because direct sequencing only allows us to detect mutations carried by more than 20% of the cells,2 we assume that more than 20% of DNT cells and less than 20% of SPT cells harbored the mutant allele. We compared expression of 7 commonly used TCR Vb chains between DNT and SPT cells and found a polyclonal repertoire in both populations (Figure 1, B), excluding expansion of a mutated clone. To test the functional consequences of the mutation in DNT cells, several attempts were made to culture sorted or enriched DNT cells for subsequent determination of CD95mediated apoptosis. However, as previously described by The Journal of Pediatrics November 2005
Figure 2. Suggested algorithm for differential diagnosis of ALPS. *Supporting clinical evidence may include: (i) elevated IgG and IgA, low IgM; (ii) elevated CD51 B cells, increased HLA-DR expression on CD31 T cells, (iii) reduced CD271 memory B cells; (iv) elevated serum IL-10; (v) elevated triglycerides, low HDL cholesterol, low APO A1.
Holzeva et al,2 DNT cells did not survive the stimulation culture.
DISCUSSION The genetic basis of ALPS includes homozygous (Type 0) or heterozygous (Type Ia) mutations in the CD95 receptor, its ligand (Type Ib), or in caspase 10, which is required for CD95-mediated signal transduction (Type IIa).4 Children with deficiency in caspase 8 (Type IIb) present with combined immunodeficiency rather than a phenotype of immune dysregulation. Patients with impaired CD95-mediated apoptosis but unknown genetic defect are classified as Type III. The key diagnostic feature for all these forms of ALPS (except for the rare type Ib) is an impaired in vitro apoptosis of lymphocytes in response to CD95 ligation. However, the recent identification of somatic CD95 mutations in 6 patients with clinical features of ALPS, but normal apoptosis and lack of mutations in DNA from PBMC (type Im, for mosaic)2 indicates the need for a change in the diagnostic approach to this disease. In an attempt to identify clinical parameters that may help to distinguish patients with somatic from those with Identical Phenotype In Patients With Somatic And Germline CD95 Mutations Requires A New Diagnostic Approach To Autoimmune Lymphoproliferative Syndrome
germline CD95 mutations, we analyzed the 10-year medical history of a new patient with ALPS type Im. Pronounced lymphoproliferation occurred within the first year of life and partially regressed over time similar to what has been described in patients with classical ALPS.5 Histopathologic changes resembled previous reports.6 Cytopenia is the major manifestation of autoimmunity in ALPS and changed little over time as previously described in ALPS type I.5 The typical immunologic features of the disease including the elevated percentage of DNT cells, hypergammaglobulinemia,1 and elevated IL-10 levels7 were present and did not change during the 10 years of follow-up, again in accordance with ALPS type I. Other changes reported in some patients with ALPS8 such as increased HLA-DR expression, elevated g/d T cells and increased CD51 B cells were not present. A recent report has documented striking abnormalities in lipid metabolism in 3 patients with ALPS type Ia and 2 patients with ALPS type III.9 The same pattern of dyslipidemia was observed in our patient. If confirmed in a larger cohort of patients with ALPS, dyslipidemia could add to the differential diagnosis of ALPS. Interestingly, the lipid changes ameliorated in parallel with the partial regression of the lymphoproliferation. 693
Lack of T-cell apoptosis after CD95 ligation can no longer be considered the gold standard for diagnosis of ALPS.2 The strong resemblance of clinical and laboratory findings and the similar long-term evolution of the disease demonstrated in our patient shows that ALPS type Im cannot be differentiated from other forms of ALPS on the basis of the clinical presentation. Therefore, if there is a high clinical suspicion, diagnostic efforts must include sequencing of CD95 in DNA obtained from sorted TCRa/b1 DNT cells. On the basis of these considerations, we propose a new diagnostic algorithm that may serve as a preliminary orientation for clinicians involved in the evaluation of patients with ALPS (Figure 2). It should be noted, however, that validation of this proposal awaits systematic prospective evaluation in a sufficient number of patients.
REFERENCES 1. Sneller MC, Wang J, Dale JK, Strober W, Middelton LA, Choi Y, et al. Clinical, immunologic, and genetic features of an autoimmune lymphoproliferative syndrome associated with abnormal lymphocyte apoptosis. Blood 1997;89:1341-8.
694
Ro¨ssler et al
2. Holzelova E, Vonarbourg C, Stolzenberg MC, Arkwright PD, Selz F, Prieur AM, et al. Autoimmune lymphoproliferative syndrome with somatic Fas mutations. N Engl J Med 2004;351:1409-18. 3. Itoh N, Yonehara S, Ishii A. The polypeptide encoded by the cDNA for human cell surface antigen Fas can mediate apoptosis. Cell 1991;66: 233-43. 4. Rieux-Laucat F, Fischer A, Deist FL. Cell-death signaling and human disease. Curr Opin Immunol 2003;15:325-31. 5. Rieux-Laucat F, Blachere S, Danielan S, De Villartay JP, Oleastro M, Solary E, et al. Lymphoproliferative syndrome with autoimmunity: a possible genetic basis for dominant expression of the clinical manifestations. Blood 1999;94:2575-82. 6. Lim MS, Straus SE, Dale JK, Fleisher TA, Stetler-Stevenson M, Strober W, et al. Pathological findings in human autoimmune lymphoproliferative syndrome. Am J Pathol 1998;153:1541-50. 7. Lopatin U, Yao X, Williams RK, Bleesing JJ, Dale JK, Wong D, et al. Increases in circulating and lymphoid tissue interleukin-10 in autoimmune lymphoproliferative syndrome are associated with disease expression. Blood 2001;97:3161-70. 8. Bleesing JJ, Brown MR, Straus SE, Dale JK, Siegel RM, Johnson M, et al. Immunophenotypic profiles in families with autoimmune lymphoproliferative syndrome. Blood 2001;98:2466-73. 9. Alvarado CS, Straus SE, Li S, Dale JK, Mann K, Le A, et al. Autoimmune lymphoproliferative syndrome: a cause of chronic splenomegaly, lymphadenopathy, and cytopenias in children-report on diagnosis and management of five patients. Pediatr Blood Cancer 2004;43:164-9.
The Journal of Pediatrics November 2005
IDENTICAL PHENOTYPE IN PATIENTS WITH SOMATIC AND GERMLINE CD95 MUTATIONS REQUIRES A NEW DIAGNOSTIC APPROACH TO AUTOIMMUNE LYMPHOPROLIFERATIVE SYNDROME JOCHEN RO¨SSLER, MD, ANSELM ENDERS, MD, GEORGIA LAHR, PHD, ANDREAS HEITGER, MD, KARL WINKLER, MD, HANS FUCHS, MD, MATTHIAS KOPP, MD, CHARLOTTE NIEMEYER, MD, AND STEPHAN EHL, MD
In a patient with a somatic mutation in the CD95 gene, the long-term evolution of the clinical phenotype was indistinguishable from that of patients with autoimmune lymphoproliferative syndrome caused by germline CD95 mutations. A new diagnostic algorithm for autoimmune lymphoproliferative syndrome is suggested incorporating studies on sorted TCRa/b+CD3+CD82 CD42 T cells. (J Pediatr 2005;147:691-4)
he wide differential diagnosis of lymphoproliferative disease with autoimmunity includes malignant, infectious, and immunologic diseases. Autoimmune lymphoproliferative syndrome (ALPS) is a genetic disorder of lymphocyte homeostasis,1 in which impaired CD95-mediated apoptosis has been identified as the main pathogenic factor. An increase in the percentage of circulating TCRa/b1CD31 T cells expressing neither CD4 nor CD8 (double negative or DNT cells), hypergammaglobulinemia, elevated serum interleukin-10 (IL-10) and mutations in one of the genes of the CD95L-CD95 pathway may support the diagnosis. The key diagnostic test is, however, the evaluation of T-cell apoptosis on CD95 ligation, which is generally impaired in patients with ALPS. Recently, 6 patients with lymphoproliferation, autoimmunity, and elevated DNT cells, but normal apoptosis and none of the known genetic defects in DNA isolated from peripheral blood mononuclear cells (PBMC) were found to carry somatic mutations in the CD95 gene. The mutations could only be detected in sorted DNT cells.2 Here we describe the long-term clinical evolution of ALPS in another patient with a somatic CD95 mutation and propose a change in the diagnostic approach to patients with suspected ALPS.
T
CASE REPORT The patient is the second child of non-consanguineous parents. Mild splenomegaly was first detected during a hospitalization for pneumonia at age 7 months. The patient subsequently had development of extensive lymphoproliferation and mild cytopenia with antiplatelet antibodies. Lipid metabolism was disturbed (Table). A bone marrow biopsy specimen was normal, and a liver biopsy specimen showed mild portal fibrosis and dense portal lymphocytic infiltrates. A lymph node biopsy specimen revealed reactive lymphadenopathy with T-cell predominance without evidence for monoclonality. No mutations were found in the Apo A1 gene. Immunologic studies at 9 years of age revealed 15% TCRa/b1 DNT cells. Serum IL-10 levels were elevated. There was no increase in Human leukocyte antigen (HLADR) expressing T cells or in CD51 B cells. Sequencing of the CD95 gene from PBMC revealed no mutations. CD95 ligand induced apoptosis in 70% of cultured patient’s Phytohemagglutinin (PHA) blasts, which was comparable to healthy control cells. For the last 2 years there was no change in the degree of cytopenia, hypergammaglobulinemia, and the percentage of DNT cells. By contrast, lipid abnormalities improved in parallel to the
ALPS IL-10 PBMC
Autoimmune lymphoproliferative syndrome Interleukin-10 Peripheral blood mononuclear cells
PCR SPT
Polymerase chain reaction Single positive T
From the Departments of Pediatrics and Adolescent Medicine and Clinical Chemistry, University of Freiburg, Freiburg, Germany, and University Children’s Hospital, University of Ulm, St.Anna-Kinderspital, Vienna, Austria. Submitted for publication Mar 23, 2005; last revision received Jun 22, 2005; accepted Jul 19, 2005. Reprint requests: Stephan Ehl, MD, Department of Pediatrics and Adolescent Medicine, University of Freiburg, Mathildenstrasse 1, 79106 Freiburg, Germany. E-mail: [email protected]. 0022-3476/$ - see front matter Copyright ª 2005 Elsevier Inc. All rights reserved. 10.1016/j.jpeds.2005.07.027
691
Table. Evolution of the clinical and immunologic phenotype
Hepatomegaly Splenomegaly Lymphadenopathy Hemoglobin (g/dl) Leukocytes (31000/ml) Thrombocytes (31000/ml) IgG (mg/dl) IL-10 (pg/ml) Triglyceride (mg/dl) HDL-Chol (mg/dl) Apo A1 (mg/dl) a-Lipoprotein (%)
7 mo
14 mo
5y
8y
11 y
Normal
2 1 2 10.5 8.1 280 n.d. n.d. n.d. n.d. n.d. n.d.
11 111 11 9.6 5.4 96 1570 n.d. 204 n.d. n.d. n.d.
11 111 1 9.6 3.9 105 1650 n.d. 289 15 56 6
1 111 1 11 2.3 72 1640 n.d. 136 13 67 12
2 11 2 9.6 3.3 93 1530 152 95 25 87 22
2 2 2 11 to 15 5 to 14 100-436 -1530 -10 30-150 45-90 100-180 45-100
Figure 1. Identification of CD95 mutation in sorted doublenegative T cells. A, Direct sequencing revealed a single nucleotide deletion in DNA extracted from TCRa/b1 DNT cells, but not from SPT cells or unsorted PBMC. Available in color online at www. jpeds.com. B, TCR Vb chain repertoire of TCR a/b1 DNT and SPT cells.
692
Ro¨ssler et al
regressing lymphoproliferation with decreasing size of lymph nodes, spleen, and liver (Table). The recent report on ALPS associated with somatic CD95 mutations2 prompted us to look for mutations in sorted double-negative T cells. Genomic DNA was extracted from DNT or CD4 or CD8 single positive T (SPT) cells purified using a MoFlo (Dako Cytomation Hamburg, Germany) high-speed cell sorter. A pre-amplification step with the GenomiPhi DNA Amplification Kit (AmershamBiosciences Little Chalfont, UK) was performed before polymerase chain reaction (PCR)–amplification. Exon-specific DNA primers were designed according to the published GenBank sequence NT_030059 (available upon request). Cycle-sequencing was performed directly on purified PCR products (MinElute PCR Purification-Kit; Qiagen Hilden, Germany) with the use of the Big Dye DNA Sequencing Kit (Perkin–Elmer Wellesley, MA) and the ABIPRISM 310 genetic analyzer automated sequencing system (Applied Biosystems Darmstadt, Germany). For verification of the mutation found in DNT cells, we repeated PCR and sequencing of the appropriate exon starting from unamplified genomic DNA. The patient had a hitherto undescribed deletion of an A nucleotide in exon 8 (999-1001 delA; NM_000043) (Figure 1, A). This leads to a premature stop codon at position 206 in the intracellular death domain [fs Glu202, stop 206] of the processed mature peptide, because the amino-terminal 16 amino acid signal peptide is cleaved and absent from the mature CD95.3 Because direct sequencing only allows us to detect mutations carried by more than 20% of the cells,2 we assume that more than 20% of DNT cells and less than 20% of SPT cells harbored the mutant allele. We compared expression of 7 commonly used TCR Vb chains between DNT and SPT cells and found a polyclonal repertoire in both populations (Figure 1, B), excluding expansion of a mutated clone. To test the functional consequences of the mutation in DNT cells, several attempts were made to culture sorted or enriched DNT cells for subsequent determination of CD95mediated apoptosis. However, as previously described by The Journal of Pediatrics November 2005
Figure 2. Suggested algorithm for differential diagnosis of ALPS. *Supporting clinical evidence may include: (i) elevated IgG and IgA, low IgM; (ii) elevated CD51 B cells, increased HLA-DR expression on CD31 T cells, (iii) reduced CD271 memory B cells; (iv) elevated serum IL-10; (v) elevated triglycerides, low HDL cholesterol, low APO A1.
Holzeva et al,2 DNT cells did not survive the stimulation culture.
DISCUSSION The genetic basis of ALPS includes homozygous (Type 0) or heterozygous (Type Ia) mutations in the CD95 receptor, its ligand (Type Ib), or in caspase 10, which is required for CD95-mediated signal transduction (Type IIa).4 Children with deficiency in caspase 8 (Type IIb) present with combined immunodeficiency rather than a phenotype of immune dysregulation. Patients with impaired CD95-mediated apoptosis but unknown genetic defect are classified as Type III. The key diagnostic feature for all these forms of ALPS (except for the rare type Ib) is an impaired in vitro apoptosis of lymphocytes in response to CD95 ligation. However, the recent identification of somatic CD95 mutations in 6 patients with clinical features of ALPS, but normal apoptosis and lack of mutations in DNA from PBMC (type Im, for mosaic)2 indicates the need for a change in the diagnostic approach to this disease. In an attempt to identify clinical parameters that may help to distinguish patients with somatic from those with Identical Phenotype In Patients With Somatic And Germline CD95 Mutations Requires A New Diagnostic Approach To Autoimmune Lymphoproliferative Syndrome
germline CD95 mutations, we analyzed the 10-year medical history of a new patient with ALPS type Im. Pronounced lymphoproliferation occurred within the first year of life and partially regressed over time similar to what has been described in patients with classical ALPS.5 Histopathologic changes resembled previous reports.6 Cytopenia is the major manifestation of autoimmunity in ALPS and changed little over time as previously described in ALPS type I.5 The typical immunologic features of the disease including the elevated percentage of DNT cells, hypergammaglobulinemia,1 and elevated IL-10 levels7 were present and did not change during the 10 years of follow-up, again in accordance with ALPS type I. Other changes reported in some patients with ALPS8 such as increased HLA-DR expression, elevated g/d T cells and increased CD51 B cells were not present. A recent report has documented striking abnormalities in lipid metabolism in 3 patients with ALPS type Ia and 2 patients with ALPS type III.9 The same pattern of dyslipidemia was observed in our patient. If confirmed in a larger cohort of patients with ALPS, dyslipidemia could add to the differential diagnosis of ALPS. Interestingly, the lipid changes ameliorated in parallel with the partial regression of the lymphoproliferation. 693
Lack of T-cell apoptosis after CD95 ligation can no longer be considered the gold standard for diagnosis of ALPS.2 The strong resemblance of clinical and laboratory findings and the similar long-term evolution of the disease demonstrated in our patient shows that ALPS type Im cannot be differentiated from other forms of ALPS on the basis of the clinical presentation. Therefore, if there is a high clinical suspicion, diagnostic efforts must include sequencing of CD95 in DNA obtained from sorted TCRa/b1 DNT cells. On the basis of these considerations, we propose a new diagnostic algorithm that may serve as a preliminary orientation for clinicians involved in the evaluation of patients with ALPS (Figure 2). It should be noted, however, that validation of this proposal awaits systematic prospective evaluation in a sufficient number of patients.
REFERENCES 1. Sneller MC, Wang J, Dale JK, Strober W, Middelton LA, Choi Y, et al. Clinical, immunologic, and genetic features of an autoimmune lymphoproliferative syndrome associated with abnormal lymphocyte apoptosis. Blood 1997;89:1341-8.
694
Ro¨ssler et al
2. Holzelova E, Vonarbourg C, Stolzenberg MC, Arkwright PD, Selz F, Prieur AM, et al. Autoimmune lymphoproliferative syndrome with somatic Fas mutations. N Engl J Med 2004;351:1409-18. 3. Itoh N, Yonehara S, Ishii A. The polypeptide encoded by the cDNA for human cell surface antigen Fas can mediate apoptosis. Cell 1991;66: 233-43. 4. Rieux-Laucat F, Fischer A, Deist FL. Cell-death signaling and human disease. Curr Opin Immunol 2003;15:325-31. 5. Rieux-Laucat F, Blachere S, Danielan S, De Villartay JP, Oleastro M, Solary E, et al. Lymphoproliferative syndrome with autoimmunity: a possible genetic basis for dominant expression of the clinical manifestations. Blood 1999;94:2575-82. 6. Lim MS, Straus SE, Dale JK, Fleisher TA, Stetler-Stevenson M, Strober W, et al. Pathological findings in human autoimmune lymphoproliferative syndrome. Am J Pathol 1998;153:1541-50. 7. Lopatin U, Yao X, Williams RK, Bleesing JJ, Dale JK, Wong D, et al. Increases in circulating and lymphoid tissue interleukin-10 in autoimmune lymphoproliferative syndrome are associated with disease expression. Blood 2001;97:3161-70. 8. Bleesing JJ, Brown MR, Straus SE, Dale JK, Siegel RM, Johnson M, et al. Immunophenotypic profiles in families with autoimmune lymphoproliferative syndrome. Blood 2001;98:2466-73. 9. Alvarado CS, Straus SE, Li S, Dale JK, Mann K, Le A, et al. Autoimmune lymphoproliferative syndrome: a cause of chronic splenomegaly, lymphadenopathy, and cytopenias in children-report on diagnosis and management of five patients. Pediatr Blood Cancer 2004;43:164-9.
The Journal of Pediatrics November 2005