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Background: Although serum levels of squamous cell carcinoma antigen (SCCA) are elevated in atopic dermatitis (AD), their clinical utility has not been fully elucidated. Methods: Thirty-three cases of AD who admitted to our hospital were analyzed. Results: Baseline characteristics on admission were as follows: median age 19 months [interquartile range (IQR), 12–52 months], median objective severity scoring of atopic dermatitis (O-SCORAD) 19.2 (IQR, 4.2–36.0), and median serum SCCA levels 3.2 ng/mL (IQR, 2.1–6.8 ng/mL). O-SCORAD significantly correlated with serum SCCA levels (rs = 0.865, P

We report a 10-year-old boy with immunoglobulin (Ig)A vasculitis (IgAV) with prolonged cutaneous manifestations who was successfully treated with colchicine. At the age of 9 years, he was diagnosed as having IgAV by typical purpura, abdominal pain, and haematochezia. Initially, his severe gastrointestinal manifestation subsided by prednisolone 60 mg/day and intravenous methylprednisolone pulse therapy. However, his gastrointestinal manifestation was glucocorticoid-dependent and refractory to factor XIII concentrate, intravenous IgG, and mycophenolate mofetil. His abdominal pain and haematochezia responded to the combination therapy with dapsone and low dose of prednisolone 5 mg/day and did not relapse even after discontinuation of dapsone. On the other hand, the effect of dapsone on his cutaneous manifestation was dose-dependent as well as dapsone had no glucocorticoid-sparing effect. Approximately 12 months after onset, colchicine treatment was started, which resulted in remission of his chronic cutaneous manifestation. After prednisolone was tapered off, his cutaneous manifestation is currently well-controlled on colchicine 0.5 mg/day without adverse events. He had never complicated kidney involvements. In conclusion, it is observed that colchicine treatment exerts a beneficial effect in IgAV patients with prolonged cutaneous manifestation refractory to multiple drugs.

We report a Japanese boy with Graves’ disease (GD) which developed during drug-free remission of juvenile dermatomyositis (JDM). He had been diagnosed with JDM at the age of 6 years by typical skin rashes, muscle weakness, elevated serum transaminase levels, and typical findings of both magnetic resonance imaging and muscle biopsy. Although anti-melanoma differentiation antigen 5 autoantibody was positive, there was no complication of interstitial lung disease. He showed good response to methylprednisolone pulse therapy followed by oral prednisolone in combination with weekly methotrexate (MTX) and achieved drug-free remission after 3.5 years of treatment. Nevertheless, serum levels of soluble interleukin-2 receptor (sIL-2R) gradually elevated to 3185 U/ml despite no signs of relapse or malignancy. Hyperactivity and attention deficit was also noted. One year and 3 months after the cessation of MTX, he presented with abdominal pain, tachycardia, and apparent goitre. Laboratory tests showed elevated free triiodothyronine, undetectable thyroid stimulating hormone (TSH), and positive anti-TSH receptor antibodies. 99mTc scintigraphy showed high levels of thyroid uptake. He was diagnosed with GD and treated with 15 mg/day of thiamazole. Although transient drug eruption was observed, his thyroid functions are currently well-controlled on 5 mg/day of thiamazole. In conclusion, to our knowledge, this is the first report in English literature describing complication of GD with JDM. Unexpected elevation of sIL-2R could be a clue to the diagnosis of GD during the follow-up of JDM.

Intravenous immunoglobulin (IVIG) is a standard therapy for Kawasaki disease (KD), because it prevents formation of coronary artery aneurysm, a major complication of KD. Herein, we report a 3-year-old boy with KD complicated by haemolytic anaemia (HA) which developed following two courses of IVIG. Although both direct and indirect antiglobulin tests and anti-M antibodies were positive in his blood obtained after the onset of HA, indirect antiglobulin tests and anti-M antibodies were negative either in the blood sample before the treatment or the same lot of IVIG products as those used for the therapy, suggesting autoimmune mechanism. This is, to our knowledge, the first report of autoimmune HA caused by anti-M autoantibodies after IVIG therapy in KD.

Juvenile idiopathic arthritis (JIA) is the most common disease in pediatric rheumatism. There is no specific symptom or examination finding for JIA, and the diagnosis is made by exclusion and differentiation. Because non-pediatric rheumatologists are sometimes involved in medical care, 'proposal for JIA guidance on diagnosis and treatment for primary care pediatricians and non-pediatric rheumatologists' was first published in 2007. In these 10 years, a number of new findings on pathophysiology and treatment of JIA have been published; therefore, we propose this guidance of 2018th edition aiming at updating and standardization of JIA medical care in Japan. This edition included the management of uveitis, macrophage activation syndrome, infectious diseases before and during treatment. Moreover, details of biologics are also described. Although this guidance is tailored to adaptation of examinations and drugs, we do not purpose to limit the physicians' discretion in clinical practice. This guidance should be viewed as recommendations and be individualized according to the condition of the patient. We hope that medical care for JIA will advance and more patients will get benefit based on this guidance. Then, further revisions are needed due to changes in future conditions.

Objective To validate whether the 2016 American College of Rheumatology/European League Against Rheumatism classification criteria of macrophage activation syndrome (MAS) complicating systemic juvenile idiopathic arthritis (JIA) is practical in the real world. Methods A combination of expert consensus and analysis of real patient data was conducted by a panel of 15 pediatric rheumatologists. A total of 65 profiles comprised 18 patients with systemic JIA-associated MAS and 47 patients with active systemic JIA without evidence of MAS. From these profiles, 10 patient data points for full-blown MAS, 11 patient data points for MAS onset, and 47 patient data points for acute systemic JIA without MAS were evaluated. Results Evaluation of the classification criteria to discriminate full-blown MAS from acute systemic JIA without MAS showed a sensitivity of 1.000 and specificity of 1.000 at the time of full-blown MAS. Sensitivity was 0.636 and specificity was 1.000 at the time of MAS onset. The number of measurement items that fulfilled the criteria increased in full-blown MAS compared to that at MAS onset. At MAS onset, the positive rates of patients who met the criteria for platelet counts and triglycerides were low, whereas those for aspartate aminotransferase were relatively high. At full-blown MAS, the number of patients who met the criteria for each measurement item increased. Conclusion The classification criteria for MAS complicating systemic JIA had a very high diagnostic performance. However, the diagnostic sensitivity for MAS onset was relatively low. For the early diagnosis of MAS in systemic JIA, the dynamics of laboratory values during the course of MAS should be further investigated.

The purpose of this study is to evaluate systemic disease activity of pediatric Sjögren's syndrome (SS) using European League Against Rheumatism (EULAR) Sjögren's syndrome disease activity index (ESSDAI).We retrospectively reviewed medical records of patients with SS who have been diagnosed according to 1999 Japanese diagnostic criteria for SS before 16 years old at KKR Sapporo Medical Center, Hokkaido University Hospital, and affiliated hospitals. We analyzed clinical and laboratory data and calculated ESSDAI at both diagnosis and peak activity.Twenty-five patients (2 boys and 23 girls) were enrolled. Only 4 patients had sicca symptoms at diagnosis. Mean ESSDAI scores at diagnosis and peak activity were 12.68 (2-31) and 15.08 (2-38), respectively. Only 3 patients were inactive (ESSDAI score 5) at diagnosis. Frequently involved domains at diagnosis were the biological (96%) followed by the constitutional (68%), glandular (44%), articular (44%), cutaneous domains (28%), renal (16%), and central nervous system (12%). At peak activity, biological domain (96%) was followed by the constitutional (72%), glandular (60%), articular (44%), cutaneous (28%), central nervous system (20%), and renal domains (16%).Pediatric SS is suspected from active systemic manifestations. The items of ESSDAI are useful clues to the diagnosis of pediatric SS.

Background This study aimed to determine the influence of tocilizumab (TCZ) in modifying the clinical and laboratory features of macrophage activation syndrome (MAS) complicating systemic juvenile idiopathic arthritis (s-JIA). Furthermore, we assessed the performance of the 2016 MAS classification criteria for patients with s-JIA-associated MAS while treated with TCZ. Methods A panel of 15 pediatric rheumatologists conducted a combination of expert consensus and analysis of real patient data. Clinical and laboratory features of s-JIA-associated MAS in 12 TCZ-treated patients and 18 untreated patients were evaluated. Possible MAS was defined as having characteristic laboratory features but lack of clinical features of MAS, or atypical MAS, or early treatment that prevented full-blown MAS. Results Clinically, the TCZ-treated patients with s-JIA-associated MAS were less likely febrile and had significantly lower ferritin, triglyceride, and CRP levels than the untreated patients with s-JIA-associated MAS. Other laboratory features of MAS including lower platelet counts and lower fibrinogen were more pronounced in TCZ-treated patients. The TCZ-treated patients with s-JIA-associated MAS were less likely to be classified as MAS based on the MAS classification criteria (25% vs 83.3%, p Conclusion TCZ could modify the clinical and laboratory features of s-JIA-associated MAS. When evaluating the s-JIA patients while treated with TCZ, it is not applicable to use MAS classification criteria. Care must be taken to not underdiagnose MAS based on the MAS classification criteria.

Background Previous studies including a systematic literature review revealed clinical manifestations and laboratory features of systemic juvenile idiopathic arthritis (s-JIA) associated macrophage activation syndrome (MAS) could be modified in patients treated with tocilizumab (TCZ) 1,2. Objectives To clarify whether TCZ modifies clinical manifestations and laboratory features of s-JIA associated MAS, and to assess performance of the 2016 MAS classification criteria for patients with s-JIA associated MAS while treated with TCZ in the real world. Methods A combination of expert consensus and analysis of real patient data was conducted by a panel of 15 pediatric rheumatologists. Clinical manifestations and laboratory features of s-JIA associated MAS at the MAS diagnosis in 12 patients while treated with TCZ and 18 patients not treated with TCZ were evaluated. Possible MAS was defined as having characteristic laboratory features but lack of clinical features of MAS, or atypical MAS, or early treatment that prevented fulminant MAS 3,4. Results Among 12 patients while treated with TCZ, only 2 patients were diagnosed with definite MAS, and other 10 patients were diagnosed with possible MAS. On the other hand, among 18 patients not treated with TCZ, 10 patients were diagnosed with definite MAS, and other 8 patients were diagnosed with possible MAS. MAS classification criteria could classify the patients diagnosed with definite MAS while treated with TCZ as having MAS as well as the patients not treated with TCZ (100% and 100%, respectively). However, this criteria were less likely to classify the patients diagnosed with possible MAS while treated with TCZ as well as the patients not treated with TCZ (60% and 75%, respectively). Furthermore, the patients with possible MAS while treated with TCZ were less likely febrile and significantly less often had rash, and had notably lower ferritin levels (587 versus 8518 ng/ml; P=0.0021), compared to the patients with possible MAS not treated with TCZ. Other laboratory features of MAS including lower platelet counts, lower fibrinogen were more pronounced in patients treated with TCZ. Conclusion These findings show TCZ could modify clinical manifestations and laboratory features of s-JIA associated MAS. When evaluating s-JIA patients while treated with TCZ, care must be taken to not underdiagnose MAS based on MAS classification criteria. References [1] Shimizu M, et al. Cytokine 2012;58:287-294. [2] Sculert GS, et al. Arthritis Care Res 2018;70:409-419 [3] Grom AA, et al. Arthritis Rheumatol 2016;68:218-228. [4] Yokota S, et al. J Rheumatol 2015;42:712-722. Disclosure of Interests Masaki Shimizu: None declared, Mao Mizuta: None declared, Takahiro Yasumi Shareholder of: Takeda, Speakers bureau: AbbVie, Novartis, CSL Behring, Naomi Iwata: None declared, Yuka Okura: None declared, Noriko Kinjo: None declared, Hiroaki Umebayashi Speakers bureau: AbbVie, Eisai, Novartis, Ono, Chugai, Tomohiro Kubota: None declared, Yasuo Nakagishi: None declared, Kenichi Nishimura: None declared, Masato Yashiro: None declared, Junko Yasumura: None declared, Hiroyuki Wakiguchi: None declared, Nami Okamoto: None declared, Masaaki Mori Grant/research support from: Tokyo Medical and Dental University (TMDU) received unrestricted research grants for Department of Lifetime Clinical Immunology from AbbVie GK, Ayumi Pharmaceutical Corporation, Chugai Pharmaceutical Co., Ltd., CSL Behring K.K., Japan Blood Products Organization, Mitsubishi Tanabe Pharma Corporation, Nippon Kayaku Co., Ltd., Ono Pharmaceutical Co., Ltd., Towa Pharmaceutical Co., Ltd., UCB Japan Co. Ltd.

Background Although there are many reports on Juvenile Idiopathic arthritis-associated uveitis (JIA-U) from various countries, especially from Europe and North America, there are few reports from Asia. Our aim was to investigate the epidemiology, characteristics and predictors of JIA-U in Japan. Methods Data were retrospectively collected on 726 patients with JIA from medical records as of April 2016 at 15 medical centers specialized in pediatric rheumatic diseases. Of these, patients with uveitis were further investigated for the specific characteristics of this manifestation. Results The prevalence of uveitis was 6.1% in the 726 JIA patients examined. Incidence of uveitis was significantly higher in patients with an earlier arthritis onset (2.6-vs.-5.8 years, P

The aim of our study is to clarify the association of myositis-specific autoantibodies (MSAs) with clinical and laboratory features in Japanese patients with juvenile idiopathic inflammatory myopathies (JIIMs).We retrospectively analyzed the frequency of MSAs and their association with clinical or laboratory findings in 25 Japanese patients with JIIMs in Hokkaido district.Eighteen of the 25 patients (72%) were positive for MSAs; seven with anti-melanoma differentiation associated gene (MDA) 5 (28%), five with anti-transcriptional intermediary factor (TIF)-1γ (20%), four with anti-MJ/nuclear matrix protein (NXP)-2 (16%), two with anti-Jo-1 (8%), one with anti- HMG-CoA reductase, one with anti-signal recognition peptide (SRP) antibodies (4% each), including co-existence and transition of MSAs in one patient each. Anti-MDA5 antibodies were related to interstitial lung disease (ILD) and arthritis but not to amyopathic juvenile dermatomyositis. Drug-free remission was achieved, once ILD was overcome in this group. Anti-TIF-1γ antibodies were associated with typical rashes and mild myositis. Anti-MJ/NXP2 and anti-SRP antibodies were associated with severe muscle weakness. No patient was complicated with malignancy.Anti-MDA5 antibodies are prevalent and closely associated with ILD in our series compared with other countries. There was no apparent difference in clinical features associated with other MSAs among races.

Chronic granulomatous disease (CGD) is a primary immunodeficiency disease that is characterized by susceptibility to bacterial and fungal infections. Various mutations in CYBB encoding the gp91(phox) subunit of the phagocyte nicotinamide adenine dinucleotide phosphate (NADPH) oxidase impair the respiratory burst of all types of phagocytic cells and result in X-linked CGD (X-CGD). We here sought to evaluate the underlying cause in an attenuated phenotype in an X-CGD patient. The patient is a 31-year-old male who had been diagnosed as having X-CGD based on the absence of nitroblue tetrazolium reduction and the presence of a CYBB mutation at the age of 1 year. He has been in good health after overcoming recurrent bacterial infections in infancy. We investigated genomic DNA analysis of CYBB gene, residual activity of NADPH oxidase, and expression of gp91(phox) in both polymorphonuclear leukocytes (PMNs) and monocytes/macrophages in the present patient. Although his underlying germline mutation, c.1016C > A (p.P339H) in the CYBB gene, was identified in both PMNs and monocytes, the expression and functional activity of gp91(phox) retained in monocytes/macrophages, in stark contrast to markedly reduced PMNs. Our results indicate that residual reactive oxygen intermediates (ROI) production in PMNs plays an important role in infantile stage in X-CGD, but thereafter retained function of monocytes/macrophages might compensate for the function of NADPH oxidase deficient PMNs and might be an important parameter for predicting the prognosis of X-CGD patients.

We report a 19-year-old patient with systemic-onset juvenile idiopathic arthritis (JIA) who developed a mediastinal germinoma during treatment with infliximab. Although the cancer risk of infliximab is controversial, this agent may have accelerated the growth of the germinoma. We conclude that the indications for tumor necrosis factor (TNF) inhibitors should be strictly decided and that a nationwide cohort study is necessary to assess the risk of cancer in patients with JIA exposed to biologics.

Chronic granulomatous disease (CGD) is a primary immunodeficiency disease characterized by recurrent life-threatening bacterial and fungal infections with granuloma formation. Species of the genus Fusarium are opportunistic environmental microorganisms that are rarely pathogenic in humans. We report here the first case of X-linked CGD complicated with epidural abscess caused by Fusarium falciforme infection. The abscesses extended along the dura mater for >7 years and finally resulted in fatal meningitis and cervical myelitis. Early intervention with hematopoietic stem cell transplantation should be considered, especially in patients with severe CGD, before the development of serious infectious complication.

Mixed connective tissue disease (MCTD) is rare in pediatric rheumatic diseases. Pulmonary arterial hypertension (PAH) associated with MCTD usually progresses gradually and is difficult to note at the asymptomatic phase. We report a 11-year-old girl with MCTD complicated with rapidly progressive PAH. Although PAH was not detected by echocardiogram or chest CT scan at the initial examination, it became clear in 1 year and suddenly came to cardiac arrest during an invasive procedure. She was successfully treated with extracorporeal assist and both vasodilative and immunosuppressive medication. A combination of echocardiogram and plasma BNP levels could be a useful marker for the follow-up of such cases. PAH could develop early in the course of pediatric MCTD and needs attention to unexpected acute exacerbation, especially under emotional stress.

Objective We here describe treatment outcomes in two adenosine deaminase (ADA)-deficiency patients (pt) who received stem cell gene therapy (SCGT) with no cytoreductive conditioning. As this protocol has features distinct from those of other clinical trials, its results provide insights into SCGT for ADA deficiency. Patients and Methods Pt 1 was treated at age 4.7 years, whereas pt 2, who had previously received T-cell gene therapy, was treated at age 13 years. Bone marrow CD34(+) cells were harvested after enzyme replacement therapy (ERT) was withdrawn; following transduction of ADA cDNA by the gamma-retroviral vector GCsapM-ADA, they were administered intravenously. No cytoreductive conditioning, at present considered critical for therapeutic benefit, was given before cell infusion. Hematological/immunological reconstitution kinetics, levels of systemic detoxification, gene-marking levels, and proviral insertion sites in hematopoietic cells were assessed. Results Treatment was well tolerated, and no serious adverse events were observed. Engraftment of gene-modified repopulating cells was evidenced by the appearance and maintenance of peripheral lymphocytes expressing functional ADA. Systemic detoxification was moderately achieved, allowing temporary discontinuation of ERT for 6 and 10 years in pt 1 and pt 2, respectively. Recovery of immunity remained partial, with lymphocyte counts in pts 1 and 2, peaked at 408/mm(3) and 1248/mm(3), approximately 2 and 5 years after SCGT. Vector integration site analyses confirmed that hematopoiesis was reconstituted with a limited number of clones, some of which were shown to have myelo-lymphoid potential. Conclusions Outcomes in SCGT for ADA-SCID are described in the context of a unique protocol, which used neither ERT nor cytoreductive conditioning. Although proven safe, immune reconstitution was partial and temporary. Our results reiterate the importance of cytoreductive conditioning to ensure greater benefits from SCGT.

X-linked chronic granulomatous disease (X-CGD) is a primary immunodeficiency disease of phagocytes caused by mutations in the cytochrome b(558)β (CYBB) gene. We, for the first time, detected somatic mosaicism in two unrelated male patients with X-CGD caused by de novo nonsense mutations (p.Gly223X and p.Glu462X) in the CYBB gene. In each patient, a small subset of granulocytes was normal in terms of respiratory burst (ROB) activity, gp91(phox) expression, and CYBB sequences. Cells with wild-type CYBB sequence were also detected in buccal swab specimens and in peripheral blood mononuclear cells. The normal cells were shown to be of the patient origin by fluorescent in situ hybridization analysis of X/Y chromosomes, and by HLA DNA typing. Two possible mechanisms for this somatic mosaicism were considered. The first is that the de novo disease-causing mutations in CYBB occurred at an early multicellular stage of embryogenesis with subsequent expansion of the mutated cells, leaving some unmutated cells surviving. The second possibility is that the de novo mutations occurred in oocytes which was followed by reversion of the mutations in a small subset of cells in early embryogenesis.

The presence of the anti-melanoma differentiation-associated gene 5 antibody was evaluated in 13 patients with juvenile dermatomyositis (JDM). The antibody was positive in 5 of the 6 patients with JDM-associated interstitial lung disease (ILD), but not in the 7 patients without ILD. This antibody is a useful marker for early diagnosis of JDM-associated ILD.

X-linked agammaglobulinemia (XLA) is a primary immunodeficiency disease caused by mutations in the gene coding for Bruton's tyrosine kinase (Btk). Most XLA patients have severely reduced or absent peripheral blood B cells and serum immunoglobulins, since the expression or function of Btk, critical for the maturation of B cell lineages at pro-B and pre-B cell stages, is deficient. Early and accurate diagnosis of XLA is important, since the affected patients suffer from severe and recurrent infections unless they receive intravenous immunoglobulin (IVIG) replacement therapy. However, the diagnosis of XLA is not always easy because some patients have detectable ( approximately 2%) B cells in the peripheral blood and have significant levels of serum immunoglobulins. In this study, we report on a patient who was diagnosed with XLA at the age of 10years. The diagnosis was delayed due to near-normal levels of serum immunoglobulins, although he presented with severe and recurrent bacterial infections since the age of 1year. He was demonstrated to have a novel non-invariant splice-site mutation in intron 10 (IVS10 -11C-->A) of the Btk gene, which was not detected by the standard PCR-based mutation analysis. This mutation resulted in no detectable Btk expression. This case suggests that patients suffering from severe or recurrent bacterial infection should be suspected to have XLA even though they may have significant levels of serum immunoglobulins. Furthermore, significant levels of serum immunoglobulins in XLA patients do not necessarily mean less severe phenotype.

Background Dermatomyositis (DM) is an inflammatory disease characterized by weakness in the proximal muscles and pathognomonic skin rash. Although interstitial lung disease (ILD) is a common complication of DM [1] and makes poor prognosis, the etiology of ILD developing in DM (JDM) cases was still unknown. Recent report has demonstrated that serum interleukin (IL)-18 levels are significantly higher in adult patients with DM-associated ILD than those without ILD [2]. On the other hand, complication of ILD is rare and not well characterized in JDM. Objectives To evaluate the clinical significance of serum IL-18 levels and other JDM-associated markers in JDM cases with or without ILD. Methods 13 JDM patients, 5 with ILD (ILD+) and 8 without ILD (ILD-) followed-up at Hokkaido University Hospital from 1990 to 2008 were enrolled. Sex ratio and the age of onset were not significantly different between both groups. The samples were obtained at diagnosis and remission after treatment. Serum IL-18 levels were measured by Human IL-18 ELISA kit (BML, Nagoya, Japan). Serum neopterin, ferritin and soluble (s) IL-2 receptor (R) levels were also measured. Statistical analyses were performed by Mann-Whitney’s U test and Pearson product-moment correlation coefficient. Results Serum IL-18 levels at diagnosis were significantly higher (p Conclusions In JDM-ILD, serum IL-18 levels were significantly high in active phase and decreased with remission, suggesting involvement of innate immunity, particularly of macrophages, in the pathogenesis of ILD. On the other hand, serum levels of neopterin, ferritin and sIL-2R could be affected by the disease severity of JDM itself or other complication such as hemophagocytic syndrome. References Feldman BM, Rider LG, Reed AM, Pachman LM. Juvenile dermatomyositis and other idiopathic inflammatory myopathies of childhood. Lancet. 2008 Jun 28;371(9631):2201-12. Gono T, Kawaguchi Y, Sugiura T, Ichida H, Takagi K, Katsumata Y, Hanaoka M, Okamoto Y, Ota Y, Yamanaka H. Interleukin-18 is a key mediator in dermatomyositis: potential contribution to development of interstitial lung disease. Rheumatology (Oxford). 2010 Oct;49(10):1878-81. Disclosure of Interest None Declared

Abstract 4571 Severe combined immunodeficiency (SCID) is the most severe form of the primary immunodeficiencies (PID), the most frequent type of which is X-linked SCID (X-SCID; T-B+NK-SCID). Hematopoietic stem cell transplantation (SCT) is the only curative treatment for these high-risk patients. Recently, some PID cases treated with unrelated cord blood stem cell transplantation (CBT) have been reported. To avoid severe infection during SCT and late complications, such as mental and growth retardation, reduced-intensity conditioning (RIC) regimens have been used for unrelated SCT for PID patients. However, reports of X-SCID patients receiving CBT with reduced-intensity stem cell transplantation (RIST) are quite limited. We report successful allogenic RIST from unrelated cord blood (CB) for treatment of X-SCID in our single centre. Three patients with X-SCID who had no HLA-matched sibling received unrelated CBT. Mutations in the common gamma chain gene were detected in all patients. Pre-transplantation conditioning for all patients consisted of fludarabine (FLU) (30 mg/m2/day) from day -7 to day -2 (total dose 180 mg/m2) and busulfan (BU) 4 mg/kg/day from day -3 to day -2 (total dose 8 mg/kg). All CB units were serologically matched HLA-A, B, and DR loci. Though two of the patients suffered from fungal or bacterial pneumonia before transplantation, there were no additional infectious complications during transplantation. All patients achieved engraftment with an absolute neutrophil count > 500/μ l with a mean of 22 days (range, 19–27 days), and they showed 100% donor chimerism by fluorescence in situ hybridization of their peripheral mononuclear cells using × and Y chromosome probes at one-year post transplantation. Full donor chimerism of both T and B cells was also confirmed. Only one patient (patient 2) developed grade III acute graft versus host disease (GVHD), which resolved with increased oral corticosteroid. None of the patients have developed chronic GVHD, received intravenous immunoglobulin replacements after the transplantations, or showed delayed psychomotor development during 21 to 77 months of follow-up. Only one patient (patient 3) had short stature (-2.4SD) at 21-month follow-up. The most commonly used RIC regimens worldwide have been the FLU/melphalan (LPAM) and the FLU/BU regimens. LPAM has broad stem cell toxicity to both primitive and committed stem cells, while BU may spare committed stem cells, resulting in early onset and a prolonged duration of neutropenia with the FLU/LPAM regimen. Moreover, it has been reported that the LPAM-containing conditioning regimen is a risk factor for hepatic veno-occlusive disease. Although conditioning regimens including standard-dose BU may be associated with a high rate of treatment-related complications due to organ toxicity, reduced-dose BU in combination with FLU is less myelosuppressive and less toxic than the FLU/LPAM regimen. Moreover, CBT has some advantages with regard to incidence and intensity of GVHD and availability compared with other alternative stem cell sources. Patients 1 and 2 had overcome pre-existing fungal and bacterial pneumonias, respectively, and recovered after transplantation. Thus, immediate SCT using an RIC regimen could be indicated for patients with X-SCID to reconstitute the immune system regardless of pre-existing infections. Since pre-existing infections are the principal risk factors for poor SCT outcomes, early diagnosis and transplantation before any infectious episodes is necessary for X-SCID patients. In conclusion, CBT is a suitable alternative to bone marrow transplantation for X-SCID patients requiring urgent SCT with no sibling donors. RIC consisting of FLU and BU is an effective and safe treatment for such cases.Table 1.Patients’ CharacteristicsPatient 1Patient 2Patient 3Age at diagnosis (months)840Age at CBT (months)953Common gamma chain mutation682T>G in exon 59_10insA in exon 1216G>A in exon 2CD34+ cell dose (×105/kg)6.75.33.2Hematological recovery Neutrophils>500/μ lday+19day+22day+27 Platelets>50×109/lday+28day+43day+31Chimerism (donor%)100100100 B cell engrafted (donor% (day))100 (day+120)100(day+89)100(day+83)OutcomeAlive +77 monthsAlive +69 monthsAlive +21 months Height−0.53SD−0.49SD−2.4SD Body mass index15.016.115.6 Mental statusnormalnormalnormalCBT, cord blood transplantation Disclosures: No relevant conflicts of interest to declare.