Takehiko Doi

Impaired Protection against Mycobacterium bovis Bacillus Calmette-Guérin Infection in IL-15-Deficient Mice

To investigate the potential role of endogenous IL-15 in mycobacterial infection, we examined protective immunity in IL-15-deficient (IL-15−/−) mice after infection with Mycobacterium bovis bacillus Calmette-Guérin (BCG) or recombinant OVA-expressing BCG (rBCG-OVA). IL-15−/− mice exhibited an impaired protection in the lung on day 120 after BCG infection as assessed by bacterial growth. CD4+ Th1 response capable of producing IFN-γ was normally detected in spleen and lung of IL-15−/− mice on day 120 after infection. Although Ag-specific CD8 responses capable of producing IFN-γ and exhibiting cytotoxic activity were detected in the lung on day 21 after infection with rBCG-OVA, the responses were severely impaired on days 70 and 120 in IL-15−/− mice. The degree of proliferation of Ag-specific CD8+ T cells in IL-15−/− mice was similar to that in wild-type mice during the course of infection with rBCG-OVA, whereas sensitivity to apoptosis of Ag-specific CD8+ T cells significantly increased in IL-15−/− mice. These results suggest that IL-15 plays an important role in the development of long-lasting protective immunity to BCG infection via sustaining CD8 responses in the lung.

Paediatric presentation and outcome of congenital protein C deficiency in Japan

Severe heritable protein C (PC) deficiency is quite rare, although heterozygous PROC mutation is the second leading cause of genetic predisposition to thrombosis in Japanese adults. The aim of the study was to search the optimal management, the paediatric onset and outcomes of PC deficiency were characterized in Japan. The genetic study, postmarketing survey of activated PC (aPC) concentrate (Anact®C) and intensive review in Japan for 20 years enabled the analysis of the disease onset, genotype, treatment and prognosis. Symptomatic PC deficiency was determined in 27 Japanese children. All but two patients presented within 16 days after birth (three prenatal and six neonatal onsets). Postnatal‐onset cases had normal growth at full‐term delivery. Of the 27 patients, 19 suffered intracranial thrombosis or haemorrhage (ICTH) (three foetal hydrocephalies), 16 developed purpura fulminans (PF) and 10 had both at the first presentation. ICTH preceded PF in both affected cases. Low PC activities of 18 mothers and/or 12 fathers indicated 20 inherited PC deficiencies (2 homozygotes, 11 compound heterozygotes and 7 heterozygotes) and seven unidentified causes of PC deficiency. Nine of 11 patients studied had PROC mutations. Four unrelated patients (50%) carried PC nagoya (1362delG). No PC‐deficient parents had experienced thromboembolism. Of the 18 patients with aPC therapy, two died and eight evaluable survivors had neurological sequelae. This first comprehensive study of paediatric PC deficiency suggested that perinatal ICTH was the major presentation, occurring earlier than neonatal PF. PC nagoya was prevalent in paediatric, but not adult, patients in Japan. Early maternal screening and optimal PC therapy are required for newborns at risk of PC deficiency.

H2-M3-Restricted CD8+ T Cells Induced by Peptide-Pulsed Dendritic Cells Confer Protection against Mycobacterium tuberculosis

One of the oligopolymorphic MHC class Ib molecules, H2-M3, presents N-formylated peptides derived from bacteria. In this study, we tested the ability of an H2-M3-binding peptide, TB2, to induce protection in C57BL/6 mice against Mycobacterium tuberculosis. Immunization with bone marrow-derived dendritic cell (BMDC) pulsed with TB2 or a MHC class Ia-binding peptide, MPT64190–198 elicited an expansion of Ag-specific CD8+ T cells in the spleen and the lung. The number of TB2-specific CD8+ T cells reached a peak on day 6, contracted with kinetics similar to MPT64190–198-specific CD8+ T cells and was maintained at an appreciable level for at least 60 days. The TB2-specific CD8+ T cells produced less effector cytokines but have stronger cytotoxic activity than MPT64190–198-specific CD8+ T cells. Mice immunized with TB2-pulsed BMDC as well as those with MPT64190–198-pulsed BMDC showed significant protection against an intratracheal challenge with M. tuberculosis H37Rv. However, histopathology of the lung in mice immunized with TB2-pulsed BMDC was different from mice immunized with MPT64190–198-pulsed BMDC. Our results suggest that immunization with BMDC pulsed with MHC class Ib-restricted peptides would be a useful vaccination strategy against M. tuberculosis.

Treatment choice of immunotherapy or further chemotherapy for Epstein-Barr virus-associated hemophagocytic lymphohistiocytosis.

Epstein–Barr virus‐associated hemophagocytic lymphohistiocytosis (EBV‐HLH) leads to an aggressive and often fatal course without appropriate treatment. Etoposide therapy is crucial for the better prognosis, although it remains unknown what patients need cytotoxic agents. Since we have complied with step‐up strategy in a tertiary center, treatment outcomes were studied to search predictors for disease course.

Potent Induction of IFN-γ Production from Cord Blood NK Cells by the Stimulation with Single-Stranded RNA

Natural killer (NK) cells play important roles in the innate immunity against viral infections. Although newborn infants are more susceptible to severe and recurrent viral infections than adults, the precise role of NK cells in the innate immunity against viral infections during neonatal period is not known. To clarify the functional characteristics of cord blood (CB) NK cells, we examined the capacity of CB NK cells to produce interferon gamma (IFN-γ) in response to the Toll-like receptor (TLR) ligands. We found that NK cells produced a large amount of IFN-γ by the stimulation with ssRNA, a TLR8 ligand, in the presence of interleukin-2 (IL-2), Interferon alpha (INF-α), and monocytes. Surprisingly, CB NK cells produced higher amount of IFN-γ than adult peripheral blood NK cells in this condition. IL-12 produced from monocytes by the stimulation with ssRNA was indispensable for the production of IFN-γ by NK cells. NK cells in cooperation with other innate immune cells may play more important role during the neonatal period than in adults in the host defense against viral infections by high capacity of IFN-γ production to compensate immature acquired immunity.

Neonatal asphyxia and renal failure as the presentation of non-inherited protein C deficiency

Inherited or acquired protein C (PC) deficiency leads to thromboembolic events. Plasma PC activity in infancy is physiologically lower than in adults. We describe a case of neonatal asphyxia and acute renal failure associated with isolated PC deficiency. A full-term male infant was born to a healthy mother by caesarean section because of fetal distress. The small-for-gestational age infant showed 2 and 7 of Apgar scores at 1 and 5 minutes, respectively. Hypercoagulability required repeated infusions of fresh frozen plasma. Coagulation study revealed PC activity, 6%, protein S activity, 61%, and high D-dimer levels, along with normal factor VII activity and absent vitamin K deficiency. Anticoagulant and activated PC therapy improved coagulopathy and nephropathy. Imaging analyses indicated no visceral infarctions. Renal function and PC activity have been slowly normalized until 6 months of age. He had no PROC mutation or PC-deficient parents. Selective PC deficiency may occur as an acquired cause of hypercoagulable crisis in the stressed newborn.

Recurrent atrial fibrillation after high-dose methylprednisolone therapy in a girl with lupus-associated hemophagocytic syndrome

Hemophagocytic syndrome (HPS) is a serious complication of systemic lupus erythematosus (SLE). A 15-year-old female with lupus-nephritis developed HPS. Bone marrow study showed florid thrombophagocytosis. There was no associated infection. High-dose methylprednisolone therapy ameliorated HPS. However, atrial fibrillation (Af) repeated after the infusion and required direct-current cardioversion. No underlying diseases were found in the heart and endocrine system. Chest roentgenogram and echocardiography were normal. Electrocardiogram showed slightly prolonged PR interval in sinus rhythm. Af occurred at high circulating levels of interferon-γ and interleukin (IL)-10, but not IL-6, IL-2, tumor necrosis factor-α, C-reactive protein or catecholamines. This is the first observation that high-dose corticosteroid induced Af in a case of lupus-HPS. Af is unusual in SLE children without cardiac disease, while conduction defect occurs associated with lupus-myocarditis. Lupus-HPS may be an aggressive SLE subset with cardiac involvement. High-dose corticosteroid infusion controls lupus activity, but could disclose the cardiac stress in lupus-HPS patients.

Erratum to: Long-term liposteroid therapy for idiopathic pulmonary hemosiderosis

Page 1476, Methods, Liposteroid therapy, line 4-5 The sentence, “It was intravenously infused at 0.8 mg/kg/day for three consecutive days at the time of acute bleeding, after the obtainment of informed consent from parents.” was corrected to “It was intravenously infused at 0.05-0.08 mg (of dexamethasone)/kg/day for three consecutive days at the time of acute bleeding, after the obtainment of informed consent from parents.”

Limited renal prophylaxis in regular plasmatherapy for heritable ADAMTS13 deficiency

To the Editor: Germline mutations of ADAMTS13 cause chronic relapsing-thrombotic thrombocytopenic purpura (TTP), called Upshaw–Schulman syndrome. Affected patients with the rare disease may develop renal impairment with a need for dialysis unless thrombotic microangiopathy is controlled [1]. Plasma exchange is the standard therapy for disease control. There is little information about the long-term effects of plasmatherapy on renal disease. We report the outcomes of patients who underwent >15-years’ regular plasma infusion. Three unrelated patients were treated in our hospitals (Table I) [2]. All presented the classical triad of neonatal jaundice, hemolytic anemia, and thrombocytopenia requiring whole-blood exchange transfusion. Chronic relapsing-TTP was diagnosed in Pt-1, Pt-2, and Pt-3 at age 16 months, 7 years, and 1 month, respectively. Pt-1 suffered a varicella-induced TTP at age 7 months. On-demand infusion of plasma-derived intermediate purity factor VIII concentrates, Confact F (Kaketsuken, Kumamoto, Japan) or Conco-eight (Green Cross Corp., Osaka, Japan) was the first line treatment [3,4]. In Japan, they were replaced by monoclonal antibody-purified/recombinant FVIII products, therefore, not appropriate replacement. Pathogen-inactivated plasma was unavailable. Regular infusion of fresh-frozen plasma (FFP) was then started to control repetitive bouts. No IgG-antibody against ADAMTS13 was detected in any patient. The FFP prophylaxis and current renal functions are shown in Table I. At the time of infusion, all patients showed petechiae, thrombocytopenia at around 10 10/L, and non-severe hemolysis represented by changing hemoglobin, total bilirubin, and lactate dehydrogenase levels, along with proteinuria and hematuria/ hemoglobinuria. However, stable hematological responses led to no hospitalization in three patients. Two patients had anti-hepatitis C virus (HCV) antibody, but not HCV RNA or abnormal transaminase levels. Pt-1 had occasional infusion reactions including anaphylaxis. No immunologic disorders developed. Serum concentrations of creatinine ranged normally in Pt-1 and Pt-2, but increased in Pt-3 beyond 20 years of prophylaxis. All had <90ml/min/1.73m of the estimated glomerular filtration rate (eGFR), that was calculated by the formula [5]. Pt-3 had high urine protein to creatinine ratio. At the time of FFP infusion, Pt-3 always showed hemoglobinuria, hematuria, proteinuria, and granular casts, Pt-1 had proteinuria only, and Pt-2 showed neither. Pt-1 accepted to undergo the renal biopsy at age 9 years, histopathology of which demonstrated a few microthrombotic glomeruli but no significant inflammation (Supplemental Fig. 1). One third of patients with heritable ADAMTS13 deficiency have stroke and mostly relapse if untreated, and half of them suffer from neurologic sequelae [6]. Plasma prophylaxis has not been demonstrated to prevent the end-stage renal failure in childhood [7]. The 20 years’ prophylaxis controlled TTP bouts without apparent inhibitors, but did not prevent the development of some renal impairment. Our patients shared the genotype, severity, and treatment response [2,8]. Pt-3 had symptomatic urine at each infusion compared with two others. Anti-thrombotic effects require at least 5% of plasma ADAMTS13 activity [9]. Our protocol might insufficiently replace the activity to protect from chronic kidney injury. Nevertheless, the early prophylaxis in Pt-1 might sustain higher GFR. Long-term renal prophylaxis using ADAMTS13 products may overcome the limit of plasmatherapy, as in the joint prophylaxis in hemophiliacs [10].

Development of Kawasaki disease in a patient with PFAPA

Periodic fever, aphthous stomatitis, pharyngitis and cervical adenitis syndrome (PFAPA) is one of the autoinflammatory diseases of unknown etiology characterized by regularly recurrent fever episodes with attacks lasting 3–6 days every 3–8 weeks associated with at least one of the three cardinal clinical signs: aphthous stomatitis, pharyngitis, and cervical adenitis. Kawasaki disease (KD) is an acute, self‐limited systemic vasculitis that occurs predominantly in infants and young children. In most KD patients, i.v. immunoglobulin leads to a rapid amelioration of clinical symptoms and significantly decreases the risk of coronary artery aneurysms. Although the etiology of KD is still unknown, it was reported that innate immunity was activated in the patients. Described herein is a patient with PFAPA who developed KD. This is the first report of KD development in a PFAPA patient. The association between KD and PFAPA may represent a genetic predisposition to dysregulated innate immune response.