Use of tocilizumab to treat arthritis associated with mixed connective tissue disease complicated by ovarian teratoma: a case report.

Mixed connective tissue disease (MCTD) is characterized by mixed features of systemic lupus erythematosus, systemic sclerosis, and polymyositis/dermatomyositis and is rare in children. Here, we report a case of MCTD in a 10-year-old girl who presented at our hospital with arthralgia, Raynaud's phenomenon, and fatigue. Blood tests were positive for anti-U1-ribonucleoprotein (RNP) antibodies and for rheumatoid factors (RFs) IgG-RF and anti-galactose-deficient IgG. Levels of myogenic enzymes and hypergammaglobulinemia were elevated. Macrophages were prominent in bone marrow, with scattered phagocytic macrophages. MCTD was diagnosed based on the patient's symptoms and laboratory findings. Methylprednisolone pulse therapy combined with oral tacrolimus was administered, which led to resolution of symptoms. Three months after pulse therapy, arthralgia worsened and methotrexate was administered. Arthralgia improved but did not resolve. Magnetic resonance imaging performed to investigate the hip pain revealed a mature ovarian teratoma, which was surgically removed. Because the pain persisted and interfered with her daily life, she was treated with tocilizumab for joint pain relief, which decreased the pain level. Tocilizumab is a candidate for additional treatment of juvenile idiopathic arthritis-like arthritis associated with childhood-onset MCTD.

Long-term remission of unusual plasmoacanthoma on the nasal canthus achieved by intralesional corticosteroid injection: Insights into the pathogenesis and treatment planning based on a literature review.

Plasmoacanthoma (PA) is a verrucous tumor predominantly developing on periorificial areas, which has been considered as an unusual subtype of plasmacytosis circumorificialis. Because of its rarity and clinical resemblance to several verrucous dermatological disorders, accurate diagnosis of PA is quite challenging. Herein, we present an extremely unusual case of PA which arose on both sides of the nasal canthus and was successfully treated with intralesional corticosteroid injections. To elucidate clinicopathological features of this condition, a literature review was also attempted. A 78-year-old woman visited us with a 2-year history of eruptions affecting both sides of the nasal canthus. At a local clinic, the diagnosis and treatment had been unsuccessful due to non-specific histological findings, leading to the referral to our institute. On physical examination, verrucous and lobulated reddish plaques were observed. In histology, psoriasiform epidermal change and dense plasma cell infiltration in the dermis were detected. The diagnosis of PA was made. After 5-monthly intralesional triamcinolone acetonide injections, the lesions became hardly noticeable with no evidence of recurrence. A literature review found five PA cases. PA predominantly arose on the periorificial area, mostly in or around the mouth, except one case which developed on the extra-oral or perioral area. Intralesional corticosteroid injection has been preferably performed, which frequently achieved successful remission. Chronic inflammation has been reported as a preceding condition. Abundance of plasma cells in the lacrimal glands and conjunctiva, together with pre-existing allergic conjunctivitis and habitual scratching, might have contributed to PA development in our case. Histopathological detection of psoriasiform epidermal change and dense dermal plasma cell infiltration is indispensable for the diagnosis of PA. For accurate diagnosis, optimization of treatment, and further accumulation of extra-oral/perioral PA cases, a skin biopsy needs to be proactively performed on verrucous lesions on relatively unfamiliar orifice sites.

Adipose tissue-derived stem cells suppress coronary arteritis of Kawasaki disease in vivo.

BACKGROUND: Kawasaki disease (KD) is a systemic inflammatory disease resulting in an acute febrile syndrome commonly affecting children younger than 5 years. Coronary arteritis in KD is occasionally non-responsive to several treatments. Recently, adipose tissue-derived stem cells (ADSCs) have been shown to have anti-inflammatory, immunosuppressive, and tissue-repair characteristics and are considered a useful treatment for inflammatory disease. The present study aimed to elucidate whether the administration of ADSCs can suppress KD-associated vasculitis in vivo. METHODS: Candida albicans water-soluble fraction is often used to model KD via the induction of severe coronary arteritis. Kawasaki disease model mice were intravenously administered ADSCs and phosphate-buffered saline (PBS). On day 29, the mice were sacrificed and hearts from mice in each group were dissected. This was followed by serum collection. Cardiac tissue sections were subjected to histopathological examination to evaluate the inflammatory area. The levels of pro-inflammatory cytokines in the serum were analyzed at days 15 and 29. The survival rates of both groups were compared. RESULTS: The mean inflammatory area in coronary arteritis was significantly lower in the ADSC group compared to the PBS group (P < 0.01). Furthermore, the levels of pro-inflammatory cytokines, such as IL-1ß, IL-12, IL-17, RANTES, INF-γ, and TNF-α, in the ADSC group were significantly lower than those in the PBS group. Moreover, the ADSC group had a significantly higher survival rate than the PBS group. CONCLUSIONS: These findings highlight that ADSCs have anti-inflammatory and immune regulatory functions that could provide novel cell-based therapeutic strategies for severe KD.

Safety and Immunogenicity of the Quadrivalent HPV Vaccine in Japanese Boys: a Phase 3, Open-Label Study.

Human papillomavirus (HPV)-associated disease is common among men with HPV infection. A quadrivalent HPV (qHPV) vaccine has demonstrated 85.9% efficacy against HPV6/11/16/18-related, persistent (≥ 6 month) infection in a study of Japanese men aged 16-26 years old. Here, we report the results of an open-label study of the immunogenicity and tolerability of the qHPV vaccine (NCT02576054), conducted to bridge findings from Japanese men to Japanese boys aged 9-15 years old. A total of 100 boys completed a three-vaccination regimen (Day 1, and Months 2 and 6), and 99 boys were included in the primary analysis population. The rate of seroconversion at one month after vaccine Dose 3 (Month 7) was high for each type of HPV (anti-HPV6/11/16/18 seroconversion rates [95% CI]: 94.9% [85.5%, 98.3%], 99.0% [94.4%, 100.0%], 99.0% [94.5%, 100.0%], and 99.0% [94.4%, 100.0%], respectively). Moreover, anti-HPV6/11/16/18 geometric mean titers were 482.9 mMU/mL, 1052.8 mMU/mL, 3878.3 mMU/mL, and 1114.5 mMU/mL, respectively. Immune responses to the qHPV vaccine were non-inferior among Japanese boys included in the current study and compared with young Japanese men from a separate study. Injection-site reactions were the most common adverse events, and administration of the vaccine was well tolerated in Japanese boys.

Therapy-related Secondary Malignancy After Treatment of Childhood Malignancy: Cases from a Single Center.

BACKGROUND: Therapeutic outcomes for childhood malignancy have dramatically improved. However, secondary malignancies are a major concern, as they greatly affect the quality of life of survivors. This retrospective study evaluated the cumulative incidence, clinical features, and outcomes of secondary malignancies at Nippon Medical School Hospital. METHODS: We examined data from 275 cases of primary childhood malignancy diagnosed between 1980 and 2014. Information regarding treatment of the primary malignancy, including irradiation dose, site, and cumulative dose of anticancer drugs, was assessed. We also collected data on secondary malignancy, including patient sex, age at diagnosis, malignancy site, time from primary to secondary malignancy, and outcomes. RESULTS: Secondary malignancies developed in 11 patients and included acute myeloid leukemia (AML) (4), meningioma (4), Ewing sarcoma (1), germ cell tumor (1), and malignant parotid gland tumor (1). The primary malignancies included acute lymphoblastic leukemia (ALL) (9), non-Hodgkin lymphoma (1) and brain tumor (1). In 7 of the 9 ALL patients, chemoradiotherapy was the primary treatment. The meningiomas and 1 solid tumor developed within the radiation field. All AMLs and meningiomas developed within 5 years and after 20 years, respectively, of the primary diagnosis. The 10- and 20-year cumulative incidence rates for secondary malignancy in our hospital were 1.9% and 5.8%, respectively. CONCLUSIONS: Our results revealed that the type of secondary malignancy depends on the interval after the end of treatment for primary malignancy. Meningioma, notably, develops many years after completion of primary malignancy treatment. Early detection during long-term follow-up is therefore essential.

Cutaneous Metaplastic Synovial Cyst: Case Report and Literature Review from the Dermatological Point of View.

Cutaneous metaplastic synovial cysts (CMSCs) are rare tumors typically comprising a solitary, well-circumscribed cystic mass that is not connected to the joint. Synovial cysts have been reported predominantly by orthopedists or pathologists; however, the presence of CMSC is not generally well recognized by dermatologists. Herein, we report a CMSC in a 68-year-old woman receiving systemic corticosteroid therapy for the treatment of eosinophilic granulomatosis with polyangiitis (EGPA). We attempt to delineate the clinical characteristics of this unusual neoplasm by reviewing the literature, focusing especially on dermatological descriptions. Histologic examination of the surgical specimen in the current case revealed that the cystic wall was lined with layers of flattened synovial cell-like cells and connective tissues, mimicking the synovial membrane. Positive immunoreactivity of the lining cells against vimentin was detected, but no immunoreactivity against cytokeratin, carcinoembryonic antigen (CEA), CD68, or S-100 was detected. The pathogenesis of CMSC remains unclear, but it has been tightly linked to direct traumatic stimuli or relative tissue fragility, which potentially accounts for CMSC development in our case. Most CMSCs reported by dermatologists are located on the extremities, whereas those described by other specialists tend to be distributed more globally. Preoperative diagnoses are often either epidermal cyst or suture/foreign body granuloma. Incomplete surgical excision of usual synovial cysts may lead to local recurrence, which has been reported in oral and maxillofacial surgery, but not in dermatologic surgery. This fact could be explained by the technical difficulties of surgical excision related to anatomical location. Dermatologists need to be aware of CMSC, and CMSC should be included in the differential diagnosis of subcutaneous cysts.

Effectiveness of ethinylestradiol/drospirenone for premenstrual symptoms in Japanese patients with dysmenorrhea: Open-label pilot study.

AIM: A combined oral contraceptive containing ethinylestradiol 20 µg plus drospirenone 3 mg (EE20 + DRSP) in a 24/4 regimen has been shown to alleviate the symptoms of premenstrual syndrome and premenstrual dysphoric disorder. This study was conducted to evaluate the efficacy of EE20 + DRSP in Japanese patients with premenstrual symptoms. MATERIAL AND METHODS: A multicenter, prospective, open-label, single-arm, phase IV study was performed in Japanese women with dysmenorrhea and premenstrual symptoms. They were treated with EE20 + DRSP to alleviate the symptoms of dysmenorrhea for six treatment cycles. Premenstrual symptoms were evaluated using a Premenstrual Symptoms Questionnaire at baseline and after three and six cycles of EE20 + DRSP. The degree of dysmenorrhea was also evaluated using a visual analog scale at baseline and after one, three, and six cycles of EE20 + DRSP. RESULTS: Forty-eight patients were treated with EE20 + DRSP. Most of the premenstrual symptoms were alleviated significantly by three and six cycles of EE20 + DRSP treatment. EE20 + DRSP treatment significantly improved the severity of premenstrual symptoms. We also confirmed the effectiveness of EE20 + DRSP for the treatment for dysmenorrhea. CONCLUSION: This study showed that EE20 + DRSP could be a useful treatment strategy for premenstrual symptoms in Japanese women.

Successful coil embolization for life-threatening hemorrhage in childhood leukemia induction therapy.

An 11-year-old boy was experienced severe life-threatening hemorrhage from a branch of the superior mesenteric artery (SMA) after acute lymphoblastic leukemia induction therapy. The patient had a history of attention deficit hyperactivity disorder (ADHD), diagnosed at 3 years of age. Subsequent to discontinuing his psychotropic medication, the patient's mental status deteriorated and treatment with midazolam for 3 weeks was necessary to allow the completion of the leukemia induction regimen. On day 51, although there was no indication of thrombocytopenia or a coagulation disorder, the patient began to hemorrhage suddenly from anal with resulting hypovolemic shock, and large-volume blood transfusion was initiated. Although upper and lower endoscopy failed to determine the location of the hemorrhage, angiography enabled us to determine that it was a branch of the SMA (the middle colic artery #6), and selective arterial embolization was used to arrest the bleeding. There could have been underlying causes, such as, a probable malformation or aneurysm in that area, although there was no indication before or after the event. This is a rare case of arterial hemorrhage from a branch of the SMA that occurred in a pediatric patient idiopathically during the induction therapy of leukemia.

A syringotropic variant of cutaneous sarcoidosis: presentation of 3 cases exhibiting defective sweating responses.

BACKGROUND: Although nodular collections of epithelioid histiocytes and multinuclear cells can be present at all levels of the dermis in cutaneous sarcoidosis, sarcoidal granulomas characterized by marked syringotropism of epithelioid histiocytes have not been previously reported to our knowledge. OBJECTIVE: We sought to determine whether syringotropic sarcoidosis bears characteristic clinical and histologic features and exhibits defective sweating responses. METHODS: We investigated the clinical, histologic, and immunohistochemical features of syringotropic sarcoidosis, and sweating responses to thermal stress in 3 patients. RESULTS: Multiple erythematous patches/plaques predominantly affected the extensor aspect of the lower legs and thighs. Immunohistochemical analyses of the sweat glands surrounded by syringotropic granulomas exhibited profoundly decreased expression of dermcidin and aquaporin 5, both of which are constitutively expressed in sweat glands of control subjects, suggesting functional defects. Indeed, sweating responses to thermal stress were markedly decreased in the involved area, as compared with those in the uninvolved area and in healthy control subjects. LIMITATIONS: There were a limited number of cases in our study. CONCLUSION: A syringotropic variant of cutaneous sarcoidosis might be a distinct entity clinically and histologically or represent an abortive variant.

Infantile case of early manifestation of SLE-like symptoms in complete C1q deficiency.

C1q deficiency is a rare complement deficiency in the early part of the complement cascade. Patients with C1q deficiency have severe recurring life-threatening infections and systemic lupus erythematosus (SLE)-like symptoms. We report on a boy with recurrent life-threatening infections and SLE-like recurrent skin conditions before 2 years of age. Immunological studies revealed an undetectable level of C1q. No abnormality was observed in the urine, but renal biopsy showed segmental granulonephritis. However, the changes observed were atypical for SLE nephritis. This case of C1q deficiency was unusual because the SLE-like symptoms appeared earlier than that normally seen in complement deficiency. Therefore, this case provides insights into the development of autoimmune disease, particularly in the early phase of component deficiency, and in managing renal disease that may develop in the future.

Defective sweating responses in atopic dermatitis.

While sweat is thought to be one of the important factors provoking exacerbations of clinical symptoms in atopic dermatitis (AD), little attention has been drawn to a beneficial role of sweat in the development of AD lesions. However, if the permeability barrier and antimicrobial barrier dysfunction represents the primary event in the development of AD, an evaluation of sweating responses in AD is a logical place to look for changes that predispose to the disease. In this regard, there have been conflicting data regarding whether sweating responses are impaired, normal or enhanced in AD patients. Consistent with the results of most recent studies, our recent study showed that most AD patients exhibit a defective ability to deliver sweat to the skin surface in response to thermal stress. Despite such defective sweating responses observed in the most part, a marked augmentation in the sweating response with delayed kinetics can be paradoxically detected in some sweating glands of these AD patients, indicating compensatory hyperhidrosis. Dermcidin, a new antimicrobial peptide exclusively produced by sweat glands, was abundantly detected not only in the sweat glands and ducts, and the lumen, but also in the dermal tissues adjacent to the sweat glands. These results indicate that the sweat may be retained in the lumen or pour into the dermal tissues, thereby causing inflammation. Thus, chronic inflammation in AD may be caused in part by a dysfunction of the sweat delivery system.

The assessment of human erythroid output in NOD/SCID mice reconstituted with human hematopoietic stem cells.

The third-generation NOD/LtSz-scid/IL2Rγ(null) (NOD/SCID IL2Rγ(null)) mouse represents a significantly improved xenograft model allowing high levels of human leukocyte engraftment over extended follow up. One remaining limitation of this mouse model, however, is the low level of circulating human erythrocytes. We established a practical ex vivo erythroid culture system of xenograft marrow progenitors to enrich for human erythroid progeny. At various time points after transplant, erythroid cells were easily assayed after 17 days of ex vivo culture of xenograft marrow, with nearly all nucleated cells of human origin and approximately 60% human GPA or CD71 positive. We then transplanted cord blood CD34(+) cells marked with a lentiviral vector encoding green fluorescent protein (GFP). Three months later, ex vivo culture of xenograft marrow progenitors showed 41.3% of the cultured erythroid cells were positive for GFP and human CD71, and 56.2% were positive for GFP and human GPA, similar to that of circulating leukocytes at the same time point. Next, G-CSF mobilized peripheral blood CD34(+) cells from a sickle cell trait subject were infused in this mouse model to determine if the hemoglobin pattern could be modeled. CD34(+) cells from the sickle cell trait subject engrafted equally compared to CD34(+) cells from normal subjects, establishing the sickle cell trait phenotype. Lastly, a comparison of adult-derived peripheral blood CD34(+) cells and cord blood-derived CD34(+) cells xenografted mice was made, and long term follow-up demonstrated a recapitulation of the fetal to adult hemoglobin switch. This approach should prove a useful tool for testing strategies for genetic manipulation of erythroid progeny and the study of hemoglobin switching.

Dextran sulfate and stromal cell derived factor-1 promote CXCR4 expression and improve bone marrow homing efficiency of infused hematopoietic stem cells.

Although the homing of hematopoietic stem cells (HSC) to the bone marrow (BM) is a crucial step in hematopoietic development and BM repopulation, the mechanisms underlying these processes have not been fully clarified. Recent studies suggest that interaction between the chemokine receptor CXCR4 and its ligand, stromal cell-derived factor 1 (SDF-1), plays a critical role in these processes. In addition, dextran sulfate increases plasma SDF-1 levels in mice and nonhuman primates. Thus, we examined the effects of preconditioning with SDF-1 and dextran sulfate on the homing efficiency of HSCs following BM transplantation in mice. We found that the preconditioning of donor mice with either SDF-1 or dextran sulfate enhanced the homing efficiency of infused HSCs in vivo. The greatest effects were obtained with dextran sulfate. Moreover, reverse transcriptase polymerase chain reaction analysis demonstrated that SDF-1 and dextran sulfate increased transcription of a variety of homing-related genes, including those for CXCR4, lymphocyte function associated antigen-1, matrix metalloproteinase-9, very late antigen-4/5, and macrophage inflammatory protein-1. We suggest that whereas SDF-1 directly acts to upregulate CXCR4 expression in HSCs, dextran sulfate acts via multiple pathways involved in the induction of various homing-related molecules, in addition to SDF-1. Thus, preconditioning donors with dextran sulfate offers a novel clinical approach for improving the homing and engraftment of HSCs in the BM.

Development of a human immunodeficiency virus type 1-based lentiviral vector that allows efficient transduction of both human and rhesus blood cells.

Human immunodeficiency virus type 1 (HIV-1) vectors transduce rhesus blood cells poorly due to a species-specific block by TRIM5alpha and APOBEC3G, which target HIV-1 capsid and viral infectivity factor (Vif), respectively. We sought to develop a lentiviral vector capable of transducing both human and rhesus blood cells by combining components of both HIV-1 and simian immunodeficiency virus (SIV), including SIV capsid (sCA) and SIV Vif. A chimeric HIV-1 vector including sCA (chiHIV) was superior to the conventional SIV in transducing a human blood cell line and superior to the conventional HIV-1 vector in transducing a rhesus blood cell line. Among human CD34(+) hematopoietic stem cells (HSCs), the chiHIV and HIV-1 vectors showed similar transduction efficiencies; in rhesus CD34(+) HSCs, the chiHIV vector yielded superior transduction rates. In in vivo competitive repopulation experiments with two rhesus macaques, the chiHIV vector demonstrated superior marking levels over the conventional HIV-1 vector in all blood lineages (first rhesus, 15 to 30% versus 1 to 5%; second rhesus, 7 to 15% versus 0.5 to 2%, respectively) 3 to 7 months postinfusion. In summary, we have developed an HIV-1-based lentiviral vector system that should allow comprehensive preclinical testing of HIV-1-based therapeutic vectors in the rhesus macaque model with eventual clinical application.

Transient in vivo beta-globin production after lentiviral gene transfer to hematopoietic stem cells in the nonhuman primate.

Inherited disorders of globin synthesis remain desirable targets for hematopoietic stem cell (HSC)-based therapies. Gene transfer using retroviral vectors offers an alternative to allogeneic HSC transplantation by the permanent integration of potentially therapeutic genes into primary autologous HSCs. Although proof of principle has been demonstrated in humans, this approach has been met by formidable obstacles, and large-animal models have become increasingly important for the preclinical development of gene addition strategies. Here we report lentiviral gene transfer of the human beta-globin gene under the control of the globin promoter and large fragments of the globin locus control region (LCR) in the nonhuman primate. Using an HIV-1, vesicular stomatitis virus glycoprotein G (VSV-G)-pseudotyped vector, modified to overcome a species-specific restriction to HIV-1, gene transfer to colony-forming units (CFU) derived from mobilized peripheral blood (PB) rhesus CD34+ cells was 84.4 +/- 2.33%. Erythroid cells derived from transduced rhesus CD34+ cells expressed human beta-globin at high levels as assessed by flow cytometry with a human beta-globin-specific antibody. Two rhesus macaques (RQ3586 and RQ3583) were transplanted with mobilized PB CD34+ cells transduced with our modified HIV vector at a multiplicity of infection of 80. High gene transfer rates to CFUs were achieved in vitro (RQ3586, 87.5%; RQ3583, 83.3%), with efficient human beta-globin expression among erythroid progeny generated in vitro. Early posttransplantation, gene transfer rates of 5% or higher were detectable and confirmed by genomic Southern blotting, with equivalent-level human beta-globin expression detected by flow cytometry. Long-term gene marking levels among mononuclear cells and granulocytes assessed by quantitative polymerase chain reaction gradually decreased to about 0.001% at 2 years, likely due to additional HIV-1 restrictive elements in the rhesus macaque. No evidence of clonal hematopoiesis has occurred in our animals in up to 2 years. Current efforts are aimed at developing a lentiviral vector capable of efficiently transducing both human and rhesus HSCs to allow preclinical modeling of globin gene transfer.

Long-term vector integration site analysis following retroviral mediated gene transfer to hematopoietic stem cells for the treatment of HIV infection.

We previously reported the efficacy of nonmyeloablative allogeneic transplantation in 2 HIV positive recipients, one of whom received retrovirus transduced hematopoietic stem cells to confer resistance to HIV. Here we report an assessment of retroviral integration sites (RISs) recovered out to 3 years post-transplantation. We identified 213 unique RISs from the patient's peripheral blood samples by linear amplification-mediated PCR (LAM-PCR). While vector integration patterns were similar to that previously reported, only 3.76% of RISs were common among early (up to 3 months) and late samples (beyond 1 year). Additionally, common integration sites were enriched among late samples (14.9% vs. 36.8%, respectively). Three RISs were found near or within known oncogenes, but 2 were limited to early timepoints. Interestingly, an integration site near the MDS1 gene was detected in long-term follow-up samples; however, the overall contribution of MDS1 integrated clone remained stably low during follow-up.

Busulfan produces efficient human cell engraftment in NOD/LtSz-Scid IL2Rgamma(null) mice.

Xenografting immunodeficient mice after low-dose irradiation has been used as a surrogate human hematopoietic stem cell (HSC) assay; however, irradiation requires strict and meticulous animal support and can produce significant mortality rates, limiting the usefulness of this model. In this work, we examined the use of parenteral busulfan as an alternative conditioning agent. Busulfan led to dose-dependent human HSC engraftment in NOD/LtSz-scid/IL2Rgamma(null) mice, with marked improvement in survival rates. Terminally differentiated B and T lymphocytes made up most of the human CD45+ cells observed during the initial 5 weeks post-transplant when unselected cord blood (CB) products were infused, suggesting derivation from existing mature elements rather than HSCs. Beyond 5 weeks, CD34+-enriched products produced and sustained superior engraftment rates compared with unselected grafts (CB CD34+, 65.8% +/- 5.35%, vs. whole CB, 4.27% +/- 0.67%, at 24 weeks). CB CD34+ group achieved significantly higher levels of engraftment than mobilized CD34+-enriched peripheral blood (PB CD34+). At 8 weeks, all leukocyte subsets were detected, yet human red blood cells (RBCs) were not observed. Transfused human red cells persisted in the chimeric mice for up to 3 days; an accompanying rise in total bilirubin suggested hemolysis as a contributing factor to their clearance. Recipient mouse-derived human HSCs had the capacity to form erythroid colonies in vitro at various time points post-transplant in the presence of human transferrin (Tf). When human Tf was administered singly or in combination with anti-CD122 antibody and human cytokines, up to 0.1% human RBCs were detectable in the peripheral blood. This long evasive model should prove valuable for the study of human erythroid cells.

Apoptotic cell death and regeneration in the newborn retina after irradiation prior to bone marrow transplantation.

PURPOSE: We studied the contribution made by circulating bone marrow (BM)-derived cells to the newborn and mature retinas of BM-transplanted mice. METHODS: Newborn and adult C57BL/6J mice were administered a lethal dose of total-body irradiation, after which pathologic changes to the retinas were periodically assessed. In addition, mice received BM cells from 8-week-old green fluorescent protein (GFP) transgenic mice, and the subsequent differentiation of GFP+ cells was studied. RESULTS: Within 5 hr after irradiation of newborn mice, retinal cells began to die due to apoptosis. By contrast, irradiation of adult mice elicited no histologic changes in the retina. BM cells generally did not differentiate in adult mice, but numerous GFP+ BM cells were integrated into the retinal tissue of newborn mice, where they expressed various cell type-specific markers. Finally, examination of whole retina mounts showed that GFP+ cells also contributed to retinal vascularization. CONCLUSIONS: Our findings underscore the importance of careful evaluation of the biological effects of irradiation in models making use of BM transplantation.