ABSTRACT
Most patients with acquired pure red cell aplasia (PRCA) and some with acquired aplastic anemia (AA) respond well to cyclosporine (CsA), but thereafter often show CsA dependency. The mechanism underlying this dependency remains unknown. We established a reliable method for measuring the regulatory T cell (Treg) count using FoxP3 and Helios expression as markers and determined the balance between Tregs and other helper T cell subsets in 16 PRCA and 29 AA patients. The ratios of interferon-γ-producing CD4(+) (Th1) T cells to Tregs in untreated patients and CsA-dependent patients were significantly higher (PRCA 5.77 ± 1.47 and 7.38 ± 2.58; AA 6.18 ± 2.35 and 8.94 ± 4.06) than in healthy volunteers (HVs; 3.33 ± 0.90) due to the profound decrease in the percentage of Tregs. In contrast, the ratios were comparable to HVs in convalescent CsA-treated AA patients (4.74 ± 2.10) and AA patients in remission after the cessation of CsA treatment (4.24 ± 1.67). Low-dose CsA (100 ng/ml) inhibited the proliferation of conventional T cells (Tconv) to a similar degree to the inhibition by Tregs in a co-culture with a 1:1 Treg/Tconv ratio. The data suggest that CsA may reverse the hematopoietic suppression in PRCA and AA patients by compensating for the inadequate immune regulatory function that occurs due to a profound decrease in the Treg count.
Subject(s)
Anemia, Aplastic/drug therapy , Cyclosporine/pharmacology , Hematopoiesis/drug effects , Immunosuppressive Agents/pharmacology , Red-Cell Aplasia, Pure/drug therapy , T-Lymphocytes, Regulatory/immunology , Adult , Aged , Aged, 80 and over , Anemia, Aplastic/immunology , Antigens, Differentiation, T-Lymphocyte/analysis , Cyclosporine/therapeutic use , Female , Flow Cytometry , Hematopoiesis/immunology , Humans , Immune Tolerance , Immunophenotyping , Immunosuppressive Agents/therapeutic use , Interferon-gamma Release Tests , Lymphocyte Count , Male , Middle Aged , Red-Cell Aplasia, Pure/immunology , Remission Induction , Retrospective Studies , Substance-Related Disorders/etiology , Substance-Related Disorders/immunology , T-Lymphocyte Subsets/immunology , T-Lymphocytes, Helper-Inducer/immunology , T-Lymphocytes, Regulatory/pathologyABSTRACT
Hemophagocytic lymphohistiocytosis (HLH) is a rare and fatal hematological syndrome that causes a disturbance of the immune system. Overall mortality of HLH is greater than 50% and the majority of patients who die do so within the first 8 weeks of chemotherapy treatment. To find clinical parameters relating to high-risk HLH patients, this study examined associations between an early fatal outcome and potential prognostic clinical factors and laboratory findings on admission. Eighty-nine pediatric HLH patients were prospectively recruited in Children's Hospital No. 1, Ho-Chi-Minh City, Vietnam, during the period from January 2010 to August 2012. Associations between early fatal outcome and clinical and laboratory findings, including a cerebrospinal fluid examination and virological test on admission, were examined. During the 8-week therapy, 25 (28%) HLH patients died. Persistent fever (>2 weeks), severe thrombocytopenia (<75 × 10(9)/L), hyperbilirubinemia, and prolonged activated partial thromboplastin time (APTT) (>33 sec) were significant risk factors of early fatal outcome. Multivariate logistic regression analysis revealed that thrombocytopenia and prolonged APTT (P for trend was 0.054 and 0.013, respectively) were independently associated with the early fatal outcome. Persistent fever, severe thrombocytopenia, hyperbilirubinemia, and prolonged APTT on admission will be useful and practical predictors to determine high-risk HLH patients.