A sensitive sandwich ELISA for measuring thrombopoietin in human serum: serum thrombopoietin levels in healthy volunteers and in patients with haemopoietic disorders

A sensitive sandwich enzyme-linked immunosorbent assay (ELISA) has been established to estimate serum thrombopoietin (TPO) concentrations in healthy volunteers and patients with haemopoietic disorders. The ELISA uses a mouse monoclonal antibody (Ab) as the capture Ab and a biotinylated rabbit polyclonal Ab as the detector. The ELISA was reproducible, highly sensitive and specific for human TPO. The coefficients of intra- and inter-assay variation were from 3.0% to 4.9% and from 5.9% to 6.1%, respectively. The quantitative limit of the ELISA was 0.09 fmol/ml in serum. The quantitative limit was lower than the normal level. The dose–response curves of serum samples from healthy volunteers and patients with haemopoietic disorders were parallel to the standard curves. The ELISA did not cross-react with a variety of blood components and cytokines to produce false-positive results.
The serum TPO concentrations from 29 normal males and 21 females were 0.79 ± 0.35 and 0.70 ± 0.26 fmol/ml, respectively. Serum TPO levels in patients with aplastic anaemia (AA), acute lymphocytic leukaemia (ALL) and essential thrombocythaemia (ET) were measured using the ELISA. The serum TPO levels in the patients with ET ( n  = 6, 2.80 ± 1.55 fmol/ml) were higher than the normal level. The patients with AA ( n  = 7, 18.53 ± 12.37 fmol/ml) and ALL ( n  = 5, 10.36 ± 5.57 fmol/ml) had significantly higher serum TPO levels than normal individuals. These results indicate that the ELISA specific to TPO should prove useful in measuring the TPO concentration in serum samples.     

Infectious mononucleosis in Japan: Comparison with acute viral hepatitis type A

In order to clarify the characteristics of infectious mononucleosis hepatitis (IMH) in Japan, 20 cases with IMH treated at Kamo Hospital during the past 6 years (Group I) were analysed in comparison with cases of acute viral hepatitis, especially type A. The test for heterophil antibody was positive in only two cases. During the same period 209 cases were treated for acute viral hepatitis (type A: 77 cases = Group A; type B: 61 cases; type non-A, non-B: 71 cases). In Group I the common clinical symptoms and signs were headache, sore throat and lymph node swelling; jaundice was not as common as in Group A. GOT and GPT activities increased moderately in the acute stage, but they were significantly lower than those in Group A. LDH, AP, GGT and LAP activities were disproportionately higher to GPT activity in Group I. Liver biopsy in the convalescent stage showed that lipofuscin deposition and sinusoidal mononuclear cell infiltration were more prominent in Group I, while sinusoidal neutrocyte infiltration and focal necrosis at periportal areas were more common in Group A. Differential diagnosis of the two diseases could be made using these clinical features and histological findings. However, immunological differentiation is required for specific diagnosis because some features such as fever, prolonged elevation of thymol turbidity test, atypical lymphocytes in peripheral blod and predilection for young people were observed in both groups. Furthermore, the present study indicated that IMH is no longer rare and most cases do not demonstrate heterophil antibody in Japan.     

Aqueous fraction of Sauropus androgynus might be responsible for bronchiolitis obliterans

Background and objective: Bronchiolitis obliterans (BO) has been reported to develop following ingestion of Sauropus androgynus (SA), a leafy shrub distributed in Southeast Asia. Little is known about direct effects of SA on airway resident cells or haematopoietic cells in vitro. Identification of the SA component responsible for the development of BO would be an important key to elucidate its mechanism. We sought to elucidate the direct effects of SA on airway resident cells or haematopoietic cells and identify the SA element responsible for the pathogenesis of BO. Methods: SA dry powder was partitioned into fractions by solvent extraction. Human and murine monocytic cells, epithelial cells and endothelial cells were cultured with SA solution or fractions eluted from SA. We also investigated the effect of SA in vivo using a murine BO syndrome (BOS) model. Results: The aqueous fraction of SA induced significant increases of inflammatory cytokine and chemokine production from monocytic lineage cells. This fraction also induced significant apoptosis of endothelial cells and enhanced intraluminal obstructive fibrosis in allogeneic trachea allograft in the murine BOS model. We found individual differences in tumour necrosis factor α (TNF‐α) production from monocytes of healthy controls stimulated by this aqueous fraction of SA, whereas it induced high‐level TNF‐α production from monocytes of patients with SA‐induced BO. Conclusions: These results suggest that an aqueous fraction of SA may be responsible for the pathogenesis of BO.