Toxoplasma gondii: enzyme-linked immunosorbent assay based on a recombinant multi-epitope peptide for distinguishing recent from past infection in human sera.

Enzyme-linked immunosorbent assays (ELISAs) based on a recombinant multi-epitope peptide (rMEP) were used in an attempt to differentiate pregnant women with Toxoplasma serologic profiles (TSPs) indicative of recently acquired infections (acute profile) from those with TSPs indicative of infections acquired in the distant past (chronic profile). The recombinant expression vector pET-32c-MEP encoding MEP constructed previously was expressed in Escherichia coli and the rMEP was purified as a bioactive fusion protein. The IgG-ELISA and IgM-ELISA based on the purified rMEP were developed, and used to detect IgG and IgM antibodies against Toxoplasma gondii in human sera. Immunoblot assays showed that the purified rMEP could be strongly recognized by IgM antibodies in the pooled sera from women with acute profiles, and by IgG antibodies in the pooled sera from women with chronic profiles. ELISA results also proved that the reactivities of IgG and IgM antibodies differed significantly in sera from women with acute and chronic profiles. Compared with two commercial ELISA tests for seradiagnosis of toxoplasmosis, the total concordance (including positive and negative sera) of this rMEP-based assay was 93.2% and 95.7% for the detection of IgG and IgM antibodies, respectively. Our study suggests that the rMEP protein could be used as the diagnostic antigen to differentiate recent from past infections in human toxoplasmosis.

Lipoprotein glomerulopathy: clinical features and pathological characteristics in Chinese.

BACKGROUND: Lipoprotein glomerulopathy (LPG), once recognized as a rare glomerular disease, has been reported around the world in recent years. In this study, we reported 8 patients of LPG and aimed to explore the clinical features and pathological characteristics of LPG under light microscope, immunofluorescence staining, and electron microscope. METHODS: Clinical manifestations were recorded on the day of renal biopsy. Biochemical patterns of lipids and lipoproteins were detected by routine examination. Plasma concentrations of apo B and apo E were determined by radial immunodiffusion assays. Biopsy specimens were then processed for light microscopy, immunohistochemical staining for immunoglobulins and complement components, and electron microscopy. Glomerular deposition of apo A, B, and E were detected using monoclonal antibodies on cryostatic sections. RESULTS: All of the eight patients presented with edema, microscopic hematuria, severe proteinuria, anemia, and enlarged kidney size. Biochemical profiles revealed high levels of triglycerides, apo B, and apo E. We noted increments of glomerular size and lipoprotein thrombi occupying capillary lumina in the glomeruli of all patients. Immunofluorescence staining showed that the thrombi were strongly positive for apo A, B, and E. Granules and various sizes of vacuoles were observed in the thrombi under electron microscope. CONCLUSION: Compared with previous reports on LPG in other countries, unique clinical and pathological features were found in this group of Chinese LPG patients.

Sex differences in estrogen receptor gene polymorphism and its association with lupus nephritis in Chinese.

BACKGROUND/AIMS: Lupus nephritis (LN) is a clinical heterogeneous autoimmune disease and genetic factors contribute to the development of LN. One of the most striking characteristics in LN is the high prevalence among childbearing women, as well as that its clinical manifestation differs in women and men, suggesting the role of sex hormones in its pathogenesis. METHODS: The PvuII and XbaI restriction fragment length polymorphism (RFLP) of estrogen receptor (ER) gene were analyzed in 245 biopsy-proven LN patients (58 males and 187 females) and 172 normal controls (101 males and 71 females) by PCR-RFLP. The clinical and pathological features of 49 male and 152 female LN patients with different genotypes were analyzed. RESULTS: It was found that genotype PpXx, ppxx and Ppxx were three major genotypes of ER gene in both of lupus patients and control groups. The distribution of ER gene polymorphism was quite different in lupus patients of different genders. The frequency of the PpXx genotype in male LN patients was significantly higher than both the gender matched normal controls (p < 0.05) and the female LN patients (p < 0.05), while no difference was shown in the frequency of PpXx genotype between female LN patients and gender matched controls. Interestingly, skin rashes and arthritis were found more common in the patients with PpXx genotype. The frequency of hematological abnormalities and hypertension were higher in patients with ppxx genotype (p < 0.05), while capillary thrombi and glomerular sclerosis were more frequently complicated in the patients with ppxx genotype. In addition, the renal vasculitis and interstitial injury were more frequent in those with Ppxx genotype (p < 0.01). CONCLUSION: The distribution of ER gene polymorphism in LN patients is distinct with different gender. The PpXx genotype of ER gene may be associated with the susceptibility of SLE in male. ER gene polymorphism is probably one of the genetic factors contributing to the development of clinical heterogeneity and sexually dimorphic manifestations of LN.