Antibody isotype responses to Schistosoma japonicum antigens in subjects from a schistosomiasis area with repeated praziquantel chemotherapy compared with a new endemic zone in Hunan Province, P.R. China.

To demonstrate the dynamics of specific antibody isotypes against schistosome adult worm (AWA) and soluble egg (SEA) antigens, we evaluated (in 1999-2000) 112 subjects infected with Schistosoma japonicum from 2 regions of Hunan Province, China. Fifty-eight subjects were from Area A, a well-known endemic area with repeated chemotherapy. Area B (n = 54) is a new endemic focus in another part of the same province. Serum samples were collected prior to praziquantel (PZQ) chemotherapy, and at 2 and 12 months post-treatment. IgM, IgA, IgG, IgG2, IgG4 and IgE antibodies to AWA and SEA were measured by quantitative enzyme-linked immunosorbent assay (ELISA). Pre-treatment antibody isotype levels from Area A, except IgA against AWA and SEA, were significantly higher than those from Area B. In response to chemotherapy, most antibody isotype levels fell or remained stable. However, in Area A there was a significant increase in the IgA, IgE and IgG4 responses to AWA 2 months after PZQ--which fell to approach pre-treatment levels by 12 months. A similar response was seen in Area B with IgE and IgG4 to AWA. Levels of all AWA-specific IgE and IgG4 were significantly higher in subjects from Area A compared with Area B at all time-points. AWA-IgE levels demonstrated significant linear correlations with age and number of previous PZQ treatments in Area A only. All SEA-specific isotypes in both areas fell significantly in response to treatment--except IgE, which remained stable in both area. All SEA-specific isotype levels (except IgA) were significantly higher from Area A at baseline. This significant difference was maintained through 12-months follow-up for IgE, IgG2 and IgG4 only. This study suggests that multiple episodes of schistosome infection may be required to generate antibody isotype levels that have been associated with resistance to re-infection in other studies. Further, a surrogate marker of successful chemotherapy (AWA-IgG4) performed less effectively in patients with previous treatment courses.

The relationship of a clonal outbreak of Enterococcus faecium vanA to methicillin-resistant Staphylococcus aureus incidence in an Australian hospital.

Australian isolates of vancomycin-resistant enterococci (VRE) have been widely scattered geographically, predominantly polyclonal and of the VanB phenotype. Forty-nine VRE were isolated from 47 patients in our hospital from October 1996 to December 1999. Forty-four of these VRE were Enterococcus faecium with a vanA glycopeptide resistance genotype. Four isolates were pathogenic. Thirty-five VRE were from an outbreak in the Renal and Infectious Diseases Units over a four-month period. Pulsed-field gel electrophoresis (PFGE) demonstrated that 41 of the 49 VRE were indistinguishable or closely related. Enhanced environmental cleaning, strict contact isolation of colonized patients and reducing inpatient admissions terminated the epidemic. Cohorting of methicillin-resistant Staphylococcus aureus (MRSA)-positive patients was restricted because VRE patients occupied the isolation facilities. This resulted in a statistically significant increase in MRSA infections across the hospital. VRE epidemics have the ability to influence the epidemiology of other nosocomial pathogens when infection control resources are exhausted.

Mycobacterium avium complex causing endobronchial disease in AIDS patients after partial immune restoration.

OBJECTIVE: To report the development of an unusual manifestation of pulmonary Mycobacterium avium complex (MAC) infection in two patients with the acquired immune-deficiency syndrome (AIDS) after the commencement of combination antiretroviral chemotherapy. PATIENTS: Two Caucasian males with human immunodeficiency virus (HIV) infection and CD4 lymphocyte counts <0.05 x 10x9/1 and with plasma HIV polymerase chain reaction (PCR) >100,000 copies/ml who were commenced on combination antiretroviral chemotherapy including a protease inhibitor. RESULTS: Both patients developed endobronchial polypoid tumours within two months of commencing antiretroviral chemotherapy. Histology demonstrated granuloma formation and acid-fast bacilli. Tissue from both patients grew M. avium. Both patients achieved significant suppression of viral replication and had significantly improved CD4 lymphocyte counts. Both required antimycobacterial therapy. CONCLUSIONS: Endobronchial polypoid tumours due to MAC infection have only been described in HIV-infected patients receiving antiretroviral chemotherapy. A degree of restored immunity is implicated in the pathogenesis of this unusual disease.

Fine mapping of a human chromosome 6 ferritin heavy chain pseudogene: relevance to haemochromatosis.

We have used a somatic cell hybrid regional mapping panel for the short arm of chromosome 6, linkage analysis and a population study to map in detail a previously described ferritin heavy chain pseudogene sequence on chromosome 6. Our results show that this sequence maps to the short arm of chromosome 6 centromeric to the glyoxylase locus. The ferritin pseudogene locus is thus distant from the locus for the iron storage disease haemochromatosis, confirming previous evidence that this sequence is not a candidate for the haemochromatosis gene.