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Abnormalities of the p53 gene are known to confer detrimental effects in chronic lymphocytic leukaemia (CLL) and are associated with short survival. We have used high dose methylprednisolone (HDMP) to treat 25 patients with advanced refractory CLL of whom 45% had p53 abnormalities shown by one or more methods: flow cytometry, fluorescent in situ hybridisation and direct DNA sequencing. Fifteen were resistant to fludarabine and 16 were non-responders to their most recent therapy. Methylprednisolone had a cytotoxic effect on lymphocytes from 95% of cases assessed by an ex vivo apoptotic drug sensitivity index (DSI). HDMP was given alone or in combination with other drugs: vincristine, CCNU, Ara-C, doxorubicin, mitoxantrone and chlorambucil, according to the results of DSI. Three patients were treated twice and each treatment was analysed separately. The overall response rate was 77% with a median duration of 12 months (range 7 -23+). Responders included 5/10 with abnormal p53, of which two achieved nodular PR. Patients with p53 abnormalities fared worse than those with normal p53. There were no differences in response according to whether HDMP was used alone or in combination. Nine of the 22 evaluable patients (3 NR and 6 PR) have died from progressive disease or transformation. Main toxicity was infection in 7/25 patients. Event free and overall survival were significantly better in responders vs non-responders ( P>0.0001 and P=0.04 respectively). Patients with a DSI of 100% to steroids had a better overall and event free survival, but this was not statistically significant. This study demonstrates that HDMP alone or in combination with other agents is a useful treatment strategy in refractory CLL including patients with p53 abnormalities.

Volunteer studies have shown that a 60-megadalton plasmid is required for full virulence of the human enteropathogenic Escherichia coli (EPEC) strain E2348/69 (0127:H6). The plasmid, designated pMAR2, encodes localized adherence to HEp-2 cells in tissue culture via the adhesin known as the EPEC adherence factor (EAF). Using a DNA probe for the EAF, we have previously shown that these genes are specific for EPEC and are usually encoded on plasmids ranging from 55 to 65 megadaltons. In this study, Southern blot analysis and S1 nuclease homology determination reveal a high degree of sequence conservation among these plasmids, despite some variation in restriction maps. Phenotypic characterization of the prototype EAF plasmid pMAR2 reveals that the plasmid belongs to the group IncFII and is negative for alpha-hemolysin, colicin, and aerobactin synthesis, as well as biochemical markers and antibiotic resistance. Regions encoding adherence to HEp-2 cells were localized by Tn801 insertion mutagenesis. Adherence genes were then cloned as two distinct plasmid regions which confer the adherence phenotype only when complementing each other in trans.

Serum C-reactive protein was studied serially by a 1-hour laser nephelometric assay in 25 patients with leukaemia who developed 34 episodes of infection. The serum level rose above, or by, 100mg/l in 29 of the episodes. Serial measurement of this acute-phase reactant was of value in detecting infection in the neutropenic patient and in monitoring the response to antibiotic therapy.

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