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Objective: To test the hypothesis that Staphylococcus aureus genome has regulatory genes which coordinate the expression of extracellular products, and particular genes not expressed in vitro conditions may be turned on in a vivo environment., Methods: The study was conducted at the Immunology and Infectious Disease Research Laboratory (IIDRL), Microbiology Department, Husein Ebrahim Jamal Research Institute (HEJ), Animal House, Karachi University, from July to December 2009. Micro pore Teflon cages using a mouse cage model were fixed into the subcutaneous tissue in Albino mice (BALB/c) on their dorsal surface. After 15 days, the holes closed down with healthy tissue. Three staphylococcal isolates from clinical samples confirmed by DNA sequencing of 16s ribosomal RNA were tested for expression of extracellular protein in vitro and were later injected into the cages. After the institution of infection, the fluid aspirated from the cages was analysed by Sodium dodecyl polyacrylamide gel electrophoresis (SDS-PAGE). This was done to test for possible induction of additional extracellular proteins in vivo., Results: The appearance of enhanced extracellular products was observed in the fluid recovered from the cages of two mice on days 5 and 7 subsequent to the institution of infection, suggesting a turn-on of particular genes which were not expressed in vitro conditions., Conclusions: In-vivo host and environmental signals contribute to the induction of genes for the production of extracellular proteins.

Warm antibody autoimmune haemolytic anaemia, a rare disease (0.2-1 per 100,000 populations), is due to the presence of warm agglutinins that react with protein antigens on the surface of red blood cells causing their premature destruction. Here, we present a case report of a 10 year old girl who came with features of haemolytic anaemia and history of blood transfusion since 3 years. On admission. laboratory test revealed that she had autoimmune hepatitis type 1 and was also an asymptomatic carrier of hepatitis B virus with positive HBs Ag. Steroid therapy resulted in clinical and laboratory remission. Direct antiglobulin test was negative after anaemia resolution, hepatitis B virus antigenemia persisted. To our knowledge, warm antibody autoimmune hemolytic anaemia has not previously been described in association with autoimmune hepatitis and asymptomatic carrier state of hepatitis B virus.