The ability to create multi-epitope-presenting nanoparticles that can orthogonally bind to specific monoclonal antibodies has been demonstrated using both ELISA and immunological QCM. Determination of the extent of antibody-functionalized nanoparticle binding is rapid using the QCM compared to ELISA. Also, like ELISA, the immunological response is specific, with QCM incurring less nonspecific binding. Interaction of the epitope with its antibody was improved through the use of a PEG linkage for epitope attachment to the MPC. Binding studies at the QCM show that polyfunctionalized gold nanoparticles exhibit the expected affinity to both antibodies that a normal immunological response is achieved from matched antibody-antigen couples and that an orthogonal response results otherwise. The results demonstrate that binding of polyfunctionalized gold nanoparticles could be used to determine sensor functionality, without resorting to the use of attenuated or killed microorganisms, or extracted and purified whole proteins. Hepatitis G Virus associated aplastic anemia: A recent case from Pakistan BACKGROUND: Aplastic anemia (AA) is a serious and rare disorder characterized by a hypocellular bone marrow. Hepatitis associated aplastic anemia (HAAA) is a variant of aplastic anemia in which aplastic anemia follows an acute attack of hepatitis. Several reports have noted an association between HGV and hepatitis-associated aplastic anemia besides other hepatitis causing viruses. CASE PRESENTATION: A female girl of age 11 year with a history of loose motion for one month, vomiting for last 15 days and poor oral intake for last few days is reported here. The physical examination presents fever, pallor whereas bleeding, hepatomegaly, Splenomegaly and bruising were absent, abdominal ultrasonography confirmed the absence of hepatomegaly, Splenomegaly and lymphodenopathy. The laboratory investigation parameters were: haemoglobin 6.2 g/L, total leucocytes count 1.51, neutrophils 0.47%, absolute reticulocyte count 0.5%, Monocytes 0.16%, red cell count 3.2 mil/uL, Picked cell volume (PCV) 30.13%, Mean Corpuscular Volume (MCV) 78 fL, Mean Corpuscular Hemoglobin (MCH) 26.3 pg. The liver enzymes were alanine aminotransferease (ALT) 98 IU/L, aspartate aminotransferase (AST) 114 IU/L. Serologic and molecular tests for hepatitis A, B, C, D, E, TTV, B19 were negative, whereas HGV RNA PCR test was found positive for hepatitis G virus. The bone marrow aspirate and trephine biopsy examination revealed hypo- cellularity, erythropoiesis, myelopoiesis and megakaryopoiesis. CONCLUSION: HAAA is an uncommon but severe condition, which may occur following idiopathic cases of acute hepatitis. Our finding suggests the involvement of HGV in the development of aplastic anemia. In patients presenting with pancytopenia after an episode of acute hepatitis, the definitive diagnosis should be considered and confirmed by RT-PCR and if possible by bone marrow biopsy. Hepatitis G virus was reported first time has a non-A-E hepatitis and placed as flavivirus [1] .The induction of this new agent in the family of Hepatitis has attracted significant attention because of its etiology [2] . Hepatitis G virus has been marked as a cause of non-A through E acute viral hepatitis and sharp liver failure. Aplastic anemia complicating hepatitis is an uncommon but well recognized phenomenon. Hepatitis associated aplastic anemia is a severe disorder with a high mortality (85%) [3] .Hepatitis associated aplastic anemia (HAAA) is a deviation of aplastic anemia in which aplastic anemia follows an acute attack of hepatitis. The marrow failure can be severe and is usually lethal if untreated. Lorenz and Quazier has documented first time HAAA in two case back in 1955 [4] , by 1975 more than 193 cases had been reported [5] . Adil et al has reported, severe aplastic anaemia (SAA) 51.4%, very severe (VSAA) in 16.7% of 144 patients of aplastic anemia cases [6] . A number of reports have mentioned alliance between HGV and HAAA [7] [8] [9] [10] . Number of HAAA cases with a history of multiple blood transfusions has been reported [11, 12] . Crespo et al has documented a case of 24 year old man have community acquired HGV that later progress into severe aplastic anemia, point out HGV for both hepatitis and aplastic anaemia. However greater number of serum samples are needed to prove the association of hepatitis G virus and aplastic anaemia [13] . Moatter et al. has reported 5/43 patients of haemodialysis with raised liver enzyme, reduced platelet count and 21/100 patients of polytransfused b-thalassemia major children infected with HGV RNA form Pakistan [14, 15] . 