Simultaneous measurement of HbA1C and Hemoglobin by Turbidimetric inhibition immunoassay from a single punch of dried blood spot samples

Hemoglobin and glycosylated hemoglobin (HbA1C) are frequently monitored health indicators in population based studies for information about the status of nutrition and diabetes control. We present here possibly for the first time the findings of simultaneous estimation of Hemoglobin and HbA1C on Dried blood spot (DBS) samples by a single test. Validation was done by turbidimetric inhibition immunoassay (TINIA) using Roche Integra 400 plus instrument. Paired whole blood and DBS samples were tested for HbA1C estimation by Integra 400 plus. Total hemoglobin values obtained during HbA1C estimation were compared with hemoglobin values estimated by Coulter AcT 5 Diff CP Hematology counter. Agreement in HbA1C and hemoglobin values between paired whole blood and DBS samples was found to be high with R2 values of 0.994 and 0.9349, respectively. Intra- and inter- assay precision was found to be within 10% for both parameters. Values obtained after assaying DBS samples prepared by spotting proficiency samples on Whatman 903 protein saver cards demonstrated acceptable standard deviation indices resulting in successful participation in EQAS programs for both these parameters. The results reveal the potential of TINIA for simultaneous estimation of hemoglobin and HbA1C from a single punch of the DBS samples.

A review on peripheral blood CD4+ T lymphocyte counts in healthy adult Indians.

The CD4+ T lymphocytes are the crucial cells in the cascade of events in forming immune response to the foreign antigen and hence monitoring the CD4+ T cell counts to understand the extent of immune deficiency is a common practice. CD4+ T cells are also the primary target cells for human immunodeficiency virus (HIV). Hence CD4+ T lymphocyte count is the most important marker of immune dysfunction in HIV disease progression. The estimation of CD4+ T cell counts is used to decide the initiation of anti retroviral therapy (ART), to monitor the efficacy of ART and to start treatment for opportunistic infections (OIs). To develop the threshold levels of CD4+ T cell counts, data from western countries are being used in India. The CD4+ T cell counts are known to be influenced by race and environmental factors. Hence it is important to establish the reference ranges for the CD4+ T cell counts in the target population to understand the immune dysfunction. The information on the lower limits of the CD4+ T cells count is necessary to decide the initiation and monitoring of ART. The published data on the CD4+ T cells count in healthy Indian adult population have been reviewed, analyzed and discussed in this review article. The requirement of establishment of reference ranges in Indian population is discussed.

Safety & immunogenicity of tgAAC09, a recombinant adeno-associated virus type 2 HIV-1 subtype C vaccine in India.

Background & objective: A phase 1 trial of adeno-associated virus based HIV-1 subtype C vaccine (tgAAC09) was conducted at two sites in Germany and Belgium and one site in India. This paper reports the safety and immunogenicity of tgAAC09 in healthy adult Indian volunteers. Methods: Between January 2005 and December 2006, 30 consenting volunteers were enrolled in the placebo controlled double-blind dose-escalation trial [3x109, 3x1010 and 3x1011 DNase resistant particles (DRPs)/ml]. Single injection of the candidate vaccine was administered to ten volunteers randomized in 8:2 ratio in vaccine and placebo arms at each dosage level. Results: The mean age of study volunteers (16 men and 14 women) was 34 yr. Six local reactogenicity events and 14 systemic reactogenicity events like malaise, fever, headache and myalgia were reported, both were dose-dependent. The difference between the adverse events reported by vaccine and placebo recipients (79 and 67%) was not significant. A modest IFN-γ ELISPOT response [248 spot forming units (SFU)/million cells] was detected in one volunteer from high dose group and low response (56 and 75 SFU/million cells) in two volunteers in low and mid-dose groups. A post-vaccination dose-dependent increase was observed in anti AAV2 neutralizing titres. None of the volunteers showed a positive antibody response to HIV-1. Interpretation & conclusions: The trial was a benchmark in phase I clinical evaluation of HIV candidate vaccines in India. The vaccine was generally well tolerated and raised no safety concerns. The vaccine was found to be weakly immunogenic. It is essential to understand the role of pre-existing immunity against vectors and significance of evaluation in a prime-boost strategy.