Kalayanee Khupulsup

Immunoglobulin values in healthy Thai children aged ≤ 24 months determined by nephelometry.

BACKGROUND Variation of normal immunoglobulin (Ig) levels between different genetic and environment factors has been studied. Although antibody deficiency diseases can start from infancy, data of Ig reference levels in children aged ≤24 months are still limited, especially in Asian children. PURPOSE The aim of this study was to determine serum IgG, IgA, IgM, and IgG subclasses in healthy Thai children from the newborn period to age 24 months. METHODS Serum samples were collected from healthy Thai children age <1-24 months to measured serum IgG, IgA, IgM, and IgG subclasses by nephelometry. RESULTS Of the 100 infants, 44% were female with a median (range) age of 13 (0.3-24) months. The geometric mean IgG was 803 mg/dL, IgA 36 mg/dL, and IgM 102 mg/dL. The mean IgG1 was 646 mg/dL, IgG2 127 mg/dL, IgG3 45 mg/dL, and IgG4 17 mg/dL. The average ratios of IgG subclass 1:2:3:4 were 77:15:6:2%. No significant differences in each immunoglobulin isotype between genders were found. Our mean IgG level was slightly lower than that in healthy Thai children, measured by radial diffusion method but not significant except 1-3 months (p = 0.016). However, the mean IgG level in our study was higher than that reported by radial diffusion in healthy US children (p <0.001). CONCLUSIONS This study illustrated the importance of having normal Ig values from age- and ethnically-matched controls by high precision nephelometric assay in order to appropriately diagnose immunologic disorders in Asian infants.

Serum ferritin levels in normal and HIV-1 infected pregnant women.

Between May, 1994 and May, 1995 serum ferritin concentrations were measured in 74 pregnant women who were HIV‐1 positive (17 with CD4 cell counts below 200 cells/uL) and in 148 HIV‐1 negative pregnant controls in first trimester of gestation to determine if a high level of serum ferritin is present in pregnant women with HIV‐1 infection. Comparisons were made between groups stratified by CD4 cell counts. Pregnant women with HIV‐1 infection had 92% higher mean serum ferritin levels (112.8 versus 58.8 ug/L, p<0.005) compared to controls, whereas the mean maternal age, parity, gestational age, haemoglobin levels and body mass index at entry into the study did not differ significantly between the control and HIV‐1 infection groups. The serum ferritin levels inversely correlated with the percentage of CD4 lymphocytes, CD4 cell counts and the CD4/CD8 ratio. This study suggests that serum ferritin levels can also be used as an immunological marker in HIV‐1 infected pregnant women.

A new solid phase passive hemagglutination test for IgM antibody to hepatitis B core antigen.

There is a need for a simple, sensitive, specific, and inexpensive test for immunoglobulin M antibody to hepatitis B core antigen (anti-HBc IgM). A solid phase passive hemagglutination test (SP-PHA) was developed for this purpose and compared with the enzyme-linked immunosorbent assay (ELISA) test. Hepatitis B core antigen (HBcAg) used in PHA and SP-PHA was synthesized in Escherichia coli. Human IgM was captured to a microtiter plate coated with anti-human IgM, and the presence of anti-HBc IgM was demonstrated by the adherence of HBcAg-sensitized erythrocytes to the bottom of a U-shaped microtiter plate. ELISA and SP-PHA were made at 1:100 and 1:1,000 serum dilution, respectively. Both were positive in 100% of 36 cases of acute hepatitis B, 68.18% of 22 cases of chronic hepatitis B, and 20% of 75 healthy carriers of hepatitis B surface antigen (HBsAg) but none in 65 anti-HBc-positive blood donors that had negative results for HBsAg. Results of both tests were identical but were false positive because rheumatoid factor was found only in ELISA. End-point titration by SP-PHA and PHA was also found useful for the differentiation of acute hepatitis B from chronic hepatitis B and HBsAg carriers.

Nephelometry determined serum immunoglobulin isotypes in healthy Thai children aged 2-15 years

Knowledge of what constitute normal serum immunoglobulin (Ig) concentrations are important for the diagnosis of immunologic disorders. Data on normal Ig evaluated by nephelometry are limited in healthy Asian children, none being available for Thai children. One hundred and forty‐eight healthy Thai children aged 2–15 years were tested for serum immunoglobulins G, A, M, G1, G2, G3, and G4 (Ig G, A, M, G1, G2, G3, and G4) by nephelometry. Sixty‐three percent were girls of median interquartile range age 6.9 (4.8–9.7) years. The geometric means for each Ig were summarized and categorized by age. Statistical analyses were used to compare Igs between sexes and age groups, and to compare IgG in this study with data from other published studies. The average ratios of IgG subclasses/IgG for Ig G1:2:3:4 were 66:22:5:7%. IgG, IgA, IgG2, and IgG3 concentrations showed a gradual increase with increasing age. There were no significant sex differences for any immunoglobulin isotype (P= 0.971). Our mean IgG concentration was lower than that measured by the radial diffusion method in healthy Thai children (P < 0.05). In all age groups, the mean IgG concentration in our study was significantly higher than that reported in Turkish and USA children, evaluated by the nephelometric and radial diffusion techniques, respectively (both P < 0.001). This study provides information about normal Ig concentrations measured by nephelometry in healthy Asian children and illustrates the importance of ascertaining normal Ig values for age‐ and ethnic‐matched controls using the same assay to diagnose immunologic disorders correctly.

A passive hemagglutination test for antibody to Naja naja siamensis toxin 3

Abstract A passive hemagglutination test for the semiquantitative determination of antibody to Naja naja siamensis toxin 3 was developed. The assay involved a one-step coupling of the toxin to sheep erythrocyte. The toxin-coupled erythrocyte was stable for at least 4 months at 4°C and upon incubations with various elapid venoms there was no detectable hemolysis. The hemagglutination of the coupled sheep erythrocyte was specific, as shown by inhibition tests with various snake venoms. An application of the hemagglutination test in monitoring antibody production by rabbits during a course of immunization was studied.