Concentration of IgG, IgA, and IgM in terms of international units in the sera of healthy individuals

Bull. Org. mond. Santi 1973, 49, 217-218 Bull. Wld Hlth Org. Concentration of IgG, IgA, and IgM in terms of international units in the sera of healthy individuals D. SINKOV, V. TOLEV, & T. 9TEREVA 1 Abstract This paper describes experiments on the determina- tion ofthe level ofIgG, IgA, andIgM in normal human sera, using an international reference preparation for comparison. The concentration of immunoglobulins (Ig) in human serum has been studied extensively. However, very different results are obtained by different authors (Hein, 1969). Among the reasons for this diversity are the general tendency to express immunoglobulin concentrations in weight units per millilitre and the lack of a unified reference preparation for compari- son (Rowe et al., 1970, 1972). In order to remedy this situation, WHO developed an international reference preparation for expressing the immunoglobulin con- centration in international units per millilitre and recommended it for use in radial immunodiffusion (Rowe et al., 1970; Europ. J. Immunol., 1971). This communication describes experiments to determine the level of IgG, IgA, and IgM in normal human sera, the WHO reference preparation serving for comparison. Materials and methods Sixty healthy individuals (30 men and 30 women) from Sofia, Bulgaria, aged between 21 and 50 years, were included in the study. The experiments were carried out by the method of Mancini et al. (1965), with monospecific anti-IgG (Wellcome), anti-IgA (Behringwerke), and anti-IgM (Institute of Haematology, Sofia) sera.ApH 8.6 buffer (barbital plus barbital sodium) was used in the agar. The rings obtained were read after standing at 37°C for 24 h, washing, drying, and finally staining with amido black lOB. The concentration was plotted against the diameter of the precipitation rings. 1 Research Fellows, Department of Immunohaematology, Institute of Haematology and Blood Transfusion, Plovdivsko pole 6, Sofia 56, Bulgaria. IU 260 I' 1 ISO 0*L 400 0 4" 000 - - 0000 000 0 -16000~~~0 000000 000 0 0600 000 0 @0440 @000 00 00 @000 00 - :000 0000 0 so 000000 000 000 8000 00- 6. -- ~tiko- IgG IgA IgM Igm males females Fig. 1. Distribution of the individual values of IgG, IgA, and IgM. Table 1. Concentration (in IU) of IgG, IgA, and IgM in the sera of healthy individuals Mean Standard IndividualIg Sex a No. value dvain vle(IU) dvain vle IgG M+F 60 129.4 28.6 64-180 IgA M+F 60 114.3 40.5 48-240 IgM M 30 114.7 51.5 60-295 F 30 147.0 34.4 90-220 M + F 60 130.8 46.6 60-295 a M = males; F = females. 3105 - 217 218 BRIEF COMMUNICATIONS Table 2. Concentration (in IU) of IgG, IgA, and IgM in the sera of healthy individuals, according to various workers Place No. Age (years) IgG IgA IgM Sofia, Bulgaria a 95 19-21 119+80 148+62 not tested Skopje, Yugoslavia b 100 136±50 249±113 96+40 Lausanne, Switzerland c 100 20-29 135 136 178 (87-208) (56-334) (81-380) Offenbach, F. R. of Germany c 45 20-29 124 108 133 (86-187) (48-244) (59-298) Utrecht, Netherlands c 100 20-29 116 94 127 (65-206) (40-228) 48-334) a To§kov & Abralev, 1972 (arithmetic means). b Dejanov & Bojadliev, 1972 (arithmetic means). c D.S. Rowe, personal communication (geometric means). A reference preparation (67/97) was supplied by the WHO International Reference Centre for Immuno- globulins, Lausanne. Five dilutions of the prepara- tion (1: 4-1: 64) were used for plotting the standard curves for IgG; for IgA and IgM, the preparation was used undiluted and in dilutions up to 1: 32. The data were calculated in accordance with the instructions for the use of the preparation (Rowe et al., 1970) and statistically treated by the method of variation ana- lysis. Results and discussion The results are presented in Table I and Fig. 1. The individual values varied within wide limits. However, the standard deviations did not differ from those reported by Hein (1969) and other workers (Table 2). Fig. 1 indicates that only a limited number of indivi- duals showed high upper limits of IgA and IgM values. The values ofIgG in men and in women were rather close, no statistically significant differences being found (P > 0.1). The same was true for IgA. In contrast, the IgM concentration in females was substantially higher than that in males (Table 1 and Fig. 1). Analogous data obtained by other workers (Butterworth et al., 1967) and the confidence level (P < 0.01) of the difference found (about 30 units) reflect the influence of sex on the IgM concentration. Table 2 shows the concentrations of immuno- globulins expressed in international units per milli- litre. The quantitative ratios between the three main classes found when the concentrations were ex- pressed by weight (IgG > IgA > IgM) disappeared when the international units were introduced. This might render the interpretation of certain dysglo- bulinaemia states difficult for those who are not yet familiar with the international units. For this reason, we suggest that concentrations of immuno- globulins should be expressed in both ways when appropriate. REFERENCES Butterworth, M. et al. (1967) Nature, 214, 1224 Dejanov, I. I. & BojadEiev, I. (1972) In: Proceedings ofthe Symposium on Fractionation and Immunochemistry of Plasma Proteins, Varna, 9-11 October 1972, Sofia, Centre of Medical Scientific Information Europ. J. Immunol., 1, 224-225, 1971 Hein, H. (1969), Fortschr. Med., 87, 22-25 Mancini, G. et al. (1965) Immunochemistry, 2, 235-245 Rowe, D. S. et al. (1970) Bull. Wld Hlth Org., 42, 535-552 Rowe, D. S. et al. (1972) Bull. Wld Hlth Org., 46, 67-79 Togkov, A. & Abra§ev, I. (1972) In: Proceedings of the Symposium on Fractionation and Immunochemistry of Plasma Proteins, Varna, 9-11 October 1972, Sofia, Centre of Medical Scientific Information