Measurements of concentrations of human serum immunoglobulins.

PREVALENCE OF a1-ANTITRYPSIN DEFICIENCY IN JAPAN 255 level in 19 of 47 heterozygotes, suggesting that the a,-AT level may be raised to the normal range under certain physiological or pathological conditions such as infection and pregnancy. ACKNOWLEDGEMENTS The authors express their thanks to Professor S. Imamura and Dr Y. Shinozaki for allowing them to perform the survey, and to Dr E. C. Foulkes for correct- ing the manuscript. REFERENCES Briscoe, W. A., Kueppers, F., Davis, A. L. & Beam, A. G. (1966) Amer. Rev. resp. Dis., 94, 529 Eriksson, S. (1964) Acta med. scand., 175, 197 Eriksson, S. (1965) Acta med. scand., 177, Suppl., p. 432 Ganrot, P. O., Laurell, C.-B. & Eriksson, S. (1967) Scand. J. clin. Lab. Invest., 19, 205 James, K., Collins, M. L. & Fudenberg, H. H. (1966) J. Lab. clin. Med., 67, 528 Kueppers, F., Briscoe, W. A. & Beam, A. G. (1964) Science, 146, 1678 Kueppers, F., Fallat, R. & Larson, R. K. (1969) Science, 165, 899 Laurell, C.-B. & Eriksson. S. (1965) Clin. chim. Acta, 11, 395 Lieberman, J. (1969) New Engl. J. Med., 281, 279 Lieberman, J., Mittman, C. & Schneider, A. S. (1969) J. Amer. med. Ass., 210, 2055 Talamo, R. C., Blennerhassett, J. B. & Austen, K. F. (1966) New Engi. J. Med., 275, 1301 Talamo, R. C., Allen, J. D., Kahan, M. G. & Austen, K. F. (1968) New Engi. J. Med., 278, 345 Tarkoff, M. P., Kueppers, F., Miller, W. F. (1968) Amer. J. Med., 45, 220 Measurements of Concentrations of Human Serum Immunoglobulins * Concentrations of immunoglobulins in human se- rum are frequently measured for both clinical and research purposes, and the values have been ex- pressed in terms such as mg/ml. However, there has been little confidence that concentrations, as estimated by different laboratories using different reference materials, are comparable. With the object of improving the uniformity of estimates by diffe- rent laboratories, a freeze-dried preparation ofhuman serum, coded 67/86, has been assessed for use as a standard for measurements of human serum immu- noglobulins IgG, IgA, and IgM by techniques of immunodiffusion (Rowe, Anderson & Grab, 1970). Part of this batch of material has been established by the World Health Organization 1 as the Inter- national Reference Preparation of Human Immuno- globulins IgG, IgA, and IgM, and international units have been assigned to it such that each ampoule of the International Reference Preparation contains on average 100 IU of IgG, 100 IU of IgA, and 100 IU of IgM. The signatories of this note met recently to consider ways in which the International Reference Preparation might be used to promote uniformity of measurement. * This Note was drafted in February 1971 by the signa- tories listed on page 256. 1 WHO Expert Committee on Biological Standardization (1971) Wld Hlth Org. tecmn. Rep. Ser., No.1463. 2722c International collaborative studies have shown that reasonable agreement between estimates can be achieved in the measurement of IgG, IgA, and IgM in normal human serum using the International Refe- rence Preparation as a standard. (For example, the ratio of the highest and lowest values obtained by 11 different laboratories on one serum sample was 1.36 for IgG, 1.17 for IgA, and 1.31 for IgM). How- ever, estimates in terms of mg/ml of the immuno- globulin contents of a solution of the International Reference Preparation, obtained by comparison with purified immunoglobulins using gel-diffusion tech- niques, showed widely divergent values. The ratio of the highest and lowest values obtained by 9 or 10 different specialized laboratories was 2.2 for IgG, 3.2 for IgA, and 5.0 for IgM (Rowe, Anderson & Grab, 1971). Such divergence of results is consistent with the present lack of uniformity of the numerous immunoglobulin standards prepared in different laboratories, for which concentrations are usually expressed as mg/ml. There would be more agree- ment between laboratories if serum concentrations of IgG, IgA, and IgM were estimated by comparison with the International Reference Preparation, and expressed in terms of International Units per ml. It is therefore proposed: (1) That concentrations of IgG, IgA, and IgM in working standards, as distributed by manufac- 256 NOTES turers and others for serum estimation, should be expressed in international units per milrditre, follow- ing direct comparison of the working standard with the International Reference Preparation or other suitably calibrated preparation. (2) That concentrations of IgG, IgA, and IgM in human sera should be expressed in international units per millilitre following comparison with the calibrated working standards. This is of special importance for data that are to be published. (3) That, to ensure continuity with previous prac- tice, manufacturers and others should continue, for a transitional period, to indicate the estimated im- munoglobulin contents of their standards by weight as well as in international units. The relationships between estimated weight and international units for a given immunoglobulin may be expected to differ between different standards; hence the relationship established for any one batch of standards should not be used as a " conversion factor " for any other standard. (4) That the same principles regarding measure- ments and expression of serum concentrations of IgG, IgA, and IgM in units should also apply to the measurement of IgD and IgE, for each of which a national research standard is now available (Rowe, Anderson & Tackett, 1970; Rowe et al., 1970) and national units have been defined. It is hoped that at a later stage international reference preparations of these immunoglobulins will be established and international units defined. It is recognized that the use of international units to express immunoglobulin content will initially be unfamiliar. International units will come into general use more rapidly if it is realized that they give greater agreement between estimates than is obtainable in other ways at the present time. There is a need to familiarize clinicans, clinical pathologists, and all others involved in measuring immunoglo- bulin levels with the advantages of these proposals. It is hoped that the concentrations of IgG, IgA, and IgM in all standards will be indicated in inter- national units per millilitre by the beginning of 1972. The levels and ranges of serum immunoglo- bulins in IU/ml in populations grouped according to age, race, and locality and in health and disease should be investigated and published as a matter of urgency. Preparations related to the International Reference Preparation and calibrated in terms of international units are now generally available, free of charge. In the Americas preparation 67/95 is available from the Director, NCI Immunoglobulin Reference Centre, 6715 Electronics Drive, Springfield, Va. 22151, USA. In the United Kingdom, preparation 67/99 is avail- able from the Director, Division of Biological Stan- dards, National Institute for Medical Research, Mill Hill, London, N.W.7., England. Workers elsewhere should request preparation 67/97 from the Director, WHO International Reference Centre for Immuno- globulins, 21 rue du Bugnon, 1011 Lausanne, Switzerland. The International Reference Preparation of Hu- man Immunoglobulin IgG, IgA, and IgM is avail- able only in limited quantities; in general, it is reserved for the calibration of national standards. For this purpose it may be obtained from the Director, WHO International Laboratory for Biolo- gical Standards, Statens Seruminstitut, Amager Boulevard 80, Copenhagen S, Denmark. The national Research Standards for IgE and IgD are available as follows: the Research Standard for IgE, coded 68/341, and the Research Standard for IgD, coded 67/37, may be obtained from the indicated addresses in London, England, by workers in the United Kingdom, and from the address in Lausanne, Switzerland, by workers elsewhere. * * * Dr S. G. Anderson, Division of Biological Standards, National Institute for Medical Research, Mill Hill, London, England Dr D. R. Bangham, Director, Division of Biological Standards, National Institute for Medical Research, Mill Hill, London, England Dr Irene Batty, Wellcome Research Laboratories, Becken- ham, Kent, England Dr W. Becker, Behringwerke AG, Marburg/Lahn, Federal Republic of Germany Dr B. Cinader, President, International Union of Immu- nological Societies, Department of Medical Cell Bio- logy, University of Toronto, Toronto, Canada Dr M. van der Giessen, Central Laboratory of the Nether- lands Red Cross Blood Transfusion Service, Amster- dam, the Netherlands Dr F. Hymes, Director, Meloy Laboratories, Biological Products Division, Springfield, Va., USA Dr D. Long, Wellcome Research Laboratories, Becken- ham, Kent, England Dr F. Peetoom, Director of Research, Hyland Labora- tories, Costa Mesa, Calif., USA Dr K. Pondman, Central Laboratory of the Netherlands Red Cross Blood Transfusion Service, Amsterdam, the Netherlands MEASUREMENTS OF CONCENTRATIONS OF HUMAN SERUM IMMUNOGLOBULINS 257 Dr M. Raynaud, Chairman, Standardization Committee of the International Union of Immunological Societies, Institut Pasteur, Annexe de Garches, Garches, France Dr C. B. Reimer, Biological Reagents Section, Center for Disease Control, Atlanta, Ga., USA Dr D. S. Rowe, Director, WHO International Reference Centre for Immunoglobulins, Lausanne, Switzerland Dr H. G. Schwick, Behringwerke AG, Marburg/Lahn, Federal Republic of Germany Dr S. Vrancheva, Biological Standardization, World Health Organization, Geneva, Switzerland REFERENCES Rowe, D. S., Anderson, S. G. & Grab, B. (1970) Bull. Wld Hlth Org., 42, 535 Rowe, D. S., Anderson, S. G. & Grab, B. (1971) Bull. Wld Hlth Org., (In press) Rowe, D. S., Anderson, S. G. & Tackett, L. (1970) Bull. Wid Hlth Org., 43, 607 Rowe, D. S., Tackett, L., Bennich, H., Ishizaka, K., Johansson, S. G. 0. & Anderson, S. G. (1970) Bull. Wid Hlth Org., 43, 609 A Suction Dredge for Collecting Biomphalaria and other Molluscs from Deep Water by M. A. PRENTICE 1 & G. E. EALDEN 2 Snails of the Biomphalaria choanomphala group occur in certain great lakes of Africa both in shallow water and down to depths of at least 40 feet (12 m) (Mandahl-Barth, 1958). Investigation of the significance of these snails as intermediate hosts of Schistosoma mansoni under natural conditions has hitherto been hampered by the difficulty of collecting adequate numbers from deep-water habitats. None of the usual methods of collecting samples of lake-bottom fauna are satisfactory (Webbe, 1965); the Eckman grab will operate only on suitable substrates and samples a very small area during a working day, and although conven- tional dredges will sample larger areas they cannot be used on rocky or boulder-strewn bottoms. The suction dredge was constructed in an attempt to overcome these sampling problems. It can be operated continuously over any type of bottom and the collected material is presented as a well-washed, silt-free sample consisting mainly of live molluscs and gravel. The sample from each run may be pooled or, by changing the collecting sieve at inter- vals, fractionated. Very large areas of bottom can be scanned in a few hours and approximate distri- bution patterns for various molluscs are quickly visualized. 1 Senior Entomologist, Vector Control Division, Ministry of Health, Kampala, Uganda. 2 Senior Field Officer, Vector Control Division, Ministry of Health, Kampala, Uganda. 2722D Apparatus The apparatus consists of a petrol-driven pump mounted on a small boat powered by an outboard motor; material is pumped off the lake bottom through a trailing pipe and discharged into a wire- mesh collecting basket (Fig. 1, 2). The pump is of the diaphragm type 3 and has only one simple flap valve on the intake side. The diaphragm is free at the periphery and acts as its own delivery valve. The generous working clearances of the pump and the flexible diaphragm result in minimal damage to live material (dragonfly nymphs, for example, are delivered unharmed) and small stones up to 3/4 in (18 mm) diameter pass without damage to the pump. The intermittent suction, charac- teristic of this type of pump, helps to prevent the inlet being blocked by detritus. Centrifugal- type pumps have been found unsuitable because of their small working clearances. To preserve the smooth gradient of the intake pipe, and to prevent the outlet becoming blocked by accumulated sand or gravel, the pump is mounted on bearers resting on the gunwales of the boat. The discharge from the pump is directed down a slight gradient into a removable wire sieve (3-5 mm mesh) supported in a frame attached outboard to the side of the boat. For preliminary work over large areas, 3 Simplite MK III, manufactured by W. B. Selwood, Chandlersford, Hampshire, England.