Abstract. A modification of the conventional antiglobulin test for routine use is described. Saline as the red cell suspension medium is substituted with salt solution of low ionic strength. This permits a considerable decrease in the incubation time, which is of practical importance in clinical work. The sensitivity of the reaction does not seem to be decreased by this procedure, in some instances even an increase in reaction strength can be observed.

The mixed leukocyte reaction (MLR) is impaired in multiple sclerosis and certain arthritides, notably rheumatoid arthritis. The present study shows that this phenomenon is not disease‐Specific: cells from patients with multiple sclerosis react poorly also with cells from patients with arthritis. A time study of the reaction excludes the possibility of an initial Strong MLR followed by cell death – a phenomenon sometimes seen in animal experiments. A study of the affect ot patient sera on a two‐way MLR between normal individuals shows that a small depressive effect is present with the patient sera, but this is not of the magnitude that it can explain the MLR impairment under study.

Frequencies of HLA A, B, C, and DR antigens were studied in 100 schizophrenic patients and 919 controls from South Sweden. The patients were diagnosed according to the DSM III criteria and divided into four clinical subgroups (hebephrenic, paranoid, residual, and undifferentiated). In the schizophrenic patients as a whole significant increases were found for A2, A3, B17, B27, and Cw2 and decreases for A1, A11, and B8. A previous positive association with A9 from the same population was not confirmed. A significant heterogeneity between the four clinical subgroups was found for A3 and Bw35. Most of the associations between HLA antigens and schizophrenia reported in the literature appear to be fortuitous and dependent on the large number of trials made. However, confirmed increases have been found for A9 and B17, and confirmed decreases have been observed for A1 and B7. Some evidence for a heterogeneity between clinical subgroups was found in the present as well as in previous investigations.

The phenotype frequencies of HL-A specificities have been investigated in 47 chronic schizophrenics subdivided in an older and a younger group. The frequency of HL-A 9 was significantly increased in the psychotics as compared to a reference group of 1,263 healthy blood donors, pregnant women and potential kidney donors. Deviations in frequency were also found concerning W 19 and HL-A 5. As HL-A 9 was mainly found in the older group of schizophrenics, it is suggested that HL-A 9 might be associated to some form of schizophrenia with a chronic course.

To find out whether IgG genes are involved in atopy we studied 26 of 101 laboratory technicians who had developed laboratory animal allergy (LAA). The genes for the constant region of the heavy chains of IgG subclasses were analyzed by serum Gm allotypes, representing products on allelic level of the IGHCG1, IGHCG2 and IGHCG3 on chromosome 14q32. There was a significantly increased frequency of the Gm(f,f;n,n;b,b) genotype (57.7 instead of 22.3%, p < 0.001) representing IgG1, IgG2 and IgG3 molecules and in particular increased frequency of Gm genotypes with the homozygous expression of G2m (nn) (69.2 instead of 27.4%, p < 0.001) and of the Gm(fnb) haplotype (75 instead of 44.8%, p < 0.001) compared to a normal Caucasian population. An increased HLA-DR4 content of the LAA group (61.5 instead of 33.7%, p < 0.01) was further investigated for Gm allotypes. Among 16 HLA-DR4 LAA individuals, the Gm(f,f;n,n;b,b) genotype (56.3 instead of 22.3%, p < 0.01) and the Gm genotypes with the homozygous expression G2m(n, n) (62.6 instead of 27.4%, p < 0.01) dominated. However, the HLA-DR4 frequency among Gm(f,f;n,n;b,b) of LAA patients did not deviate from the frequency of healthy individuals of the same Gm genotype. The increased frequency of HLA-DR4 antigen in LAA patients might be due to its association to the Gm(f,f;n,n;b,b) genotype. This study supports the following concept: the susceptibility of developing LAA is associated with Gm allotypes Glm(f) expressed from IGHCG1, G2m(n) from IGHCG2 and G3m(b) from IGHCG3 on both alleles situated close to IGHCE on chromosome 14q32. The association of LAA to Gm allotypes [Gm(f,f;n,n;b,b)] expressed from chromosome 14q32 and of HLA class II antigens (HLA-DR4) expressed from chromosome 6p21.3 further confirms the polygenic inheritance of the immune response in atopy.