HLA B27 in ankylosing spondylitis: differences in frequency and relative risk in American Blacks and Caucasians

Twenty-eight HLA alleles of the A and B loci were determined in 23 American Blacks and 50 Caucasians with primary ankylosing spondylitis (AS). The prevalence of HLA B27 was significantly increased in American Black patients (48 per cent) vs Black controls (two per cent), but was much less than the 94 per cent found in Caucasian patients (controls eight per cent). The lower prevalence of B27 in American Black patients vs Caucasian patients was significant (p less than 0.001), and indicated that susceptibility to AS is not as closely associated with B27 in Blacks as in Caucasians. No other HLA antigen was significantly associated with AS in either racial group. Among B27 positive individuals, the relative risk of developing AS was significantly lower in American Blacks than in Caucasians. These data indicate that for diagnostic purposes, the absence of B27 is less important in ruling out AS in Blacks than in Caucasians.

The origin of serum protein, A, B, and H blood group, and Gm and Inv antigens in house dust

Materials precipitated from an aqueous extract of house dust by saturation with ammonium sulphate showed immunological reaction with antisera to human serum albumin, human alpha1-acid glycoprotein, human IgG, Gm and Inv antigens and to A, B and H antigens. It is concluded that the albumin and alpha1-acid glycoprotein are of human origin. It seems that the apparent IgG activity is due to cross-reactivity since, from the anticipated specificities of the Fab and Fc fragments of human IgG, the former could not be detected, and since Gm (6) activity was present, unexpectedly, in Swiss house dust. The A, B and H blood group antigenic activities were detected in relative concentration different from those expected if they were solely of human origin. It is concluded that they are from both human and non-human sources.

The karaite community of Iraq in Israel: a genetic study

Ninety-eight of 136 (72%) individuals at least 6 years of age from a small isolate of the Karaite community, known to have lived in Iraq since the tenth century, were examined. In Iraq this group maintained a highly inbred existence but married Karaites from Egypt after their immigration to Israel in 1951. Observations of several unique gene frequencies for blood group and isoenzyme markers, not described among other Jewish groups, are explicable by isolation and genetic drift in a very small community.

The Diego blood groups: a genetic linkage analysis

Data are presented which show that the Diego blood groups are not part of the Dombrock or Yt blood group systems and that the locus controlling Di is not closely linked to the loci controlling ABO, Fy, Jk, Kell, MNSs, Rh, Gm, Inv, AcP,ADA, PGD, and UMPK.

Gammaglobulin groups of the Khoisan peoples of Southern Africa: evidence for polymorphism for a Gm1,5,13,14,21 haplotype among the San

The Gm and Inv types were determined for eight San (Bushman) populations, two Khoikhoi (Hottentot) populations, one Coloured population, 112 San families in which the genotypes of the parents could be unambiguously determined, and for 65 San families in which the genotype of one or both parents could not be determined with certainty. The population and family data establish that the haplotype array of the San is composed of Gm1,21, Gm1,13, Gm1,5,13,14, and Gm1,5,13,14,21; Gm1,5,6 and Gm1,5,6,14 are also present but may have been acquired through admixture with Negroes. The Gm1,5,13,14,21 haplotype has not been found to be polymorphic in any other population. The haplotype array of the Khoikhoi is composed of Gm1,2,21, Gm1,13, and Gm1,5,13,14; Gm1,5,6 and Gm1,5,6,14 are also present but, as in the case of the San, may be due to admixture. The San and Khoikhoi differ from each other in that the former have the Gm1,21 and Gm1,5,13,14,21 haplotypes not present in the latter, and the Khoikhoi have the Gm1,2,21 haplotype not present in the San. These three haplotypes and Gm1,13 serve to distinguish the Khoisan people from other African peoples.

Comparison of the value of the two- and one-hour glucose levels of the oral GTT in the diagnosis of diabetes in Pima Indians

In many population and screening studies of diabetes, the one-hour glucose level of the GTT has been used to define the diabetic status of subjects. The one-hour postglucose load determination has been preferred over the two-hour value by many investigators primarily because of convenience and justified on the basis of the high correlation between the two values. Venous plasma glucose levels, one and two hours after 75-gm. carbohydrate load, were determined on over 1600 Pima Indians. In most sex and age groups, the frequency distributions of both the one-hour and two-hour glucose levels were clearly bimodal. By the logarithms of the glucose values these distributions were consistent with a model of two overlapping Gaussian distributions. The data indicate that for the Pima the amount of overlap of the distributions was greater for the one-hour than for the two-hour values. For each sex and decade the probabilities of misclassification of a normal as "hyperglycemic" and vice versa were smaller for the two-hour than for the one-hour values. Such misclassifications for the two-hour levels averaged 6.6 per cent and 11.6 per cent for the one-hour levels. The reproducivility of the GTT taken one to three weeks apart in a sample of ninety-nine Pima Indians showed that the two-hour level was superior to the one-hour level as measured by the mean values of the absolute difference between log GTT levels for test and retest values. The one-hour measurements also gave more disagreements between the classifications of diabetic status than the two-hour test values. If a single measure of glucose tolerance is to be selected for the diagnosis of diabetes among Pima Indians, these data provide a mathematical rationale for preferring the two-hour level to the one-hour determination.

Haptoglobin-ABO interaction: a possible explanation for the excess of Hp 1 among offspring of ABO incompatible matings

The Hp1 frequency among ABO phenotypes varies in the Hutterite population as follows: O less than A less than B less than AB. Within group O, the Hp1 frequency is significantly lower than the Hp1 frequency among the other groups combined. The Hp1 frequencies among ABO genotypes, known by means of family pedigrees, vary as follows: OO less than AO less than BO less than AB less than AA less than BB. This holds for both main subjects of this isolate, although they have been reproductively isolated since World War I. The higher Hp1 frequency among type A, B, and AB individuals explains the observation of the higher Hp1 frequencies found among H-leut offspring who are incompatible with their mothers (mainly AO offspring of OO mothers) compared to offspring from the same matings who are compatible with their mothers.