A significant increase of HLA-DR3 and DR2 in systemic lupus erythematosus among blacks.

We found a highly significant increase in the incidence of HLA-DR3 and DR2 antigens in black patients with systemic lupus erythematosus (SLE). HLA-DR3 was found in 62% of patients and 20% of controls (p less than 0.0001), and DR2 in 41% of patients and 18% of controls (p less than 0.001). The relative risk (RR), conferred by DR3 was 6.41, and that by DR2 was 3.03. Further, 84% of the patients had DR3 and/or DR2; the combined RR for SLE with these antigens was 9.0. A significant proportion of the patients (57%) developed lymphocytotoxic antibodies; of these, 19% had HLA specific antibodies.

The HLA antigens and ABO blood groups in an American Black population with mitral valve prolapse.

A total of 42 American Black patients with mitral valve prolapse and 194 healthy individuals of similar ethnic background were tested for the distribution of various HLA antigens and ABO blood groups. The most significant result was an increased frequency of Bw35 in patients (74%) as compared with controls (39%), with a P value of less than 0.0001; the relative risk was 4.45.

The HL-A and ABO antigens in trophoblastic disease.

No statistically significant deviations in phenotype frequencies of the 25 HL-A antigens or the ABO antigens were seen when 111 Caucasian patients with trophoblastic disease were compared with 1,259 healthy Caucasian controls. However, an increasein the incidence of HL-A11 was found in 39 patients who currently had the disease, but not in 72 who had recovered from the disease. Further, an increase in the frequency of W18 was observed among 18 patients who currently had 'invasive' disease (choriocarcinoma or invasive mole), but not in 44 who had recovered from such disease. If valid for larger patient population, these increases may suggest association of HL-A11 and W18 with the 'morbidity' of the trophoblastic disease. No increase in histocompatibility was seen in 45 patient-couples over 67 control-couples in terms of decrease in the number of male spouse's HL-A incompatibilities, and no significant difference was seen in the distribution of pregnancies in the two groups. No significant difference was observed in the incidence of different male-female combinations of ABO blood groups between 95 patient-couples and an equal number of control-couples. Lymphocytotoxic antibodies were found in 64 patients (158 sera) or 36% of the 178 patients (413 sera) examined. HL-A specific antibodies were found in 30 or 17% patients (39 sera). Of these 30, 24 patients had molar pregnancies and six had choriocarcinoma. Whether these antibodies have a role in the destruction of neoplastic tissue remains to be determined.

Inactivation of pea leaf phosphofructokinase by light and dithiothreitol.

When intact pea (Pisum sativum L.) plants are illuminated, the glycolytic enzyme phosphofructokinase is inactivated. In crude extracts the enzyme is inhibited by dithiothreitol. It would seem that this cytoplasmic enzyme, like glucose-6-P dehydrogenase, is light-inactivated when the enzymes of photosynthetic carbon metabolism are light-activated.

Chloroplast and cytoplasmic enzymes : V. Pea-leaf carbonic anhydrases.

Chloroplastic and cytoplasmic forms of pea (Pisum sativum L.) leaf carbonic anhydrase were separated by isoelectric focusing. The two forms have identical pH optima, 7.0 for the hydration reaction and 7.5 for the dehydration reaction, and identical Michaelis constants for CO2, 0.03 M. Neither isozyme is affected by any of several compounds involved in carbon metabolism in the green plant.