Sixty six patients with systemic lupus erythematosus (SLE) were genotyped using aHindIII restriction fragment length polymorphism identified by CR1.1 cDNA, then were followed up for an average of 50 months to evaluate the stability of their CR1 activities. The gene frequencies for the two alleles which correlate with the numeric expression of CR1 on the erythrocytes were not significantly different between 66 patients with SLE and 52 normal controls. A discrepancy between homozygosity for a high allele and a negative CR1 activity was found in many patients. These patients, however, had significantly lower concentrations ofserum complement than did patients with a positive CR1, and some were in an active state of the disease. Furthermore, there were several patients in whom the CR1 activities changed from negative to positive together with an increase in serum complement. Our results suggest that the decreased expression of CR1 on erythrocytes in patients with SLE is not inherited, rather it is a consequence of the disease processes.

The expression of c‐kit ligand and interleukin 6 (IL‐6) genes in mouse bone marrow‐derived stromal cell lines was examined using quantitative polymerase chain reaction (PCR) analysis based on the design of an internal DNA control. The stromal cells studied included the 14F1.1 endothelial‐adipocytes that support long‐term hemopoiesis and two additional cell lines (MBA‐1, MBA‐13) which do not have this function. All the cell lines expressed c‐kit ligand gene constitutively, and this expression was not increased by lectins. On the other hand, the expression of the IL‐6 gene was markedly induced in all the lines by lipopolysaccharide (LPS) and by phorbol 12‐myristate 13 acetate (PMA). The constitutive expression of c‐kit ligand in 14F1.1 cells was the lowest among the three cell lines studied and could be increased by stimulation with IL‐4. Thus, we observed some quantitative differences among the cell lines in their expression of cytokine genes. However, the unique capacity of 14F1.1 cells to support in vitro hemopoiesis cannot thus far be explained solely on the basis of the ability of these cells to secrete cytokines which are not produced by other stromal cell lines. c‐kit ligand may be necessary, but its presence alone is not sufficient for 14F1.1 cells to support prolonged hemopoiesis.

Mouse endothelial-adipocyte cell line (14F1.1), which induces proliferation of mouse stem cells in culture, is also capable of supporting long-term survival in culture of human myeloid progenitor cells; colony forming unit-granulocyte/macrophage (CFU-GM) was recovered from cultures incubated with the 14F1.1 cell line after over a month of incubation. The CFU-GM population increased beyond the input number, whereas, in control cultures initiated without stromal cells, the number of progenitors gradually declined. Addition of a relatively low concentration of human colony-stimulating factors (CSFs) into the cultures promoted the formation of "cobblestone areas," where mouse stroma and human hemopoietic cells closely interacted. 14F1.1 supernatant alone did not support the survival of human CFU-GM but synergized with the function of human granulocyte-macrophage colony-stimulating factor (GM-CSF) to stimulate adherent macrophage proliferation.

We studied rearrangement of human T cell receptor genes (TCR) of C beta, C gamma, V gamma and J gamma in 34 cases of adult T cell leukemia/lymphoma (ATLL), consisting of 29 cases with monoclonally integrated HTLV-I proviral DNA (ATLL-W) and five without monoclonal integration (ATLL-O), in comparison with 12 cases of other peripheral T cell lymphomas (non-ATLL). All cases of both ATLL and non-ATLL showed some rearrangement of T cell receptor genes (TCRs) of C beta, C gamma, V gamma, or J gamma. Rearrangement of TCR beta was found in 28 of 29 cases of ATLL-W, all cases of ATLL-O, and eight of 12 cases of non-ATLL. Rearrangement of TCR gamma was observed in 21 of 22 cases of ATLL-W, and in all cases of ATLL-O and non-ATLL. In TCR gamma, rearrangement of C gamma was seen in six of 20 cases of ATLL-W, none of three ATLL-O cases and three of six cases of non-ATLL. V gamma rearrangement occurred in 14 of 18 cases of ATLL-W, one of two cases of ATLL-O, and three of six cases of non-ATLL. Rearrangement of J gamma was found in 16 of 22 cases of ATLL-W, two of five ATLL-O cases, and six of seven non-ATLL cases. Rearrangement was more frequent in ATLL-W than in ATLL-O and non-ATLL. The incidence rate of rearrangement of V gamma families of V gamma 1, V gamma 2, and V gamma 3 was nearly the same in each group, except for deletion of V gamma 3, which was often observed in ATLL but was absent in non-ATLL. These results indicate the usefulness of detection of TCR and HTLV-I proviral DNA to differentiate ATLL from other T cell malignancies.

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