In HLA-nonidentical bone marrow transplantation, we studied the characteristics of donor NK cells, recipient leukemia cells, and the cytokine environment that predict the antileukemia effects of allogeneic NK cells. We found that the risk of relapse in pediatric patients with hematologic malignancies was best predicted by a model taking into consideration the presence of inhibitory killer cell Ig-like receptors (KIRs) on the donor’s NK cells and the absence of corresponding KIR ligand in the recipient’s HLA repertoire (a receptor-ligand model). The risk of relapse was prognosticated less precisely by the Perugia donor-recipient KIR ligand-ligand mismatch model or by a natural cytotoxicity model. In contrast to the ligand-ligand model, we found that the new receptor-ligand model was accurate when analysis was applied to patients with lymphoid malignancy. These findings corroborate our observations that the recipient’s KIR repertoire, which was derived from highly purified, HLA-disparate CD34+ cells, resumed a donor-specific pattern within 3 mo of transplantation, but did not correlate evidently with the donor or recipient ligand repertoire. In an in vitro assay and an in vivo mouse model, human NK cell cytotoxicity toward human leukemia cells with 11q23 chromosomal rearrangement increased with the number of receptor-ligand mismatch pairs or prestimulation with IL-12 and IL-18. These findings provide new insights into the determinants of antileukemia effects of allogeneic NK cells and therapeutic strategies.

Rheumatoid-like lesions developed in 9 of 25 (36%) Old English rabbits drinking cow’s milk for 12 weeks. The incidence of lesions in male and female animals was similar. The majority of rabbits drinking cow’s milk developed increased numbers of nucleated cells and raised percentages of T lymphocytes in their synovial fluids, compared to control rabbits. The cell counts and T cell percentages correlated with the severity of the histological lesions. No evidence of glomerulonephritis was observed in any of the experimental animals.

SUMMARY Rabbits receiving repeated intravenous injections of killed bacteria (Escherichia coli or Bacillus subtilis) developed IgM rheumatoid factor which reacted with autologous heataggregated IgG. In addition, 5/7 'Old English' and 7/8 'Sandy Lop' rabbits receiving killed E.coli developed rheumatoid-like synovial lesions. 'Old English' rabbits developed lesions of a more severe nature. Three of eight 'Sandy Lop' rabbits injected with killed B.subtilis had high levels of rheumatoid factor but only mild joint lesions.Key words: arthritis, autologous heat-aggregated IgG, Escherichia coli, Bacillus subtilis.Rheumatoid factor-like substances (RFLS) have been described in rabbits after the administration of a variety of bacterial' or protein23 antigens. However, joint lesions were not reported in any of these models. In this paper we report the induction of both rheumatoid factor (RF), reacting with autologous heat-aggregated IgG, and rheumatoid-like synovial lesions in rabbits injected with either killed Escherichia coli or Bacillus subtilis. subtilis (B. subtilis NCTC 3610) were grown in 1 litre volumes in 3 litre Erlenmeyer flasks at 37°C for 48 hours in brain/heart infusion broth (Difco). Formalin (final concentration of 0-6%) was then added to the broth cultures, which were left for 24 h at 20°C in order to kill the bacteria. The bacteria were harvested by centrifugation, and the deposit was washed three times in phosphate-buffered saline (PBS). The bacteria were resuspended in PBS and standardised by opacity testing to 6 x 109 bacteria/ ml. The bacteria were finally sterilised by steaming for 1 h and thereafter stored at -20°C. Control 'Old English' and 'Sandy Lop' rabbits did not receive any bacteria. Rabbits were bled at monthly intervals from the marginal vein of the ear. Sera were frozen and stored at -20°C. ASSESSMENT OF ARTHRITIS

Such histologic diagnoses are extremely rare, and this is the 26th case report to our knowledge in English language journals. These lesions should be treated surgically to exclude malignancy. This is the first case reported in the United Kingdom and the first to be excised by pure laparoscopic means, which we believe provides effective and successful surgical management.

SUMMARY A 34 year old man is described with systemic lupus erythematosus and recurrent massive pleural effusions. Systemic treatment with corticosteroids and azathioprine controlled all other manifestations of the disease apart from the pleural effusions. These were finally, successfully treated by pleurectomy.