A Role of NKR-P1A (CD161) and Lectin-like Transcript 1 in Natural Cytotoxicity against Human Articular Chondrocytes.

Normal cartilage cells are susceptible to lysis by NK cells. This phenomenon may play a role in immune cartilage destruction; however, the mechanisms of chondrocyte recognition by NK cells remain poorly understood. Therefore, the aim of this study was to reveal a possible role of NKR-P1A/lectin-like transcript 1 (LLT1) interaction in NK cell-mediated cytotoxicity against normal human articular chondrocytes. Chondrocytes were isolated from articular cartilage obtained during talonavicular joint surgery. PBMC or polyclonal NK cells isolated from normal donors served as effector cells. Cell-mediated cytotoxicity against chondrocytes was evaluated by means of 18-h 51Cr-release assay. Specific mRNA expression was evaluated by classical and quantitative RT-PCR, and proteins were detected by Western blot analysis. We found that lysis of articular chondrocytes by PBMC or polyclonal NK cells was potentiated by stimulation with IL-2. Stimulation of effector cells with IL-2 downregulated mRNA expression of inhibitory NKR-P1A NK cell receptor, and blocking of NKR-P1A with specific mAbs resulted in increased chondrocyte killing. Chondrocytes constitutively expressed LLT1, a ligand of NKR-P1A. LLT1 expression by chondrocytes could be upregulated by IL-1α and TNF. Chondrocyte treatment with IL-1α resulted in their increased resistance to killing by natural cytotoxic cells. This could be reversed by blocking of NKR-P1A. These results show that susceptibility of normal articular chondrocytes to lysis by NK cells is modulated by NKR-P1A/LLT1 interactions. Thus, NKR-P1A/LLT1 interaction might provide some novel target for therapeutic interventions in the course of pathological cartilage injury.

Constitutive expression of ligand for natural killer cell NKp44 receptor (NKp44L) by normal human articular chondrocytes.

Normal chondrocytes display susceptibility to lysis by natural killer (NK) cells and this phenomenon may play a role in some inflammatory cartilage disorders. The mechanisms of chondrocyte recognition and killing by NK cells remain unclear. Using flow cytometry and immunohistochemical staining we found that normal human articular chondrocytes constitutively express a ligand for NKp44, one of stimulatory NK cell receptors involved in recognition and killing of target cells. Expression of NKp44 ligand by normal articular chondrocytes is not involved in their killing by unstimulated NK cells; however, it is responsible for anti-chondrocyte cytotoxicity mediated by long-term activated NK cells. Thus, expression of NKp44 ligand may play a role in chondrocyte destruction in course of chronic inflammatory cartilage disorders.

Surgical outcome for children in the early phase of Perthes' disease.

Background. This article presents long-term outcomes in the surgical treatment of children in the early phase of Perthes' disease, i.e. Reinberg phases I and II. Material and methods. From among 650 children operated during the period 1976-1998, 128 patients reported for follow-up, including 102 boys and 26 girls, who had been operated by transverse inter- and sub-trochanteric osteotomy according to the authors' own concept. These children ranged in age at surgery from 3 to 13 years (average 7 years); the observation period ranged from 5 to 25 years (average 11 years). The radiological picture of the femoral head in long-term follow-up after surgery was assessed according to the Stulberg and Mose classification schemes. Results. There were 72% good outcomes, 23% satisfactory, and 5% poor. Retrospectively, 105 hips (81%) of the total 128 were classified radiologically to Herring group A or B. This large percentage of A and B results indicates that the disease process was just beginning, and had not yet involved the entire femoral head. Of all the operated patients, 77 (60%) did not go through the fragmentation period or only just entered the initial phases of stage III. Conclusions. Our observations would indicate that in the course of surgery the progress of the disease is halted, as though the femoral osteotomy released an unknown factor limiting the development of the disease and halting its progress at the phase at which the surgery is performed.

The surgical treatment of children with Perthes' disease: 26 years of experience.

Background. The purpose of this article is to present the history of the authors' own technique for the surgical treatment of children with Perthes' disease by means of inter- and subtrochanteric osteotomy, and to describe the outcomes achieved. Material and methods. We analyzed 208 hip joints treated during the period 1976-1998 (162 boys and 46 girls, m/f ratio 78/22). The average age at surgery was 7.8 years, and at final check-up, 13 years; the average observation period was 11 years (range 5-25). After surgery the children were immobilized in a plaster cast for 8 weeks, and then for 8 more weeks in an exercise cast. Results. We analyzed the results, assessed according to the Stulberg and Mose systems, in 3 age groups with differing outcome. In the 3-5 years age bracket there were 81% good outcomes, 22% satisfactory, and 5% poor. In the 6-8 age bracket, there were 77% good outcomes, 18% satisfactory, and 5% poor. In the 9-14 age bracket we found 50% good outcomes, 40% satisfactory, and 10% poor. Conclusions. In 60% of the children operated in the early phase of the disease we observed cessation of the disease process and accelerated healing of the necrosis in the femoral head. These joints either did not pass through a fragmentation phase or only entered it. The outcomes we achieved and the short period of immobilization in plaster cast are good reasons to recommend this type of treatment.

[Results of surgical treatment of congenital clubfeet with the Sotirow method]. / Ocena wyników operacyjnego leczenia wrodzonej stopy konsko-szpotawej metoda Sotirowa.

Clinical and radiological results of surgical treatment of congenital clubfeet by an antero-lateral approach first introduced by Sotirow in 1976 are presented. The aim of this paper was to assess long-term results of this procedure on children (aged 5-18 months at the time of surgery). A series of 65 feet in 42 cases diagnosed with congenital talipes equinovarus was evaluated. Forty-two cases were treated conservatively with casts--changed on a weekly basis for 2-3 months and then every 2 weeks. Magone's score criteria were used to assess the method. Average follow-up was 7 years. Clinically 72% of the results were rated as excellent or good. We found the biggest problem during the Sotirow procedure was placing the trochlea of the talus bone into his anatomical into its' anatomical position in the talo-crural joint. The method introduced by Sotirow seems to be highly effective and worth applying. It enables a real elimination of soft-tissue contractures, which retains the deformity of the foot through an antero-lateral approach.