Decreased NA+, K+-ATPase activity in erythrocyte membrane from rheumatoid arthritis patients

The activity of the plasma membrane Na+/K+-ATPase and cellular sodium (Nai) and potassium (Ki) content were analysed in RBCs from 15 rheumatoid arthritis (RA) and 30 reference subjects (11 healthy controls, 12 osteoarthritis and 7 gouty patients). Na+/K+-ATPase activity was determined by measuring the inorganic phosphate (Pi) released by incubation in a reaction medium in the presence and absence of K ions or ouabain. Nai and Ki were measured with an ion-selective electrode analyser on the hemolysates, after washing the RBCs in 110 mM MgCl2. The Na/K-ATPase activity was significantly lower in RA patients than in both healthy controls and patients with osteoarthritis or gout. A slight but significant increase in Nai was observed in rheumatoid subjects. It is hypothesized that the decrease in the Na+/K+-ATPase activity in RA may be the result of a defective expression of membrane proteins, which is probably related to the altered cell sensitivity observed.

Essential cryoglobulinemia: a therapeutic dilemma

Our data confirm those already reported in the literature. There is no univocal therapy for essential cryoglobulinemia. Several therapeutic strategies may be employed according to severity of the clinical picture. Skin and articular involvement may benefit from the administration of non-steroidal antiinflammatory drugs. The presence of visceral involvement requires steroids and/or immunosuppressive drugs. Plasma-exchange should be used in patients with severe progressive disease. However, data showing that anyone of the proposed treatment could irreversibly stop the clinical course of the disease are lacking. Immunological parameters except serum viscosity cannot help in the decision to initiate a plasma-exchange program and in monitoring its efficacy.

Abnormalities in dermal vessel walls of normal skin of patients with essential mixed cryoglobulinemia. An ultrastructural study

Immune deposits have been detected in vessel walls of forearm normal skin of patients with essential mixed cryoglobulinemia. No inflammatory cells were present around the vessel walls. These findings suggest that simple deposition of immune complexes is not sufficient to trigger an inflammatory reaction.

Immune deposits in normal skin of patients with systemic lupus erythematosus: relationship to the serum capacity to solubilize immune complexes

Immunofluorescent deposits at the dermal-epidermal junction (DEJ) of the skin (lupus band test or LBT) were evaluated in 134 patients with various connective tissue diseases. LBT was found positive in 23 of 32 (71.8%) patients with systemic lupus erythematosus (SLE), in 3 of 53 (5.6%) patients with rheumatoid arthritis (RA), and in 1 of 5 cases of mixed connective tissue disease (MCTD). No deposits were found in patients with systemic sclerosis and with vasculitis. In patients with SLE a positive LBT showed a direct correlation with serum Clq binding activity (ClqBA) and with hypocomplementemia. The mean ClqBA was 13.49 +/- 12.85 and 2.38 +/- 2.27% in SLE patients with positive and negative band test, respectively (P less than 0.005). Likewise depressed mean serum levels of C3 and C4 were detected in patients with skin deposits (P less than 0.005). Sera from SLE patients showed an overall decreased capacity to solubilize preformed immune complexes when compared to normal sera. Furthermore 10 band-positive patients were less able to solubilize immune complexes than sera from LBT-negative lupus patients (45 +/- 16 and 62 +/- 11%, respectively; P less than 0.01). Also the capacity to inhibit the precipitation of immune complexes was decreased in SLE patients with negative LBT (P less than 0.05). In conclusion our data suggest that in SLE patients a decreased complement-mediated solubilization of immune complexes is involved in the persistence of high levels of circulating immune aggregates and, considered its correlation with positive LBT, may be responsible for the deposits of immunoglobulins at the dermal-epidermal junction of the skin.

Immune complexes and complement profile in essential mixed cryoglobulinemia before and after plasma exchange

Five patients affected by essential mixed cryoglobulinemia (EMC) with renal involvement unresponsive to high doses of corticosteroids, have been treated with 16 plasma exchanges (PE). The plasma removed at each apheresis was 1652 +/- 416 ml. The following data were evaluated before and after PE: levels of immune complexes as detected by cryocrit and C1q binding assay; total complement activity (CH50) and alternative pathway complement activity (APCH 50); concentrations of 9 complement components (C1q, C1s, C4, C3, C5, C6, B, I and H) and of the C3 split product C3d. By definition all serum samples had detectable cryoprecipitates and 4 out 5 had C1q binding activity higher than the upper limit of 2 SD. The effect of the PE was the decrease of cryocrit and of C1q binding activity approximately to one half their initial values. The basal complement profile suggested and excessive activation of complement through the classical pathway. Indeed we found low levels of the early complement components (C1q, C1s and C4), reduced CH50, normal levels of C3 and an increase of C3 split product C3d concentrations. APCH50 as well as C5, C6, B, I and H concentrations were found within the normal range. After each PE a significant decrease of the previously normal components was observed. The decrease was independent of the replacement fluid used (5% albumin solution or fresh plasma or cryoglobulin-depleted autologous plasma) and had a short duration. Indeed all these components after the drop following the PE increased rapidly reaching the basal level over a period of 24-48 hours.(ABSTRACT TRUNCATED AT 250 WORDS)

Rheumatoid lung disease. (A clinical, physiological and histological study in 33 patients)

Clinical, physiological and histological investigations on lung involvement are reported in 33 rheumatoid patients. The clinico-pathological patterns of rheumatoid lung disease observed in 19/27 non-smoking female patients were characterized radiologically by diffuse interstitial opacities, functionally by V/Q inequality and microscopically by peribronchiolar and/or alveolar fibrosis. Emphasis is placed on the ventilation/perfusion relationship as well as histopathological studies for a more accurate diagnosis of lung disease in RA. Patients with pulmonary nodules and pleural opacities were also observed. A possible immunological aetiology is suggested on the basis of the simultaneous finding of IgG, complement and fibrinogen in the pulmonary tissue.

[Lymphocyte typing in chronic lymphoid leukemia]

We used the membrane fluorescence and the rosette formation test to study the lymphocyte populations in 25 patients with untreated chronic lymphocytic leukemia (CLL). The results show a significant increase, absolute and percent of S-Ig bearing cells, whereas the E and EA rosette forming cells are decreased in per cent, increased in absolute. The number of lymphocytes with the receptor for the Fc fragment of IgG, is unchanged. The lymphocytosis causes mainly a significant decrease in percentage of E rosette forming cells. A big splenomegaly and a bad clinical stage, according to Rai et al. classification, are responsible for a decrease of E, EA, EAC rosette forming cells; unchanged the percentage of S-Ig bearing cells. Such a modification of the surface receptor pattern is present not only in those CLL more advanced in clinical stage and with hyperleucocitosis and/or splenomegaly, but also in those forms with worse clinical feature and prognosis. Our work confirms that CLL is mainly a B proliferative disease; we observed only one case due to T cell proliferation. Four cases were impossible to classify immunologically: one had no cells bearing the markers, three had a subnormal surface receptor pattern.