Olivera Josimovic-Alasevic

Serum levels of soluble CD30 molecule (Ki-1 antigen) in Hodgkin's disease: relationship with disease activity and clinical stage

In all cases of Hodgkins disease (HD) Reed‐Sternberg (RS) cells express the CD30 antigen. It has been recently demonstrated that this molecule can be released from the cell membrane of CD30+ neoplastic cells in a soluble form (sCD30), detectable in culture supernatants and body fluids. In this paper we investigated by an immunoassay the serum levels of sCD30 in 58 patients with HD, in order to define the possible relationship of this molecule to the clinical and pathological findings. sCD30 molecule was found at detectable levels in 24 out of 50 patients (48%) with active disease, whereas it was always absent in control sera and in cases in complete remission. Among the patients with active HD, the incidence and mean values of detectable levels (±SEM) of sCD30 were higher in cases with progressive or relapsing disease (61.5%, mean 458±190 U/ml) as compared to those at presentation (43.2%, mean 116 ± 3 3 U/ml). Among the cases at presentation, detectable levels were observed more often in patients with advanced stages (III+IV: 61%) and constitutional symptoms (‘B’: 61‐5%) than in early stages (I+11: 26%) and without symptoms (‘A’: 33.3%). In addition, higher mean values were found in stages III+IV (182±60 U/ml) and in ‘B’cases (208±73 U/ml) than in stages I+II (65 ± 30 U/ml) or ‘A’patients (64 ± 26 U/ ml).

Regulation of interleukin-2 receptor expression and receptor release.

The generation and cell surface expression of IL-2 receptors was monitored by: (i) an ELISA that permits quantitative determination of detergent-solubilized or soluble IL-2 receptors; and (ii) detection of the binding of 125I-labelled recombinant IL-2 and of anti-IL-2 receptor antibodies to receptor bearing cells. Upon lectin stimulation both high and low affinity IL-2 receptors became expressed in parallel at the cell surface. Both high and low affinity receptors were upregulated by IL-2. Upon lectin activation the amount of cell-associated receptors increased and on day 2 of the culture period IL-2 receptors were detectable in the culture supernatant. IL-2 upregulated both high and low affinity IL-2R expression on T-lymphoblasts. IL-2R bearing leukemic cells and T lymphoblasts released IL-2R when cultured in vitro. IL-2R release by T lymphoblasts was enhanced dramatically by IL-2. On the other hand, IL-2-receptor positive leukemic cells released receptors in an IL-2 independent manner. Release of receptors could also be detected in serum-free medium. At least a part of the released receptors could be specifically bound to immobilized pure recombinant IL-2 and to monoclonal anti-IL-2-receptor antibodies. Small but significant amounts of soluble IL-2 receptors were detectable in the sera of normal mice. In sera of mice inoculated with IL-2-receptor positive syngeneic leukemic cells, elevated levels of IL-2 receptors were detectable. Release of IL-2 receptors seems to represent one of the major routes by which the receptors are cleared from the cell surface.

Increased serum levels of soluble IL-2 receptor, CD30 and CD8 molecules, and gamma-interferon in angioimmunoblastic lymphadenopathy: possible pathogenetic role of immunoactivation mechanisms

Summary. Abnormal immunoreaction associated with increased cell activation phenomena might play a role in the pathogenetic events leading to the development of angioimmunoblastic lymphadenopathy (AILD). In the present study we investigated the serum levels of some soluble molecules related to cell activation in 24 patients with AILD at presentation. In particular, we measured by immunoenzymatic or immunoradiometric techniques the levels of the Tac peptide (sIL‐2R), soluble CD30 (sCD30) and CD8 (sCD8) antigens, and gamma‐IFN (gIFN). The results show that all the above molecules are increased as compared to normal controls, with a different pattern of increase for the different molecules. The sIL‐2R levels were very high in all cases with no overlap between AILD and control samples (mean 6315±3374 U/ml, controls 271±112 U/ml, P<0.001). Very high values of the sCD30 antigen (722±895 U/ml) were detected in all cases but five, as opposed to the lack of detectable levels in controls. A significant increase of sCD8 (978±646 U/ml, controls 334±95 U/ml, P<0.01) and gIFN (329±236 U/ml, controls 97±43 U/ml, P<0.01) was also observed with some overlap between AILD samples and controls.

Factors influencing the response to hepatitis B vaccination of hemodialysis patients

The response rate and HBsAG antibody concentrations were examined after hepatitis B vaccination in 78 hemodialysis patients aged between 29 and 79 years. The values were related to age, duration of hemodialysis, body weight, creatinine, urea nitrogen, serum concentrations of beta 2-microglobulin and soluble interleukin-2 receptor (IL-2R). Patients with low anti-HBsAG antibody concentrations (10-100 mU/ml) had significantly higher IL-2R serum concentrations than those with high anti-HBsAG antibody concentrations (greater than 3,000 mU/ml; p less than 0.05). Discriminant multivariate analysis (p = 0.032) revealed the influence (62%) of IL-2R on the response rate while other factors were similar in all patient groups. It is concluded that preactivation of T cells with an increased release of IL-2R may contribute to impaired immune response after hepatitis B vaccination.

Enzyme-linked immunosorbent assay of mouse interleukin-2 receptors

An enzyme-linked immunosorbent assay (ELISA) which measures soluble mouse interleukin-2 receptor (IL-2R) was developed, using two monoclonal anti-mouse IL-2R antibodies directed against two different epitopes of the IL-2R molecule. The ELISA-reactive material was identical with the IL-2R material which was capable of binding to affinity support beads coupled with recombinant interleukin-2 (IL-2). Quantitation of IL-2R in detergent-lysed cells was compared to that of the purified IL-2R, and the detection limit was estimated to be within the range of 2-10 ng/ml of a test sample. This sensitivity made it possible to determine soluble IL-2R levels in cell culture supernatants and mouse sera.

High Serum Levels of Soluble Interleukin-2 Receptor and Absence of Detectable Levels of Soluble CD30 Molecule: A Specific Diagnostic Combination for Hairy Cell Leukemia

Hairy cell leukemia (HCL) is almost constantly characterized by the presence of very high levels of a soluble form of the interleukin-2 receptor (sIL-2R). Since several other hematologic neoplasias also display very high levels of sIL-2R, this feature cannot be considered specific for HCL. On the other hand, most of the above hematologic disorders are also characterized by the presence of detectable levels of the soluble CD30 molecule (sCD30). In the present study we investigated the sera from 22 patients with HCL for the presence of detectable circulating levels of sCD30 in combination with the detection of sIL-2R. In this report we demonstrate that the high serum levels of sIL-2R found in all HCL patients were never associated with the presence of sCD30. Since this pattern is unlikely to be found in neoplastic conditions other than HCL, we suggest that the combined serum determinations of sIL-2R and sCD30 be used as a reliable additional tool for the diagnosis of HCL.