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We experienced an abnormal blood sample which showed larger numbers of white blood cells and platelets counted by the electric resistance system and of platelets in mechanical counting by the flow system, than those in manual counting. Many precipitates were observed in this blood sample at room temperature or 4 degrees C, but were not observed at 37 degrees C. The precipitates were clarified to be caused by the mixed type (IgA, IgG and IgM) cryoglobulin by using an immunofluorescence method and an ouchterlony method. These data indicate that precipitation of cryoglobulin at room temperature induce falsely high value of platelet count in mechanical counting systems.

By using the Coulter Counter S-Plus IV erroneous measurements of leukocytes, platelets and red cells were experienced in blood from two patients with cryoglobulinaemia. Leukocyte levels were estimated too high owing to contamination of the leukocyte counting chamber by unlysed erythrocytes. One of the patients had leukopenia, but the Coulter Counter reported white blood cell counts within normal limits. Rewarming of the sample to 37 degrees C eliminated the problem.

An impaired function of splenic macrophages, measured as the clearance rate of erythrocytes coated with IgG (E-IgG), was observed in 7 out of 8 cryoglobulinemic patients with severe urinary abnormalities and systemic symptoms, and in 0 out of 6 patients without urinary symptoms and only mild systemic signs of disease. The E-IgG clearance rate was not related to HLA or Rh phenotype, patients' age or disease duration. Moreover, longitudinal studies showed this parameter to be strictly related to disease activity. To investigate the nature of the defect, five series of analyses were planned using peripheral blood phagocytes (PBP) from 8 patients: a) detection of cell-bound immune material by using the antibody CE59 directed to the Fc fragment of IgG modified by the antibody-antigen reaction; b) cytofluorometric and/or radiometric analyses of the cell surface expression of HLA II, CR1 and FcR structures by means of specific monoclonal antibodies (MoAbs); c) electron microscopy (EM) examination of diverse combinations of cryoglobulins incubated with PBP from patients and normals; d) analysis of cryoglobulin-induced inhibition of E-IgG phagocytosis; e) measurement of the generation of chemiluminescence (CL) in response to Zymosan, Phorbol Myristate Acetate and n-Formyl-Methyonine-Leucine-Phenilalanine (n-FMLP). Patients' PBP were found to have a higher amount of cell-bound immune material as compared to normals (p less than 0.01). CR1 and FcR expression was not different from controls, whereas a slight increase in percentage of monocytes bearing HLA II structures was found in patients (p less than 0.05). Upon EM examination no obvious differences were found in the internalization capacity of cryoglobulins between patients and controls. The CL production was lower than normal (p less than 0.02), whatever stimulus used, with a maximal impairment for n-FLMP (p less than 0.005), the most specific test probe for cytoskeleton integrity. Finally, a remarkable cryoglobulin-induced inhibition of E-IgG phagocytosis was shown. A combination of saturation mechanisms and intracellular abnormalities could underlie the apparent discrepancy between E-IgG clearance defect and preserved potential of cryoglobulin internalization in cryoglobulinemia.

Our aim was to assess whether the amount of complement C3b/C4b receptors (CR1) on erythrocytes shows a correlation to disease activity in various connective tissue diseases such as systemic lupus erythematosus (SLE), rheumatoid arthritis (RA) and essential mixed cryoglobulinemia (EMC). Using an anti-CR1 monoclonal antibody, 26 patients with SLE, 34 with RA and 22 patients with EMC were investigated for erythrocyte CR1 expression. The control group consisted of 30 healthy individuals. The mean number of CR1/erythrocyte in the control group was 568 +/- 197 (range 174-1060), significantly higher than studied (EMC:379 +/- 248; p = 0.0005;SLE 147 +/- 56, p less than 0.0001; RA 298 +/- 177, p less than 0.0001). In patients with RA and in SLE, but not in patients with EMC, the number of CR1 numbers and anticardiolipin antibody (aCl) titers (r2 = 0.493; p = 0.034). A statistically significant correlation between CR1 numbers and CH50 values was found in patients with SLE, while in 3 patients with RA 4 months of therapy with cyclosporine A led to a further 30% reduction in CR1 number. Our conclusions are that (a) the decreased expression of erythrocyte CR1 is apparently a common feature of patients with various connective tissue diseases; (b) several acquired factors such as disease activity, complement activation, aCl and drugs may contribute to the loss of CR1 from erythrocytes; (c) in patients with RA and SLE, but not in patients with EMC, CR1 enumeration on erythrocytes may serve as a variable for clinical monitoring.

Efficiency of albumin (Alb) and immunoglobulin G (IgG) separation from cryoprecipitable proteins (CPP) and IgM was compared between a membrane plasma fractionator with a mean pore diameter (MPD) of 0.1 micron, surface area of 0.65 m2, and a new large pore diameter filter with a MPD of 4.3 microns, and surface area of 0.14 m2. In five in vitro tests at 4 degrees C using polyclonal cryoglobulinemic (CG) plasma from a patient treated by plasma exchange (PE), the large pore filter retained only 22% of the mass of Alb, and a comparable amount of CPP and IgM, as compared to the plasma fractionator, at a fraction of its total retention capacity. The new filter can replace PE in treatment of polyclonal CG.

Cryoglobulin was isolated from a horse which had glomerulo-nephritis and a history of swelling and skin ulcers of the limbs in the winter. The isolated cryoglobulin showed a single peak on a gel permeation chromatography column with an apparent molecular mass (Mr) of 180,000 which could be divided into two gamma bands by cellulose acetate electrophoresis. Immunoelectrophoretic analysis revealed that the cryoglobulin formed two precipitation lines with anti-horse IgG. Spur formation was observed when the cryoglobulin and the IgG purified from a normal healthy horse were cross-reacted with anti-horse IgG on a double diffusion gel. In addition, sodium dodecyl sulfate-polyacrylamide gel electrophoresis under the reduced conditions showed that the isolated cryoglobulin consisted of two doublets of polypeptides with Mr values of 52,000 and 50,000, and 31,000, and 30,000, corresponding to the heavy chain and the light chain of the horse IgG molecules, respectively. These results suggest that the isolated cryoglobulin might consist of two different IgG molecules, and that the manifestations such as foot swelling with skin ulcers and renal failures were all induced by the cryoglobulin in the serum.

A 93-year-old woman presented with profound anemia (hematocrit 23% [0.23]); there was clumping of her red cells in test tubes and on peripheral blood smears. There was also a marked decrease in erythroid precursors in the bone marrow and reticulocytopenia in the peripheral blood. An IgM kappa monoclonal gammopathy was found in low concentration (approximately 1%) in her serum, and the cold agglutinins had a titer of 2560. However, the cold agglutinin titer of the supernatant after cryoglobulin precipitation was 40. Redissolving the cryoglobulin in the supernatant resulted in a cold agglutinin titer of 1280. Moreover, the addition of the patient's whole serum inhibited erythroid colony formation in culture. The inhibition was removed by cryoprecipitation of the cryoglobulin. The patient was given steroid therapy, to which she responded with reticulocytosis and an elevation of hematocrit. By 3 months, the cold agglutinin titer had fallen to 10. She remained well 4 years later. Whereas reports of cryoprecipitable cold agglutinins are rare, this case is unique because there have been no previous reports that these cold active proteins also have erythroid stem cell-suppressant properties.

The mixed cryoglobulinemia is considered to be a nonmalignant human B-cell proliferation that frequently produces a monoclonal IgM with anti-IgG activity (rheumatoid factor). Using murine monoclonal anti-idiotypic antibodies specific for private or minor idiotopes on monoclonal IgM from three patients suffering from nonmalignant mixed cryoglobulinemia, we investigated the presence of the CD5 antigen on the monoclonal IgM producing cells in these patients. It is shown by two-color cytofluorometric analysis that the majority of the peripheral blood monoclonal IgM rheumatoid factor secreting cells is CD5 negative in these three patients. One of the monoclonal rheumatoid factor K variable regions was sequenced at the protein level and belongs to the human VK III group, as a high proportion of monoclonal rheumatoid factors and some B-cell chronic lymphocytic leukemia (CLL) membrane bound Igs. Thus, despite the preferential use of similar VK genes and the absence of somatic mutation affecting these variable regions in both malignant B-cell CLL and nonmalignant mixed cryoglobulinemia, these proliferating B cells differ in the CD5 membrane expression.

Cryofibrinogenemia, a rare disease, is diagnosed by the presence of reversible cryoprecipitate in plasma, which may cause various clinical manifestations of thromboembolic or hemorrhagic disorders. A 66-year-old female patient suffered from recurrent reticulate erythema, purpura and gangrene on the distal portion of the extremities and face during the winter for 5 years. Cryofibrinogenemia was proven with the following evidences: (1) Histopathologic findings revealed many eosinophilic cylinders, about 6-9 microns in diameter, deposited within the lumen of the blood vessels in the dermis and subcutaneous tissue. There was no evidence of vasculitis. These cylinders were fibrinogen in nature, as proven by direct immunofluorescence. (2) Cryofibrinogen was detected in the citrated plasma, which was confirmed by double immunodiffusion, the presence of an IgG-kappa M protein was also revealed by immunofixation. Debridement and skin grafts were performed, and prednisolone combined with cyclophosphamide were given. Skin lesions improved without recurrence, and the "cryocrit" decreased from 13.6% to less than 2% during the follow up. We conclude that if there is any case with the similar cutaneous manifestations, cryofibrinogenemia should be considered.

We investigated the influence of carbohydrate on the binding of human rheumatoid factors (RF) to the Fc fragment of IgG. The monoclonal RF studied were derived from the serum of patients with mixed cryoglobulinemia or from hybridomas generated from patients with rheumatoid arthritis (RA) and systemic lupus erythematosus. Polyclonal RF were derived from patients with RA. The carbohydrate located on the Fc fragment, regardless of whether it contained different amounts of mannose or reduced amounts of galactose, or was removed, did not affect the binding of the RF. In contrast, the isotype of the Fc was found to be critical. Two groups of hybridoma RF could be delineated. One group bound preferentially to IgG1 and/or IgG2, and a second group (primarily from patients with RA) bound preferentially to IgG3 and/or IgG4. Our results indicate that the isotype of the Fc fragment, and not the extent of galactosylation, influences the binding of the RF.

Blood, plasma and serum viscosity and blood filtration were investigated in 43 unselected mixed cryoglobulinemia patients. A hyperviscosity syndrome was present in only one patient, and rapidly improved after plasma exchange and cyclophosphamide therapy. A clear-cut increase in blood viscosity was infrequently observed in mixed cryoglobulinemia, although significant differences were present in the plasma and serum viscosity of patients and controls. In contrast, blood filtration was severely impaired in a high percentage of cases (51 and 72% of the values recorded at 37 degrees and 25 degrees C, respectively), and was on the average significantly higher in patients than in controls. Indirect evidence suggests that blood viscosity is at least in part related to cryoglobulins. In 19 patients studied before and after cryoglobulin removal, serum viscosity significantly decreased when the serum was deprived of cryoglobulins. In addition, the cryocrit correlated with all the hemorheological parameters with the exception of blood filtration. The hemorheological findings were compared with multisystemic features of the disease, i.e. liver, renal, lung, neurologic, vascular and funduscopic alterations. The potential clinical relevance of the hemorheological parameters was stressed by the close correlation between blood filtration parameters and serum creatinine. Furthermore, by discriminant analysis, viscosity and blood filtration changes were the serological parameters most significantly associated with the presence of renal, liver and neurological involvement. Thus, hemorheological parameters are frequently abnormal in mixed cryoglobulinemia patients, and seem to play a significant clinical role; they should therefore be included in the work-up of these patients.

As many as 130 patients with Sjögren's disease (SD) were examined for blood cryoglobulins during 1977-1982. Cryoglobulinemia was discovered in 25 (19.2%) patients with SD. The clinical manifestations such as severe xerostomia, appreciable increase of the parotid salivary glands, hepatosplenomegaly, purpura, polyneuropathy, lesions of the lungs and kidneys were mostly detectable in SD patients with cryoglobulinemia. Ten cryoprecipitates of SD patients with cryoglobulinemia showed the monoclonal immunoglobulins IgMk-9 and IgA-1. All the patients had high titers of antinuclear antibodies and 90% manifested antinuclear Ro/La antibodies. Over the 5-year period. SD patients with cryoglobulinemia manifested the growth of hepatosplenomegaly, ulcerous-necrotic vasculitis, polyneuropathy, polyneuritis, cerebral vasculitis, lesions of the lungs and kidneys. The development of the grave systemic manifestations of the disease was attended by a decrease of immunological activity and the rise of inflammatory activity. The 5-year survival of SD patients with cryoglobulinemia was 64% against 98% in SD patients without cryoglobulinemia (p less than 0.001).

A new type of interference of cryoglobulins on hemocytometric tests is described. The precipitation of temperature-dependent proteins produced a pseudolymphocytosis on a three-part differential leukocyte count of Coulter S-Plus VI, whereas unaffected results, identical to the microscopical count, were obtained using the cytometer Coulter VCS. The laboratory detection of cryoglobulin interference on hematological data is very important in patients with underlying diseases, where the accuracy of absolute and differential leukocyte counts is critical for follow-up. Histograms from the Coulter S-Plus VI can help detect these cases.

The high cost and clinically associated side-effects of plasma exchange treatment warrant development of on-line plasma fractionation techniques. Cryoglobulin removal from cryoglobulinemic plasma is particularly amenable to membrane filtration in the cold (cryofiltration). Temperature effects on filtration were studied in vitro using a large pore (nominal average size, 3 microns), low surface area (0.14 m2) filter. Plasmas with high concentrations of cryoprecipitable proteins (CPP; greater than 1.1 micrograms/ml) and immune complexes (IC; greater than 400 U/ml) were obtained from consenting cryoglobulinemic patients by plasma exchange. Removals of IC and CPP were highly temperature dependent, and high ratios of IC, CPP, and albumin removal were achieved (e.g., sieving coefficient [SC] = 0.05 and 0.91 for CPP, and SC = 0.94 and 0.95 for albumin at 4 degrees C and 23 degrees C, respectively). Clinically required volumes of plasma (greater than 2L) were processable. Cryofiltration with this new, high performance cryoglobulin filter is selective and may substantially reduce the clinical need for plasma replacement products.

There is a close connection between molecular changes of the Ig molecule with sinking temperature and the syndrome of hyperviscosity. The cryoglobulins are usually macroglobulins or complexes between IgM and other immunoglobulin classes. Many of these molecules can also be characterized as euglobulins. The connection between precipitation in the cold and in solutions with low electrolyte content is studied. Data on these connections are presented. The dependence of relative viscosity on the temperature has been investigated in a large number of sera from patients with different diseases. It is clear that most of these cold-sensitive globulins are macroglobulins (IgM). A number of viscosity curves at different temperatures in such sera are given. Also a few sera from patients with IgG myeloma have similar curves. The change in viscosity with lower temperatures implies that relative viscosity has to be determined at 37 degrees C in order to correspond to the condition in the living body. In practice, however, it is usually correct to state that IgM levels above 40 g/l are an indication that plasmapheresis should be considered. The best clinical sign is obtained by ophthalmoscopy. Difficulties with the counting of leukocytes and platelets in electronic counters may be caused by the presence of macroglobulins, usually but not always, cryoglobulins.

Two patients with cryoglobulinemia were treated with plasmapheresis in combination with immunosuppressive therapy. One had Waldenstrom's macroglobulinemia, and the other suffered from systemic lupus erythematosus. Membrane plasmapheresis, using membrane plasma separators, was performed, and the initial plasmapheresis treatments were unsatisfactory because of clotting of hollow fibers by cryoglobulin. The plasma filtration rate and the clearance of immunoglobulins fell rapidly with the clotting of the hollow fibers. This technical difficulty was overcome by prediluting the blood with normal saline before passing it through the membrane plasma separator. The mechanism of preventing clotting of hollow fiber by saline predilution is likely to be the reduction of serum viscosity and the lowering of cryoglobulin concentration. This modification is simple and efficient and enables membrane plasmapheresis to be performed effectively in patients with cryoglobulinemia without complicated and expensive machines.

Isolated and washed cryoglobulins obtained from 30 patients with different diseases were studied for the presence of fibronectin by immunoelectrophoresis. Two of the isolated cryoglobulins were of the type I, 3 were of the type II, while the other 25 were of type III. Despite extensive washing, fibronectin was detected in all the cryoprecipitates. Our results indicate the constant presence of fibronectin in the cryoprecipitates from patients with different diseases and types of cryoglobulin. The possible mechanisms by which fibronectin could act in the precipitation of immunoglobulins are discussed.

Abnormalities in the size frequency histogram generated by the Coulter S Plus STKR at room temperature raised the possibility of the presence of a cryoglobulinaemia in a man admitted to the hospital with pneumonia. The leucocyte and platelet counts generated by the Coulter S Plus STKR were higher when counts were done at room temperature than counts done at 37 degrees C. Further investigation of the patient revealed the presence of Non-Hodgkin's Lymphoma which had not been suspected on clinical grounds. The importance of testing samples at 37 degrees C, where an abnormality in the Coulter S Plus STKR histogram has been detected at room temperature, is emphasized.

Fourteen cases of Essential Mixed Cryoglobulinemia (EMC) are described in this report. Clinical and laboratory manifestations in our patients were similar to those previously reported in literature, although involvement of the peripheral nervous system was much more prevalent in our series. We suggest that peripheral neuropathy should be systematically searched in EMC patients.

Report on a 50-year-old patient with cryofibrinogenemia, suffering from a recurrent exanthema induced by cold exposure.

Cross-linked fibrin degradation products (XDP) were measured with a highly sensitive and specific ELISA in 21 patients with essential mixed cryoglobulinemia (EMC) and in 16 controls. Patients had significantly increased levels of XDP, together with abnormalities in routine coagulation tests. Moreover, XDP were higher in patients with more severe disease. These results support the hypothesis that EMC patients have a chronic disseminated intravascular coagulation (DIC), and underline the significance of XDP measurement in the evaluation of these patients.

Plasma fibronectin (FN) was measured in 17 patients with essential mixed cryoglobulinaemia (EMC) and in 17 normal subjects by single radial immunodiffusion (RID) and enzyme-linked immunosorbent assay (ELISA). In 9 patients the presence of FN in the cryoprecipitates was also assessed by immunoblotting. In the EMC group, plasma FN levels were significantly lower than in control subjects, using both methods, and FN was constantly demonstrated in EMC cryoprecipitates. Capillaroscopic observation of the capillary bed in skin and bulbar conjunctiva, performed in all cases, showed severe alterations of microcirculation in EMC patients. A negative correlation between plasma FN and capillaroscopic abnormalities of skin capillaries was observed. These data support the hypothesis that plasma fibronectin plays a role in the pathogenesis of systemic vasculitis in EMC.

Nine patients with mixed cryoglobulinemia and severe membranoproliferative glomerulonephritis were treated with plasma exchange alone or in combination with medium to low amounts of corticosteroids, but never with cytotoxic drugs. In 5 patients renal function and/or proteinuria improved after plasma exchange, and no clinical relapse usually occurred when the procedures were reduced or discontinued. These procedures seemed of particular effect in the presence of histologically active and not irreversible lesions and rapid deterioration of renal function. While cryocrit almost invariably decreased, circulating immune complex or complement levels were unpredictably affected by plasma exchange. Cryocrit, but not immune complex or complement levels, was the serological parameter which most often closely correlated with signs of renal involvement (i.e., proteinuria and/or serum creatinine). Thus, plasma exchange might be a safe and useful tool in the treatment of an often drug-resistant and rapidly progressive renal involvement occurring in patients with mixed cryoglobulinemia.

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.

Cryoglobulins are serum proteins with heterogeneous etiopathogenetic and immunochemical properties. What they have in common is temperature-dependent insolubility, in that at temperatures below 37 degrees C (often around 4 degrees C) they precipitate, and then redissolve at 37 degrees C. When the etiopathogenesis of the cryoglobulinemia is unknown, which is true for many patients, the condition is called idiopathic or essential cryoglobulinemia, whereas it is termed secondary whenever it appears to be associated with one of several diseases. Cryoglobulinemia has indeed been found in patients with lymphoproliferative and autoimmune disorders, liver diseases, infectious (viral, bacterial, fungal and parasitic) diseases, and so on. Cryoglobulins are usually classified according to their immunochemical properties as single-type monoclonal, mixtures of a monoclonal Ig with non-immunoglobulin material (DNA, lipoprotein, complement), mixed with one monoclonal Ig or mixed polyclonal, in which constitutive Ig fractions are polyclonal. As compared with normal Ig, cryoimmunoglobulins have sometimes been found to exhibit a peculiar amino acid structure of their heavy chains, less often of their light chains as well, and to have a lower carbohydrate content. Such structural abnormalities may contribute to their loss of solubility at low temperatures, possibly associated to the steric changes induced by the low temperature, causing the precipitate to form. The most common clinical features of cryoglobulins are correlated with vasculitis in the various organs and sometimes with increased viscosity of the plasma. Signs and symptoms include purpura, ulcers of the extremities, arthralgia, proteinuria, hepatic damage, abdominal pain, congestive heart failure, mental confusion, oligo-anuria, hemorrhagic diathesis, and coma. Pyroglobulins are also serum proteins with temperature-dependent insolubility. However, although they precipitate out of serum heated at 56 degrees C for half an hour, they do not resolubilize when the serum is returned to 37 degrees C. Pyroglobulins have been mainly found in patients with lymphoproliferative diseases (especially Waldenström's macroglobulinemia, with or without cryoglobulinemia), systemic lupus erythematosus, and neoplasia. So far, only single monoclonal IgG, IgM or IgA pyroglobulins have been described. Since they precipitate only at 56 degrees C, pyroglobulins do not cause clinical symptoms and they are usually discovered by chance.

We studied the effects of cryoapheresis combined with different immunosuppressive treatments on the course of the glomerulonephritis of essential mixed cryoglobulinemia. The study was carried out on 11 patients. The effects of immunosuppressive treatments on cryoglobulin rebound after cryoapheresis varied widely. In those responding with sustained reduction in serum cryoglobulin levels, creatinine clearance increased, an effect that lasted several years in 4 patients. In one patient cryoglobulin disappeared, with almost fully recovery of renal function and normalization of blood pressure. One patient died of acute liver failure shortly after the first observation and another entered regular dialysis treatment. All the other patients are still alive after follow-up of 2-9 years. These results compare favourably with those reported by other investigators and suggest that cryoapheresis and cytostatic drugs are beneficial for glomerulonephritis associated with essential mixed cryoglobulinemia.

An 82-year-old woman with essential mixed cryoglobulinemia type II (IgM K IgG) presented with moderate renal failure and nephritic syndrome. Mesangiocapillary glomerulonephritis with mesangial and subendothelial granular deposits containing IgG, IgM, and C3 in conjunction with small-vessel vasculitis was seen on renal biopsy. Renal symptomatology preceded by a period of 10 months the development of leg ulcers and purpura. The onset of the skin lesions was accompanied by an acute decline of renal function and an increase in liver alkaline phosphatase. Plasmapheresis with a 50% plasma exchange each week over 12 weeks led to improvement in renal function, healing of leg ulcerations, disappearance of purpura, and a return to the baseline of alkaline phosphatase in association with the disappearance of circulating cryoglobulins.

Cryoglobulins are serum proteins which precipitate at 4 degrees C and redissolve during warming. When purified, they can be divided by immunochemical analysis into three main groups: monoclonal cryoglobulin, mixed cryoglobulin containing a monoclonal immunoglobulin, and polyclonal mixed cryoglobulins. There is a close correlation between the immunochemical composition of cryoglobulins and the symptoms or diseases associated with their presence.

Cryoglobulinemias in connective tissue diseases (CTD) represent, according to various authors, 12-30% of all cryoglobulinemia cases. Among CTD, systemic lupus erythematosus (SLE), rheumatoid arthritis (RA) and Sjögren's syndrome are the diseases most frequently involved in the presence of cryoglobulins (8-48%). The cryoglobulinemias are mostly of the third type and sometimes of the second type. When clinical symptoms are present, usually they are represented by Raynaud's phenomenon, arthralgias, urticaria, purpura and liver involvement. However, the presence of cryoglobulins in a patient with CTD often does not correlate with clinical picture and other laboratory findings. Eight of our 28 cases (15 SLE and 13 RA) showed third type cryoglobulinemias (7 IgM-IgG and one IgM-IgG-Clq) with a remarkable decrease of serum C4 levels.

Lung involvement in essential mixed cryoglobulinemia (EMC) has been recently described. In order to assess whether patients with EMC experience an accelerated deterioration of lung function, nineteen patients (17 females, 2 males; 49.6 +/- 6.6 years) underwent a short-term follow-up of lung function, chest X-ray and serologic investigations. Reduction of forced expiratory flows and presence of roentgenologic signs of interstitial involvement were confirmed in the baseline evaluation. In addition, a decrease of diffusing capacity was shown. After a mean interval of 15 months, no significant change in lung function was found, with the exception of decrease in maximal expiratory flow at 50% of forced vital capacity, total lung capacity, functional residual capacity, coefficient of transfer of CO. A slight decrease of hemolitic complement (CH50) and of complement fraction (C3) was also observed. This study suggests that patients with EMC tend to have an involvement of pulmonary interstitial space, possibly related to immune complex deposition, but they do not show a severe decline of lung function. Periodical assessment of lung function and chest X-ray is, however, worthwhile.

The potential therapeutic value of anti-idiotypic antibodies during B cell proliferations largely depends on the stability of the target Ig idiotopes. We investigated this stability in a clinical condition of so called nonmalignant monoclonal B cell proliferation, mixed cryoglobulinemia. The idiotypic profile of a single IgM kappa monoclonal auto-antibody with anti-IgG activity (rheumatoid factor (RF] which originated from a patient suffering from a nonmalignant mixed cryoglobulinemia was followed over a period of 3 yr. As judged from the reactivity of a panel of five different mouse monoclonal anti-idiotypic antibodies mapping the RF variable regions, there was no idiotypic change in the serum IgM RF. At a cellular level, in vitro stimulation of the patient's PBL gives rise to IgM kappa auto-antibodies that were shown to bear the same idiotypic determinants as the serum IgM kappa. We then investigated the effects of the anti-idiotypic antibodies on the in vitro IgM kappa production. When stimulated with PWM and in the presence of anti-idiotypic antibodies (10 micrograms/ml), the patient's PBL produced less IgM RF (18 to 62% inhibition). The same inhibition of IgM RF production was observed after EBV infection of the patient's PBL (from 19 to 90% inhibition). In both cases, the remaining IgM RF production was idiotypically indistinguishable from the serum IgM RF. The implications of the idiotypic stability and of the results of in vitro idiotypic manipulation could be important in view of both the understanding of nonmalignant cryoglobulinemia and of the possible therapeutic use of anti-idiotypic antibodies in diseases.