Enhanced B cell survival in familial macroglobulinaemia is associated with increased expression of Bcl-2.

A family with three cases of macroglobulinaemia of undetermined significance (MGUS), and one case each of immunoblastic lymphoma, Waldentröm's macroglobulinaemia and multiple myeloma was first described 20 years ago. We have previously identified 10 out of 35 healthy family members tested whose lymphocytes produced abnormally high amounts of immunoglobulins in culture. In the present study lymphocyte subpopulations of these hyper-responders have been further characterized and lymphocyte reactivity and survival in vitro have been studied. No differences were detected in the proportions of resting B lymphocytes (CD19+) co-expressing CD5, CD10, CD11b, or CD38, and the CD4/CD8 ratio of T cells was normal before and after stimulation with pokeweed mitogen (PWM). The initial rate of response in terms of immunoglobulin production was not increased, but immunoglobulin levels continued to rise during the second week of culture whereas the production peaked at 8 days in control cultures. This was associated with significantly greater survival of lymphocytes and at 14 days surviving B cells could only be identified in samples from hyper-responders. A lymph node removed because of tuberculosis from a family member 23 years before the diagnosis of multiple myeloma showed very marked Bcl-2 expression in a B cell follicle. This was not seen in a tuberculous lymph node from an unrelated subject. Stimulated cultures from three hyper-responders tested demonstrated significantly higher retention of Bcl-2 in B cells compared with one family control and six unrelated controls. We conclude that the increased production of immunoglobulins previously observed in this family with an inherited tendency for benign and malignant B cell proliferation is the result of enhanced B cell survival, which is associated with increased expression of Bcl-2 following stimulation.

Effect of long-term use of moisturizer on skin hydration, barrier function and susceptibility to irritants.

Moisturizers are often used in the prevention and treatment of irritant contact dermatitis. The present study was to determine whether long-term daily use of a moisturizer on normal skin would affect skin barrier function, hydration state, or susceptibility to sodium lauryl sulphate. Healthy volunteers used a moisturizer on one forearm 3 times daily for 4 weeks. The other forearm served as a control. Afterwards both forearms were challenged with a patch-test of sodium lauryl sulphate. Skin barrier function was evaluated by measuring trans-epidermal water loss and skin hydration by measuring electrical capacitance. Electrical capacitance was significantly increased on the treated arm during the treatment period. After challenge with sodium lauryl sulphate, transepidermal water loss was significantly higher on the arm treated with moisturizer than on the control arm. The results suggest that long-term treatment with moisturizers on normal skin may increase skin susceptibility to irritants.

Familial macroglobulinaemia: hyperactive B-cells but normal natural killer function.

An Icelandic family with two cases of benign monoclonal gammopathy and one case each of Waldenström's macroglobulinaemia, histiocytic lymphoma and multiple myeloma was first described in 1978. Nine family members had then shown raised values for se-IgM. Of these one has since died and another was not available for testing. In four of the remaining seven se-IgM had returned to normal; the three subjects who still showed raised se-IgM included the case of multiple myeloma diagnosed in 1985. Baseline production of IgM, IgG and Ig in vitro was normal in the 35 family members studied compared with 13 healthy control subjects, but the mean production of all immunoglobulin classes in response to minimal stimulation with PWM (1 microgram/ml) was significantly increased (P < 0.05). Ten family members showed markedly increased production of all three immunoglobulin classes (> 3 x SD above mean for controls). Raised production of IgM never occurred alone, indicating intact class switching. One family member showed extremely high values: IgA: 5.15 micrograms/ml, IgG: 16.3 micrograms/ml, IgM: 24.8 micrograms/ml (means for controls: 0.066, 0.123, 0.185 respectively). These 10 family members were of both sexes, ranged in age from 16 to 84 years and were clustered mainly in three distinct groups within the pedigree suggesting heredity. Proliferative responses to PWM were not significantly increased. Serum levels of interleukin-4 were tested in the patient with multiple myeloma and the family member with highest Ig production and found to be normal. We found no evidence for depressed NK function. Thus, in this family with a tendency for macroglobulinaemia and B cell derived malignancies B cell hyperreactivity was detectable by in vitro testing in several asymptomatic family members, of both sexes and all ages. No evidence was obtained for defects in regulatory mechanisms.

Natural killer cell function and malignant cell phenotype in hairy cell leukaemia.

We have followed for 33 months the changes that occurred in natural killer (NK) cell numbers and activity in a patient (A) with hairy cell leukaemia (HCL), using a single cell assay and a microcytotoxicity assay. The composition of the peripheral blood mononuclear cell population and malignant cell phenotype were also analysed. During this period he received treatment with interferon and his grossly enlarged spleen was removed. Four further patients were also studied, two were splenectomized and all had received treatment with interferon. In four of the five patients studied there was an apparent link between low NK activity and presence of a tumour-infiltrated spleen, and in the fifth patient, who was aleukemic and had no splenomegaly, NK function was related to disease activity. There was no correlation between NK activity and the number of target binding (TB) cells in these five patients. IFN had little direct effect on overall NK activity, but the proportion of killing cells among TB cells was increased. Three patients showed binding of several cells to a single target. Further analysis revealed that in the patients most of the TB cells were not CD56-positive NK cells, in contrast to TB cells from normal subjects. In patient A a large proportion (84%) of TB cells were identified as malignant cells and in patient E 15% of TB cells were malignant cells. The phenotype of the malignant cells was: CD19+, HLA-DR+ and CD25(Tac)+, except for patient A. In this patient the hairy cells were positive for the NK marker CD56 as well as the monocyte marker CD14. Furthermore, a change occurred in phenotype as only later samples carried CD25. It is concluded that the level of NK function correlates closely with disease activity in HCL and that competitive target cell binding by malignant cells may be one cause of depressed NK-cell function in hairy cell leukaemia.