Cytoplasmic immunoglobulins in bone marrow cells of polyclonal and of monoclonal origin

Immunoglobulin gene rearrangement in multiple myeloma: limitations of Southern blot analysis

Thirty-six patients with early and advanced multiple myeloma were investigated with Southern blot analysis to determine the presence of immunoglobulin gene rearrangement as evidence of clonality. Rearrangements were not uniformly found, being detected in only 14 of 19 patients with newly diagnosed myeloma and in 15 of 17 cases of clinically advanced myeloma. A correlation between percentage of bone marrow plasma cells and detection of immunoglobulin gene rearrangement was noted; however, in four cases of early myeloma with > 10% marrow plasma cells, no rearrangement was found. These results suggest that Southern blot analysis may not be an optimal method for the determination of clonality in plasma cell dyscrasias or, alternatively, that a proportion of the plasma cells found on bone marrow examination in some patients with early myeloma may not be monoclonal.

Nonsecretory multiple myeloma

Among 186 patients with multiple myeloma (MM), five women were diagnosed as having MM without M-component in serum and or urine at the diagnosis and along the evolution. Bone marrow plasmacytosis at greater than 30% was found in all patients and bone x-rays showed lytic lesions in all but one case, osteoporosis in all, and pathologic fractures in two. Serum electrophoresis showed a striking hypogammaglobulinemia in all, and polyclonal immunoglobulin levels were markedly reduced. The immunofluorescence of plasma cells in bone marrow was positive for monoclonal light chain polypeptides in four patients, and the ultrastructure showed mature plasmocytes with a wide rough endoplasmic reticulum (RER) and an intact Golgi apparatus. In three patients, therapy with melphalan plus prednisone was started. The remaining two were treated with an M-2 protocol. Death was an early event in two patients; the response was good in the remaining patients, without differences regarding secretory MM. Despite some reports stressing an unfavourable prognosis in MM without M-component, in our series it is roughly the same as in MM with secretion.

Quantitation of the monoclonal plasma cell component in bone marrow from patients with serum paraproteinemia and nondiagnostic marrow morphology

Twenty-one patients with serum monoclonal gammopathy but lacking acceptable morphological evidence of myelomatosis were studied with reference to the degree, if any, of monoclonal plasma cell expansion in aspirated marrow samples, enriched for plasma cells and analysed with respect to light chain distribution. Four of these patients had a biopsy-proven plasmacytoma of bone. Bone marrow aspirated from sites distant to the tumor showed clear evidence of infiltration by monoclonal plasma cells in two of the cases studied; the other two patients had normal results. Of the 17 other cases, 14 showed evidence of a monoclonal plasma cell component qualitatively concordant with the serum paraprotein as one would expect. These cases could be subdivided into those with myeloma (six cases) and those with monoclonal gammopathy of undetermined significance (eight cases) on the basis of conventional biochemical and radiological criteria. Three of the 17 patients, however, did not show evidence of monoclonal plasma cell infiltration, despite the presence of lytic lesions. It is important to recognize this minority group that simulates myeloma but that may well reflect alternative pathology that has not been identified.

Bone-marrow plasmocytosis--an immunohistological study

Bone-marrow biopsies and smears from 59 patients with reactive plasmocytosis (22), multiple myeloma (24), solitary plasmocytoma (3) and monoclonal gammopathy of undetermined significance (MGUS) (10) were examined. To demonstrate cytoplasmic immunoglobulin the immunoperoxidase method was applied and evaluated quantitatively. Immunohistology yielded different ranges in kappa/lambda ratio for reactive plasmocytosis (0.4-3.5), multiple myeloma (less than or equal to 0.1 and greater than or equal to 11.2) and MGUS (0.2-3.0). As a result this method seems to be helpful in characterizing a plasmocytosis and distinguishing overt myeloma from monoclonal gammopathy of undetermined significance and reactive plasmocytosis. A differentiation of monoclonal gammopathy of undetermined significance from reactive plasmocytosis is not possible histologically and immunohistologically.

Applications and limitations of peripheral blood lymphocyte immunoglobulin light chain analysis in the evaluation of non-Hodgkin's lymphoma

Surface immunoglobulin (sIg) light chain analysis of peripheral blood lymphocytes (PBL) from 63 patients with non-Hodgkin's lymphoma (NHL) was performed to determine the ratio of kappa-bearing lymphocytes to lambda-bearing lymphocytes (kappa/lambda ratio). In 43% an abnormal kappa/lambda ratio was detected, implying the presence of a malignant clone in the peripheral blood (clonal excess). In 67% of cases with an abnormal kappa/lambda ratio, the absolute lymphocyte count was within normal limits and 20% did not have morphologic bone marrow involvement. Light chain analysis of bone marrow aspirates was performed in three of four patients with a circulating clone and normal bone marrow morphology. All three patients had abnormal bone marrow aspirate kappa/lambda ratios. The presence of a circulating clone was associated with morphologic bone marrow involvement (P less than 0.05). Nine patients with documented B-cell NHL were followed with repeated examinations. The presence of a circulating clone persisted in two patients refractory to therapy and in two patients otherwise believed to be in remission. Conversion to an abnormal kappa/lambda ratio occurred in two patients coincident with the development of new bone marrow involvement and in a third patient prior to the onset of frank leukemia. In three instances, the PBL light chain analyses remained within normal limits in patients with stable lymphadenopathy. The kappa/lambda ratio returned to normal in one patient responding to treatment with a partial remission, and remained within normal limits despite progression of lymphadenopathy in one patient, and local disease recurrence in another patient. These findings suggest that the detection of a circulating clone by sIg light chain analysis may be useful as a noninvasive approach to identify disseminated disease activity unsuspected on the basis of morphologic evaluations, but may not reflect the presence, progression, or recurrence of localized tissue lesions.

Bone marrow histology in myeloma: its importance in diagnosis, prognosis, classification and staging

A study has been made of 420 bone marrow biopsies from patients with multiple myeloma (220), idiopathic monoclonal gammapathy (50), reactive plasmacytosis (42) and solitary plasmacytoma (22). Histology and immunohistological parameters were more reliable than cytology in distinguishing a reactive from a neoplastic plasmacytosis. Histological variables were correlated with the clinical features of the patients to determine the factors which were of value in predicting prognosis. Plasma cell maturity and the extent of infiltration in the biopsy by myeloma cells proved to be highly significant in predicting the duration of survival. On the basis of these criteria multiple myeloma was classified into two types: plasmacytic of low-grade malignancy and plasmablastic of high-grade malignancy; and into three stages which accurately reflected the progression of the disease. We conclude that a bone biopsy provides useful information for the diagnosis, classification and staging of patients with multiple myeloma.

Lymphomas and pseudolymphomas of the alimentary tract. An immunohistochemical study with clinicopathologic correlations

One hundred one lymphoproliferative lesions of the gastrointestinal tract (66 malignant lymphomas, 20 pseudolymphomas, and 5 borderline lesions) were reviewed. The pathologic features were compared to the clinical findings, with reference to differential diagnosis and prognosis. Special attention was paid to immunohistochemical features. The gross appearance was diagnostic in only a limited number of cases. Endoscopic biopsy alone was also of limited value because only a diagnosis of probability could be made in several cases. In most of them the definitive diagnosis had to be based on histologic examination of the resected specimen. Immunohistochemical examination was found to be very useful as an ancillary diagnostic technique. Malignant lymphomas displayed either cytoplasmic immunoglobulins with a monoclonal pattern (47.1 per cent) or a negative reaction, whereas the pseudolymphomas were generally characterized by polyclonal immunoglobulins. Ninety per cent of malignant lymphomas with cytoplasmic immunoglobulins contained lambda chains. The survival probability was found to be related to the size of the lesion, the depth of infiltration, and the immunohistochemical characteristics of the tumors. The histologic type of the lymphomas was of limited value as a predictor of prognosis in the present series.