Richard L. Humphrey

Cytotoxic Antibody in Normal Human Serums Reactive with Tumor Cells from Acute Lymphocytic Leukemia

Serums showing complement-dependent cytotoxic reactions to acute lymphocytic leukemia cells were detected in three normal unimmunized subjects. These serums were reactive with tumor cells from 514 (514 tested) acute lymphocytic leukemia patients, and three (12 tested) patients with acute myelocytic leukemia; they did not react with tumor cells from patients with acute monocytic leukemia (two tested), with chronic lymphocytic leukemia (two tested) or with leukolymphosarcoma (two tested); nor did they react with normal lymphocytes from 52 different donors. These reactive serums appear to recognize antigens primarily associated with acute lymphocytic leukemia.

Direct bone resorbing activity of murine myeloma cells

The cellular mechanism(s) responsible for tumor-associated bone resorption in multiple myeloma remain uncertain. Both in vivo and in vitro evidence is presented for the direct resorption of bone by mouse plasmacytomas. Morphological examination of autopsy specimens from tumor-bearing mice revealed in vivo erosion of bony surfaces at sites of tumor cell-bone matrix apposition. No osteoclastic bone resorptive activity was evident. Using a 45Ca-labelled, devitalized bone explant assay system, mouse myeloma cells caused the release of isotope at levels from 200-300% above control values. Control cells such as normal spleen lymphocytes and liver cells did not resorb bone. Demonstration of the ability of myeloma cells to independently destroy bone is important to the understanding of the causes of and development of chemotherapeutic approaches to myelomatous bone resorption.

Gamma heavy chain disease in a patient with diabetes and chronic renal insufficiency: diagnostic assessment of the heavy chain fragment.

Heavy chain diseases are rare B‐cell disorders that are characterized by an overproduction of abnormal and structurally incomplete monoclonal immunoglobulin (Ig) heavy chains and are devoid of light chains. We describe a case of a 62 year‐old African‐American woman with a long history of poorly controlled type 2 diabetes and subsequent probable diabetic nephropathy, hypertension, and recent onset of peripheral neuropathy involving all extremities. Routine laboratory testing revealed a distinct beta spike by urine protein electrophoresis (UPEP). No serum abnormality was noted on serum protein electrophoresis (SPEP). Serum and urine immunofixation demonstrated an IgG heavy chain protein devoid of any corresponding light chains. IgG subclasses identified IgG1 as the predominant IgG component but when we added all the subclasses, the sum, 683.4u2009mg/dL, failed to come close to our total IgG of 1,770u2009mg/dL. Therefore, a urine IgG subclass determination was performed in‐house and we identified a subclass 3 gamma chain. In conclusion, we portray a patient with an underlying monoclonal gamma heavy chain disease (HCD) who presented with a complex medical history. The evaluation of IgG subclasses in the context of a HCD may be limited by the capability of the test to recognize the particular IgG fragment. J. Clin. Lab. Anal. 22:146–150, 2008.

Studies with murine LPC-1 plasmacytoma using [6-14C]arginine.

[6‐14C]Arginine ([6‐14C]Arg) was used as an in vivo pulse label to study BALB/c murine LPC‐1 plasmacytoma synthesis and secretion of its tumour‐associated M component (IgG2a, k). With this isotope, an eight‐ to ten‐fold enhancement in the labelling of the γ globulin region and ten‐fold reduction in the albumin labelling were observed. Production and secretion of the M component was detected (within 30 min) after cell transfer. Only mice which received tumour cells showed significant labelling in the γ globulin region 24 hr after isotope injection. The labelling behaviour of the tumour M component correlated with the administered cell dose. The peak heights of radioactivity in the γ region increased with increments in cell number. When the percentage radioactivity diverted into M component was plotted as a function of cell dose, a linear relationship was noted. This study demonstrates the feasibility of using [6‐14C]Arg as a tool to follow the newly synthesized tumour‐associated protein, and provides a means of estimating tumour cell number.

Amino acid sequence of the human myeloma lambda chain win

The complete amino acid sequence of the variable region of a human myeloma immunoglobulin light chain (Win) has been determined. The sequence of the constant region has been verified by compositional analysis of its tryptic peptides. The amino acid sequence of the light chain Win corresponds to sub group II and shows no unusual amino acid replacements in its constant or variable regions when compared to other human gamma chains.

T cell-specific human alloantisera-detecting antigens segregating outside the major histocompatibility complex

Two sera demonstrated non-HLA lymphocytotoxicity on the basis of reactivity with the cells of siblings genotypically identical to the serum donors for the major histocompatibility complex. These two sera, B1 and Caf, once contaminating HLA antibodies were removed by absorption with pooled platelets, demonstrated allogeneic lymphocytotoxicity that was restricted to T lymphocytes. Reactivity of the absorbed sera segregated independently of the major histocompatibility complex in 3 of 12 families tested. Unlike both cold lymphotoxins and HLA antibodies, the absorbed sera showed little temperature sensitivity against allogeneic cells, although reactivity of the B1 serum to autologous cells and to cells of the donors HLA identical sibling did show a decrease with increasing temperature and restriction of activity to the 19S-containing fraction. Granulocytes were unreactive with the absorbed sera. Such sera may provide probes of minor transplantation antigens or markers, or both, of lymphoid subpopulations.

γ/IgG ratio: role in distinguishing monoclonal spikes from fibrinogen

Serum protein electrophoresis (SPEP) is a standard screening method for detecting monoclonal gammopathies. Presence of fibrinogen, however, can mimic a true monoclonal spike and interfere with accurate monoclonal protein identification. We describe a novel approach for distinguishing fibrinogen spikes from true monoclonal spikes. We classified 600 individual patient samples into four groups: group 1, 58 samples with a fibrinogen spike; group 2, 127 samples with a spike due to a monoclonal gammopathy; group 3, 181 samples with previously established monoclonal gammopathies but resolved posttreatment; and group 4, 234 control samples without monoclonal gammopathies. The value of using a γ regionfraction/IgG ratio in distinguishing fibrinogen from true monoclonal spikes was assessed. The γ/IgG ratio in the fibrinogen group is significantly (P<0.0001) higher than this ratio in the other three groups. A γ/IgG ratio cut‐off value of 1.13 discriminates true monoclonal gammopathies from fibrinogen. Moreover, exclusion of elevated IgA or IgM cases improves the ratios predictive power. The probability cut‐off is 0.756, corresponding to a γ/IgG ratio of 1 (93% sensitivity, 91% specificity). Using the γ/IgG ratio improves the screening power of SPEP and offers a simple and reliable diagnostic tool for distinguishing fibrinogen spikes from true monoclonal spikes. J. Clin. Lab. Anal. 25:332–336, 2011.

In Vivo Pulse Labeling Studies of Murine LPC-1 Plasmacytoma Using 6-14C-Arginine

Guanido labeled arginine (6-14C-arg) was used as an in vivo pulse label of murine LPC-1 plasmacytoma M component (IgG 2a,κ) to study early events immediately following tumor cell transfer in BALB/c mice. This radiolabeling technique was found more sensitive than conventional staining methods in detecting newly synthesized tumor protein. Significant labeling in the plasma γ region corresponding to the M component electrophoretic mobility was observed only in mice injected with tumor cells and isotope. The effective duration of 6-14C-arg availability for protein biosynthesis was less than 30 mins. Using 6-14C-arg pulse labeling technique, a reduction of M component labeling was observed from days 1 to 7 with a nadir on day 3. Recovery of M component labeling to the 30 min level was complete by day 13. This period of dramatic decrease “eclipse” in newly synthesized M component was two days shorter in mice pretreated with pristane or cyclophosphamide (CY) prior to tumor cell injection and in athymic BALB/c nu/nu mice. The “eclipse” period seems to correspond to the classical lag following tumor cell transfer before tumor growth can be detected by conventional methods. Modification of the eclipse period suggests that plasmacytoma cells respond to variations in the condition of the host. Some of the host variables that modify tumor growth may include normal regulatory functions. In vivo 6-14C-arg pulse labeling technique thus serves to probe early dynamic events of host-tumor cell interactions.