Chemical and Chemoenzymatic Synthesis of Peptide and Protein Therapeutics Conjugated with Human N-Glycans.

Glycosylation is one of the most ubiquitous post-translational modifications. It affects the structure and function of peptides/proteins and consequently has a significant impact on various biological events. However, the structural complexity and heterogeneity of glycopeptides/proteins caused by the diversity of glycan structures and glycosylation sites complicates the detailed elucidation of glycan function and hampers their clinical applications. To address these challenges, chemical and/or enzyme-assisted synthesis methods have been developed to realize glycopeptides/proteins with well-defined glycan morphologies. In particular, N-glycans are expected to be useful for improving the solubility, in vivo half-life and aggregation of bioactive peptides/proteins that have had limited clinical applications so far due to their short duration of action in the blood and unsuitable physicochemical properties. Chemical glycosylation performed in a post-synthetic procedure can be used to facilitate the development of glycopeptide/protein analogues or mimetics that are superior to the original molecules in terms of physicochemical and pharmacokinetic properties. N-glycans are used to modify targets because they are highly biodegradable and biocompatible and have structures that already exist in the human body. On the practical side, from a quality control perspective, close attention should be paid to their structural homogeneity when they are to be applied to pharmaceuticals.

Cap Analysis of Gene Expression Clarifies Transcriptomic Divergence Within Monozygotic Twin Pairs.

Phenotypic variation is the result of gene expression based on complex interaction between genetic and environmental factors. It is well known that genetic and environmental factors influence gene expression, but our understanding of their relative importance remains limited. To obtain a hint for the understanding of their contributions, we took advantage of monozygotic twins, as they share genetic and shared environmental factors but differ in nonshared factors, such as environmental differences and stochastic factors. In this study, we performed cap analysis of gene expression on three pairs of twins and clustered each individual based on their expression profiles of annotated genes. The dendrogram of annotated gene transcripts showed a monophyletic clade for each twin pair. We also analyzed the expression of retrotransposons, such as human endogenous retroviruses (HERVs) and long interspersed nuclear elements (LINEs), given their abundance in the genome. Clustering analyses demonstrated that HERV and LINE expression diverged even within monozygotic twin pairs. Thus, HERVs and LINEs are more susceptible to nonshared factors than annotated genes. Motif analysis of differentially expressed annotated genes suggests that specificity protein/Krüppel-like factor family transcription factors are involved in the expression divergence of annotated gene influenced by nonshared factors. Collectively, our findings suggest that expressions of annotated genes and retrotransposons are differently regulated, and that the expression of retrotransposons is more susceptible to nonshared factors than annotated genes.

Prognostic value of post-treatment serum soluble interleukin-2 receptor in newly diagnosed diffuse large B-cell lymphoma patients who achieved complete metabolic response following R-CHOP therapy.

Patients with DLBCL achieving complete metabolic response (CMR) after initial treatment with R-CHOP generally have a favourable prognosis; however, there are no established prognostic biomarkers for relapse in these patients. Soluble interleukin-2 receptor (sIL-2R) levels at diagnosis are prognostic factors in patients with DLBCL. However, the significance of post-treatment sIL-2R levels is unclear. To determine the significance of post-treatment serum sIL-2R levels on subsequent relapse and survival, we retrospectively analysed 485 patients with newly diagnosed DLBCL who received R-CHOP treatment and achieved CMR. The cumulative incidence of relapse (CIR) was significantly higher in patients with elevated post-treatment sIL-2R levels than in those with normal sIL-2R levels (five-year CIR; 38.8% vs. 12.8%). The prognostic value remained significant in multivariable analysis (hazard ratio, 2.30; p < 0.001). Five-year progression-free survival (49.0% vs. 83.5%) and overall survival (61.7% vs. 91.6%) rates were lower in patients with elevated post-treatment sIL-2R levels than in those with normal sIL-2R levels (p < 0.001 for both). In patients with newly diagnosed DLBCL who achieved CMR after R-CHOP treatment, the post-treatment serum sIL-2R level was an independent prognostic marker of subsequent relapse and survival.

Better Peptides via Chemical Glycosylation: Somatostatin Analogues Having a Human Complex-Type N-Glycan with Improved Drug Properties.

Somatostatin (somatotropin release-inhibiting factor, SRIF) is a growth hormone inhibitory factor in the form of a 14- or 28-amino acid peptide. SRIF affects several physiological functions through its action on five distinct SRIF receptor subtypes (sst1-5). Native SRIF has only limited clinical applications due to its rapid degradation in plasma. To overcome this obstacle, we have developed glycosylated SRIF analogues that possess not only metabolic stability but also high affinity to all five receptor subtypes by attaching human complex-type oligosaccharides. Such glycosylated SRIF analogues with improved pharmacokinetic profiles could be potent and novel therapeutic drugs for SRIF-related diseases in which several SRIF receptor subtypes are closely involved, and also shed light on new indications. Our results show that chemical glycosylation can be a powerful tool for the development of peptide and protein analogues superior to the original molecules with enhanced drug properties.

[Assessment of Chemotherapy-Induced Adverse Events Using a Sharing System of Patient-Reported Information via a Touch Panel].

Screening for total pain and sharing of patient information including adverse events for patients receiving chemotherapy by medical staff is needed in clinical practice. We introduced a sharing system for patient-oriented outcome sheets via a touch panel at an outpatient chemotherapy clinic. This study aimed to assess whether the system contributes to the improved management of treatment-related adverse events. We retrospectively analyzed data from a total of 215 patients at Ehime University Hospital using their electronic medical records from April to August 2015. Forty of these patients had received interventions relating to treatment-related adverse events. The proportion of a total number of interventions before and after the sharing system was 42/282(14.9%)and 45/215(20.9%), respectively. The proportion of a total number of interventions at the first course of outpatient chemotherapy also increased from 9/40(22.5%)to 14/40(35%)compared with before the sharing system. The purpose of interventions were for insomnia, anorexia, and cancer-related pain, etc., listed in order of degree of frequency. These results suggest that a sharing system of patient-reported interview sheets contributes to tracking treatment -related adverse events and aids in ensuring interventions can be efficiently performed by multidisciplinary team members.

Direct comparison of target-reactivity and cross-reactivity induced by CAR- and BiTE-redirected T cells for the development of antibody-based T-cell therapy.

The development of chimeric antigen receptor (CAR) and bispecific T-cell engager (BiTE) has led to the successful application of cancer immunotherapy. The potential reactivity mediated by CAR- and BiTE-redirected T cells needs to be assessed to facilitate the application of these treatment options to a broader range of patients. Here, we have generated CAR and BiTE possessing the same single chain fragment variable (scFv) specific for the HLA-A2/NY-ESO-1157-165 complex (A2/NY-ESO-1157). Using HLA-A2+NY-ESO-1+ myeloma cells and peptides presented by HLA-A2 molecules as a model, both sets of redirected T cells recognized and killed HLA-A2+NY-ESO-1+ myeloma cells in an A2/NY-ESO-1157-specific manner in vitro. Moreover, CAR- and BiTE-activated T cells showed similar functional avidity, as assessed by cytokine production and killing activity, both displaying antitumor reactivity against HLA-A2+NY-ESO-1+ myeloma cells in vivo. Interestingly, cross-reactivity for homologous peptides presented by HLA-A*02:01 and NY-ESO-1157 peptide presented by HLA-A2 alleles was not identical between CAR- and BiTE-redirected T cells, probably due to structural differences of modified antibodies. These results have demonstrated that both antitumor CAR- and BiTE-activated T cells have comparable potential to recognize tumors, while paying attention to unknown off-target reactivity that would differ for each antibody-based modality even if the same scFv was employed.

[A Case of Microangiopathic Hemolytic Anemia with Bone Marrow Carcinomatosis from Breast Cancer].

We report a case of microangiopathic hemolytic anemia(MHA)caused by metastatic breast cancer treated with weekly paclitaxel. A 58-year-old woman was diagnosed with metastatic breast cancer 2 years earlier. She was treated with various chemotherapy regimens and hormonal therapy, before being switched to fulvestrant 3 months earlier. She presented with severe anemia, and was diagnosed with MHA with bone marrow carcinomatosis following bone marrow biopsy. She was treated with weekly paclitaxel and recovered successfully. A subsequent biopsy showed that the bone marrow carcinomatosis had decreased. MHA due to breast cancer is rare and is associated with poor prognosis; however, rapid initiation of chemotherapy may be effective.

Bortezomib plus dexamethasone vs thalidomide plus dexamethasone for relapsed or refractory multiple myeloma.

A randomized phase II selection design study (JCOG0904) was carried out to evaluate the more promising regimen between bortezomib (Bor) plus dexamethasone (Dex; BD) and thalidomide (Thal) plus Dex (TD) in Bor and Thal-naïve patients with relapsed or refractory multiple myeloma (RRMM). Patients ≥20 and <80 years old with a documented diagnosis of symptomatic multiple myeloma (MM) who received one or more prior therapies were randomized to receive BD (Bor 1.3 mg/m2 ) or TD (Thal 200 mg/d). In both arms, 8 cycles of induction (3-week cycle) were followed by maintenance phase (5-week cycle) until disease progression, unacceptable toxicity, or patient refusal. The primary end-point was 1-year progression-free survival (PFS). Forty-four patients were randomized and assigned to receive BD and TD (n = 22, each group). At a median follow-up of 34.3 months, the 1-year PFS in the BD and TD arms were 45.5% (95% confidence interval (CI), 24.4%-64.3%) and 31.8% (95% CI, 14.2%-51.1%), respectively, and the overall response rates were 77.3% and 40.9%, respectively. The 3-year overall survival (OS) was 70.0% (95% CI, 44.9%-85.4%) in the BD, and 48.8% (95% CI, 25.1%-69.0%) in the TD arm. Among grade 3/4 adverse events, thrombocytopenia (54.5% vs 0.0%) and sensory peripheral neuropathy (22.7% vs 9.1%) were more frequent in BD when compared with the TD arm. Patients treated with BD had better outcomes than those treated with TD with regard to 1-year PFS and 3-year OS. Thus, BD was prioritized over TD for further investigations in Bor and Thal-naïve RRMM patients. (Clinical trial registration no. UMIN000003135.).

[A Case of Stage IV Breast Cancer with Long-Term Survival by Chemotherapy Developing Pulmonary Tumor Thrombotic Microangiopathy during the Treatment Course].

Pulmonary tumor thrombotic microangiopathy(PTTM)caused by pulmonary artery microscopic tumor emboli and fibrocellular and/or fibromuscular proliferation leads to progressive pulmonary hypertension and respiratory failure.The prognosis is extremely poor and most patients die shortly after onset.We report a patient with Stage IV breast cancer and long-term survival who developed PTTM during chemotherapy treatment.A 63-year-old woman with multiple metastases in her cerebellum, bone, lung, and lymph node after left breast conserving surgery started to experience dyspnea and malaise 7 years after the surgery.Two months later, she was urgently admitted to hospital because of respiratory failure and was diagnosed with pulmonary hypertension.However, pulmonary thrombosis and tumor thrombus were not observed.We clinically diagnosed her with PTTM and administered chemotherapy in addition to treatment for pulmonary hypertension.Her medical condition improved gradually and she survived for the subsequent 2 years.When observing progressive hypoxia and pulmonary hypertension without obvious pulmonary embolism findings on imaging, PTTM should be considered.Early diagnosis and immediate induction of chemotherapy for primary disease can improve the survival of patients with PTTM.

Gene-modified human α/ß-T cells expressing a chimeric CD16-CD3ζ receptor as adoptively transferable effector cells for anticancer monoclonal antibody therapy.

The central tumoricidal activity of anticancer monoclonal antibodies (mAb) is exerted by FcγR IIIa (CD16)-expressing effector cells in vivo via antibody-dependent cell-mediated cytotoxicity (ADCC), as observed for natural killer (NK) cells. In practice, chemotherapy-induced leukopenia and exhaustion of NK cells resulting from ADCC often hamper the clinical efficacy of cancer treatment. To circumvent this drawback, we examined in vivo the feasibility of T cells, gene-modified to express a newly generated affinity-matured (158V/V) chimeric CD16-CD3ζ receptor (cCD16ζ-T cells), as a transferable alternative effector for cancer mAb therapy. cCD16ζ-T cells were readily expandable in ex vivo culture using anti-CD2/CD3/CD28 beads and recombinant human interleukin-2 (rhIL-2), and they successfully displayed ADCC-mediated tumoricidal activity in vitro. During ADCC, ligation of opsonized cancer cells to the introduced cCD16ζ-T cells stimulated the effector cells to produce proinflammatory cytokines and release toxic granules through the activation of the Nuclear factor of activated T cells (NFAT) pathway after phosphorylation of the CD3ζ chain. In parallel, these stimulated cCD16ζ-T cells transiently proliferated and differentiated into effector memory T cells. In contrast, NK cells activated by rhIL-2 displayed similar ADCC activity, but failed to proliferate. Human cCD16ζ-T cells infused concomitantly with anti-CD20 mAb synergistically inhibited the growth of disseminated Raji cells, a CD20(+) lymphoma cell line, in immunodeficient mice, whereas similarly infused rhIL-2-treated NK cells survived for a shorter time and displayed less effective tumor suppression. Our findings strongly suggest the clinical feasibility of cCD16ζ-T cells as adoptively transferable ADCC effector cells that could potentially enhance the clinical responses mediated by currently available anticancer mAbs.

Adoptive transfer of genetically engineered WT1-specific cytotoxic T lymphocytes does not induce renal injury.

Because WT1 is expressed in leukemia cells, the development of cancer immunotherapy targeting WT1 has been an attractive translational research topic. However, concern of this therapy still remains, since WT1 is abundantly expressed in renal glomerular podocytes. In the present study, we clearly showed that WT1-specific cytotoxic T lymphocytes (CTLs) certainly exerted cytotoxicity against podocytes in vitro; however, they did not damage podocytes in vivo. This might be due to the anatomical localization of podocytes, being structurally separated from circulating CTLs in glomerular capillaries by an exceptionally thick basement membrane.

Development of a novel redirected T-cell-based adoptive immunotherapy targeting human telomerase reverse transcriptase for adult T-cell leukemia.

Although adult T-cell leukemia (ATL) has a poor prognosis, successful allogeneic hematopoietic stem cell transplantation (allo-HSCT) in some cases suggests that a cellular immune-mediated strategy can be effective. So far, however, no effective target for anti-ATL immunotherapy has been defined. Here we demonstrated for the first time that human telomerase reverse transcriptase (hTERT) is a promising therapeutic target for ATL, and we developed a novel redirected T-cell-based immunotherapy targeting hTERT. hTERT messenger RNA was produced abundantly in ATL tumor cells but not in steady-state normal cells. Rearranged human leukocyte antigen-A*24:02 (HLA-A*24:02) -restricted and hTERT461-469 nonameric peptide-specific T-cell receptor (TCR) α/ß genes were cloned from our previously established cytotoxic T lymphocyte clone (K3-1) and inserted into a novel retroviral TCR expression vector encoding small interfering RNAs for endogenous TCR genes in redirected T cells (hTERT-siTCR vector). Consequently, allogeneic or autologous gene-modified CD8(+) T cells prepared using the hTERT-siTCR vector successfully killed ATL tumor cells, but not normal cells including steady-state hematopoietic progenitors, in an HLA-A*24:02-restricted manner both in vitro and in vivo. Our experimental observations support the development of a novel hTERT-targeting redirected T-cell-based adoptive immunotherapy for ATL patients, especially those for whom suitable allo-HSCT donors are lacking.

Co-introduced functional CCR2 potentiates in vivo anti-lung cancer functionality mediated by T cells double gene-modified to express WT1-specific T-cell receptor.

BACKGROUND AND PURPOSE: Although gene-modification of T cells to express tumor-related antigen-specific T-cell receptor (TCR) or chimeric antigen receptor (CAR) has clinically proved promise, there still remains room to improve the clinical efficacy of re-directed T-cell based antitumor adoptive therapy. In order to achieve more objective clinical responses using ex vivo-expanded tumor-responsive T cells, the infused T cells need to show adequate localized infiltration into the tumor. METHODOLOGY/PRINCIPAL FINDINGS: Human lung cancer cells variously express a tumor antigen, Wilms' Tumor gene product 1 (WT1), and an inflammatory chemokine, CCL2. However, CCR2, the relevant receptor for CCL2, is rarely expressed on activated T-lymphocytes. A HLA-A2402(+) human lung cancer cell line, LK79, which expresses high amounts of both CCL2 and WT1 mRNA, was employed as a target. Normal CD8(+) T cells were retrovirally gene-modified to express both CCR2 and HLA-A*2402-restricted and WT1(235-243) nonapeptide-specific TCR as an effector. Anti-tumor functionality mediated by these effector cells against LK79 cells was assessed both in vitro and in vivo. Finally the impact of CCL2 on WT1 epitope-responsive TCR signaling mediated by the effector cells was studied. Introduced CCR2 was functionally validated using gene-modified Jurkat cells and human CD3(+) T cells both in vitro and in vivo. Double gene-modified CD3(+) T cells successfully demonstrated both CCL2-tropic tumor trafficking and cytocidal reactivity against LK79 cells in vitro and in vivo. CCL2 augmented the WT1 epitope-responsive TCR signaling shown by relevant luciferase production in double gene-modified Jurkat/MA cells to express luciferase and WT1-specific TCR, and CCL2 also dose-dependently augmented WT1 epitope-responsive IFN-γ production and CD107a expression mediated by these double gene-modified CD3(+) T cells. CONCLUSION/SIGNIFICANCE: Introduction of the CCL2/CCR2 axis successfully potentiated in vivo anti-lung cancer reactivity mediated by CD8(+) T cells double gene-modified to express WT1-specific TCR and CCR2 not only via CCL2-tropic tumor trafficking, but also CCL2-enhanced WT1-responsiveness.

Phase I/II study of docetaxel, cisplatin and S-1 in locally advanced, recurrent and metastatic head and neck squamous cell carcinoma.

The purpose of this study was to evaluate the maximum tolerated dose, dose-limiting toxicities and preliminary efficacy of chemotherapy with cisplatin, docetaxel and S-1 (TPS) to treat advanced head and neck squamous cell cancer. S-1 was administered orally twice daily on days 1-14 and docetaxel and cisplatin were injected intravenously on day 8, with one course lasting 4 weeks. The recommended dose obtained from a phase I study was set at docetaxel 60 mg/m(2), cisplatin 60 mg/m(2) and S-1 80 mg/m(2)/day. The phase II study revealed that the overall response rate was 81%, comprising 95% in untreated patients with localized advanced cancer and no distant metastases, 50% in untreated patients with distant metastases and 33% in previously treated patients with recurrence. The overall survival rate of untreated patients with localized advanced cancer and no distant metastases was 95% at 1 year and 64.33% at 2 years. In terms of grade 3 or higher hematotoxicity, neutropenia occurred in 100%, thrombocytotopenia in 4% and anemia in 4%. Febrile neutropenia occurred in 46%, with the rate rising to 57% in elderly patients ≥66 years. Grade 3 or higher non-hematotoxicity consisted of loss of appetite in 8%, diarrhea in 8%, hyponatremia in 13% and hypokalemia in 13%. This TPS therapy may be recommended for use as induction chemotherapy. For patients ≤65 years, the appropriate dose was docetaxel 60 mg/m(2), cisplatin 60 mg/m(2) and S-1 80 mg/m(2), whereas for those ≥66 years, it was docetaxel 60 mg/m(2), cisplatin 60 mg/m(2) and S-1 60 mg/m(2).

[Analysis of the correlation with KRAS gene mutation status and the benefit of cetuximab plus irinotecan as third- line chemotherapy for the Treatment of unresectable metastatic colorectal cancer].

Mutation of the KRAS gene in patients with metastatic colorectal cancer(mCRC)has been established as a predictive marker of poor response to anti-EGFR cetuximab. The Japanese Society of Medical Oncology recommends that the KRAS mutation status at codon 12 and codon 13 should be genotyped by direct-sequencing or allele-specific PCR. In this study, we tested the point mutation of codon 12 and 13 in the KRAS gene by Luminex(xMAP)flow cytometry with sequence-specific oligonucleotide probes for 39 out of 64 unresectable mCRC patients enrolled from Sep 2008 to Oct 2009, who were administered cetuximab in combination with irinotecan(CPT-11)as third-line therapy. We retrospectively analyzed the relationship between KRAS mutation status and responses to combination therapy. Mutations in the KRAS gene were detected in 38. 5% of cases(codon12: 73%, codon 13: 27%), and the median follow-up time was 8. 2 months(range, 1. 4-15. 2 months). The response rates for patients with KRAS wild-type and patients with KRAS mutations were 33. 3%(95%CI 14. 5-52. 2%)and 0%(p=0. 015); the disease control rates were 75%(95%CI 57. 7-92. 3%)and 40%(95%CI, 15. 2-64. 8%; p=0. 044); the median TTF was 7 months(95%CI 4. 6-9. 3)and 2. 3 months(95%CI 1. 3-3. 2; p=0. 0007), and the median OS was 12. 9 months(95%CI 6. 7-19. 1)and 10. 8 months(95%CI 5. 0-16. 7; p=0. 15), respectively. Therefore, we concluded that the KRAS mutation in mCRC is a predictive factor for the lack of response to combination therapy with cetuximab plus CPT- 11, as reported in previous clinical studies.

[Efficacy of CHOP+/-Rituximab-like therapy plus radiation therapy for patients with diffuse large B-cell lymphoma stage I].

Clinically, R-CHOP-like therapy plus radiation therapy is commonly performed for patients with limited stage diffuse large B-cell lymphoma. However, the efficacy and the safety of the management have not been evaluated properly. In particular, we have few definitive reports about patients with stage I DLBCL. This time we evaluated the effect of CHOP+/-R-like therapy plus radiation therapy, by analyzing 28 patients with stage I DLBCL, retrospectively. 15 patients were treated with the RCHOP-like therapy, and 13 received CHOP-like therapy combined with radiation therapy. A complete response was observed in all of the patients. With a median follow-up time of 14 months, 1-year progression-free survival (PFS) was 100%, and the 1-year overall survival (OS) was 100% for the patients receiving the R-CHOP-like therapy. With a median follow-up time of 68 months, 5-year PFS was 84. 6%, and 5-year OS was 100% for patients receiving the CHOP-like therapy. Since the followup time was not enough and the patient numbers were too few, the benefit of the addition of Rituximab to the CHOP therapy could not be clarified. We need to assess the safety and the efficacy of the combined modality therapy for patients with limited-stage DLBCL by a larger prospective study.

An imaging-based rapid evaluation method for complement-dependent cytotoxicity discriminated clinical response to rituximab-containing chemotherapy.

PURPOSE: Rituximab has greatly improved the efficacy of chemotherapy regimens for CD20-positive non-Hodgkin's lymphoma. However, although several mechanisms of action of rituximab have been identified, the exact therapeutic functions of these mechanisms remains to be clarified. In addition, there is no established prognostic marker to predict an individual response. This study verified the validity of ex vivo complement-dependent cytotoxicity (CDC) susceptibility as a predictor of pathologic tumor regression in patients undergoing rituximab-containing chemotherapy and examined whether CDC contributes to the mechanism of action of rituximab. EXPERIMENTAL DESIGN: A rapid assay system was established to evaluate the tumoricidal activity of rituximab using a living cell-imaging technique. We analyzed lymph node biopsies obtained from 234 patients with suspected lymphomas and estimated the association between CDC susceptibility and the response to rituximab-containing chemotherapy in diffuse large B-cell lymphoma and follicular lymphoma. RESULTS: This study revealed that CDC susceptibility of lymphoma cells freshly obtained from patients was strongly associated with response to rituximab-containing chemotherapy in both diffuse large B-cell lymphoma and follicular lymphoma. This correlation was not apparent in cases that received chemotherapy without rituximab. CONCLUSIONS: The system that we have established allows a successful assessment of rituximab-induced CDC and can distinguish cases refractory to rituximab-containing chemotherapy. The association between CDC susceptibility and therapy response suggests that CDC is pivotal in the ability of chemotherapy including rituximab to induce remission.

[IgG-kappa type multiple myeloma with cytoplasmic crystalline inclusions].

An 82-year-old male was admitted to our hospital because of anemia with Hb 6.9/dl. The serum monoclonal IgG of the kappa type was detected. Bone marrow aspiration showed the presence of 38.9% atypical plasma cells with crystalline inclusions. These crystalline inclusions were stained with acid phosphatase, and remained unstained with MPO, PAS and Congo-Red staining. Immunofluorescence studies showed the plasma cells were positive for IgG-kappa type immunoglobulin and CD138. Electron microscopy revealed varying numbers of stick-like, rod-shaped, rhomboid or rectangular crystals of a variety of lengths and sizes with a periodicity giving an appearance of longitudinal striation. The inclusions were most often surrounded by ribosomes. Some crystalline inclusions were located in the rough-surfaced endoplasmic reticulum. Their presence was probably due to an abnormality in the synthesis and/or secretion of immunoglobulin.