Prognostic significance of serum immunoglobulin paraprotein in patients with chronic lymphocytic leukemia

Case report: Acute kidney injury as the initial manifestation of chronic lymphocytic leukemia/small lymphocytic lymphoma

Chronic lymphocytic leukemia (CLL) is a lymphoproliferative disorder often diagnosed after incidental finding of leukocytosis. Renal involvement is usually clinically silent. Symptomatic renal impairment due to CLL/small lymphocytic lymphoma (SLL) cell infiltration in the kidney tissue is uncommon, and acute kidney injury (AKI) as a presenting feature is rare. In this case report, we describe the case of a patient with AKI caused by CLL/SLL infiltration as a presenting feature. Our report highlights the possibility of kidney injury as the first evident symptom of CLL/SLL. Kidney biopsy is the mainstay in these cases in order to establish a diagnosis. Treatment with zanubrutinib resulted in improved kidney function.

Serum Paraprotein Is Associated with Adverse Prognostic Factors and Outcome, across Different Subtypes of Mature B-Cell Malignancies-A Systematic Review

The presence of a serum paraprotein (PP) is usually associated with plasma-cell dyscrasias, Waldenstrom Macroglobulinemia/lymphoplasmacytic lymphoma, and cryoglobulinemia. However, PP is also often reported in other high- and low-grade B-cell malignancies. As these reports are sparse and heterogeneous, an overall view on this topic is lacking, Therefore, we carried out a complete literature review to detail the characteristics, and highlight differences and similarities among lymphoma entities associated with PP. In these settings, IgM and IgG are the prevalent PP subtypes, and their serum concentration is often low or even undetectable without immunofixation. The relevance of paraproteinemia and its prevalence, as well as the impact of IgG vs. IgM PP, seems to differ within B-NHL subtypes and CLL. Nonetheless, paraproteinemia is almost always associated with advanced disease, as well as with immunophenotypic, genetic, and clinical features, impacting prognosis. In fact, PP is reported as an independent prognostic marker of poor outcome. All the above call for implementing clinical practice, with the assessment of paraproteinemia, in patients' work-up. Indeed, more studies are needed to shed light on the biological mechanism causing more aggressive disease. Furthermore, the significance of paraproteinemia, in the era of targeted therapies, should be assessed in prospective trials.

An updated perspective on immunoglobulin replacement in chronic lymphocytic leukaemia in the era of targeted therapies

Chronic lymphocytic leukaemia (CLL) is a malignancy of clonally expanded antigen-switched, neoplastic, mature B cells. CLL is characterised by a variable degree of immunosuppression and secondary hypogammaglobulinemia. B-cell depleting therapies have historically been deployed with a proportion of patients becoming resistant to multiple lines of treatment with an associated worsening of immunosuppression and heightened infection risk. Advances in molecular diagnostics and the development of new therapies targeting Bruton's tyrosine kinase and B-cell lymphoma-2 have resulted in novel insights into the cellular mechanisms associated with an increased infection risk and T-cell escape from the complex tumour environment found in CLL. Generally, immunoglobulin replacement therapy with polyvalent human immunoglobulin G (IgG) is indicated in patients with recurrent severe bacterial infections and low IgG levels, but there is no consensus on the threshold IgG level for initiation of such therapy. A proportion of CLL patients have residual IgG production, with preserved quality of the immunoglobulin molecules, and therefore a definition of 'IgG quality' may allow for lower dosing or less frequent treatment with immunoglobulin therapy in such patients. Immunoglobulin therapy can restore innate immunity and in conjunction with CLL targeted therapies may allow T-cell antigen priming, restore T-cell function thereby providing an escape from tumour-associated autoimmunity and the development of an immune-mediated anti-tumour effect. This review aims to discuss the mechanisms by which CLL-targeted therapy may exert a synergistic therapeutic effect with immunoglobulin replacement therapy both in terms of reducing tumour bulk and restoration of immune function.

Detection and Characterization of Paraproteinemia in Canine Chronic B-cell Lymphocytic Leukemia Using Routine and Free Light Chain Immunofixation

BACKGROUND

Hyperglobulinemia is reported in 26% of canine chronic B-cell lymphocytic leukemia (B-CLL) cases. However, few cases have been characterized by protein electrophoresis and immunofixation (IF), and the incidence of a monoclonal protein (M-protein) is unknown using these techniques.

OBJECTIVE

To characterize and determine the proportion of canine B-CLL cases with an M-protein using plasma protein electrophoresis (PPE), routine and free light chain (fLC) IF, and to assess if productive B-CLL cases express MUM1/IRF4 by cell tube block (CTB).

METHODS

PPE, routine (targeting IgG, IgA, IgM, IgG4, and light chain) and fLC IF were performed using 48 dog B-CLL plasma samples from patients diagnosed via peripheral blood flow cytometry. CTB was performed on a separate cohort of 15 patients.

RESULTS

Hyperproteinemia (>7.5 g/dL) was present in 17/48 cases (35%). An M-protein was detected in 32/48 cases (67%). Of these, 19/32 cases (59%) had only complete (monoclonal heavy and light chain) M-proteins detected, 10/32 cases (31%) had both complete and fLC M-proteins detected, and 3/32 cases (9%) had only an fLC M-protein detected. IgM was the most common clonal immunoglobulin isotype detected (23 cases). CD21⁺ cell counts were higher in cases with detectable M-protein. Plasma fLC IF suggested β-γ region interference, likely caused by clotting proteins. All B-CLL cases consistently expressed PAX5 and did not express MUM1/IRF4.

CONCLUSIONS

Most B-CLL cases had an M-protein and were not hyperproteinemic. Most cases with paraproteins had a complete IgM monoclonal gammopathy; a subset had documented fLCs. The prognostic significance of heavy and fLC presence should be evaluated.

Case Report: Chronic Lymphocytic Leukemia With Recurrent Complement-Mediated Thrombotic Microangiopathy and C3 Glomerulonephritis

Chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) is a monoclonal B cell lymphocytosis that produces nephrotoxic monoclonal immunoglobulin (MIg). However, the role of MIg in CLL and how it affects CLL patient survival are still unknown. Here, we report a case of MIg with renal significance (MGRS) associated with CLL. A 59-year-old Chinese woman complaining of abdominal pain, skin purpura, and typical soy-colored urine was admitted to the hospital for investigation. Laboratory tests revealed that she had microangiopathic hemolytic anemia, thrombocytopenia, acute kidney injury (AKI), and hypocomplementemia. She also reported cryoglobulinemia, thrombotic microangiopathy (TMA), and AKI 2 years previously. Peripheral blood smears at that time showed 4% schistocytes, a negative Coombs' test, and elevated lactate dehydrogenase (LDH). Based on a diagnosis of complement-mediated TMA, the patient was treated by plasmapheresis and achieved clinical disease remission. However, the serum hypocomplement 4 and cryoglobulinemia persisted. Further investigation showed elevated B lymphocytes and monoclonal serum IgMκ; however, the cryoprecipitate contained monoclonal IgMκ and polyclonal IgG, as well as immunoglobulins κ and λ. After plasmapheresis, her LDH, platelets, and complement 3 (C3) levels returned to normal. Biopsies of the bone marrow and an enlarged subclavicular lymph node revealed CLL/SLL. Renal pathological findings indicated significant arteriolar endothelial cells myxoid edema and glomerular endothelial cells swelling, however no thromboli, cryoglobulin formation and vasculitis were observed. We also found mild mesangial proliferative C3 glomerulonephritis and renal interstitial CLL cells infiltration. Collectively, these clinical and pathological manifestations were attributed to monoclonal IgMκ, which triggered C3 activation. MGRS associated with CLL was finally confirmed. Six cycles of rituximab, cyclophosphamide, verodoxin, and dexamethasone therapy were administered, after which she received ibrutinib. The patient experienced disease remission, and her serum C4 level returned to normal. Cryoglobulin and IgMκ were not detected. This is a special presentation of CLL/SLL with monoclonal IgMκ, which is a type of MGRS. Activation of the complement system by MIg led to TMA with C3 glomerulonephritis. Treatment for TMA and CLL/SLL should be initiated in a timely manner to improve patient prognosis.

The pathological features of leukemic cells infiltrating the renal interstitium in chronic lymphocytic leukemia/small lymphocytic lymphoma from a large single Chinese center

Background

Chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) is rare in Asians, and patients with CLL/SLL seldomly undergo kidney biopsy. The histopathological features and clinical relevance of tubulointerstitial injury in CLL/SLL have not been extensively characterized. Hence, we attempted to describe the clinical characteristics, renal pathology and clinical outcome of a well-characterized population of CLL/SLL patients with CLL cell infiltration in the renal interstitium from a large single center in China.

Methods

Between January 1st, 2010 and September 31st, 2020, 31946renal biopsies were performed at Peking University First Hospital, and 10 CLL/SLL patients with CLL cell infiltration in the renal interstitium were included. Complete clinical data were collected from these 10 patients, and renal specimens were examined by routine light microscopy, immunofluorescence and electron microscopy.

Results

The extent of the infiltrating CLL cells in patients with CLL/SLL varied among different patients and ranged from 10 to 90% of kidney parenchyma. Six (60%) of 10 patients presented with an extent of infiltrating CLL cells ≥50%. Interestingly, we found that three patients (3/10, 30%) expressed monoclonal immunoglobulins in the infiltrating CLL cells, and special cytoplasmic crystalline structures were found in two of the three patients by electron microscopy for the first time. Severe renal insufficiency (Scr ≥200 μmol/L) was associated with ≥50% interstitial infiltration of CLL cells in the renal interstitium.

Conclusions

The current study confirmed that CLL cells infiltrating the renal interstitium can directly secrete monoclonal immunoglobulins, indicating that the interstitial infiltrating CLL cells possibly cause renal injury directly by secreting monoclonal immunoglobulins in situ. This finding may prove a new clue to elucidate the pathogenetic mechanism of renal injury involved with CLL/SLL.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13000-021-01120-4.

Clinical outcome and prognostic factors in dogs with B-cell chronic lymphocytic leukemia: A retrospective study

BACKGROUND

B-cell chronic lymphocytic leukemia (BCLL) in dogs generally is considered an indolent disease, but previous studies indicate a wide range in survival times.

OBJECTIVES

We hypothesized that BCLL has a heterogeneous clinical course, similar to chronic lymphocytic leukemia in humans. We aimed to assess presentation and outcome in dogs with BCLL and evaluate the prognostic relevance of clinical and flow cytometric factors.

ANIMALS

One hundred and twenty-one dogs with BCLL diagnosed by flow cytometry. Three breed groups were represented: small breed dogs (n = 55) because of increased risk of BCLL; Boxers (n = 33) because of preferential use of unmutated immunoglobulin genes; and other breeds (n = 33).

METHODS

Retrospective study reviewing signalment, clinicopathologic data, physical examination findings, treatment, and survival of dogs with BCLL. Cellular proliferation, determined by the percentage of Ki67-expressing CD21+ B-cells by flow cytometry, was measured in 39 of 121 cases. Clinical and laboratory variables were evaluated for association with survival.

RESULTS

The median survival time (MST) for all cases was 300 days (range, 1-1644 days). Boxers had significantly shorter survival (MST, 178 days) than non-Boxers (MST, 423 days; P < .0001), and no significant survival difference was found between small breeds and other non-Boxer breeds. Cases with high Ki67 (>40% Ki67-expressing B-cells) had significantly shorter survival (MST, 173 days) than did cases with <40% Ki67 (MST undetermined; P = .03), regardless of breed. Cases with a high lymphocyte count (>60 000 lymphocytes/μL) or clinical signs at presentation had significantly shorter survival.

CONCLUSIONS AND CLINICAL IMPORTANCE

B-cell chronic lymphocytic leukemia had a variable clinical course and Boxer dogs and cases with high Ki67 had more aggressive disease.

The Spectrum of Monoclonal Immunoglobulin-Associated Diseases

The spectrum of immunoglobulin paraprotein-associated diseases requiring therapy extends beyond multiple myeloma and AL amyloidosis. Awareness of these is essential in ensuring timely accurate diagnosis and appropriate treatment. As most paraprotein-associated diseases are fairly uncommon, therapeutic decisions must often be made in the absence of data from randomized controlled trials. Treatment is generally directed at the underlying clonal cell population. This review focuses on the spectrum of the less common paraprotein-associated disorders. In most instances, the monoclonal immunoglobulin plays a direct role in the pathophysiology of the disease course; in a select few, the paraprotein may be a disease marker.

Monoclonal gammopathy and serum immunoglobulin levels as prognostic factors in chronic lymphocytic leukaemia

The relationship between chronic lymphocytic leukaemia (CLL) and qualitative/quantitative gammaglobulin abnormalities is well established. Nevertheless, in order to better understand this kind of connection, we examined 1505 patients with CLL and divided them into four subgroups on the basis of immunoglobulin (Ig) aberrations at diagnosis. A total of 73 (4·8%), 149 (10%), 200 (13·2%) and 1083 (72%) patients were identified with IgM monoclonal gammopathy (IgM/CLL), IgG monoclonal gammopathy (IgG/CLL), hypogammaglobulinaemia (hypo-γ) and normal Ig levels (γ-normal) respectively. IgM paraprotein was significantly associated with a more advanced Binet/Rai stage and del(17p)/TP53 mutation, while IgG abnormalities correlated with a higher occurrence of trisomy 12. Patients with any type of Ig abnormality had shorter treatment-free survival (TFS) but no significant impact affecting overall survival (OS) compared to those with normal Ig levels.

Cryoglobulinemic vasculitis with interruption of ibrutinib therapy for chronic lymphocytic leukemia (CLL)

Chronic lymphocytic leukemia (CLL) can trigger autoimmune phenomena, with immune thrombocytopenia (ITP) the most common presentation. Upon cessation of CLL therapy, including ibrutinib, autoimmune flares can occur. In a 68-year-old man with CLL, ibrutinib was held for 2 weeks prior to elective shoulder surgery. Eleven days after stopping therapy, he presented with a purpuric rash on his right hip, buttock, and lower extremities. He experienced two episodes of seizure activity while hospitalized. MRI brain demonstrated patchy areas of altered signal involving deep white matter and sub-cortical white matter structures concerning for cerebral vasculitis. Although there was no evidence of hemolysis, serum cold agglutinin titer was elevated at > 1:512 and cryoglobulin levels were positive at 36%. He was diagnosed with type I cryoglobulinemia and treated with rituximab, plasmapheresis, methylprednisolone, and ibrutinib was restarted. This regimen resolved his symptoms. A rare complication of CLL is the production of cryoglobulins, which can present at initial diagnosis or in relapsed disease. Our case demonstrates that the cessation of ibrutinib therapy, even for a short time, can precipitate complications. To our knowledge, we report the first case of a patient with well-controlled CLL who rapidly developed cryoglobulinemic vasculitis after stopping ibrutinib therapy.

A new risk model to predict time to first treatment in chronic lymphocytic leukemia based on heavy chain immunoparesis and summated free light chain

BACKGROUND

Chronic lymphocytic leukemia (CLL) is frequently accompanied by immune dysregulation.

AIMS

In this multicenter prospective study, we investigated whether heavy + light chains (HLC: IgGκ, IgGλ, IgAκ, IgAκ, IgMκ, IgMλ) and IgG subclasses (IgG1, IgG2, IgG3, and IgG4) could be used as novel prognostic markers of immunoparesis in 105 treatment-naïve patients with CLL.

RESULTS

Heavy + light chains immunoparesis of ≥1, ≥2, and ≥3 isotypes was evident in 74 (70%), 58 (55%), and 36 (34%) patients, respectively. Severe HLC immunoparesis was identified in 40 (38%) patients. Of the IgG subclasses, IgG1 and IgG2 were most frequently suppressed, affecting 46 (44%) and 36 (34%) patients, respectively; 63 (60%) patients had low levels of at least one IgG subclass. In multivariate analysis, severe HLC immunoparesis (hazard ratio [HR]: 36.5; P = .010) and ΣFLC ≥ 70 mg/L (HR: 13.2; P = .004) were the only factors independently associated with time to first treatment (TTFT). A risk model including these variables identified patients with 0, 1, and 2 risk factors and significantly different TTFT (P < .001). Patients with two factors represented an ultra-high-risk group with a median TTFT of only 1.3 months.

CONCLUSION

The above findings demonstrate the potential for the use of HLC immunoparesis, together with sFLC measurements, as future prognostic biomarkers in CLL.

Normal serum protein electrophoresis and mutated IGHV genes detect very slowly evolving chronic lymphocytic leukemia patients

More than 35 years after the Binet classification, there is still a need for simple prognostic markers in chronic lymphocytic leukemia (CLL). Here, we studied the treatment-free survival (TFS) impact of normal serum protein electrophoresis (SPE) at diagnosis. One hundred twelve patients with CLL were analyzed. The main prognostic factors (Binet stage; lymphocytosis; IGHV mutation status; TP53, SF3B1, NOTCH1, and BIRC3 mutations; and cytogenetic abnormalities) were studied. The frequencies of IGHV mutation status, cytogenetic abnormalities, and TP53, SF3B1, NOTCH1, and BIRC3 mutations were not significantly different between normal and abnormal SPE. Normal SPE was associated with Binet stage A, nonprogressive disease for 6 months, lymphocytosis below 30 G/L, and the absence of the IGHV3-21 gene rearrangement which is associated with poor prognosis. The TFS of patients with normal SPE was significantly longer than that of patients with abnormal SPE (log-rank test: P = 0.0015, with 51% untreated patients at 5.6 years and a perfect plateau afterward vs. a median TFS at 2.64 years for abnormal SPE with no plateau). Multivariate analysis using two different Cox models and bootstrapping showed that normal SPE was an independent good prognostic marker for either Binet stage, lymphocytosis, or IGHV mutation status. TFS was further increased when both normal SPE and mutated IGHV were present (log-rank test: P = 0.008, median not reached, plateau at 5.6 years and 66% untreated patients). A comparison with other prognostic markers suggested that normal SPE could reflect slowly advancing CLL disease. Altogether, our results show that a combination of normal SPE and mutated IGHV genes defines a subgroup of patients with CLL who evolve very slowly and who might never need treatment.

Lymphoma-like monoclonal B cell lymphocytosis in a patient population: biology, natural evolution, and differences from CLL-like clones

High-count monoclonal B cell lymphocytosis (MBL) with a chronic lymphocytic leukemia (CLL) phenotype is a well-known entity, featuring 1-4% annual risk of progression towards CLL requiring treatment. Lymphoma-like MBL (L-MBL), on the other hand, remains poorly defined and data regarding outcome are lacking. We retrospectively evaluated 33 L-MBL cases within our hospital population and compared them to 95 subjects with CLL-like MBL (C-MBL). Diagnoses of L-MBL were based on asymptomatic B cell clones with Matutes score < 3, B cells < 5.0 × 10³/μl, and negative computerized tomography scans. We found that median B cell counts were considerably lower compared to C-MBL (0.6 vs 2.3 × 10³/μl) and remained stable over time. Based on immunophenotyping and immunogenetic profiling, most L-MBL clones did not correspond to known lymphoma entities. A strikingly high occurrence of paraproteinemia (48%), hypogammaglobulinemia (45%), and biclonality (21%) was seen; these incidences being significantly higher than in C-MBL (17, 21, and 5%, respectively). Unrelated monoclonal gammopathy of undetermined significance was a frequent feature, as the light chain type of 5/12 paraproteins detected was different from the clonal surface immunoglobulin. After 46-month median follow-up, 2/24 patients (8%) had progressed towards indolent lymphoma requiring no treatment. In contrast, 41% of C-MBL cases evolved to CLL and 17% required treatment. We conclude that clinical L-MBL is characterized by pronounced immune dysregulation and very slow or absent progression, clearly separating it from its CLL-like counterpart.

Cryoglobulinemia in a patient with chronic lymphocytic leukemia - A case report and review of literature of renal involvement in CLL

The incidence of glomerulonephritis, as a manifestation of chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL), has always been considered low. Though renal infiltration is usually detected at post-mortem, it does not often interfere with kidney function [1]. Though immunoglobulin (Ig) levels in most CLL patients are subnormal, small monoclonal Ig peaks are occasionally detected in serum. They were present in a number of reported CLL nephropathy patients, and not all were cryoglobulins; serum and glomerular staining were concordant for Ig type [2,3,4]. Myeloma, which secretes monoclonal light chains, causes nephropathy in 25% of patients. But the little presumably secreted by small plasma cell clones, without myeloma, may also be nephrotoxic. The same is true of the low secretory CLL cells, which may occasionally be associated with cryoglobulins and other nephrotoxic Igs [5]. We report a patient with early stage CLL (Rai stage 0) with cryoglobulins, which led to membranoproliferative glomerulonephritis (MPGN), and death. We located reports of 51 patients with CLL-associated nephrotic syndrome or nephropathy, mostly from MPGN related to local Ig deposits. In those patients screened for cryoglobulins, about half tested positive. Many were early stage cases, where MPGN developed long after CLL presentation, and responded to its treatment. As early diagnosis and treatment CLL-related nephropathy may be curative, we propose a prospective study to determine the incidence of hyperalbuminuria development after presentation.

The mystery of chronic lymphocytic leukemia (CLL): Why is it absent in Asians and what does this tell us about etiology, pathogenesis and biology?

Chronic lymphocytic leukemia/small lymphocytic lymphoma is common in persons of predominately European descent but rare in Asians. Why is unknown but is likely genetically-determined. Environmental factors may also operate but are likely to be less important. When CLL occurs in Asians it has different features than CLL in persons of predominately European descent. The reason(s) for this is also not understood. We reviewed data on CLL in Asians (mostly Han Chinese but also other ethnic groups) and compared these data with those from persons of predominately European descent with CLL. CLL incidence was about 5-10-fold less in Asians. Asians with CLL are younger, have atypical morphologic and immunologic features, an increased proportion of IGHV mutations and rearrangements and briefer freedom-from-progression than persons of predominately European descent with CLL. These observations provide clues to the etiology and biology of CLL. But the mystery continues; more research is needed.

IgM peak independently predicts treatment-free survival in chronic lymphocytic leukemia and correlates with accumulation of adverse oncogenetic events

We examined the significance of IgM peaks in chronic lymphocytic leukemia (CLL), including its association with newly reported MYD88, BIRC3, NOTCH1 and SF3B1 mutations. A total of 27, 25, 41 and 57 patients with monoclonal IgM or IgG peaks (IgM and IgG groups), hypogammaglobulinemia (Hypo-γ group) and normal immunoglobulin serum levels (normal-γ group) were, respectively, included. IgM peaks were mainly associated with Binet stage C and the del(17p). Biased usage of IGHV3-48 was shared by both IgM and IgG groups. IGHV3-74 and IGHV4-39 gene rearrangements were specific for IgM and IgG peaks, respectively. SF3B1, NOTCH1, MYD88 and BIRC3 mutation frequencies were 12%, 4%, 2% and 2%, respectively, being over-represented in IgM, IgG and Hypo-γ groups for SF3B1, and being equal between normal-γ and IgM groups for MYD88. Overall, 76%, 87%, 49% and 42% of cases from IgM, IgG, Hypo-γ and normal-γ groups had at least one intermediate or poor prognosis genetic marker, respectively. By multivariate analysis, IgM peaks were associated with shorter treatment-free survival independently from any other univariate poor prognosis biological parameters, including IgG peaks, Hypo-γ, IGHV status, SF3B1 mutations, cytogenetics and lymphocytosis. Therefore, as with IgG peaks, IgM peaks aggravated the natural course of CLL, with increased accumulation of adverse genetic events.

Serum immunoglobulin levels at diagnosis have no prognostic significance in stage A chronic lymphocytic leukemia: a study of 1113 cases from the Israeli CLL Study Group

OBJECTIVES

Hypogammaglobulinemia, commonly encountered in chronic lymphocytic leukemia (CLL), is one of the main causes of morbidity and mortality; however, its prognostic significance in patients diagnosed in early stages of disease remains uncertain. The aim of this study was to evaluate the predictive power of hypogammaglobulinemia at Bonet stage A.

METHODS

Using the database of the Israeli CLL Study Group, we analyzed the relationship between low serum levels of IgG, IgA, and IgM; the presence of paraproteinemia, as well as other well-recognized prognostic markers in CLL; and time to first treatment (TTT) and overall survival. A total of 1113 patients consecutively diagnosed during the last 25 yrs with Binet stage A CLL were evaluated, and baseline information on serum immunoglobulin levels was found in 857 of the cases.

RESULTS

Overall survival times correlated with age >65 yr, male gender, the presence of lymphadenopathy, high serum beta 2-microglobulin (b2m), CD38 and ZAP-70 expression, but not with low levels of immunoglobulin or the presence of paraproteinemia. By univariate analysis, patients with low IgA levels had a shorter TTT; however, on multivariate analysis, the presence of lymphadenopathy (P 0.02), b2m (P 0.04), CD38 (P < 0.001), and ZAP-70 (P < 0.001) was the only laboratory parameters with prognostic significance.

CONCLUSIONS

In our cohort of patients with early-stage CLL, baseline hypogammaglobulinemia and the presence of paraproteinemia were not found to correlate with prognosis.

C3 glomerulonephritis associated with monoclonal gammopathy: a case series

BACKGROUND

C3 glomerulonephritis (GN) is a proliferative GN resulting from glomerular deposition of complement factors due to dysregulation of the alternative pathway of complement. Dysregulation of the alternative pathway of complement may occur as a result of mutations or functional inhibition of complement-regulating proteins. Functional inhibition of the complement-regulating proteins may result from a monoclonal gammopathy.

STUDY DESIGN

Case series.

SETTING & PARTICIPANTS

32 Mayo Clinic patients with C3 GN, 10 (31%) of whom had evidence of a monoclonal immunoglobulin in serum.

OUTCOMES

Clinical features, hematologic and bone marrow biopsy findings, kidney biopsy findings, kidney measures, complement pathway abnormalities, treatment, and follow-up of patients with C3 GN that was associated with a monoclonal gammopathy.

RESULTS

Mean age of patients with C3 GN associated with monoclonal gammopathy was 54.5 years. Bone marrow biopsy done in 9 patients revealed monoclonal gammopathy of undetermined significance in 5 patients, small lymphocytic lymphoma/chronic lymphocytic leukemia in one patient, and no abnormal clones in the other 3 patients. Kidney biopsy showed membranoproliferative GN with bright capillary wall C3 staining in all 10 patients. Evaluation of the alternative pathway of complement showed abnormalities in 7 of 9 patients tested. No mutation in complement-regulating proteins was detected in any patient. As an index case, one patient with C3 GN and chronic lymphocytic leukemia was treated with rituximab, cyclophosphamide, vincristine, and prednisone, and one patient with C3 GN and monoclonal gammopathy of undetermined significance was treated with dexamethasone and bortezomib. Both patients showed significant decreases in hematuria and proteinuria and stabilization of kidney function.

LIMITATIONS

Studies to show evidence of direct activation of the alternative pathway by monoclonal immunoglobulin were not done.

CONCLUSIONS

The study highlights the association of C3 GN and monoclonal gammopathy, in particular in the older population, and the importance of targeting the underlying hematologic malignancy as an approach to treating C3 GN.