[Show abstract][Hide abstract] ABSTRACT: Primary iron overload in African Americans has been reported predominantly from autopsy studies.
We characterized hepatic iron phenotypes in 83 African Americans who underwent liver biopsy during the interval 1990 to 1995. We tabulated pathology report form data, iron grades in hepatocytes (0-4) and Kupffer cells (0-3) and abnormal liver histology. Increased iron was defined as hepatocyte or Kupffer iron grades ≥2, respectively. Heavy iron was defined as hepatocyte iron grade 3 or 4. Primary iron overload was defined as the presence of grade 3 or 4 hepatocellular iron in the absence of evidence of chronic alcohol effect, viral hepatitis, steatosis, unexplained inflammation, chronic erythrocyte transfusion or chronic ingestion of iron supplements.
There were 37 men and 46 women (mean age: 53 ± 15 [SD] years). We observed heavy ethanol consumption, 12.0%; viral hepatitis, 26.5%; steatosis without heavy ethanol consumption, 43.4%; inflammation, 45.6%; fibrosis, 26.2% and bridging fibrosis/cirrhosis, 29.4%. Logistic regression on bridging fibrosis/cirrhosis revealed positive associations with heavy ethanol consumption (P = 0.0410) and viral hepatitis (P = 0.0044). The 22 patients (26.5%) with increased iron had greater mean age, proportion of men and heavy ethanol consumption. Five patients had heavy iron staining, among whom were 3 women (mean age: 54 years) with primary iron overload. Two of the 3 women had cirrhosis and diabetes mellitus.
Among 83 adult African Americans who underwent liver biopsy, 3.6% had hepatic iron phenotypes consistent with primary iron overload.
The American Journal of the Medical Sciences 01/2015; 349(1):50-5. · 1.52 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Abstract Background: In some reports, serum ferritin (SF) has been associated with insulin resistance and metabolic syndrome. Methods: We studied non-Hispanic whites without diabetes mellitus in a postscreening examination. Participants included cases [HFE C282Y homozygosity; and transferrin saturation (TS) >50% and SF >300 μg/L (males) and TS >45% and SF >200 μg/dL (females), regardless of HFE genotype] and controls [HFE wild-type (wt/wt) and TS/SF 25th-75th percentiles]. We excluded participants with overnight fasts <8 hr, cirrhosis, hepatitis B or C, pregnancy, or missing data. Observations were age, sex, C282Y homozygosity, body mass index (BMI), systolic and diastolic blood pressures (SBP, DBP), lymphocytes, alanine aminotransferase (ALT), aspartate aminotransferase (AST), C-reactive protein (CRP), TS, SF, and glucose/insulin. Insulin resistance was defined as homeostasis model assessment of insulin resistance (HOMA-IR) 4th quartile (≥2.70). Results: A total of 407 women and 362 men (mean age 54 years) included 188 C282Y homozygotes and 371 wt/wt. Significant trends across HOMA-IR quartiles included age, male sex, BMI, SBP, DBP, lymphocytes, ALT, CRP >0.5 mg/dL (positive), and TS (negative). Multiple regression on HOMA-IR revealed significant associations with male sex, BMI, SBP, lymphocytes, ALT, CRP>0.5 mg/dL (positive), and DBP and SF (negative). Logistic regression on HOMA-IR 4th quartile revealed significant positive associations with age, male sex, BMI, and lymphocytes. Metabolic syndrome occurred in 53 participants (6.9%). Logistic regression on metabolic syndrome revealed these odds ratios: HOMA-IR 4th quartile [9.1 (4.8, 17.3)] and CRP >0.5 mg/dL [2.9 (1.6, 5.4)]. Conclusions: Age, male sex, BMI, and lymphocytes were positively associated with HOMA-IR after correction for other factors. HOMA-IR 4th quartile and CRP >0.5 mg/dL predicted metabolic syndrome.
Metabolic Syndrome and Related Disorders 11/2014; · 1.92 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Background
Our informal observations suggested that some patients with acute sensorineural hearing loss (ASNHL) have subnormal serum immunoglobulin (Ig) levels. We evaluated 28 consecutive adults (18 men, 10 women) at ASNHL diagnosis using: antibodies to 68 kD protein, 30 kD protein, and type II collagen; and serum total IgG, IgG subclasses, total IgA, and IgM. Reference ranges for Ig levels were mean¿±¿2 SD. We compared prevalences of subnormal IgG subclasses to those in 275 healthy European adults in previous reports. We also reviewed charts of consecutive adult index patients with primary Ig deficiency (35 common variable immunodeficiency, 406 IgG subclass deficiency) to identify other patients with probable ASHNL.ResultsMean age was 53¿±¿10 (SD) y. Six patients (21.4%) had other autoimmunity manifestations. Antibodies to 68 kD protein, 30 kD protein, and type II collagen were detected in 21.4% (6/28), 21.1% (4/19) and 18.8% (3/16), respectively. Three patients (10.7%) had subnormal IgG1, six (21.4%) had subnormal IgG3, and four (14.3%) had subnormal IgG1 and IgG3. Some had subnormal IgG2, IgG4, IgA, and IgM (n¿=¿1, 2, 3, and 1, respectively). Prevalences of subnormal IgG1 or IgG3 were greater in ASNHL patients (25.0% and 35.7%) than 275 controls (2.1% and 3.3%), respectively (p¿<¿0.0001, each comparison). Relative risks of subnormal IgG1 and IgG3 in ASNHL were 11.5 [95% CI: 4.1, 31.7] and 10.9 [4.8, 25.6], respectively. Hearing improved after initial therapy in 17 patients (60.7%). Multiple regressions on Ig levels revealed no significant associations with other available variables. Logistic regressions on initial therapy response revealed a positive association with men (p¿=¿0.0392) and a negative association with IgA (p¿=¿0.0274). Our estimated prevalence of probable ASNHL in 35 patients with common variable immunodeficiency during a follow-up interval of 8¿±¿4 y was 0% [95% CI: 0, 12.3%]). Prevalence of probable ASNHL in 406 patients with IgG subclass deficiency during the same interval was 0.74% [0.19, 2.33].Conclusions
Serum levels of IgG1 or IgG3 were subnormal in 46.4% of 28 patients with ASNHL. Among adults who present with primary Ig deficiency, some may have or later develop ASNHL.
[Show abstract][Hide abstract] ABSTRACT: Common variable immunodeficiency (CVID) and immunoglobulin (Ig) G subclass deficiency (IgGSD) are heterogeneous disorders characterized by respiratory tract infections, selective Ig isotype deficiencies, and impaired antibody responses to polysaccharide antigens. Using univariable analyses, we compared observations in 34 CVID and 398 IgGSD adult index patients (81.9% women) referred to a hematology/oncology practice. Similarities included specialties of referring physicians, mean ages, proportions of women, reactivity to Pneumovax, median serum IgG3 and IgG4 levels, median blood CD56+/CD16+ lymphocyte levels, positivity for HLA-A and -B types, and frequencies of selected HLA-A, -B haplotypes. Dissimilarities included greater prevalence of autoimmune conditions, lower median IgG, IgA, and IgM, and lower median CD19+, CD3+/CD4+, and CD3+/CD8+ blood lymphocytes in CVID patients. Prevalence of Sjögren's syndrome and hypothyroidism was significantly greater in CVID patients. Combined subnormal IgG1/IgG3 occurred in 59% and 29% of CVID and IgGSD patients, respectively. Isolated subnormal IgG3 occurred in 121 IgGSD patients (88% women). Logistic regression on CVID (versus IgGSD) revealed a significant positive association with autoimmune conditions and significant negative associations with IgG1, IgG3, and IgA and CD56+/CD16+ lymphocyte levels, but the odds ratio was increased for autoimmune conditions alone (6.9 (95% CI 1.3, 35.5)).
Research Journal of Immunology 01/2014; 2014:542706.
[Show abstract][Hide abstract] ABSTRACT: Hereditary Hemochromatosis (HH) is a recessively inherited disorder of iron overload occurring commonly in subjects homozygous for the C282Y mutation in HFE gene localized on chromosome 6p21.3 in linkage disequilibrium with the human leukocyte antigen (HLA)-A locus. Although its genetic homogeneity, the phenotypic expression is variable suggesting the presence of modifying factors. One such genetic factor, a SNP microhaplotype named A-A-T, was recently found to be associated with a more severe phenotype and also with low CD8(+)T-lymphocyte numbers. The present study aimed to test whether the predictive value of the A-A-T microhaplotype remained in other population settings. In this study of 304 HH patients from 3 geographically distant populations (Porto, Portugal 65; Alabama, USA 57; Nord-Trøndelag, Norway 182), the extended haplotypes involving A-A-T were studied in 608 chromosomes and the CD8(+) T-lymphocyte numbers were determined in all subjects. Patients from Porto had a more severe phenotype than those from other settings. Patients with A-A-T seemed on average to have greater iron stores (p = 0.021), but significant differences were not confirmed in the 3 separate populations. Low CD8(+) T-lymphocytes were associated with HLA-A*03-A-A-T in Porto and Alabama patients but not in the greater series from Nord-Trøndelag. Although A-A-T may signal a more severe iron phenotype, this study was unable to prove such an association in all population settings, precluding its use as a universal predictive marker of iron overload in HH. Interestingly, the association between A-A-T and CD8(+) T-lymphocytes, which was confirmed in Porto and Alabama patients, was not observed in Nord-Trøndelag patients, showing that common HLA haplotypes like A*01-B*08 or A*03-B*07 segregating with HFE/C282Y in the three populations may carry different messages. These findings further strengthen the relevance of HH as a good disease model to search for novel candidate loci associated with the genetic transmission of CD8(+) T-lymphocyte numbers.
PLoS ONE 11/2013; 8(11):e79990. · 3.53 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Objective
We sought to identify predictors of diabetes diagnosed before hemochromatosis.Research Design and Methods
We studied these 16 variables in 159 non-screening hemochromatosis probands with HFE C282Y homozygosity: age; sex; body mass index (BMI); diabetes reports in first-degree family members (dichotomous); heavy ethanol consumption; cigarette smoking; elevated serum ALT/AST levels; non-alcoholic fatty liver; chronic viral hepatitis; cirrhosis; hand arthropathy; iron removed by phlebotomy; and positivity for HLA-A*01, B*08; A*03, B*07; and A*03, B*14 haplotypes. We performed univariable and multivariable analyses.ResultsTwenty-three probands (14.5%) had diabetes; 19 were men. Each of the 23 probands had type 2 diabetes. Mean BMI was greater in probands with diabetes (31.7 ± 8.5 (SD) kg/m(2) vs. 27.6 ± 5.1 kg/m(2); p = 0.032). Reports of any first-degree family member with diabetes were more prevalent in probands with than in probands without diabetes (69.6% vs. 17.6%; p <0.0001). In probands with diabetes, the odds ratio (OR) of maternal diabetes was 6.7 ((95% CI 2.3, 19.7); p = 0.0005) and of sibling diabetes was 11.7 ((95% CI 3.0, 45.5); p = 0.0004). In a logistic regression model, predictors of diabetes at hemochromatosis diagnosis in 159 probands were diabetes reports in family members (OR 8.5 (95% CI 2.9, 24.8); p<0.0001) and BMI (OR 1.1 (1.0, 1.2); p=0.049). This model explained 26.0% of total deviance contributing to diabetes.Conclusions
In non-screening hemochromatosis probands with HFE C282Y homozygosity, a heritable factor(s) increases the risk of diabetes diagnosed before hemochromatosis.
[Show abstract][Hide abstract] ABSTRACT: Many patients referred for an elevated serum ferritin level <1000 µg⁄L are advised that they likely have iron overload and hemochromatosis.
To determine the prevalence of HFE mutations in the hemochromatosis gene for 11 serum ferritin concentration intervals from 200 µg⁄L to 1000 µg⁄L in Caucasian participants in a primary care, population-based study.
The Hemochromatosis and Iron Overload Screening study screened 99,711 participants for serum ferritin levels, transferrin saturation and genetic testing for the C282Y and H63D mutations of the HFE gene. This analysis was confined to 17,160 male and 27,465 female Caucasian participants because the HFE C282Y mutation is rare in other races. Post-test likelihood was calculated for prediction of C282Y homozygosity from a ferritin interval. A subgroup analysis was performed in participants with both an elevated serum ferritin level and transferrin saturation.
There were 3359 male and 2416 female participants with an elevated serum ferritin level (200 µg⁄L to 1000 µg⁄L for women, 300 µg⁄L to 1000 µg⁄L for men). There were 69 male (2.1%) and 87 female (3.6%) C282Y homozygotes, and the probability of being a homozygote increased as the ferritin level increased. Post-test likelihood values were 0.3% to 16% in men and 0.3% to 30.4% in women.
Iron loading HFE mutations are unlikely to be the most common cause of an elevated serum ferritin level in patients with mild hyperferritinemia. Patients should be advised that there are many causes of an elevated serum ferritin level including iron overload.
Canadian journal of gastroenterology = Journal canadien de gastroenterologie. 07/2013; 27(7):390-2.
[Show abstract][Hide abstract] ABSTRACT: HFEC282Y homozygotes have an increased risk for developing increased iron stores and related disorders. It is controversial whether dietary iron restrictions should be recommended to such individuals.
To determine whether dietary iron content influences iron stores in HFEC282Y homozygotes as assessed by serum ferritin concentration.
Serum ferritin concentration was measured and a dietary iron questionnaire was completed as part of the evaluation of 213 HFEC282Y homozygotes who were identified through screening of >100,000 primary care patients at five HEmochromatosis and IRon Overload Screening (HEIRS) Study Field Centers in the United States and Canada.
No significant relationships between serum ferritin concentration and dietary heme iron content, dietary nonheme iron content or reports of supplemental iron use were found.
These results do not support recommending dietary heme or nonheme iron restrictions for HFEC282Y homozygotes diagnosed through screening in North America.
Canadian journal of gastroenterology = Journal canadien de gastroenterologie 06/2012; 26(6):345-9. · 1.97 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: We report on a 46-year-old black man who resided in Alabama with normal transferrin saturation, mild hyperferritinemia, chronic hepatitis C, and 3+ iron in hepatocytes and Kupffer cells. Exome sequencing revealed heterozygosity for SLC40A1 D270V (exon 7, c.809A→T), a mutation previously reported only in 1 black patient with iron overload who resided in the Republic of South Africa. The present patient was also heterozygous for: heme transporter FLVCR1 novel allele P542S (exon 10, 1624C→T); FLVCR1 T544M (rs3207090); hemopexin (HPX) R371W (rs75307540); ferritin scavenger receptor (SCARA5) R471H (rs61737287); and transferrin receptor (TFRC) G420S (rs41295879). He had no HFE, TFR2,HJV, or HAMP mutations. D270V was not detected in 19 other African Americans with iron overload who resided in Alabama. The allele frequency of SLC40A1 D270V in 258 African American adults who participated in a health appraisal clinic was 0.0019 (95% confidence interval 0-0.0057). D270V could explain 'classical' ferroportin hemochromatosis phenotypes in some African Americans.
[Show abstract][Hide abstract] ABSTRACT: We sought to determine predictors of shingles reports in adults with common variable immunodeficiency or immunoglobulin (Ig) G subclass deficiency (CVID/IgGSD). We tabulated observations at diagnosis of CVID/IgGSD in 212 white adult index patients (165 women, 47 men) who responded to a question about having had shingles. None had been vaccinated for herpes zoster. We analyzed age, sex, and shingles reports; blood levels of CD19+, CD4+, CD8+, and CD56+ mononuclear cells; serum levels of IgG subclasses, IgA, and IgM; and positivity for human leukocyte antigen (HLA)-A and -B haplotypes. Cell counts and immunoglobulin levels were normalized with loge (ln) transformation for analyses. Thirty-one patients (14.6%) reported shingles; 11 reported recurrent or disseminated shingles. Patients with shingles reports had greater mean age at diagnosis of CVID/IgGSD [54±13 (standard deviation) years vs. 47±12 years; P=0.0130] and a greater prevalence of HLA-A*01, B*08 positivity (35.5% vs. 17.7%; P=0.0227). In a 13-factor logistic regression model, there was a positive association of age with shingles reports [P=0.0151; odds ratio (1.05, 95% confidence interval 1.01, 1.08)]. HLA-A*01, B*08 positivity was also positively associated with shingles reports [P=0.0480; odds ratio 2.61 (1.00, 6.81)]. During a mean followup interval of 7.5 years after CVID/IgGSD diagnosis, the prevalence of recurrent shingles was almost five-fold greater in patients with previous shingles reports. In conclusion, in white adults at CVID/IgGSD diagnosis, age at diagnosis and positivity for HLA-A*01, B*08 have significant positive associations with reports of previous shingles.
[Show abstract][Hide abstract] ABSTRACT: TMPRSS6 A736V is associated with lower transferrin saturation (TS), hemoglobin (Hb), and mean corpuscular volume (MCV) levels in general adult populations. We sought to identify relationships of TMPRSS6 K253E, A736V, and Y739Y to iron, erythrocyte, and pica phenotypes in women with iron deficiency or depletion.
We tabulated observations on 48 outpatient non-pregnant women who had iron deficiency (serum ferritin (SF) <14pmol/L and TS <10%) or iron depletion (SF<112pmol/L). We performed direct sequencing of TMPRSS6 exons 7 and 17 in each patient. We used age, TS, SF, Hb, MCV, pica, and TMPRSS6 allele positivity (dichotomous) or mutation genotypes (trichotomous) as variables for analyses.
Forty-six women were white; two were black. 58.3% had iron deficiency. 45.8% had pica (pagophagia, each case). Allele frequencies were 41.7% (K253E), 36.5% (A736V), and 39.6% (Y739Y). K253E frequency was greater in women with TS ≥10% (p=0.0001). Y739Y was more frequent in women with TS <10% (p=0.0135). Mean TS was also lower in women positive for Y739Y (6±4% vs. 13±16%, respectively; p=0.0021). In multiple regressions, neither K253E, A736V, nor Y739Y genotypes were significantly associated with other variables.
TMPRSS6 K253E frequency was greater in women with TS ≥10%. Frequency of Y739 was greater in women with TS <10%. Mean TS was lower in women with Y739Y. We observed no other significant relationship of TMPRSS6 K253E, A736V, or Y739Y with iron, erythrocyte, or pica phenotypes.
[Show abstract][Hide abstract] ABSTRACT: We investigated the risk of death from iron overload among treated hemochromatosis probands who were homozygous for HFE C282Y and had serum levels of ferritin greater than 1000 μg/L at diagnosis.
We compared serum levels of ferritin at diagnosis and other conditions with the rate of iron overload-associated death using data from 2 cohorts of probands with hemochromatosis who were homozygous for HFE C282Y (an Alabama cohort, n = 294, 63.9% men and an Ontario cohort, n = 128, 68.8% men). We defined iron overload-associated causes of death as cirrhosis (including hepatic failure and primary liver cancer) caused by iron deposition and cardiomyopathy caused by myocardial siderosis. All probands received phlebotomy and other appropriate therapy.
The mean survival times after diagnosis were 13.2 ± 7.3 y and 12.5 ± 8.3 y in Alabama and Ontario probands, respectively. Serum levels of ferritin greater than 1000 μg/L at diagnosis were observed in 30.1% and 47.7% of Alabama and Ontario probands, respectively. In logistic regressions of serum ferritin greater than 1000 μg/L, there were significant positive associations with male sex and cirrhosis in Alabama probands and with age, male sex, increased levels of alanine and aspartate aminotransferases, and cirrhosis in Ontario probands. Of probands with serum levels of ferritin greater than 1000 μg/L at diagnosis, 17.9% of those from Alabama and 14.8% of those from Ontario died of iron overload. Among probands with serum levels of ferritin greater than 1000 μg/L, the relative risk of iron overload-associated death was 5.4 for the Alabama group (95% confidence interval [CI], 2.2-13.1; P = .0002) and 4.9 for the Ontario group (95% CI, 1.1-22.0; P = .0359).
In hemochromatosis probands homozygous for HFE C282Y, serum levels of ferritin greater than 1000 μg/L at diagnosis were positively associated with male sex and cirrhosis. Even with treatment, the relative risk of death from iron overload was 5-fold greater in probands with serum levels of ferritin greater than 1000 μg/L.
Clinical gastroenterology and hepatology: the official clinical practice journal of the American Gastroenterological Association 01/2012; 10(4):412-6. · 5.64 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Dupuytren's contracture (DC) and HFE hemochromatosis occur in some of the same at-risk populations and present with similar comorbid conditions.
We estimated DC prevalence in two cohorts of white Alabama hemochromatosis probands (294 C282Y homozygotes, 67 C282Y/H63D compound heterozygotes) in a retrospective study. We performed logistic regressions on DC using the following independent variables: age, body mass index, heavy ethanol consumption, serum ferritin, elevated serum AST/ALT, non-alcoholic fatty liver disease, viral hepatitis, cirrhosis, and diabetes.
One man and two women with C282Y homozygosity had DC (prevalence 1.02%; 95% CI 0.35%-2.96%). A man with C282Y/H63D had DC (prevalence 1.49%; 95% CI 0.26%-7.98%). DC occurred as an autosomal dominant trait in his kinship. In regression analyses, no single variable predicted DC. We observed no new DC cases after the diagnosis of hemochromatosis (mean follow-up 12.9 ± 7.5 years (1 SD), and 9.0 ± 5.1 years, respectively).
Our prevalence estimates of DC in white Alabama hemochromatosis probands are similar to those found in the white US population cohorts. DC risk was unrelated to the variables we studied.
Clinical medicine insights. Arthritis and musculoskeletal disorders. 01/2012; 5:67-75.
[Show abstract][Hide abstract] ABSTRACT: Acute kidney injury (AKI) is a rare complication of carcinoid syndrome. A 61-year-old man developed carcinoid syndrome 51 months after pneumonectomy for bronchial carcinoid, and 8 episodes of AKI 101 to 118 months after pneumonectomy. Serum chromogranin A and urine 5-hydroxyindoleacetic acid levels were elevated for more than 1 year before AKI occurred. Each episode was characterized by flushing, facial edema, mild diarrhea, necrosis of hepatic metastatic nodules, mild oliguria, hyponatremia, acidosis, hypokalemia, hypomagnesemia and hyperphosphatemia. He did not have elevated urine sodium levels or osmolality, hypotension or hypertension. Plasma levels of dopamine, epinephrine and norepinephrine, measured during a single episode, were markedly elevated. Serum creatinine levels returned to normal after most episodes. Hyponatremia persisted but was more severe during AKI. Elevated plasma levels of vasoactive substances other than 5-hydroxytryptamine, perhaps dopamine or other catecholamines, could explain recurrent AKI. The natriuretic effect of elevated plasma dopamine levels could explain chronic hyponatremia.
The American Journal of the Medical Sciences 01/2012; 343(1):106-8. · 1.52 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Hemochromatosis is considered by many to be an uncommon disorder, although the prevalence of HFE (High Iron) 282 Cys → Tyr (C282Y) homozygosity is relatively high in Caucasians. Liver disease is one of the most consistent findings in advanced iron overload resulting from hemochromatosis. Liver clinics are often thought to be ideal venues for diagnosis of hemochromatosis, but diagnosis rates are often low. The Hemochromatosis and Iron Overload Screening (HEIRS) Study screened 99,711 primary care participants in North America for iron overload using serum ferritin and transferrin saturation measurements and HFE genotyping. In this HEIRS substudy, serum hepatic transaminases activities (e.g., alanine aminotransferase [ALT] and aspartate aminotransferase [AST]) were compared between 162 C282Y homozygotes and 1,367 nonhomozygotes with serum ferritin levels >300 μg/L in men and >200 μg/L in women and transferrin saturation >45% in women and 50% in men. The probability of being a C282Y homozygote was determined for AST and ALT ranges. Mean ALT and AST activities were significantly lower in C282Y homozygotes than nonhomozygotes. The probability of being a C282Y homozygote increased as the ALT and AST activities decreased. CONCLUSION: Patients with hyperferritinemia are more likely to be C282Y homozygotes if they have normal liver transaminase activities. This paradox could explain the low yields of hemochromatosis screening reported by some liver clinics.
[Show abstract][Hide abstract] ABSTRACT: The association of an IgM-Fc receptor (FcμR) with chronic lymphocytic leukemia (CLL) was suggested more than 30 years ago, but its authenticity has never been formally addressed. We examined the expression of the recently identified FcμR by B and T cells in CLL patients using receptor-specific monoclonal antibodies. CLL B cells (CD5(+)/CD19(+)) expressed much higher levels of FcμR on their cell surface than B cells from healthy donors. Such enhanced expression was more evident in immunoglobulin heavy chain variable region (IGHV)-mutated, CD38(-) or early Rai-stage CLL than in IGHV-unmutated, CD38(+), or advanced Rai-stage CLL. Intriguingly, surface FcμR levels also were significantly elevated in the non-CLL B cells (CD5(-)/CD19(+)) and T cells (CD5(+)/CD19(-)), especially in IGHV-mutated CLL. CLL patients also had high serum titers of FcμR compared with healthy donors, and serum FcμR levels correlated significantly with circulating lymphocyte numbers but not with the IGHV mutation status or Rai stage. The serum FcμR was resolved as an ∼ 40-kDa protein, distinct from the cell surface FcμR of ∼ 60 kDa, and it was produced by both CLL B and non-CLL B cells. Mass spectrometric analysis revealed that the serum FcμR is a soluble form of the receptor encoded by an alternatively spliced FcμR transcript. These findings indicate enhanced levels of both membrane-bound and soluble forms of FcμR in CLL patients.