IgG subclass levels in referred hemochromatosis probands with HFE p.C282Y/p.C282Y

BACKGROUND

IgG subclass levels in hemochromatosis are incompletely characterized.

METHODS

We characterized IgG subclass levels of referred hemochromatosis probands with HFE p.C282Y/p.C282Y (rs1800562) and human leukocyte antigen (HLA)-A and -B typing/haplotyping and compared them with IgG subclass levels of eight published cohorts of adults unselected for hemochromatosis.

RESULTS

There were 157 probands (82 men, 75 women; mean age 49±13 y). Median serum ferritin, mean body mass index (BMI), median IgG4, and median phlebotomy units to achieve iron depletion were significantly higher in men. Diabetes, cirrhosis, and HLA-A*03,-B*44, -A*03,B*07, and -A*01,B*08 prevalences and median absolute lymphocyte counts in men and women did not differ significantly. Mean IgG subclass levels [95% confidence interval] were: IgG1 5.31 g/L [3.04, 9.89]; IgG2 3.56 g/L [1.29, 5.75]; IgG3 0.61 g/L [0.17, 1.40]; and IgG4 0.26 g/L [<0.01, 1.25]. Relative IgG subclasses were 54.5%, 36.6%, 6.3%, and 2.7%, respectively. Median IgG4 was higher in men than women (0.34 g/L [0.01, 1.33] vs. 0.19 g/L [<0.01, 0.75], respectively; p = 0.0006). A correlation matrix with Bonferroni correction revealed the following positive correlations: IgG1 vs. IgG3 (p<0.01); IgG2 vs. IgG3 (p<0.05); and IgG2 vs. IgG4 (p<0.05). There was also a positive correlation of IgG4 vs. male sex (p<0.01). Mean IgG1 was lower and mean IgG2 was higher in probands than seven of eight published adult cohorts unselected for hemochromatosis diagnoses.

CONCLUSIONS

Mean IgG subclass levels of hemochromatosis probands were 5.31, 3.56, 0.61, and 0.26 g/L, respectively. Median IgG4 was higher in men than women. There were positive associations of IgG subclass levels. Mean IgG1 may be lower and mean IgG2 may be higher in hemochromatosis probands than adults unselected for hemochromatosis.

Height of non-Hispanic white adults with homeostatic iron regulator HFE genotypes p.C282Y/p.C282Y and wt/wt

BACKGROUND

We sought to evaluate height in white adults with hemochromatosis.

METHODS

We analyzed the height of (1) post-screening examination participants with HFE p.C282Y/p.C282Y (rs1800562) and wt/wt (absence of p.C282Y and p.H63D (rs1799945)) and (2) referred hemochromatosis probands with p.C282Y/p.C282Y.

RESULTS

There were 762 participants (270 p.C282Y/p.C282Y, 492 wt/wt; 343 men, 419 women) and 180 probands (104 men, 76 women). Median height of male participants with p.C282Y/p.C282Y or wt/wt was 177.8 cm. Median height of female participants was greater in those with p.C282Y/p.C282Y than wt/wt (165.1 cm vs 162.6 cm, respectively; p = 0.0298). Median height of p.C282Y/p.C282Y participants and probands was the same (men 177.8 cm; women 165.1 cm). Regressions on height of male and female participants revealed no associations with HFE genotype and inverse and positive associations with age and weight, respectively. Height of female participants was positively and inversely associated with transferrin saturation and serum ferritin, respectively. Regressions on height of male and female probands revealed positive associations with weight.

CONCLUSIONS

The height of men with HFE p.C282Y/p.C282Y and wt/wt does not differ significantly. The height of female participants was greater in those with p.C282Y/p.C282Y than wt/wt. We found no independent association of HFE genotype with the height of men or women.

Quantifying microcyte and macrocyte percentages in archived red blood cell volume histogram images

INTRODUCTION

We sought to quantify percentages of microcytes and macrocytes in archived automated hematology analyzer (AHA) red blood cell (RBC) volume histogram images.

METHODS

In preliminary studies, we demonstrated that an on-line application of Gauss' area formula (SketchAndCalc™) measured percentage areas of 20 segments under a computer-generated normal distribution curve (-3.0 standard deviations [SD] to +3.0 SD) with accuracy and precision (Pearson's correlation of measured areas with corresponding theoretical areas r [20] = 0.9962 [p < 0.0001]). Thus, we used SketchAndCalc™ to quantify percentages of microcytes (50-80 fL) and macrocytes (110-200 fL) in archived AHA histogram images in women with previously untreated iron-deficiency anemia (IDA) and previously untreated hemochromatosis.

RESULTS

Median microcyte percentages in 13 women with IDA and 13 women with hemochromatosis were 63.6% (range 13.5-76.8) and 6.7% (range 3.4-24.8), respectively (p < 0.0001). Mean macrocyte percentages in women with IDA and hemochromatosis were 8.8% ± 6.1 SD and 33.8% ± 11.7 SD, respectively (p < 0.0001). Spearman's correlations of microcyte percentages with macrocyte percentages, mean corpuscular volume, and mean corpuscular hemoglobin in 26 women were rs [26] = -0.9485, rs [26] = -0.9641, and rs [26] = -0.9036, respectively (each p < 0.0001).

CONCLUSIONS

This method of quantifying microcyte and macrocyte percentages could enable other studies of RBC volume subpopulations in archived AHA histogram images.

Platelet counts in HFE p.C282Y/p.C282Y and wt/wt post-screening clinical evaluation participants

Our aim was to document the effects of genotype HFE p.C282Y/p.C282Y and hemochromatosis-associated laboratory and clinical manifestations on platelet counts (PC). We compiled genotype (p.C282Y/p.C282Y or HFE wt/wt (absence of p.C282Y and p.H63D (rs1799945)), age, sex, body mass index, presence/absence of chronic fatigue, swelling/tenderness of second/third metacarpophalangeal joints, and hyperpigmentation, transferrin saturation (TS), serum ferritin (SF), hemoglobin levels, absolute neutrophil, lymphocyte, and monocyte counts, C-reactive protein levels, and PC of non-Hispanic white participants in a hemochromatosis and iron overload post-screening clinical examination. There were 171 men and 254 women (141 p.C282Y/p.C282Y, 284 wt/wt) of median age 53 y. Median TS and SF were higher in p.C282Y/p.C282Y than wt/wt participants grouped by sex (p < .0001, all comparisons). Median PC by genotype was lower in men than women (p < .0001, both comparisons). Regression on PC using 14 independent variables identified these significant positive associations: absolute neutrophil, lymphocyte, and monocyte counts and C-reactive protein levels and these significant inverse associations: age, TS, and hemoglobin levels. We conclude that PC is significantly associated with absolute neutrophil, lymphocyte, and monocyte counts, and C-reactive protein (positive) and age, TS, and hemoglobin (inverse), after adjustment for other variables. HFE genotypes we studied were not significantly associated with PC.

Clinical and Laboratory Characteristics of Individuals Aged ≤17 Years With Homeostatic Iron Regulator (HFE) p.C282Y Homozygosity, a Common Hemochromatosis Genotype

Background Characteristics of cohorts of individuals aged ≤17 years with homeostatic iron regulator (HFE) p.C282Y (rs1800562) homozygosity, a common hemochromatosis genotype, have not been reported. Methodology We retrospectively tabulated characteristics of white individuals aged ≤17 years with p.C282Y homozygosity. Individuals were not recruited for this study. We defined transferrin saturation (TS) >45%, serum ferritin (SF) >300 µg/L (M) and >200 µg/L (F) as elevated and liver iron grade 3 or 4, hepatic iron index >1.9 µmol Fe/g dry weight liver/y, and phlebotomy-mobilized iron >1.0 g (M) and >0.3 g (F) as increased. Results There were nine males and six females with a mean age of 12 ± 4 years (range = 5-17 years). The mean age of 10 probands (13 ± 3 years) was greater than that of five individuals discovered in family studies (9 ± 4 years) (p = 0.0403). Presenting manifestations of probands included fatigue/lethargy (5), elevated TS (2), and polycystic ovary syndrome, amenorrhea, and diabetes (2). In 15 individuals, the mean TS was 65 ± 23%. TS was elevated in 11 (73.3%) individuals aged 5-17 years. In 14 individuals, the mean SF was 262 ± 289 µg/L. SF was elevated and liver and phlebotomy-mobilized iron were increased in two male and three female probands aged 13-16 years (5/14 individuals, 35.7%). No individual had advanced hepatic fibrosis, arthropathy, hypogonadism, cardiomyopathy, or hyperpigmentation. Conclusions We conclude that five individuals aged 13-16 years (5/14 individuals, 35.7%) had increased liver and phlebotomy-mobilized iron.

Non-alcoholic fatty liver disease in hemochromatosis probands with iron overload and HFE p.C282Y/p.C282Y

BACKGROUND

The aim of this study was to identify characteristics of non-alcoholic fatty liver disease (NAFLD) in adults with HFE p.C282Y/p.C282Y.

METHODS

We retrospectively studied non-Hispanic white hemochromatosis probands with iron overload (serum ferritin (SF) > 300 µg/L (M), > 200 µg/L (F)) and p.C282Y/p.C282Y at non-screening diagnosis who did not report alcohol consumption > 14 g/d, have cirrhosis or other non-NAFLD liver disorders, use steatogenic medication, or have diagnoses of heritable disorders that increase NAFLD risk. We identified NAFLD-associated characteristics using univariate and multivariable analyses.

RESULTS

There were 66 probands (31 men, 35 women), mean age 49 ± 14 (SD) y, of whom 16 (24.2%) had NAFLD. The following characteristics were higher in probands with NAFLD: median SF (1118 µg/L (range 259, 2663) vs. 567 µg/L (247, 2385); p = 0.0192); prevalence of elevated ALT/AST (alanine/aspartate aminotransferase) (43.8% vs. 10.0%; p = 0.0056); and prevalence of type 2 diabetes (T2DM) (31.3% vs. 10.0%; p = 0.0427). Mean age, sex, and prevalences of human leukocyte antigen-A*03 positivity, body mass index ≥ 30.0 kg/m², hyperlipidemia, hypertension, and metabolic syndrome in probands with/without NAFLD did not differ significantly. Logistic regression on NAFLD using variables SF, elevated ALT/AST, and T2DM revealed: SF (p = 0.0318; odds ratio 1.0-1.0) and T2DM (p = 0.0342; 1.1-22.3). Median iron removed to achieve iron depletion (QFe) in probands with/without NAFLD did not differ significantly (3.6 g (1.4-7.2 g) vs. 2.8 g (0.7-11.0 g), respectively; p = 0.6862).

CONCLUSIONS

NAFLD in hemochromatosis probands with p.C282Y/p.C282Y is associated with higher median SF and greater T2DM prevalence, after adjustment for other factors. NAFLD does not influence QFe significantly.

HFE hemochromatosis in African Americans: Prevalence estimates of iron overload and iron overload-related disease

BACKGROUND

Little is known about the prevalence of HFE (homeostatic iron regulator) hemochromatosis in African Americans (AA).

METHODS

We defined AA as self-identified AA, blacks, or non-Hispanic blacks. We defined hemochromatosis-associated HFE genotypes as p.C282Y/p.C282Y and p.C282Y/p.H63D. We compiled prevalences of these genotypes in AA using published population and cohort data and numbers of men and women ≥18 y‬ in 2018 U.S. Census estimates. We defined iron overload (IO) and IO-related disease by genotype as previously reported in population and cohort studies of hemochromatosis in whites of European ancestry. We used these definitions to estimate prevalences and numbers of AA with IO and IO-related disease associated with hemochromatosis-associated HFE genotypes.

RESULTS

There were ∼16,287,599 men and ∼17,644,898 women. HFE genotypes and their respective prevalences were: p.C282Y/p.C282Y, 0.00017 (6/34,905) [95% confidence interval 0.000034, 0.00031] and p.C282Y/p.H63D, 0.0012 (41/33,596) [0.000084, 0.0016]. IO prevalences were: men 0.000076 [0.000072, 0.000081] and women 0.0000061 [0.0000050, 0.0000073]. IO-related disease prevalences were: men 0.000063 [0.000059, 0.000067] and women 0.0000021 [0.0000014, 0.0000027]. There were ∼1021 [961, 1091] men and ∼36 [25, 48] women with IO-related disease.

CONCLUSIONS

We conclude that ∼1/25,061 AA >18 y have a hemochromatosis-associated HFE genotype and IO and that ∼1/32,103 AA >18 y have a hemochromatosis-associated HFE genotype and IO-related disease.

Iron overload phenotypes and HFE genotypes in white hemochromatosis and iron overload screening study participants without HFE p.C282Y/p.C282Y

Background

Screening program participants with iron overload (IO) phenotypes without HFE p.C282Y/p.C282Y are incompletely characterized.

Methods

We studied white participants who had IO phenotypes without p.C282Y/p.C282Y in post-screening clinical examinations (CE). We defined IO phenotypes as a) elevated serum ferritin (SF) and transferrin saturation (TS) at screening and CE, and b) absence of IO treatment, anemia, transfusion >10 units, alcohol intake >30 g/d, hepatitis B or C, and pregnancy. We defined IO-related disease as elevated alanine or aspartate aminotransferase (ALT/AST) or swelling/tenderness of 2nd/3rd metacarpophalangeal (MCP) joints. All participants had HFE p.C282Y and p.H63D genotyping.

Results

There were 32 men and 26 women (mean age 54±16 y). Median food/supplemental iron intakes were 14.3/0.0 mg/d. Relative risks of HFE genotypes were 12.9 (p.C282Y/p.H63D), 3.0 (p.H63D/p.H63D), 1.9 (p.C282Y/wt), 0.9 (p.H63D/wt), and 0.5 (wt/wt) compared to 42,640 white screening participants without IO phenotypes or p.C282Y/p.C282Y. Regression on SF revealed positive associations: MCV (p = 0.0006; β coefficient = 0.4531); swelling/tenderness of MCP joints (p = 0.0033; β = 0.3455); and p.H63D/wt (p = 0.0015; β = 0.4146). IO-related disease (18 elevated ALT/AST, one swelling/tenderness of MCP joints) occurred in 19 participants (7 men, 12 women). Median MCV was higher in participants with IO-related disease (97 fL vs. 94 fL; p = 0.0007). Logistic regression on IO-related disease revealed a significant association with diabetes (p = 0.0416; odds ratio 18.9 (95% confidence interval 1.0, 341.1)).

Conclusions

In the present 58 screening program participants who had IO phenotypes without HFE p.C282Y/p.C282Y, relative risks of HFE genotypes p.C282Y/p.H63D, p.H63D/p.H63D, and p.C282Y/wt were significantly higher than in 42,640 white screening participants with neither IO phenotypes nor p.C282Y/p.C282Y. SF was significantly associated with MCV, swelling/tenderness of 2nd/3rd MCP joints, and p.H63D/wt. IO-related disease was significantly associated with MCV and diabetes.

HLA-A*03, the hemochromatosis ancestral haplotype, and phenotypes of referred hemochromatosis probands with HFE p.C282Y homozygosity

Background

Human leukocyte antigen (HLA)-A*03, hemochromatosis ancestral haplotype marker, was associated with greater iron overload in hemochromatosis cohorts reported before discovery of the HFE gene. We sought to learn whether an A*03-linked locus influences phenotypes in referred HFE p.C282Y homozygotes.

Methods

We tabulated these phenotypes in probands with p.C282Y homozygosity: age, transferrin saturation (TS), serum ferritin (SF), conditions related to iron overload, fibrosis-four variables (FIB-4) index and aspartate aminotransferase-to-platelet ratio index (APRI) predictors of severe hepatic fibrosis, and iron removed to achieve depletion (QFe/age). We analyzed phenotypes of men and women separately across three A*03 subgroups.

Results

There were 104 men (57.8%) and 76 women (42.2%). Mean age (SD) was 49 ± 13 y. Mean TS was 79 ± 17%. Median SF (range) was 715 µg/L (28, 6103). Related conditions included: hemochromatosis arthropathy (21.7%); type 2 diabetes (18.9%); hypogonadotropic hypogonadism (5.8% of men); cardiomyopathy (0%); and cirrhosis (10.0%). Median QFe/age was 61 mg/y (0, 714). A*03 homozygosity, heterozygosity, and no A*03 occurred in 37 (20.6%), 104 (57.8%), and 39 probands (21.7%), respectively. In men, mean TS and median SF were significantly higher in A*03 homozygotes than heterozygotes but not A*03-negative probands. In men, median APRI was significantly lower in A*03 heterozygotes than homozygotes and A*03-negative probands. No other phenotypes, including QFe/age, differed significantly across A*03 subgroups in either men or women.

Conclusions

Our results suggest that an A*03-linked locus does not influence phenotypes in referred HFE p.C282Y homozygotes. It is unlikely that heritable factors that modify phenotypes of p.C282Y homozygotes are linked to the hemochromatosis ancestral haplotype.

Polycythemia Rubra Vera and Sporadic Bilateral Renal Angiomyolipomas: A Case Report

Polycythemia rubra vera (PRV) is a clonal myeloproliferative neoplasm characterized by autonomous production of erythrocytes, neutrophils, and platelets. Angiomyolipomas (AMLs) are benign renal perivascular epithelioid cell neoplasms of which approximately 80% are sporadic. Here, we report synchronous diagnoses of PRV and asymptomatic sporadic bilateral renal AMLs in a 71-year-old woman. We describe her treatment with phlebotomy and hydroxyurea for PRV and surveillance for renal AMLs. We compare the features and treatment of the present case with those of two previously reported women who also had PRV and sporadic renal AMLs. Finally, we discuss the management and acquired genetic basis of both neoplasms.

Hydroxychloroquine Therapy and Serum Immunoglobulin Levels in Women with IgG Subclass Deficiency and Systemic Lupus Erythematosus, Sjögren Syndrome, and Rheumatoid Arthritis: A Retrospective Study

Hydroxychloroquine (HCQ) therapy decreased immunoglobulin (Ig) levels in patients with Sjögren syndrome (SS) and rheumatoid arthritis (RA) in previous studies. We found no report of Ig levels of women with IgG subclass deficiency (IgGSD) and systemic lupus erythematosus (SLE), SS, or RA treated with HCQ. We retrospectively evaluated IgG, IgG subclass, IgA, and IgM levels and other characteristics of women at IgGSD diagnosis who did and did not take HCQ for SLE, SS, or RA. There were 132 women (48 subnormal IgG1 only, 49 combined subnormal IgG1/IgG3, and 35 subnormal IgG3 only). Mean age was 49 ± 13 years. Twenty-two women with SLE, SS, RA, or combination thereof reported HCQ ≥ 200 mg/day ≥ 6 months. In each IgGSD subtype, median Ig levels of women who took HCQ were not significantly lower than those of women who did not take HCQ. Women with combined subnormal IgG1/IgG3 who took HCQ had greater median IgG2 than women who did not take HCQ (4.89 g/L (range 4.43, 4.94) vs. 2.57 g/L (1.21, 6.44), respectively; p = 0.0123). Regressions on IgG1, IgG2, and IgG3 revealed positive associations with HCQ therapy (p = 0.0043, 0.0037, and 0.0139, respectively). There were no significant Ig associations with age, SLE, SS, or RA as independent variables. HCQ therapy of SLE, SS, or RA in women with IgGSD was not associated with significantly lower IgG, IgG subclass, IgA, or IgM levels. IgG1, IgG2, and IgG3 were positively associated with HCQ therapy, after adjustment for other variables.

Estimates of West African Ancestry in African Americans Using Alleles of Iron-Related Genes HJV, SLC40A1, and TFR2

Background: Few studies have estimated African ancestry of African Americans (AA). In sub-Saharan West African (WA) Blacks, some nonancestral alleles of iron-related genes HJV, SLC40A1, and TFR2 are common, whereas in European Americans (EA) the same alleles are rare. These alleles have not been used to estimate WA Black ancestry in AA. Methods: We estimated WA Black ancestry in AA (M) using published HJV c.929C>G (rs7540883), SLC40A1 c.744G>T (rs11568350), and TFR2 c.713C>T (rs34242818) allele frequencies in WA Blacks, AA, and EA. We computed standard error (SE) and one-sided 95% confidence intervals (CI) for each M. Results: The combined representation of WA Blacks from The Gambia and Nigeria was 79-89%. Aggregate HJV, SLC40A1, and TFR2 allele frequencies in WA Blacks were 0.1025 [95% CI: 0.0835-0.1253] (n = 405), 0.0517 [0.0469-0.0569] (n = 3839), and 0.1432 [0.1202-0.1697] (n = 405), respectively. Aggregate HJV, SLC40A1, and TFR2 allele frequencies in AA were 0.0718 [0.0648-0.0797] (n = 2352), 0.0557 [0.0506-0.0613] (n = 3590), and 0.1224 [0.1132-0.1322] (n = 2352), respectively. Aggregate HJV, SLC40A1, and TFR2 allele frequencies in 4449 EA were 0.0002 [0-0.0009], 0.0003 [0.0001-0.0010], and 0.0004 [0.0001-0.0012], respectively. M (SE [one-sided 95% CI]) for HJV, SLC40A1, and TFR2 alleles was 0.7006 (0.0818 [0.5402-1.0000]), 1.0000 (0.0752 [0.9306-1.0000]), and 0.8546 (0.0810 [0.6959-1.0000]), respectively. Mean of these M is 0.8777 (87.8%). Conclusions: The mean proportional WA Black ancestry in AA of 87.8% using HJV c.929C>G, SLC40A1 c.744G>T, and TFR2 c.713C>T allele frequencies is consistent with that of previous studies that used other autosomal markers and methods.

Acute kidney injury manifesting as renal tubular acidosis with proximal and distal renal tubular dysfunction in a dog with acute pancreatitis

Objective

To describe the clinical presentation and management of a critically ill dog with profound renal tubular acidosis (RTA) with proximal and distal renal tubular dysfunction.

Case Summary

A 3‐year‐old neutered female Border Terrier was presented with frequent regurgitation resulting from acute pancreatitis with severe ileus. Venous acid–base analysis and complete urinalysis confirmed the presence of normal anion gap metabolic acidosis with inappropriately alkaline urine (pH 8), consistent with distal RTA. Urinalysis, urine amino acids, and urinary fractional excretion of electrolytes revealed glycosuria (with normoglycemia), aminoaciduria, and increased fractional excretion of sodium, calcium, and phosphate consistent with generalized proximal renal tubulopathy or Fanconi syndrome. The dog responded well to supportive care and alkaline therapy and made a complete recovery.

New or Unique Information Provided

To the authors’ knowledge, this is the first description of RTA with proximal and distal renal tubular dysfunction in the veterinary literature. Furthermore, the authors hypothesize that the transient RTA was a manifestation of acute kidney injury secondary to acute pancreatitis, the first report of this in the literature.

Presence of accessory abductor digiti minimi muscle in two cadavers

During routine cadaveric dissection, accessory hypothenar muscles were incidentally discovered in two cadavers, both males, aged 86 and 92. Both muscles originated from the palmaris longus tendon in the distal portion of the forearm and were identified as accessory abductor digiti minimi (AADM) muscles, based on their association with abductor digiti minimi. While AADM is a common variant in the antebrachium, it is less typical for them to originate from the palmaris longus tendon. The presence of such an AADM could complicate surgical procedures requiring resection of the palmaris longus tendon. Moreover, the surrounding neurovasculature - namely the ulnar nerve as it passes through the ulnar canal between the pisiform and hook of the hamate - could be compressed by contractions of an AADM with such a proximal origin. This can manifest as ulnar neuropathies resulting in pain, weakness, or protracted flexion of the fourth and fifth digits (ulnar claw). Our description of these muscles adds to previous accounts of variation of the palmaris longus and abductor digiti minimi muscles while considering potential clinical implications.

A noninvasive method of temperature measurement using a noncontact handheld infrared thermometer fails to correlate with rectal temperature in dogs and cats

OBJECTIVE

To perform a retrospective, multicenter observational study that compares the agreement of rectal temperature with the temperature measured with noncontact infrared thermometer (NCIT) in a population of dogs and cats.

Animals

168 dogs and 61 cats.

PROCEDURES

NCIT readings were taken in triplicate from the medial pinna, then rectal temperature was taken with a standard digital rectal thermometer (RT). Ambient room temperature, signalment, presence of icterus, skin and coat color, reason for presentation, and final diagnosis were recorded.

RESULTS

In dogs, median (range) body temperature reflected by RT and NCIT measurements was 38.4 °C (33.4 to 40.3 °C) and 36.3 °C (30.8 to 40.0 °C), respectively. In cats, median (range) body temperature reflected by RT and NCIT measurements was 38.3 °C (36.2 to 40.0 °C) and 35.7 °C (31.8 to 38.0 °C), respectively. There was a weak positive correlation between body temperatures measured by NCIT and RT in dogs (Kendall tau = 0.154), but there was no correlation in cats (Kendall tau = –0.01). A significant, albeit weak, agreement was seen between temperature measured by NCIT and RT in dogs (Kappa value, 0.05), but not cats (Kappa value, –0.08). In both species, NCIT tended to underread body temperature, compared with RT (dogs: mean ± SD bias –2.2 ± 1.51 °C; cats: mean bias –2.7 ± 1.44 °C), with the degree of low measurements lessening as body temperature increased.

CLINICAL RELEVANCE

Given both poor correlation and agreement in body temperature measured by NCIT and rectal thermometer, NCIT measurements cannot be recommended at the current time as a means to determine body temperature in dogs and cats.

Abdominal pain and cirrhosis at diagnosis of hemochromatosis: Analysis of 219 referred probands with HFE p.C282Y homozygosity and a literature review

BACKGROUND

In hemochromatosis, causes of abdominal pain and its associations with cirrhosis are poorly understood.

METHODS

We retrospectively compared characteristics of referred hemochromatosis probands with HFE p.C282Y homozygosity with/without biopsy-proven cirrhosis: sex, age, diabetes, heavy alcohol consumption, abdominal pain/tenderness, hepatomegaly, splenomegaly, non-alcoholic fatty liver disease, chronic viral hepatitis, ascites, transferrin saturation (TS), serum ferritin (SF), and iron removed by phlebotomy (QFe). We performed logistic regression on cirrhosis using characteristics identified in univariate comparisons. We performed computerized and manual searches to identify hemochromatosis case series and compiled prevalence data on cirrhosis and abdominal pain and causes of abdominal pain.

RESULTS

Of 219 probands, 57.1% were men. Mean age was 48±13 y. In 22 probands with cirrhosis, proportions of men, mean age, prevalences of heavy alcohol consumption, abdominal pain, abdominal tenderness, hepatomegaly, splenomegaly, and chronic viral hepatitis, and median TS, SF, and QFe were significantly greater than in probands without cirrhosis. Regression analysis revealed three associations with cirrhosis: abdominal pain (p = 0.0292; odds ratio 9.8 (95% CI: 1.2, 76.9)); chronic viral hepatitis (p = 0.0153; 11.5 (95% CI: 1.6, 83.3)); and QFe (p = 0.0009; 1.2 (95% CI: 1.1, 1.3)). Of eight probands with abdominal pain, five had cirrhosis and four had diabetes. One proband each with abdominal pain had heavy alcohol consumption, chronic viral hepatitis B, hepatic sarcoidosis, hepatocellular carcinoma, and chronic cholecystitis, cholelithiasis, and sigmoid diverticulitis. Abdominal pain was alleviated after phlebotomy alone in four probands. In 12 previous reports (1935-2011), there was a negative correlation of cirrhosis prevalence and publication year (p = 0.0033). In 11 previous reports (1935-1996), a positive association of abdominal pain prevalence and publication year was not significant (p = 0.0802).

CONCLUSIONS

Abdominal pain, chronic viral hepatitis, and QFe are significantly associated with cirrhosis in referred hemochromatosis probands with HFE p.C282Y homozygosity. Iron-related and non-iron-related factors contribute to the occurrence of abdominal pain.

Factors associated with IgG levels in adults with IgG subclass deficiency

Background

Factors associated with IgG levels in adults with IgG subclass deficiency (IgGSD) are incompletely understood. We studied adults with IgGSD with subnormal IgG1 only, subnormal IgG1/IgG3, or subnormal IgG3 only without other subnormal IgG subclasses, IgA, or IgM. We compiled: age; sex; autoimmune condition(s) (AC); atopy; IgG, IgG subclasses, IgA, IgM; IgGsum (IgG1 + IgG2 + IgG3 + IgG4); and D (percentage difference between IgGsum and IgG). We compared attributes of patients with/without subnormal IgG (< 7.00 g/L; subnormal IgG1 subclass groups only) and analyzed IgGsum and IgG relationships. We performed backward stepwise regressions on IgG using independent variables IgG subclasses, age, and sex and on D using independent variables age and sex.

Results

There were 39 patients with subnormal IgG1 only (89.7% women), 53 with subnormal IgG1/IgG3 (88.7% women), and 115 with subnormal IgG3 only (91.3% women). Fifteen patients (38.5%) and 32 patients (60.4%) in the respective subnormal IgG1 subclass groups had subnormal IgG. Attributes of patients with/without IgG < 7.00 g/L were similar, except that AC prevalence was lower in patients with subnormal IgG1 only and IgG < 7.00 g/L than ≥ 7.00 g/L (p = 0.0484). Mean/median IgG1 and IgG2 were significantly lower in patients with IgG < 7.00 g/L in both subnormal IgG1 subclass groups (p < 0.0001, all comparisons). Regressions on IgG in three subclass groups revealed positive associations with IgG1 and IgG2 (p < 0.0001 each association). Regressions on D revealed no significant association. IgG1 percentages of IgGsum were lower and IgG2 percentages were higher in patients with subnormal IgG1 subclass levels than subnormal IgG3 only (p < 0.0001 all comparisons).

Conclusions

We conclude that both IgG1 and IgG2 are major determinants of IgG in patients with subnormal IgG1, combined subnormal IgG1/IgG3, or subnormal IgG3 and that in patients with subnormal IgG1 or combined subnormal IgG1/IgG3, median IgG2 levels are significantly lower in those with IgG < 7.00 g/L than those with IgG ≥ 7.00 g/L.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12865-021-00447-3.

Estimates of European American Ancestry in African Americans Using HFE p.C282Y

Background: HFE p.C282Y (chromosome 6p22.2; exon 4, c.845G>A; rs1800562), a hemochromatosis-associated polymorphism in European Americans, is absent in sub-Saharan West African blacks. Methods: We estimated European American ancestry in African Americans (M) using published p.C282Y allele frequencies of sub-Saharan West African blacks; and ≥50 unselected African Americans and ≥50 unselected European Americans in the same city/region. Results: p.C282Y allele frequency in 870 West African blacks (The Gambia, Ghana, Nigeria, Senegal, Sierra Leone) was 0.0000 (confidence interval [95% CI 0.0000-0.0027]). p.C282Y allele frequencies in European Americans were 0.0600 (12,592 participants; five single-site studies) and 0.0673 (54,882 participants; two multisite studies). p.C282Y allele frequencies in African Americans were 0.0102 (3084 participants; five single-site studies) and 0.0122 (30,762 participants; two multisite studies). M for all data was 0.1803 (standard error 0.0049; [95% CI 0.1706-0.1900]). City/region estimates of M differed 1.8-fold: 0.1321, Rochester, NY; 0.1456, Birmingham, AL; 0.1569, Upper Savannah Region, SC; 0.1612, Portland, OR; 0.1746, San Diego, CA; 0.1780, Hartford, CT; 0.1957, District of Columbia; 0.2377, Oakland, CA; and 0.2429, Irvine, CA. Conclusions: Estimates of M using p.C282Y are consistent with those using other autosomal markers, differ across nine cities/regions, and reflect paternal and maternal contributions of European American ancestry in African Americans.

Increased frequency of GNPAT p.D519G in compound HFE p.C282Y/p.H63D heterozygotes with elevated serum ferritin levels

Glyceronephosphate O-acyltransferase (GNPAT) p.D519G (rs11558492) was identified as a genetic modifier correlated with more severe iron overload in hemochromatosis through whole-exome sequencing of HFE p.C282Y homozygotes with extreme iron phenotypes. We studied the prevalence of p.D519G in HFE p.C282Y/p.H63D compound heterozygotes, a genotype associated with iron overload in some patients. Cases were Australian participants with elevated serum ferritin (SF) levels ≥300μg/L (males) and ≥200μg/L (females); subjects whose SF levels were below these cut-offs were designated as controls. Samples were genotyped for GNPAT p.D519G. We compared the allele frequency of the present subjects, with/without elevated SF, to p.D519G frequency in public datasets. GNPAT p.D519G was more prevalent in our cohort of p.C282Y/p.H63D compound heterozygotes with elevated SF (37%) than European public datasets: 1000G 21%, gnomAD 20% and ESP 21%. We conclude that GNPAT p.D519G is associated with elevated SF in Australian HFE p.C282Y/p.H63D compound heterozygotes.

Chromosome 6p SNP microhaplotypes and IgG3 levels in hemochromatosis probands with HFE p.C282Y homozygosity

Subnormal IgG1 or IgG3 levels occurred in 30% of hemochromatosis probands with HFE p.C282Y homozygosity and were concordant in HLA-identical siblings. We sought to identify factors associated with IgG subclasses in Alabama probands with p.C282Y homozygosity evaluated for 500 kb microhaplotypes AAT and GGG defined by SNPs in chromosome 6p genes PGBD1, ZNF193, and ZNF165. In regressions on IgG subclasses, we used: age; sex; GGG (dichotomous); iron removed to achieve depletion; CD8+ T-lymphocytes; and other IgG subclasses. Among 49 probands, AAT and GGG occurred in 95.9% and 16.3%, respectively. Thirteen probands (26.5%) had subnormal IgG1; 11 probands (22.4%) had subnormal IgG3. Mean IgG3 was higher in probands with than without GGG (75 mg/dL [95% confidence interval 63, 89] vs. 58 mg/dL [49, 71], respectively; p = 0.0321). Regression on IgG3 revealed: GGG positivity (p = 0.0106); and IgG1 (p = 0.0015). In a replication cohort of 22 Portugal probands with p.C282Y homozygosity, mean IgG3 was higher in probands with than without GGG (46 ± 16 vs. 31 ± 12 mg/dL, respectively; p = 0.0410). We conclude that mean IgG3 levels are higher in hemochromatosis probands with p.C282Y homozygosity with chromosome 6p microhaplotype GGG than in probands homozygous for microhaplotype AAT.

Iron overload and cirrhosis in referred HFE p.C282Y homozygotes with normal transferrin saturation and elevated serum ferritin

Background: Elevated transferrin saturation (TS) is an imperfect test to identify adults with high-iron gene ( HFE) p.C282Y homozygosity or elevated hepatic iron concentration. Methods: We analyzed observations of non-screening, previously untreated p.C282Y homozygotes who presented with both normal TS (<50% men, <45% women) and elevated serum ferritin (SF; men, >300 µg/L; women, >200 µg/L). Iron overload was defined as hepatocyte iron grade 3 or 4, liver iron >35 µmol/g dry weight, or iron removed by phlebotomy ≥3 g. Cirrhosis was defined as regenerating nodules of hepatocytes surrounded by bands of fibrous connective tissue. Results: Among 917 referred p.C282Y homozygotes, 58 (33 men, 25 women) had normal TS and elevated SF (6.3% [95% CI 4.9% to 8.1%]). Of 58 patients, 14 (24.1%) underwent liver biopsy; all 14 had hepatocyte iron grade 3 or 4. Fatty infiltration was reported in 6 of 14 liver biopsies (42.9%). Liver iron was >35 µmol/g dry weight in 7 of 8 patients tested (87.5%). Iron removed by phlebotomy was ≥3 g in 75.0% (15/20) of men and 62.5% (5/8) of women. Of 58 patients, 3 (5.2%) had iron overload and cirrhosis; each also had a proven or possible non-iron liver condition that may have acted in synergy with liver iron to increase cirrhosis risk. Conclusions: Iron overload is common in non-screening, previously untreated HFE p.C282Y homozygotes with normal TS and elevated SF. Among our sample, 5.2% had cirrhosis. Clinicians should not assume that patients with normal TS and elevated SF do not have HFE p.C282Y homozygosity, iron overload, or cirrhosis.

Iron overload and cirrhosis in referred HFE p.C282Y homozygotes with normal transferrin saturation and elevated serum ferritin

Background: Elevated transferrin saturation (TS) is an imperfect test to identify adults with high-iron gene ( HFE) p.C282Y homozygosity or elevated hepatic iron concentration. Methods: We analyzed observations of non-screening, previously untreated p.C282Y homozygotes who presented with both normal TS (<50% men, <45% women) and elevated serum ferritin (SF; men, >300 µg/L; women, >200 µg/L). Iron overload was defined as hepatocyte iron grade 3 or 4, liver iron >35 µmol/g dry weight, or iron removed by phlebotomy ≥3 g. Cirrhosis was defined as regenerating nodules of hepatocytes surrounded by bands of fibrous connective tissue. Results: Among 917 referred p.C282Y homozygotes, 58 (33 men, 25 women) had normal TS and elevated SF (6.3% [95% CI 4.9% to 8.1%]). Of 58 patients, 14 (24.1%) underwent liver biopsy; all 14 had hepatocyte iron grade 3 or 4. Fatty infiltration was reported in 6 of 14 liver biopsies (42.9%). Liver iron was >35 µmol/g dry weight in 7 of 8 patients tested (87.5%). Iron removed by phlebotomy was ≥3 g in 75.0% (15/20) of men and 62.5% (5/8) of women. Of 58 patients, 3 (5.2%) had iron overload and cirrhosis; each also had a proven or possible non-iron liver condition that may have acted in synergy with liver iron to increase cirrhosis risk. Conclusions: Iron overload is common in non-screening, previously untreated HFE p.C282Y homozygotes with normal TS and elevated SF. Among our sample, 5.2% had cirrhosis. Clinicians should not assume that patients with normal TS and elevated SF do not have HFE p.C282Y homozygosity, iron overload, or cirrhosis.

Prevalence of iron deficiency in 62,685 women of seven race/ethnicity groups: The HEIRS Study

Background

Few cross-sectional studies report iron deficiency (ID) prevalence in women of different race/ethnicity and ages in US or Canada.

Materials and methods

We evaluated screening observations on women who participated between 2001–2003 in a cross-sectional, primary care-based sample of adults ages ≥25 y whose observations were complete: race/ethnicity; age; transferrin saturation; serum ferritin; and HFE p.C282Y and p.H63D alleles. We defined ID using a stringent criterion: combined transferrin saturation <10% and serum ferritin <33.7 pmol/L (<15 μg/L). We compared ID prevalence in women of different race/ethnicity subgrouped by age and determined associations of p.C282Y and p.H63D to ID overall, and to ID in women ages 25–44 y with or without self-reported pregnancy.

Results

These 62,685 women included 27,079 whites, 17,272 blacks, 8,566 Hispanics, 7,615 Asians, 449 Pacific Islanders, 441 Native Americans, and 1,263 participants of other race/ethnicity. Proportions of women with ID were higher in Hispanics and blacks than whites and Asians. Prevalence of ID was significantly greater in women ages 25–54 y of all race/ethnicity groups than women ages ≥55 y of corresponding race/ethnicity. In women ages ≥55 y, ID prevalence did not differ significantly across race/ethnicity. p.C282Y and p.H63D prevalence did not differ significantly in women with or without ID, regardless of race/ethnicity, age subgroup, or pregnancy.

Conclusions

ID prevalence was greater in Hispanic and black than white and Asian women ages 25–54 y. p.C282Y and p.H63D prevalence did not differ significantly in women with or without ID, regardless of race/ethnicity, age subgroup, or pregnancy.

HLA-A and -B Type and Haplotype Frequencies in IgG Subclass Deficiency Subgroups

We sought to determine whether HLA-A and -B type and haplotype frequencies differ between subgroups of adults with IgG subclass deficiency (IgGSD). We retrospectively compared type and haplotype frequencies of three subgroups of 269 unrelated adult IgGSD patients (70 subnormal IgG1; 121 subnormal IgG3; 78 subnormal IgG1/IgG3) and controls (1,321 for types; 751 for haplotypes). We selected types and haplotypes because their uncorrected frequencies differed significantly from controls in a previous adult IgGSD/common variable immunodeficiency cohort: A*24; B*14; B*35; B*40; B*49; B*50; B*58; B*62; A*01,B*08; A*02,B*44; A*02,B*60; A*03,B*07; A*03,B*14; A*03,B*44; A*31,B*40; and A*32,B*14. We used χ² analysis (2 × 4 tables) to identify frequency differences across three subgroups and controls. If the null hypothesis was rejected (p < 0.05), we computed 2 × 2 χ² tables to compare six combinations of subgroup and control frequencies [Bonferroni p < 0.0083 (< 0.05/6)]. Mean age was 48 ± 13 years; 82.2% were women. B*35 and B*40 frequencies were higher in subnormal IgG1 than subnormal IgG3 patients (0.1000 vs. 0.0248 and 0.0571 vs. 0.0083, respectively; p ≤ 0.0061). B*62 frequencies were lower in three IgGSD subgroups than controls (p < 0.0001, respectively). A*02, B*44 frequency was higher in subnormal IgG1/IgG3 patients than controls (0.1282 vs. 0.0632, respectively; p = 0.0024). A*02, B*60 frequency was lower in subnormal IgG3 patients than controls (0.0 vs. 0.0233, respectively; p = 0.0051). HLA-B*35 and -B*40 frequencies differ significantly between some IgGSD subgroups. B*62, A*02, B*44, and A*02, B*60 frequencies differ significantly between some IgGSD subgroups and controls.

Prevalence and characteristics of anti-HCV positivity and chronic hepatitis C virus infection in HFE p.C282Y homozygotes

INTRODUCTION AND AIM

Observations of hepatitis C virus (HCV) infection in adults with hemochromatosis are limited.

MATERIALS AND METHODS

We determined associations of serum ferritin (SF) with anti-HCV in non-Hispanic white North American adults in a post-screening examination. Cases included p.C282Y homozygotes (regardless of screening transferrin saturation (TS) and SF) and participants (regardless of HFE genotype) with high screening TS/SF. Controls included participants without p.C282Y or p.H63D who had normal screening TS/SF. Participants with elevated alanine aminotransferase underwent anti-HCV testing. We determined prevalence of chronic HCV infection in consecutive Alabama and Ontario referred adults with HFE p.C282Y homozygosity.

RESULTS

In post-screening participants, anti-HCV prevalence was 0.3% [95% CI: 0.02, 2.2] in 294 p.C282Y homozygotes, 9.5% [7.2, 12.3] in 560 Cases without p.C282Y homozygosity, and 0.7% [0.2, 2.3] in 403 Controls. Anti-HCV was detected in 7.2% of 745 participants with and 0.8% of 512 participants without elevated SF (odds ratio 9.9 [3.6, 27.6]; p<0.0001). Chronic HCV infection prevalence in 961 referred patients was 1.0% (10/961) [95% confidence interval (CI): 0.5, 2.0]. Ten patients with chronic HCV infection had median age 45y (range 29-67) and median SF 1163μg/L (range 303-2001). Five of eight (62.5%) patients had biopsy-proven cirrhosis.

CONCLUSIONS

Odds ratio of anti-HCV was increased in post-screening participants with elevated SF. Prevalence of anti-HCV in post-screening participants with HFE p.C282Y homozygosity and chronic HCV infection in referred adults with HFE p.C282Y homozygosity in North America is similar to that of Control participants with HFE wt/wt and normal screening TS/SF.

African-centric TP53 variant increases iron accumulation and bacterial pathogenesis but improves response to malaria toxin

A variant at amino acid 47 in human TP53 exists predominantly in individuals of African descent. P47S human and mouse cells show increased cancer risk due to defective ferroptosis. Here, we show that this ferroptotic defect causes iron accumulation in P47S macrophages. This high iron content alters macrophage cytokine profiles, leads to higher arginase level and activity, and decreased nitric oxide synthase activity. This leads to more productive intracellular bacterial infections but is protective against malarial toxin hemozoin. Proteomics of macrophages reveal decreased liver X receptor (LXR) activation, inflammation and antibacterial defense in P47S macrophages. Both iron chelators and LXR agonists improve the response of P47S mice to bacterial infection. African Americans with elevated saturated transferrin and serum ferritin show higher prevalence of the P47S variant (OR = 1.68 (95%CI 1.07–2.65) p = 0.023), suggestive of its role in iron accumulation in humans. This altered macrophage phenotype may confer an advantage in malaria-endemic sub-Saharan Africa.

A polymorphism in human TP53 (P47S) that predominantly exists in individuals of African descent affects ferroptosis. Here, the authors show that this results in iron accumulation in macrophages leading to more productive infection by intracellular bacteria but improved anti-inflammatory response to the malarial toxin hemozoin.

Pneumococcal vaccination responses in adults with subnormal IgG subclass concentrations

BACKGROUND

We sought to compare Pneumovax®23 responses in adults with subnormal IgG subclass concentrations. We studied adults with normal total IgG, frequent/severe respiratory infection, and subnormal IgG1, IgG3, or IgG1 + IgG3 before and after Pneumovax®23. We defined response as serotype-specific IgG > 1.3 μg/mL and aggregate response as IgG > 1.3 μg/mL for ≥70% of all serotypes tested. We compared patients with and without serotype-specific responses and performed logistic regression on aggregate responses using: age; male sex; body mass index; autoimmune condition(s); atopy; other allergies; subnormal IgGSc immunophenotypes; IgA; and IgM.

RESULTS

There were 59 patients (mean age 44 ± 13 (SD) years; 83.1% women). Median days between pre- and post-Pneumovax®23 testing was 33 (range 19-158). The median post-vaccination summated concentration of serotype-specific IgG was higher in patients with subnormal IgG1 than subnormal IgG3 (responders and non-responders). All subnormal IgG1 + IgG3 non-responders responded to serotypes 8, 9 and 26, unlike other non-responders. Subnormal IgG3 responders had lower responses to serotypes 1, 4, 12, 23, 26, and 51. Subnormal IgG3 non-responders had higher responses to serotypes 1, 3, 8, 9, 12, 14, 19, 51, and 56. Response rates decreased with increasing age. Aggregate responders were: subnormal IgG1, 54%; IgG3, 46%; and IgG1 + IgG3, 46%. Regression on aggregate response revealed lower response with male sex (odds ratio 0.09 [95% CI 0.01, 0.77]) and atopy (0.17 [0.03, 0.83]).

CONCLUSIONS

Serotype-specific IgG responses to Pneumovax®23 were greater in patients with subnormal IgG1 than subnormal IgG3. Male sex and atopy were associated with lower aggregate responses.

Clinical and laboratory associations of mannose-binding lectin in 219 adults with IgG subclass deficiency

Background

Mannose-binding lectin (MBL) deficiency may increase risk of respiratory tract infection in adults unselected for IgG or IgG subclass levels. In a retrospective study, we sought to determine associations of serum MBL levels with clinical and laboratory characteristics of unrelated non-Hispanic white adults at diagnosis of IgG subclass deficiency (IgGSD). We computed the correlation of first and second MBL levels expressed as natural logarithms (ln) in a patient subgroup. We compared these characteristics of all adults with and without MBL ≤50 ng/mL: age; sex; body mass index; upper/lower respiratory tract infection; diabetes; autoimmune condition(s); atopy; other allergy; corticosteroid therapy; and subnormal serum IgG subclasses, IgA, and IgM. We performed logistic regression on MBL ≤50 ng/mL (dichotomous) using the three independent variables with the lowest values of p in univariate comparisons.

Results

There were 219 patients (mean age 51 ± 13 y; 82.5% women). Thirty-six patients (16.4%) had MBL ≤50 ng/mL. Two MBL measurements were available in 14 patients. The median interval between the first and second measurements was 125 d (range 18–1031). For ln-transformed data, we observed adjusted r² = 0.9675; Pearson correlation coefficient 0.9849; and p < 0.0001. Characteristics of patients with and without MBL ≤50 ng/mL did not differ significantly in univariate comparisons. We performed a regression on MBL ≤50 ng/mL using: subnormal IgM (p = 0.0565); upper respiratory tract infection (p = 0.1094); and body mass index (p = 0.1865). This regression revealed no significant associations. Conclusions: We conclude that the proportion of the present IgGSD patients with serum MBL ≤50 ng/mL is similar to that of healthy European adults. MBL ≤50 ng/mL was not significantly associated with independent variables we studied.

Cirrhosis in Hemochromatosis: Independent Risk Factors in 368 HFE p.C282Y Homozygotes

INTRODUCTION AND AIM

We sought to identify independent risk factors for cirrhosis in HFE p.C282Y homozygotes in a cross-sectional study.

MATERIAL AND METHODS

We evaluated 368 p.C282Y homozygotes who underwent liver biopsy and compared characteristics of those with and without cirrhosis. We performed multivariable logistic regression on cirrhosis with: age; sex; race/ethnicity; diabetes; blood pints/units donated voluntarily; erythrocyte pints/units received; iron supplement use; alcohol intake, g/d; body mass index, kg/m2; swollen/tender 2nd/3rd metacarpophalangeal joints; elevated alanine aminotransferase; elevated aspartate aminotransferase; steatosis/fatty liver; iron removed by phlebotomy, g; and GNPAT p.D519G positivity.

RESULTS

Mean age of 368 participants (73.6% men) was 47 ± 13 (standard deviation) y. Cirrhosis was diagnosed in 86 participants (23.4%). Participants with cirrhosis had significantly greater mean age, proportion of men, diabetes prevalence, mean daily alcohol intake, prevalence of swollen/ tender 2nd/3rd metacarpophalangeal joints, mean serum ferritin, elevated alanine aminotransferase, elevated aspartate aminotransferase, and mean iron removed; and significantly fewer mean blood pints/units donated. GNPAT p.D519G positivity was detected in 82 of 188 participants (43.6%). In a multivariable model for cirrhosis, there were four significant positive associations: age (10-y intervals) (odds ratio 2.2 [95% confidence interval 1.5, 3.3]); diabetes (3.3; [1.1, 9.7]); alcohol intake (14 g alcohol drinks/d) (1.5 [1.2, 1.8]); and iron removed, g (1.3 [1.2, 1.4]). There was no statistical evidence of two-way interactions between these variables.

CONCLUSION

In conclusion, cirrhosis in HFE p.C282Y homozygotes is significantly associated with age, diabetes, daily alcohol intake, and iron removed by phlebotomy, taking into account the effect of other variables.

Insulin Resistance and Metabolic Syndrome: Clinical and Laboratory Associations in African Americans Without Diabetes in the Hemochromatosis and Iron Overload Screening Study

BACKGROUND

We sought to determine associations with insulin resistance (IR) and metabolic syndrome (MetS) in African Americans.

METHODS

We studied African American adults without diabetes in a postscreening examination. Participants included Cases: transferrin saturation (TS) >50% and serum ferritin (SF) >300 μg/L (M), and TS >45% and SF >200 μg/L (F), regardless of HFE genotype; and Controls: TS/SF 25th to 75th percentiles and HFE wt/wt (wild type). We excluded participants with fasting <8 h; fasting glucose >126 mg/dL; hepatitis B or C; cirrhosis; pregnancy; or incomplete datasets. We analyzed age; sex; Case/Control; body mass index (BMI); systolic and diastolic blood pressures; neutrophils; lymphocytes; alanine aminotransferase; aspartate aminotransferase; elevated C-reactive protein (CRP >0.5 mg/L); TS; and SF. We computed homeostasis model assessment of insulin resistance (HOMA-IR) using fasting serum glucose and insulin, and defined IR as HOMA-IR fourth quartile (≥2.42).

RESULTS

There were 312 Cases and 86 Controls (56.3% men). Ninety-one percent had HFE wt/wt. None had HFE p.C282Y. A significant increasing trend across HOMA-IR quartiles was observed for BMI only. Multivariable regression on HOMA-IR revealed significant positive associations: age; BMI; lymphocytes; SF; and CRP >0.5 mg/L; and significant negative associations: neutrophils and TS. Logistic regression on IR revealed BMI [odds ratio (OR) 1.3 (95% confidence interval 1.2-1.4)] and CRP >0.5 mg/L [OR 2.7 (1.2-6.3)]. Fourteen participants (3.5%) had MetS. Logistic regression on MetS revealed one association: IR [OR 7.4 (2.1-25.2)].

CONCLUSIONS

In African Americans without diabetes, IR was associated with BMI and CRP >0.5 mg/L, after adjustment for other variables. MetS was associated with IR alone.

Clinical and Laboratory Associations with Persistent Hyperferritinemia in 373 Black Hemochromatosis and Iron Overload Screening Study Participants

BACKGROUND

373 black participants had elevated screening and post-screening serum ferritin (SF) (> 300 μg/L men; > 200 μg/L women).

MATERIAL AND METHODS

We retrospectively studied SF and post-screening age; sex; body mass index; transferrin saturation (TS); ALT; AST; GGT; elevated C-reactive protein; ß-thalassemia; neutrophils; lymphocytes; monocytes; platelets; metacarpophalangeal joint hypertrophy; hepatomegaly; splenomegaly; diabetes; HFE H63D positivity; iron/alcohol intakes; and blood/erythrocyte transfusion units. Liver disease was defined as elevated ALT or AST. We computed correlations of SF and TS with: age; body mass index; ALT; AST; GGT; C-reactive protein; blood cell counts; and iron/alcohol. We compared participants with SF > 1,000 and ≤ 1,000 μg/L and performed regressions on SF.

RESULTS

There were 237 men (63.5%). Mean age was 55 ± 13 (SD) y. 143 participants had liver disease (62 hepatitis B or C). There were significant correlations of SF: TS, ALT, AST, GGT, and monocytes (positive); and SF and TS with platelets (negative). 22 participants with SF > 1,000 μg/L had significantly higher median TS, ALT, and AST, and prevalences of anemia and transfusion > 10 units; and lower median platelets. Regression on SF revealed significant associations: TS; male sex; age; GGT; transfusion units (positive); and splenomegaly (negative) (p < 0.0001, 0.0016, 0.0281, 0.0025, 0.0001, and 0.0096, respectively). Five men with SF > 1,000 μg/L and elevated TS had presumed primary iron overload (hemochromatosis). Four participants had transfusion iron overload.

CONCLUSION

Persistent hyperferritinemia in 373 black adults was associated with male sex, age, TS, GGT, and transfusion. 2.4% had primary iron overload (hemochromatosis) or transfusion iron overload.

Implanted ports in adults with primary immunodeficiency

BACKGROUND

We sought to learn more about the utility and safety of implanted ports for monthly immunoglobulin G infusions in adults with primary immune deficiency.

METHODS

We reviewed charts of adults who were referred to a single practice during the interval 2006-2016 for evaluation and management of frequent or severe upper and lower respiratory tract and other infections, subnormal total immunoglobulin G or immunoglobulin G subclasses, and suboptimal responses to polyvalent pneumococcal polysaccharide vaccinations; were diagnosed to have primary immune deficiency; and were advised to undergo immunoglobulin G therapy.

RESULTS

Of 606 patients, 20 (19 women, 1 man; 16 immunoglobulin G subclass deficiency, 4 common variable immunodeficiency; 3.3%) needed implanted ports because they had inadequate upper extremity superficial venous access. Median age at diagnosis was 48 years (range: 32-65 years). In total, 17 of the 20 patients preferred monthly in-office intravenous immunoglobulin G treatment to weekly at-home subcutaneous immunoglobulin G. The other three patients could not be treated with subcutaneous immunoglobulin G (unfavorable self-treatment experiences and insurance limitations). Median duration of treatment via implanted ports was 73 months (range: 10-153 months). In the man, the first implanted port was replaced after 26 months due to catheter fracture of unknown cause. His second port has been used for 112 months. We observed no other port-related failure, infections, thrombosis, or other adverse events.

CONCLUSION

The utility and safety of implanted ports in adults with primary immune deficiency for whom subcutaneous immunoglobulin G therapy is not desired or feasible are probably similar to those of ports in patients without primary immune deficiency.

Intravenous Bevacizumab Therapy in a Patient with Hereditary Hemorrhagic Telangiectasia, ENG E137K, Alcoholic Cirrhosis, and Portal Hypertension

Intravenous bevacizumab decreased mucosal bleeding in some patients with hereditary hemorrhagic telangiectasia (HHT). We treated a 47-year-old male who had HHT, severe epistaxis, and gastrointestinal bleeding, alcoholic cirrhosis, and portal hypertension with intravenous bevacizumab 2.5 mg/kg every 2 weeks. We tabulated these measures weekly during weeks 1–33 (no bevacizumab); 34–57 (bevacizumab); and 58–97 (no bevacizumab): hemoglobin (Hb) levels; platelet counts; units of transfused packed erythrocytes (PRBC units); and quantities of iron infused as iron dextran to support erythropoiesis. We performed univariate and multivariable analyses. We sequenced his ENG and ACVRL1 genes. Epistaxis and melena decreased markedly during bevacizumab treatment. He reported no adverse effects due to bevacizumab. Mean weekly Hb levels were significantly higher and mean weekly PRBC units and quantities of intravenous iron were significantly lower during bevacizumab treatment. We performed a multiple regression on weekly Hb levels using these independent variables: bevacizumab treatment (dichotomous); weekly platelet counts; weekly PRBC units; and weekly quantities of intravenous iron. There was 1 positive association: (bevacizumab treatment; p = 0.0046) and 1 negative association (PRBC units; p = 0.0004). This patient had the novel ENG mutation E137K (exon 4; c.409G→A). Intravenous bevacizumab treatment 2.5 mg/kg every 2 weeks for 24 weeks was well-tolerated by a patient with HHT due to ENG E137K and was associated with higher weekly Hb levels and fewer weekly PRBC units.

Fibromyalgia in 300 adult index patients with primary immunodeficiency

OBJECTIVES

We sought to determine the prevalence and clinical and laboratory associations of fibromyalgia in adults with primary immunodeficiency (immunoglobulin (Ig) G subclass deficiency (IgGSD) and common variable immunodeficiency (CVID).

METHODS

We performed a retrospective analysis of these observations in 300 non-Hispanic white adult index patients with recurrent/severe respiratory tract infections and IgGSD or CVID: age; sex; IgGSD; fibromyalgia; chronic fatigue; autoimmune conditions (ACs); interstitial cystitis (IC); diabetes; body mass index; serum Ig isotypes; blood lymphocytes and subsets; and human leukocyte antigen (HLA)-A and -B types and haplotypes. We performed univariate comparisons, logistic multivariable regressions, and an analysis of covariance.

RESULTS

Mean age was 49 ± 12 (standard deviation) y. There were 246 women (82.0%). IgGSD was diagnosed in 276 patients (92.0%). Fifty-six patients had fibromyalgia (18.7%; female:male 13:1). Other characteristics included: chronic fatigue, 63.0%; aggregate ACs, 35.3%; Sjögren's syndrome, 8.0%; IC, 3.0%; diabetes, 10.3%; and HLA-A*29, B*44 positivity, 9.7%. Prevalences of female sex; chronic fatigue; IC; and HLA-A*29, B*44 positivity were greater in patients with fibromyalgia. Logistic regression on fibromyalgia revealed three positive associations: chronic fatigue (p=0.0149; odds ratio 2.6 [95% confidence interval 1.2, 5.6]); Sjögren's syndrome (p=0.0004; 5.2 [2.1, 13.2]); and IC (p=0.0232; 5.7 [1.3, 25.7]). In an analysis of covariance, there were significant interactions of chronic fatigue, Sjögren's syndrome, and interstitial cystitis on fibromyalgia.

CONCLUSIONS

Fibromyalgia is common in non-Hispanic white adult index patients with primary immunodeficiency, especially women. Chronic fatigue, Sjögren's syndrome, and IC are significantly associated with fibromyalgia after adjustment for other independent variables.

Diabetes in HFE Hemochromatosis

Diabetes in whites of European descent with hemochromatosis was first attributed to pancreatic siderosis. Later observations revealed that the pathogenesis of diabetes in HFE hemochromatosis is multifactorial and its clinical manifestations are heterogeneous. Increased type 2 diabetes risk in HFE hemochromatosis is associated with one or more factors, including abnormal iron homeostasis and iron overload, decreased insulin secretion, cirrhosis, diabetes in first-degree relatives, increased body mass index, insulin resistance, and metabolic syndrome. In p.C282Y homozygotes, serum ferritin, usually elevated at hemochromatosis diagnosis, largely reflects body iron stores but not diabetes risk. In persons with diabetes type 2 without hemochromatosis diagnoses, serum ferritin levels are higher than those of persons without diabetes, but most values are within the reference range. Phlebotomy therapy to achieve iron depletion does not improve diabetes control in all persons with HFE hemochromatosis. The prevalence of type 2 diabetes diagnosed today in whites of European descent with and without HFE hemochromatosis is similar. Routine iron phenotyping or HFE genotyping of patients with type 2 diabetes is not recommended. Herein, we review diabetes in HFE hemochromatosis and the role of iron in diabetes pathogenesis in whites of European descent with and without HFE hemochromatosis.

GNPAT p.D519G is independently associated with markedly increased iron stores in HFE p.C282Y homozygotes

BACKGROUND

GNPAT p.D519G positivity is significantly increased in HFE p.C282Y homozygotes with markedly increased iron stores. We sought to determine associations of p.D519G and iron-related variables with iron stores in p.C282Y homozygotes.

METHODS

We defined markedly increased iron stores as serum ferritin >2247pmol/L (>1000μg/L) and either hepatic iron >236μmol/g dry weight or iron >10g by induction phlebotomy (men and women). We defined normal or mildly elevated iron stores as serum ferritin <674.1pmol/L (<300μg/L) or either age≥40y with iron ≤2.5g iron by induction phlebotomy or age≥50y with ≤3.0g iron by induction phlebotomy (men only). We compared participant subgroups using univariate methods. Using multivariable logistic regression, we evaluated associations of markedly increased iron stores with these variables: age; iron supplement use (dichotomous); whole blood units donated; erythrocyte units received as transfusion; daily alcohol consumption, g; and p.D519G positivity (heterozygosity or homozygosity).

RESULTS

The mean age of 56 participants (94.6% men) was 55±10 (SD) y; 41 had markedly increased iron stores. Prevalences of swollen/tender 2nd/3rd metacarpophalangeal joints and elevated aspartate or alanine aminotransferase were significantly greater in participants with markedly increased iron stores. Only participants with markedly increased iron stores had cirrhosis. In multivariable analyses, p.D519G positivity was the only exposure variable significantly associated with markedly increased iron stores (odds ratio 9.9, 95% CI [1.6, 60.3], p=0.0126).

CONCLUSIONS

GNPAT p.D519G is strongly associated with markedly increased iron stores in p.C282Y homozygotes after correction for age, iron-related variables, and alcohol consumption.

Porphyria cutanea tarda associated with HFE C282Y homozygosity, iron overload, and use of a contraceptive vaginal ring

Porphyria cutanea tarda (PCT) is characterized by decreased uroporphyrinogen decarboxylase activity in hepatocytes, uroporphyrin I and heptacarboxyl porphyrin III accumulation, photosensitivity dermatitis, and increased storage iron. In women, estrogen therapy, including oral contraceptives, postmenopausal hormone replacement, and tamoxifen for breast cancer treatment, is a risk factor for PCT. We report the case of a woman who presented with PCT, HFE C282Y homozygosity, and hepatic iron overload and was using a contraceptive vaginal ring containing ethinyl estradiol, an estrogen. We discuss this case in the context of characteristics of other persons with PCT, including common HFE mutations, iron overload, and estrogen exposure.

Risk Factors for Insulin Resistance, Metabolic Syndrome, and Diabetes in 248 HFE C282Y Homozygotes Identified by Population Screening in the HEIRS Study

BACKGROUND

We sought to identify risk factors for insulin resistance, metabolic syndrome (MetS), and diabetes mellitus in 248 non-Hispanic white HFE C282Y homozygotes identified by population screening.

METHODS

We analyzed observations obtained prospectively in a postscreening examination: age; sex; body mass index (BMI); systolic/diastolic blood pressure; metacarpophalangeal (MP) joint hypertrophy; hepatomegaly; complete blood counts; alanine/aspartate aminotransferase levels; elevated C-reactive protein (>0.5 mg/dL); transferrin saturation; serum ferritin; homeostasis model assessment-insulin resistance (HOMA-IR); and MetS.

RESULTS

Twenty-six participants (10.5%) had diabetes diagnoses. A significant trend across HOMA-IR quartiles was observed only for blood neutrophils. Logistic regression on HOMA-IR fourth quartile revealed positive associations: age (P = 0.0002); male sex (P = 0.0022); and BMI (P < 0.0001). HOMA-IR fourth quartile predicted MetS (P < 0.0001). Logistic regression on diabetes revealed positive associations: age (P = 0.0012); male sex (P = 0.0068); MP joint hypertrophy (P = 0.0167); neutrophils (P = 0.0342); and MetS (P = 0.0298). Serum ferritin did not predict HOMA-IR fourth quartile, MetS, or diabetes.

CONCLUSIONS

In screening C282Y homozygotes, age, male sex, and BMI predicted HOMA-IR fourth quartile. HOMA-IR fourth quartile alone predicted MetS. Diabetes was associated with greater age, male sex, MP joint hypertrophy, greater blood neutrophil counts, and MetS.

Serum ferritin is a biomarker for liver mortality in the Hemochromatosis and Iron Overload Screening Study

BACKGROUND

We identified no reports of long-term follow-up of participants in hemochromatosis screening programs. We evaluated causes of death and survival in non-C282Y homozygous Canadian participants in the primary care-based hemochromatosis and iron overload screening (HEIRS) study.

MATERIAL AND METHODS

Initial screening (IS) included transferrin saturation (TS), serum ferritin (SF), HFE genotyping (C282Y, H63D), and health questionnaire responses. By definition, participants without C282Y or H63D had HFE wt/wt. We linked 20,306 Canadian participants to the Ontario Death Registry for dates and causes of death 9 y after IS. We computed Cox proportional hazards to identify factors with increased death risks and Kaplan-Meier curves to estimate survival of non-C282Y homozygous participants with SF ≤ 1,000 μg/L and > 1,000 μg/dL.

RESULTS

There were 19,052 evaluable participants (IS mean age 49 y; 60% women; 93 C282Y homozygotes). There were 988 deaths. Significantly increased hazard ratios for all-cause mortality were positively associated with TS, SF, men, and C282Y homozygosity, and liver disease, diabetes, and heart failure reports. Non-C282Y homozygous participants with SF > 1,000 μg/L had lower survival than those with SF ≤ 1,000 μg/L (p < 0.0001).

CONCLUSIONS

Nine years after initial screening, non-C282Y homozygous participants and SF > 1,000 μg/L was associated with decreased survival.

Undiagnosed diabetes and impaired fasting glucose in HFE C282Y homozygotes and HFE wild-type controls in the HEIRS Study

OBJECTIVE

To determine prevalences and predictors of undiagnosed diabetes mellitus (UDM) and impaired fasting glucose (IFG) in non-Hispanic whites with HFE p.C282Y homozygosity and controls without common HFE mutations identified in population screening.

RESEARCH DESIGN AND METHODS

We analyzed these observations in a postscreening examination: age; sex; body mass index; systolic/diastolic blood pressure; metacarpophalangeal joint hypertrophy; hepatomegaly; blood neutrophils; alanine and aspartate aminotransferase; elevated C reactive protein; transferrin saturation; serum ferritin; and Field Center.

RESULTS

There were 223 p.C282Y homozygotes and 449 controls without diagnosed diabetes (43.9% men). Mean age of p.C282Y homozygotes was 52±13 years (controls 57±14 years; p<0.0001). Mean transferrin saturation in p.C282Y homozygotes was 67±26% (controls 34±14%; p<0.0001). Mean serum ferritin in p.C282Y homozygotes was 607 pmol/L (95% CI 497 to 517; controls 274 pmol/L (247 to 301); p<0.0001). Overall prevalences of UDM (4.0% vs 4.2%) and IFG (23.8% vs 25.6%) did not differ significantly between p.C282Y homozygotes and wt/wt controls, respectively. In logistic regressions, male sex, body mass index, and alanine aminotransferase were significantly associated with UDM. ORs were 2.7 (1.2 to 2.8); 1.0 (1.0 to 1.1); and 1.0 (1.0 to 1.0), respectively. Age, male sex, and body mass index were significantly associated with IFG. ORs were 1.0 (1.0 to 1.1); 2.8 (1.9 to 4.2); and 1.0 (1.0 to 1.1), respectively.

CONCLUSIONS

Prevalences of UDM and IFG were similar in p.C282Y homozygotes and controls in a postpopulation screening examination. Male sex was the strongest predictor of UDM and IFG.

HFE gene: Structure, function, mutations, and associated iron abnormalities

The hemochromatosis gene HFE was discovered in 1996, more than a century after clinical and pathologic manifestations of hemochromatosis were reported. Linked to the major histocompatibility complex (MHC) on chromosome 6p, HFE encodes the MHC class I-like protein HFE that binds beta-2 microglobulin. HFE influences iron absorption by modulating the expression of hepcidin, the main controller of iron metabolism. Common HFE mutations account for ~90% of hemochromatosis phenotypes in whites of western European descent. We review HFE mapping and cloning, structure, promoters and controllers, and coding region mutations, HFE protein structure, cell and tissue expression and function, mouse Hfe knockouts and knockins, and HFE mutations in other mammals with iron overload. We describe the pertinence of HFE and HFE to mechanisms of iron homeostasis, the origin and fixation of HFE polymorphisms in European and other populations, and the genetic and biochemical basis of HFE hemochromatosis and iron overload.

Selective subnormal IgG3 in 121 adult index patients with frequent or severe bacterial respiratory tract infections

We characterized 121 adults with frequent or severe bacterial respiratory tract infections at diagnosis of selective subnormal IgG3. Mean age was 47 ± 13 (SD)y; 87.6% were women. Associated disorders included: autoimmune conditions 33.1%; hypothyroidism 14.9%; atopy 29.8%; and other allergy manifestations 41.3%. In 34.1%, proportions of protective Streptococcus pneumoniae serotype-specific IgG levels did not increase after polyvalent pneumococcal polysaccharide vaccination. Blood CD19+, CD3+/CD4+, CD3+/CD8+, and CD56+/CD16+ lymphocyte levels were within reference limits in most patients. In regression analyses, independent variables age; sex; autoimmune conditions; hypothyroidism; atopy; allergy manifestations; corticosteroid therapy; and lymphocyte subsets were not significantly associated with IgG subclass, IgA, or IgM levels. Frequencies of HLA haplotypes A*01, B*08; A*02, B*14; A*02, B*15; A*02, B*44; A*02, B*57; and A*03, B*07 were greater in 80 patients than 751 controls. We conclude that subnormal IgG3 and non-protective S. pneumoniae IgG levels contribute to increased susceptibility to respiratory tract infections.