Pelger-Huët anomaly is a benign anomaly of leukocytes and is inherited as a non-sex-linked, dominant trait. It is characterized by distinctive shapes of the nuclei of leukocytes, a reduced number of nuclear segments (best seen in the neutrophils), and coarseness of the chromatin of the nuclei of neutrophils, lymphocytes, and monocytes. The nuclei appear rod-like, dumbbell-shaped, peanut-shaped, and spectacle-like (“pince-nez”) with smooth, round, or oval individual lobes, contrasted with the irregular lobes seen in normal neutrophils.¹ The incidence of this disorder in different studies has ranged from as high as 1 in 1,000 persons², ³ to 1 in 4,000,⁴, ⁵ 6,000,⁶ or even 10,000.⁷ Originally observed mainly in Holland, Germany, and Switzerland, the anomaly has now been described in other parts of the world, including individuals of Asian⁸ and African descent and whites. The practical importance of identifying the Pelger-Huët anomaly lies in distinguishing this defect from the shift to the left that occurs in association with infection.

The discovery of this anomaly in rabbits led to breeding experiments and the production of homozygotes.², ⁵ These studies demonstrated that in the heterozygote, bilobed, rod-shaped, and spectacle forms predominate, whereas in the homozygote, round nuclei with no evidence of segmentation are predominant. In rabbits, the homozygous form was often lethal, with most animals dying in utero; some survivors suffered skeletal malformations.

Two human homozygotes have been reported.², ⁹ In them, the cytoplasm of the neutrophils appeared mature, but the nuclei were round or oval in all the neutrophils, in contrast to the fewer than 40% single-lobed neutrophils present in heterozygotes (Table 58.1).², ⁶, ⁹ In the homozygotes, the eosinophils, basophils, and megakaryocytes also were characterized by dense nuclear chromatin and rounded nuclear lobes; these individuals had fewer nuclear lobes than normal subjects.² Examination of the bone marrow revealed normal morphologic features in myeloid precursors through the myelocyte stage, and electron microscopy revealed persistence of nucleoli in the otherwise mature neutrophils that contained single oval nuclei.⁹ This finding was interpreted as indicating some retardation of nuclear maturation, because no cytochemical defects were noted in the cytoplasm. This syndrome is now known to be due to mutations in the lamin B receptor (LBR) gene, a gene important in maintaining nuclear structure.¹⁰, ¹¹, ¹²

Pelger-Huët cells appear to be normal functionally,⁹, ¹³, ¹⁴ are able to phagocytize and kill microorganisms,⁵ and survive normally in the circulation in both humans¹⁵ and dogs.¹⁶, ¹⁷

The Pelger-Huët heterozygote is recognized by finding (a) 69% to 93% of the neutrophils to be of the bilobed, pince-nez type; (b) few cells with three lobes (usually <10%); and (c) rare or no cells with four lobes (Table 58.1).⁴, ⁵, ⁶ In normal blood smears, no more than 27% of the cells are bilobed, and significant numbers of cells have three or more lobes.⁵ The presence of similar abnormalities in the blood smear in other family members also is helpful in establishing the diagnosis. In heterozygotes, mature neutrophils with round or oval nuclei of the type that is characteristic of the homozygous state may increase after stress, such as the injection of colchicine¹⁸, ³ A shift toward increased numbers of neutrophil lobes was described in a patient with the anomaly who developed pernicious anemia.¹⁹

Cells with morphologic changes, such as those just described, have been observed occasionally in association with myxedema, acute enteritis, agranulocytosis, multiple myeloma, malaria,
leukemoid reactions secondary to metastases to the bone marrow,²⁰ drug sensitivity,²¹ or chronic lymphocytic leukemia.³ More commonly, pseudo-Pelger-Huët cells (Fig. 58.1)²² are seen in patients with myeloid leukemia of either the acute or chronic type or in those with myeloid metaplasia.²³, ²⁴ In these subjects, the pseudo-Pelger-Huët cells tend to appear late in the disease, often after considerable chemotherapy has been administered. In addition, most of the nuclei are of the single oval type characteristic of the homozygous state.²³

Alder-Reilly anomaly, inherited as a recessive trait,²⁵ apparently does not interfere with leukocyte function.²⁶ It is characterized by the presence of larger-than-normal azurophil and basophil granules (Alder-Reilly bodies), which may be easily confused with granulations due to toxic states (Fig. 58.2). These granules stain dark lilac with Wright-Giemsa stains and are seen in patients with various types of bone and cartilage abnormalities.²⁷, ²⁸ They are most common, however, in association with Hurler syndrome, Hunter syndrome, and Maroteaux-Lamy polydystrophic dwarfism.²⁹

Similar inclusions may be seen in blood lymphocytes (Gasser cells) and monocytes.³⁰, ³¹ The lymphocyte inclusions stain dark red or purple with May-Grünwald-Giemsa stain and metachromatically with toluidine blue; normal azurophilic granules do not stain at all.³¹, ³² Such lymphocyte granules are found in all types of mucopolysaccharidoses except Morquio syndrome, but they are most common in the Hurler, Hunter, Sanfilippo, and Maroteaux-Lamy syndromes.²⁹, ³¹, ³² They tend to occur in clusters rather than diffusely throughout the cytoplasm, are surrounded by vacuoles, and are shaped like a dot or comma. In one series of 19 patients, 8% to 50% of the lymphocytes contained the inclusions, and their presence was thought to be of diagnostic significance.³²

These inclusions are seen inconsistently in the blood but are more common in the bone marrow. For example, in a series of 18 patients with Hurler form of mucopolysaccharidosis, Alder-Reilly bodies were present in the blood of <10% of them. Careful examination of the bone marrow, however, revealed mucopolysaccharide granules in large mononuclear cells (Buhot cells) in 17 of 18 patients.³³, ³⁴, ³⁵

The type of inclusion seen is not diagnostic of a particular type of mucopolysaccharidosis, and the frequency of the inclusions is not correlated with clinical severity.³⁶ The basic defect in this group of diseases lies in the incomplete degradation of the protein-carbohydrate complexes known as mucopolysaccharides, and the different forms of mucopolysaccharidosis involve different enzymatic deficiencies.²⁹ The accumulation of partially degraded mucopolysaccharides within lysosomes has been demonstrated by electron microscopy²⁹; the degradation of the protein core of the mucopolysaccharide appears to proceed normally, but catabolism of the carbohydrate side chains is impaired.

The May-Hegglin anomaly is a rare, dominantly inherited disorder characterized by large (2 to 5 µm), well-defined, basophilic, and pyroninophilic inclusions in granulocytes (neutrophils, eosinophils, basophils, monocytes), and accompanied by variable thrombocytopenia and giant platelets containing few granules.³⁷ For the most part, affected family members have not been ill, but occasionally abnormal bleeding has occurred.³⁸, ³⁹, ⁴⁰, ⁴¹ Clot retraction time is prolonged, and the reaction to the tourniquet test may be positive. Platelet survival was short (half-life = 3 days, as compared with the normal, which is 6.9 ± 1.5 [1 standard deviation] days).⁴² Platelet aggregation and retraction were normal, but spreading and serotonin uptake were increased.⁴³ Enzyme and substrate content per platelet were increased, but this value was decreased as related to platelet volume.⁴³ The granulocyte inclusions are similar to Döhle bodies in appearance, but they often are larger, are more round and discrete, and may be present in a large percentage of the cells.⁴⁰, ⁴¹, ⁴⁴ It is claimed that these inclusions differ from the Döhle bodies of infection in morphologic appearance in that they are present in granulocytes other than neutrophils.⁴⁴ Like Döhle bodies,⁴⁰, ⁴⁴ the inclusions were felt to consist mainly of RNA and may exhibit differing ultrastructure.⁴¹, ⁴⁵, ⁴⁶, ⁴⁷ More recently, mutations in MYH9, the gene encoding NMMHC-A,
have been found in this syndrome.⁴⁸, ⁴⁹, ⁵⁰ NMMHC-A is a nonmuscle myosin heavy chain that is part of a family of genes coding for proteins that form part of the actin-myosin force-generating complexes.⁵¹ In the bone marrow, clumping of the megakaryocyte cytoplasm has also been reported.³⁹

Mutations in MYH9 are inherited in an autosomal dominant fashion, but depending on the mutation generate a spectrum of clinical findings manifest as several syndromes due to variable expressivity of the clinical features.⁵², ⁵³, ⁵⁴, ⁵⁵, ⁵⁶, ⁵⁷, ⁵⁸ These clinical syndromes include May-Hegglin anomaly, Sebastian syndrome, Fechtner syndrome, and Epstein syndrome and are characterized by giant platelets, leukocyte inclusions, and variable thrombocytopenia, in addition to problems with hearing, vision, or renal function.⁵², ⁵³, ⁵⁴, ⁵⁵, ⁵⁶, ⁵⁷

Chédiak-Steinbrinck-Higashi anomaly, an autosomal recessive disorder, has been reported in humans,⁵⁹, ⁶⁰, ⁶¹, ⁶² mice,⁶³ mink,⁶⁴ cattle,⁶⁴ cats,⁶⁵ rats,⁶⁶ and a killer whale.⁶⁷ It is characterized by partial ocular and cutaneous albinism, increased susceptibility to pyogenic infections, the presence of large lysosome-like organelles in most granule-containing cells, and a bleeding tendency.⁶⁸ The abnormal granules are most readily seen in blood and marrow leukocytes, especially granulocytes (Fig. 58.3), and in melanocytes.

In the first families that were reported with this anomaly, the mothers noted that some of their children exhibited pale hair (Fig. 58.4) and photophobia.⁵⁹, ⁶⁰ Because these children often had infections and adenopathy and died at an early age, the children born subsequently who were similarly affected were brought to medical attention in the hope of avoiding a fatal outcome.⁶⁰ It was then that the large, peroxidase-positive granules were noted in their blood and marrow granulocytes.⁵⁹, ⁶⁰, ⁶¹ Nevertheless, without definitive treatment (bone marrow transplantation, described later) most patients die in infancy or early childhood; only a few survive into early adult life.⁶⁹, ⁷⁰, ⁷¹

During the 30 years after the first description of Chédiak-Higashi syndrome (CHS)⁷² 59 cases were reported.⁶⁹ The similar disorder in animals is of use in investigations of the pathogenic defect and is of significant economic impact in mink, in that affected animals, inbred for their unusual color, seldom survive more than a year and exhibit increased susceptibility to a slow viral infection that produces hepatitis and a myeloma-like illness (Aleutian mink disease).⁶⁴

Jordan anomaly is characterized by the presence of vacuoles in the cytoplasm of granulocytes, monocytes, and occasionally lymphocytes and plasma cells. In members of one family, all of the blood neutrophils and more than 70% of the monocytes contained three to ten vacuoles ranging in size from 2 to 5 µm; fewer and smaller vacuoles were seen in eosinophils, basophils, and lymphocytes.¹¹⁸ By means of histochemical and fluorescence microscopic analysis, the vacuoles were shown to contain lipids. These lipids were seen in promyelocytes, myelocytes, metamyelocytes, and occasionally plasma cells in the bone marrow, but they were not present in myeloblasts, erythroblasts, or megakaryocytes.¹¹⁸ This type of vacuolization must be distinguished from that characterized by fat-staining vacuoles occurring in people with serious infections, toxic hepatitis, or diabetic ketoacidosis.¹¹⁹

The disorder appears to be familial. Two members were affected in each of two unrelated families.¹¹⁸, ¹¹⁹ None of the four patients had acute disease, but in members of one family, progressive muscular dystrophy was present,¹¹⁸ whereas in members of the other, ichthyosis was associated.¹¹⁹

In an infant with congenital bile duct atresia, amorphous, roundto-oval bodies stained green or gray-green with Romanovsky stains in 3% to 13% of the blood neutrophils and in 1% to 5% of the monocytes.¹²⁰ Similar inclusions were present in all stages of myeloid cells in the bone marrow but not in lymphocytes or plasma cells. Electron microscopic analysis showed that the inclusions were not enclosed in a phagocytic vesicle.

In the blood monocytes of patients with the Hermansky-Pudlak syndrome,¹²¹ a rare familial disorder characterized by albinism, mild bleeding related to platelet dysfunction, accumulation of ceroidlike pigment in marrow macrophages, and deficiency of the tetraspan protein CD63 in platelets,¹²² lipopigment bodies as well as another type of inclusion were demonstrated.

A syndrome of recurrent staphylococcal skin and sinus infections associated with abnormal chemotaxis, impaired staphylococcal killing, and morphologic abnormalities in the neutrophils was described in a 14-year-old boy.¹²³ No other family members were affected. The patient’s polymorphonuclear neutrophils exhibited bilobed nuclei with unevenly distributed chromatin, drumsticklike nuclear projections, and nearly absent cytoplasmic granules that stained with peroxidase but not with alkaline phosphatase. Electron microscopy revealed primary granules, but specific granules were small and reduced in number. These neutrophils were capable of phagocytosis, generated H₂O₂, reduced nitroblue tetrazolium (NBT) dye, and killed Candida, but staphylococcal killing was impaired.

Since the original report, at least five cases of specific granule deficiency (SGD) have been identified with both sexes affected, leading to the assumption that the disorder is an autosomal recessive disease.¹²⁴, ¹²⁵ SGD neutrophils exhibit decreased chemotaxis and bacterial killing in vitro and decreased migration into skin windows in vivo, and they fail to upregulate CD11/CD18, laminin, or f-met-leu-phe (FMLP) receptors after activation,¹²⁴ although oxygen radical generation is apparently normal. Myeloperoxidase (MPO)-positive primary granules are present, but the specific secondary granules appeared to be absent in Wright-stained blood smears and were decreased in number and small when viewed with electron microscopy.¹²³ These structures do not stain with alkaline phosphatase. The specific granule constituents lactoferrin and B₁₂ binding protein are reduced or absent.

Lactoferrin deficiency in patients with SGD is tissue specific (i.e., confined to myeloid cells, whereas lactoferrin is secreted normally in nasal secretions) and is secondary to a deficiency of RNA transcripts.¹²⁶ Because morphologic changes have been described in the primary granule¹²⁷ and because other granule proteins, such as primary granule defensin⁹² and “tertiary” granule gelatinase, are also deficient in SGD neutrophils, it was suggested that the basic defect in SGD is one of regulation of production of these proteins.¹²⁶ Thus, this disorder may be one of incomplete granule synthesis rather than a true SGD.¹²⁷

C/EBPE is an important regulator of neutrophil secondary granule genes,¹²⁸ and mutations in the C/EBPE gene have been found in two patients with SGD.¹²⁹, ¹³⁰, ¹³¹ Neutrophils from Cebpedeficient mice have functional defects very similar to those of patients with SGD,¹²⁹, ¹³² and these mice have defects in eosinophil and macrophage function as well.¹³³, ¹³⁴ Monocyte/macrophage abnormalities have also been noted in an SGD patient.¹³⁵ One case of SGD has been reported with no mutation in the C/EBPE gene.¹³⁶

Neutrophils with a diameter of approximately 17 µm (as compared with a normal diameter of about 13 µm) are rare in blood smears from normal people (1 in 20,000 neutrophils or less). They may be seen with greater frequency in patients who are ill, but even then the number rarely exceeds 0.2% unless a disease involving leukocyte production is present or a reaction to a cytotoxic drug occurs.¹³⁷ A family with giant neutrophils in healthy members of three generations has been reported.¹³⁷ Over several years, the propositus had an average of 1.6% giant neutrophils in the blood. The large neutrophils appeared to be nearly double the normal cell volume and contained from six to ten nuclear lobes. Therefore, it was suggested that the cells may have been tetraploid. This anomaly appeared to be transmitted as an autosomal dominant trait.

Several families have been described whose members had a hereditary (autosomal dominant) increase in the number of neutrophil nuclear segments (Fig. 58.5).¹³⁸ The proportion of neutrophils containing five lobes or more exceeded 10% in most heterozygotes and was >14% in several suspected homozygotes, as compared with no more than 10% in normal controls.¹³⁸ The bone marrow findings suggested a tendency toward nuclear indentation in early myeloid forms (eosinophils and basophils as well as neutrophils).¹³⁸ The normal size of these neutrophils was thought to provide evidence against tetraploidy, but in one study of five female family members, the mean number of nuclear drumsticks appeared to be increased above normal.¹³⁹ The chief significance of this anomaly is in its differentiation from other causes of hypersegmentation such as folate or vitamin B₁₂ deficiency.

Hypersegmentation of eosinophils can be inherited as an autosomal recessive trait, and the abnormality is characterized by a lack of sudanophilia and peroxidase activity in all of the eosinophils, whereas these histochemical reactions remain positive in the neutrophils and monocytes.¹⁴⁰, ¹⁴¹ In addition, the number of eosinophilic granules per cell appears to be reduced, and some hypersegmentation of the eosinophil nucleus may occur. No disease accompanies the disorder. This has been most commonly reported in people of Jewish (predominantly Yemenite) extraction, although members of other races have not been studied adequately.