Cold Agglutinin Disease

Article Last Updated: Apr 18, 2007
Author and Editor Disclosure

Synonyms and related keywords: cold agglutinin hemolytic anemia, cold agglutinin disease (CAD), acrocyanosis, cold-induced immune hemolytic anemia, mixed autoimmune hemolysis, Mycoplasma pneumoniae, M pneumoniae, infectious mononucleosis, Epstein-Barr virus, EBV, influenza, human immunodeficiency virus, HIV, cytomegalovirus, CMV, rubella, varicella, varicella zoster virus, mumps, hemolytic anemia, subacute bacterial endocarditis, syphilis, malaria, equestrian perniosis, lymphoma, Waldenström syndrome, chronic lymphocytic leukemia, CLL, lymphoproliferative disease, autoimmune disease, myeloma, Kaposi sarcoma, Kaposi's sarcoma, angioimmunoblastic lymphoma



In 1903, Landsteiner was the first to describe the presence of cold agglutinins in the blood, which were capable of agglutinating RBCs (Landsteiner, 1903). He described the finding of a low titer of these agglutinins in healthy individuals. Later, the appearance of the I antigen on human RBCs in the postnatal period due to modification of the fetal i antigen structure (a change occurring over the first 18 mo) was found to lead to the development of low levels of anti-I agglutinins. These antibodies induce hemagglutination mainly at 4°C and not at 37°C and were therefore termed cold agglutinins.

Subsequent observations have led to the understanding that cold agglutinins are usually immunoglobulin M (IgM) antibodies (less commonly immunoglobulin A [IgA] or immunoglobulin G [IgG]) that may result in hemolytic anemia due to complement-mediated RBC destruction in the reticuloendothelial system. Slowing of blood flow with occlusion of superficial blood vessels by agglutinated RBCs can cause a Raynaudlike syndrome (acrocyanosis) (Schobuthe, 1952; Schobuthe, 1966; Dacie, 1992).


Cold agglutinin disease (CAD) usually develops as a result of the production of a specific IgM antibody directed against the I/i antigens (precursors of the ABH and Lewis blood group substances) on RBCs. These cold agglutinins commonly have variable heavy-chain regions encoded by VH (Harboe, 1965; Angevine, 1966; Garraty, 1977; Wortman, 1979; Petz, 1980; Rosse, 1980; Roelke 1981; Crisp, 1982; Sokol, 1983; Roelke, 1984; Dacie, 1992; Agarwal, 1995; Packman, 1995; Jacobs, 1996; Terness, 1997; Thorpe, 1998; Ciejka, 1999; De Silva, 2000), with a distinct idiotype identified by the 9G4 rat murine monoclonal antibody (Dacie, 1992). This 9G4 idiotope is localized to the V4-34 encoded portion of the variable region (Potter, 2000). It is found on cold agglutinin-producing malignant lymphoid cells in the bone marrow in persons with lymphoproliferative disorders, on a small proportion of normal lymphoid cells, and in the spleen of a 15-week-old fetus.

The VH genes appear to regulate not only the production of cold agglutinins, but also the formation of normal antibodies to other carbohydrate antigens, both sharing the same fundamental mechanism of production. The I/i antigen analogs are present on human lymphocytes, neutrophils, and monocytes and in human saliva, milk, and amniotic fluid. Thus, in disease states, the finding of a clone of B cells producing this antibody may be the result of expansion of a normal clone that is specific for the production of an immunoglobulin with these properties. Autoimmune and lymphoproliferative disorders can also be associated with the production of cold agglutinins.

In addition, some polyclonal IgM cold agglutinins arise in association with Mycoplasma pneumoniae infections, infectious mononucleosis, influenza B, human immunodeficiency virus (HIV), and other infections. Cytomegalovirus (CMV), rubella virus, varicella-zoster virus, Parvovirus B19, and Chlamydia psittaci have also been implicated (McNicholl, 2000). In the case of infectious mononucleosis, hemolysis tends to develop 1-2 weeks after the onset of illness but may occur simultaneously or up to 2 months after onset (McNicholl, 2000). Furthermore, increased expression of both I/i antigens have been described on hemoglobin SS erythrocytes, which suggests that such patients may have increased susceptibility to cold-mediated hemolysis (Maniatis, 1979).

In its classic presentation, with hemolytic anemia and Raynaud syndrome, CAD is usually idiopathic. As with most autoimmune diseases of a chronic nature, stimulated B lymphocytes begin to produce pathogenic antibodies against an antigen normally present in human tissue. In this disease, the antibody is an IgM, usually monoclonal, with kappa or lambda light chains. In chronic CAD, the antibody is usually directed against the I antigen on the membrane of normal adult RBCs.

Uncommonly, the antibody may be directed against only the i antigen found on fetal cord blood RBCs, which lack the mature I antigen; this has been reported in association with infectious mononucleosis (Petz, 1980). In a study of 78 patients, κ light-chain specificity was found in the majority of patients with chronic CAD or Waldenström macroglobulinemia, whereas two thirds of cold agglutinins found in patients with lymphomas had light-chain specificity. The type of light chain appears to correlate with the antigen specificity of the cold agglutinin.

Fifty-eight percent of IgM/κ (usually κIII variable region subgroup) were anti-I, but 75% of IgM/λ had other antigen specificities (Crisp, 1982). Antigen specificities of cold agglutinins other than the I/i system that have been described include those against Pr, M, P, and Lud and anti-Gd, anti-Fl, and anti-Sa (Angevine, 1966; Roelke 1981; Roelke, 1984). Exclusive occurrence of κ chains has also been shown with some cold agglutinins (Harboe, 1965). Thus, benign and malignant cold agglutinins exhibit differences in their light chains and their specificities toward membrane antigens.

In vivo, the IgM antibody attaches to RBCs and causes them to agglutinate at temperatures below 37°C and maximally at 0-5°C, resulting in impaired blood flow to the digits, nose, and ears, ie, areas more likely to have colder temperatures (in the 30°C range) when exposed to the cold. Fixation of the C3 component of complement to the RBC by the cold agglutinin usually occurs in vivo at higher temperatures compared to those required by the IgM cold agglutinin to attach to the RBC, but generally less than 31°C. When the IgM/C3b-coated RBC circulates to warmer tissues, the IgM dissociates, leaving complement C3b on the original RBC.

The dissociated IgM cold agglutinin can then bind to another RBC at lower temperatures. Fixation of complement results in C3b and/or C4b components on the RBC membrane, which may lead to phagocytosis by macrophages in the reticuloendothelial system, particularly in the liver, where the macrophages have specific complement receptors. With time, the C3b components are converted enzymatically to C3dg, which is not recognized by macrophage receptors.

In chronic CAD, complement tends to be depleted. Thus, the hemolysis is self-controlled, and anemia may only be mild or moderate because these C3dg-coated RBCs are no longer capable of reacting with the IgM antibody in the cold, the C3dg-coated RBCs are not recognized by the macrophages, and low complement levels become rate limiting.

Temporary increases in complement levels, as can occur with intercurrent febrile illnesses, can increase hemolysis. Lytic components of complement C5-C9 generally do not form on these cells, and intravascular hemolysis by complement is less likely to occur (Packman, 1995). Hemolysis develops acutely following M pneumoniae infections and lasts approximately 1-3 weeks. Subclinical mild hemolysis with reticulocytosis also may occur, and the results of a direct Coombs test may be weakly positive, especially with M pneumoniae infections.

Monoclonal cold agglutinin IgM antibodies found in patients with lymphoma are the product of the abnormal clone. Progression of an idiopathic CAD to malignant lymphoma may occur in some cases; thus, affected patients require close long-term follow-up, with obvious therapeutic implications (Petz, 1980; Roelke, 1984). One study of 86 patients in Norway showed clonal light chain predominance in 90% of patients, evidence of lymphoplasmacytic lymphoma in 50%, and lymphoma of any type in 76% overall (Gertz, 2006).

Hemolysis due to cold agglutinins can sometimes be accompanied by a warm antibody (IgG), resulting in a mixed autoimmune hemolytic anemia (Petz, 1980; Sokol, 1983), ie, cold agglutinin syndrome and warm antibody autoimmune hemolysis, with the direct antiglobulin (direct Coombs) test results positive for the presence of both IgG and complement on the surface of the sensitized RBC. In mixed antibody syndromes, the IgG and IgM antibody components can be separated. The cold autoantibodies reactive at temperatures of 30°C or higher often show blood group specificity to the adult I antigen, while the warm autoantibodies are not directed against this system. A combination of cold agglutinins and cryoglobulins has also been reported with an IgM κ monoclonal antibody with specificity to the Pr2 antigen system (Ciejka, 1999).

Several factors play a role in determining the ability of a cold agglutinin to induce an active hemolytic anemia. These factors include the ability to initiate; the extent of antibody-induced complement activation; the concentration of the antibody; the range of temperatures, including the highest temperature at which the antibody interacts with the RBC (its thermal amplitude); the qualitative binding of IgM to the red cell; and modification of the antibody's ability to fix complement components onto the RBCs (Rosse, 1980; Gertz, 2006). In addition, the presence of biphasic hemolysins implicates more severe disease. Biphasic haemolysins bind to red blood cells at low temperatures and activate complement to produce in vitro hemolysis at warmer temperatures (37°C), whereas monophasic hemolysins bind to red cells and activate complement at the same temperature (Sokol, 2000).

In vitro studies have shown that human monoclonal antibodies encoded by the V4-34 gene segment not only have cold agglutinin properties, but also exhibit multireactivity. This is in contrast to the generally monospecific I/i reactivity of sera from patients with CAD (Thorpe, 1998). Data have confirmed an immunomodulatory/immunosuppressive role of the naturally occurring anti-F(ab')2 antibodies in the production of cold agglutinins, with an inverse correlation between the titers of IgG-anti-F(ab')2 and cold agglutinins (Terness, 1997). This inverse correlation was found only in patients with anti-I/i and in the presence of a monoclonal lymphocyte population.


United States

Low titers of cold agglutinins (1:64 or less) reactive at low temperatures are commonly found in the sera of healthy persons. Postinfectious elevations in the cold agglutinin titers (eg, M pneumoniae, Epstein-Barr virus [EBV], cytomegalovirus [CMV]) are transient. Cold agglutinins develop in more than 60% of patients with infectious mononucleosis, but hemolytic anemia is rare. Development of the CAD syndrome is relatively uncommon, at least in the classic chronic form. Various reports state that 7-25% of cases of autoimmune hemolytic anemia are cold agglutinin–mediated. Incidence of both cold and warm autoimmune hemolytic anemia (combined) is approximately 1 in 80,000; the incidence of CAD, which is approximately one fourth of the total, is approximately 1 in 300,000. Among autoimmune hemolytic anemias, CAD is the second most common cause, after warm autoantibody–induced immune hemolysis.


Data regarding incidence of CAD are lacking. Frequency figures listed for the United States probably also apply to Canada and the United Kingdom.


Morbidity in chronic CAD is usually limited to symptoms precipitated by exposure to the cold. Transfusions for life-threatening symptoms due to severe anemia require prewarming and the use of washed RBCs (not cold). Occasionally, peripheral gangrene and, rarely, fatalities, have occurred after inadvertent and perhaps prolonged exposure to the cold.


A racial predilection has not been reported.


Women are affected more commonly than men (Petz, 1980; Dacie, 1992). Mixed autoimmune hemolysis has a male-to-female ratio of 1:1.5.


Infants and children are rarely affected with chronic CAD, although M pneumoniae and infectious mononucleosis are diseases of young persons. Chronic CAD appears to affect adults who are of middle age and older, with an average age more commonly older than 60 years (peaking in the seventh and eighth decades of life). Although found in persons of all age groups, mixed autoimmune hemolysis is also more frequent in later life.







Other Problems to be Considered


Lab Studies

Imaging Studies


Histologic Findings

Depending on the underlying precipitating illness, changes may be seen in the bone marrow and lymph nodes. The presence of a malignant lymphoproliferative disorder also may be evident in these biopsy samples. Clumps of RBCs may be observed in the peripheral smear, as is discussed in Lab Studies (see Image 1).


Staging is applicable only if an underlying malignant disorder is present.


Medical Care

CAD may be managed successfully using protective measures (clothing) alone in most cases. Special protective clothing is sometimes necessary in extreme cases. Therapy is directed at serious symptoms and the underlying disorder, if any is found.

Surgical Care

Splenectomy is usually ineffective because the liver is the predominant site of sequestration. However, if the patient has splenomegaly, then the disease may respond to splenectomy. More importantly, a lymphoma localized to the spleen may only be found after splenectomy.


A hematologist-oncologist working in collaboration with a blood banker is helpful in complicated cases.


Patients should include good sources of folic acid, such as fresh fruits and vegetables, in their diet.


Activities should be less strenuous compared to those for healthy people, particularly for patients with anemia. Jogging in the cold could be very hazardous because of the added windchill factor.


Folic acid supplementation is advisable to meet increased requirements of increased RBC production due to hemolytic anemia.

Immunosuppressive and immunomodulating drugs are seldom necessary; however, in cases with underlying malignancies, they are required to treat the malignancy. Potent immunosuppression to reduce the production of monoclonal antibody and to reduce/eliminate abnormal lymphocyte clone has been achieved with cyclophosphamide (1200 mg) and vincristine (2 mg) administered intravenously on day 1 and prednisone (80 mg/d) administered orally for 5 days, with some beneficial effect in an anecdotal case. The same patient was treated 10 months later with fludarabine (25 mg/m2) daily for 5 days intravenously and then every 28 days for 3 courses. Following a third course of treatment, this patient went into remission that lasted at least 4 years (Jacobs, 1996).

Bear in mind that one uncommon reported adverse effect of fludarabine is the appearance of a warm autoantibody–induced autoimmune hemolytic anemia. However, according to the authors' experience, persons with Coombs-positive hemolytic anemias have been treated effectively with fludarabine. Responses to interferon alfa therapy have been reported. This therapy may be useful for some B-cell neoplasms (O'Connor, 1989).

Chlorambucil has also been used to treat CAD (Hippe, 1970). Corticosteroids alone may not be routinely useful in all patients with CAD, although occasionally a patient may respond. Patients with mixed cold and warm immune hemolytic anemia are more likely to respond because of the warm antibody component.

In general, use of chemotherapeutic agents, which have long-term consequences for the patient and are associated with secondary malignancies such as leukemias that are hard to treat, requires very careful decision making in collaboration with a well-informed patient. They should be used only for life-threatening, severely symptomatic disease. Therapy also may need to be administered intermittently or infrequently as the case demands. Tailor therapy to individual needs. Only currently used drugs are discussed. These will change as newer drugs become available for use.

Although alkylating agents have been used in the past and references to these treatments are part of standard texts, the authors suggest that these drugs not be used in patients with CAD because of the potential for long-term adverse effects of therapy for an essentially benign disorder.

The reader is advised to read the package insert approved by the US Food and Drug Administration before using any of the agents listed.

Drug Category: Immunosuppressive alkylating agents

Metabolites cross-link DNA, thereby interfering with cell proliferation. Not needed in patients with idiopathic CAD.

Drug NameCyclophosphamide (Cytoxan)
DescriptionChemically related to nitrogen mustards. As an alkylating agent, the mechanism of action of the active metabolites may involve cross-linking of DNA, which may interfere with growth of normal and neoplastic cells. Cystitis can develop with long-term administration; leukemogenic potential should be kept in mind. Primary (idiopathic) form of disease is unlikely to require use of this class of drugs.
Adult DoseDose should be determined based on the combination regimen used to treat the underlying malignancy when CAD is secondary to an underlying malignancy
Pediatric DoseNot established
ContraindicationsDocumented hypersensitivity; severely depressed bone marrow function
InteractionsAllopurinol may enhance myelosuppressive effects; may reduce digoxin serum levels and antimicrobial effects of quinolones; coadministration with high doses of phenobarbital may increase leukopenic activity; thiazide diuretics may prolong cyclophosphamide-induced leukopenia; coadministration with succinylcholine may increase neuromuscular blockade by inhibiting cholinesterase activity
PregnancyD - Unsafe in pregnancy
PrecautionsMonitor for hematopoietic suppression with regular examination of hematologic profile (particularly neutrophils and platelets); regularly examine urine for RBCs, which may precede hemorrhagic cystitis
During chemotherapy, encourage patients to empty bladder at night before bedtime and to drink plenty of water to maintain good diuresis

Drug Category: Glucocorticoids

Used for immunosuppressant properties.

Drug NamePrednisone (Deltasone)
DescriptionImmunosuppressant for treatment of autoimmune or lymphoproliferative disorders. Modulates lymphocytes and decreases antibody production. Frequently used with alkylating agents.
Adult Dose60-80 mg/d (up to 1-2 mg/kg/d) as starting dose; used for suppression of antibody production; taper dosages after several weeks, with close monitoring of adverse effects; determine dosing regimen based on multidrug regimen chosen to treat specific underlying malignancy
Pediatric DoseNot established
ContraindicationsDocumented hypersensitivity; viral infection, peptic ulcer disease, hepatic dysfunction, connective tissue infections, and fungal or tubercular skin infections; GI disease
InteractionsCoadministration with estrogens may decrease clearance; concurrent use with digoxin may cause digitalis toxicity secondary to hypokalemia; phenobarbital, phenytoin, and rifampin may increase metabolism of glucocorticoids (consider increasing maintenance dose); monitor for hypokalemia with coadministration of diuretics
PregnancyB - Usually safe but benefits must outweigh the risks.
PrecautionsAbrupt discontinuation of glucocorticoids may cause adrenal crisis; hyperglycemia (potential contraindication, assess each patient carefully), edema, osteonecrosis, myopathy, peptic ulcer disease, hypokalemia, osteoporosis, euphoria, psychosis, myasthenia gravis, growth suppression, and infections may occur with glucocorticoid use; sleep deprivation/alteration in sleep cycle common; check potassium levels and advise patients to eat plenty of fruits and vegetables to obtain adequate potassium; weight gain due to stimulation of appetite is possibly a serious issue (advise patients of this possibility); watch for development of depression; occasionally, mania or altered sleep cycle may occur; muscle weakness and wasting may become a serious problem; hypertension can be exacerbated by steroids

Drug Category: Interferons

Variable success with these agents in cold agglutinin–induced hemolytic anemia. Expense and serious adverse effects are issues to consider up front before choosing this class of drug. Used in the treatment of lymphoproliferative disorders.

Drug NameInterferon alfa-2b (Intron-A)
DescriptionIdentifying proper drug for use in a patient depends on patient characteristics and patient participation in decision-making process. No guarantees of success can be given with any therapy in CAD. Interferon alfa is manufactured by recombinant DNA technology. Mechanism of effect is not clearly understood. However, direct antiproliferative effects against many different kinds of malignant cells have been shown in clinical disease states (eg, lymphoma, melanoma, CGL) and modulation of host immune response may play important roles.
Adult Dose3-5 million U/m2 SC 3 times/wk; tailor dosage as tolerated based on adverse effects (dosage has been used in lymphoproliferative disorders)
Pediatric DoseNot established
ContraindicationsDocumented hypersensitivity (anaphylactic sensitivity to mouse immunoglobulin (IgG), egg protein, or neomycin); autoimmune hepatitis, presence of severe depression
InteractionsPotential risk of renal failure when administered concurrently with interleukin-2; theophylline may increase toxicity by reducing clearance; cimetidine may increase antitumor effects; zidovudine and vinblastine may increase toxicity
PregnancyC - Safety for use during pregnancy has not been established.
PrecautionsDepression and suicidal ideation may be adverse effects, but drug sometimes may be tolerated by patients with depression (decide on an individual basis); prior to initiation of therapy, perform CBC count for platelets, Hb/Hct, and WBC with differential; monitor periodically during treatment to determine response to treatment; monitor for hypothyroidism; past history of severe depression may warrant caution because of risk of recurrence; caution in cardiac arrhythmias

Drug Category: Vitamin, Water Soluble

Necessary for hematopoiesis.

Drug NameFolic acid (Folvite)
DescriptionImportant cofactor for enzymes used in production of RBCs. Chronic hemolytic process requires additional folate.
Adult Dose1 mg PO qd; up to 5 mg PO qd depending on frequency and aggressiveness of hemolysis
Pediatric DoseNot established
ContraindicationsDocumented hypersensitivity
InteractionsIncrease in seizure frequency and subtherapeutic levels of phenytoin reported when used concurrently
PregnancyC - Safety for use during pregnancy has not been established.
PrecautionsBenzyl alcohol may be contained in some products as a preservative (associated with fatal gasping syndrome in premature infants); resistance to treatment may occur in patients with alcoholism and deficiencies of other vitamins

Drug Category: Immunosuppressant Agent

Agents in this class include antibody directed against the CD20 antigen found on surface of B-lymphocytes.

Drug NameRituximab (Rituxan)
DescriptionEffective lowering of IgM and IgG levels is achievable with this antiB cell antibody. Hypersensitivity reactions can be severe; users of the drug should become completely familiar with the adverse reactions known to occur.
Adult Dose375 mg/m2 IV qwk for 4 doses (days 1, 8, 15, 22)
Pediatric DoseNot established
ContraindicationsDocumented hypersensitivity; IgE-mediated reaction to murine proteins
InteractionsCoadministration with cisplatin is known to cause severe renal toxicity including acute renal failure; may interfere with immune response to live virus vaccine (MMR) and reduce efficacy (do not administer within 3 months of vaccine)
PregnancyC - Safety for use during pregnancy has not been established.
PrecautionsUse with caution in patients with dormant infections such as hepatitis B, hepatitis C, or CMV due to risk of reactivation; hypotension, bronchospasm, and angioedema may occur, premedication with acetaminophen and diphenhydramine may decrease incidence; discontinue treatment if life-threatening cardiac arrhythmias occur; must administer by slow IV infusion, do not administer IV push or bolus


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