AUTOIMMUNE HEMOLYTIC ANEMIA IN CHILDREN

Abstract

The clinical and hematological profile and treatment outcome of children with warm autoimmune hemolytic anemia (AIHA) were assessed using retrospective case record analysis. There were 26 (17 idiopathic; 9 secondary) patients with a median age of 11 years. Pallor (100%), fever (39%), and jaundice (59%) were the main presenting complaints. Jaundice was much more common in idiopathic (70%) compared to secondary (44%). Direct antiglobulin test was negative in 3 patients. Oral prednisolone produced remission in 81% patients. Four patients relapsed after a median period of 7 months (2 months to 2 year) after response. All responded to a second course of steroids in median 14 days. One child required cyclosporin A in addition. No correlation was found between response and parameters such as age, sex, jaundice, low pretreatment hemoglobin, reticulocyte count, total leukocyte count, platelet count, subtype of AIHA, and hepatosplenomegaly. Relapse correlated with increased duration between the onset of symptoms and treatment. This study indicates that oral prednisolone is an effective therapy for autoimmune hemolytic anemia. In refractory cases cyclosporine A may be useful.

Keywords:

• children
• immune hemolysis
• coticosteroids
• cyclosporin

Autoimmune hemolytic anemia (AIHA) has a prevalence of 1 per 100,000 and may be life-threatening. In children it often presents as an acute, self-limited illness, with good response to short-term steroid therapy in nearly 80% of patients [[1], [2], [3]]. In children younger than 2 years of age or in teenagers, the clinical course of the disease may show either resistance to steroids or dependence on high-dose steroids [4]. The mortality rate in these children with idiopathic AIHA has been reported to be on the order of 10% [3].

We are presenting a series of 26 cases to analyze the etiopathogenesis, clinical, and hematological profile and efficacy of the treatment.

MATERIAL AND METHODS

All children diagnosed between January 2001 and December 2005 were included in the study. We, at our institute, examine a peripheral smear of anemic children. Hemolysis is established with peripheral blood spherocytosis and fragmented cells with elevated reticulocyte count, unconjugated hyperbilirubinemia, and a positive direct antiglobulin test (DAT, Coombs' test) with or without indirect antiglobulin test (IAT). Initially we were using the conventional tube methods. Now we use a gel card using Sephadex columns for antiglobulin test as it has a higher sensitivity. Coombs' test was done using polyspecific sera. Patients who had a negative Coombs' test were not tested with a monospecific serum. Flow cytometric analysis of CD55 and CD59 is done to rule out paroxysmal nocturnal hemoglobinuria, before labeling a Coombs-negative AIHA.

A detailed drug history was taken to exclude drug-induced AIHA. Depending on the history, area of origin, clinical presentation, and peripheral blood picture, exclusion of other causes was done. All Coombs'-positive patients were investigated with high-performance liquid chromatography, G6PD screening, tests for CD55 and CD59 (before labeling Coombs-negative AIHA). All infants who present with AIHA are screened for TORCH infections. Autoimmune markers for antinuclear antibody, rheumatoid factor, and double-stranded DNA were done in patients with joint or musculoskeletal complaints. Anti-LKM1 and smooth muscle antibody were done in patients with significant hyperbilirubinemia. CT scan, ultrasonography, or bone marrow aspirate was done in those patients where leucopenia and/or thrombocytopenia was present to rule out underlying malignancies. Children who had other features consistent with AIHA but negative Coombs' test were given a trial of corticosteroids and diagnosed as Coombs-negative AIHA when they showed response.

Response criteria were transfusion independence along with Hb > 2 g/dL over baseline and absolute value more than 8 g/dL. All patients were given a course of steroid in a daily dose of 2 mg/kg till hemoglobin reached to normal level or 6 weeks, whichever was earlier. Prednisolone was very slowly tapered in patients who responded. Dose was reduced by 10% of initial dose and patients were kept at this dose for 3–4 weeks before it was tapered further. The dose was reverted to initial dosage if hemoglobin fell on reducing the dose of prednisolone. Children were also supplemented with folic acid supplementation. In children not responding to prednisolone, cyclosporin A is added at a dose of 5 mg/kg/day in children less than 5 years awaiting splenectomy. Blood transfusions are avoided as far as possible. No definite hemoglobin cutoff value is used for transfusions, which are given only in children with impending CCF or depending on the rate of fall of hemoglobin. IVIg is not used because of poor and transient response rates at our hospital earlier. Splenectomy with vaccination against pneumococcus, H. influenzae, and meningococcus is considered if children fail to respond to 6 weeks of steroids.

Data analysis was done using the computer software Epi Info version 3.2 (Chicago, IL, USA).

RESULTS

Twenty-six (11 M: 15 F) patients between 2 months and 17 years (median: 11 years) were studied. Table 1 shows the presenting manifestations of idiopathic and secondary AIHA. Prevalence of secondary AIHA in our patients was found more in females (7/9) than in idiopathic AIHA (9/17). Fever was seen in 39% children. There was no bleeding manifestation or lymphadenopathy. Unconjugated hyperbilirubinemia was seen in 18 (69%) patients. Prevalence of jaundice was much more in idiopathic cases (70%) as compared to secondary (44%). Seven (27%) patients had splenomegaly of >5 cm, with 6 in the idiopathic and 1 in the secondary group. Seven (27%) patients had anemia of >6 months duration. One patient had associated Hb H disease.

TABLE 1 Patients Characteristics

	Idiopathic AIHA (n = 17) Median (range)	Secondary AIHA (n = 9) Median (range)
Age (years)	7.5 (1.2–17)	11.5 (2.5–18)
Pallor duration (months)	3.0 (0.5–18)	6 (0.6–48)
Hemoglobin (g/dL)	5.0 (2.4–8.9)	4.5 (2.1–6.4)
Duration of jaundice (months)	4.0 (0–12)	1 (0–48)
Liver (cm below costal margin)	2 (0–5)	2 (0.5–9)
Spleen (cm below costal margin)	4 (0–7)	0.5 (0–8)
Reticulocyte count (%)	28 (2–70)	15 (8–50)
Symptom to T/t gap (months)	4 (0.3–19.5)	2 (0.1–15)
Time to response (days)	9 (6–28)	18 (4–63)

Thrombocytopenia was noted in 6 (23%) patients and all had platelet counts less than 100,000/mm³ and pancytopenia was seen in 1 (4%) child. Bone marrow examination in such cases showed erythroid hyperplasia with megalobastic changes but no visible change in myeloid cells or megakaryo-cytes. Peripheral smear examination showed spherocytosis in 20 (77%) patients. DAT and ICT were negative in 3 (11.5%) and 8 (31%) children, respectively. Antinuclear antibody was positive in 3, rheumatoid factor in 2, and ds DNA in 2 (3.8%) patients. Significant correlation was found between degree of anemia with jaundice (r =. 93, p =. 0001) and also with reticulocyte count (r =. 40, p =. 002). No drug was incriminated as the cause of hemolysis in our series. Table 2 shows the conditions associated with AIHA.

TABLE 2 Distribution of Secondary Conditions Associated with AIHA

Conditions	Number of patients (n = 9)
Autoimmune conditions	5 (56%)
Evan syndrome	2 (22%)
ESLE	2 (22%)
EJRA	1 (12%)
Infections	2 (22%)
ECMV	1 (11%)
ERubella	1 (11%)
Others	2 (22%)
EEndocrine disease	1(11%)
ENephritis	1 (11%)

One secondary AIHA (rubella) was followed up for resolution of anemia without treatment. Steroids were prescribed in all the other cases. Three patients were lost to follow-up. Response was achieved in 21 (81%) patients. Median response time in our patients was 14 days (6–29 days). Steroids were continued for a period varying from 6 to 48 months. One child with idiopathic AIHA required splenectomy. No correlation was found between response and parameters like age, sex, jaundice, low pretreatment hemoglobin, reticulocyte count, TLC, platelet count, and hepatosplenomegaly. Four patients of idiopathic AIHA relapsed after a median period of 7 months (2 months to 2 years) after response. There was no relapse in secondary cases. Three responded to a second course of steroids in response in 14 days to 2 months (median 14 days). Another child required cyclosporin A (5 mg/kg/day) in addition to prednisolone and response was seen in the 3rd week. All were DAT positive and 3 were ICT positive. Relapse rate correlated with increasing duration between the onset of symptoms and treatment (r =. 996; p =. 0001).

DISCUSSION

The clinical pattern of AIHA in children is predominantly an acute, transient type lasting for 3–6 months in 70–80% of cases. Chronic hemolysis develops in 30% of patients with an underlying secondary cause [5]. Autoantibodies in AIHA (predominantly IgG) are antigen specific against substances on RBC, i.e., agglutinogen like A-B-O, H-N, and Rh − Hr system [6]. Rh erythrocyte antigen is involved in more than 70% of cases. Coombs' test has false-negative and false-positive rates in about 2–4% and 8% of all cases, respectively [7].

Nine (35%) children had secondary AIHA in this series. Median age at presentation was 11 years (range 0.2–17), which is in contrast to the data published from other centers with a median age of 2 years [2] and 8 years [10]. Buchanan et al. [8] found a 32% incidence of secondary AIHA. Median hemoglobin in our series is 6.0 g/dL (2.4–14.3). The hemoglobin level in our patients did not correlate with the strength of DAT positivity. This is because the severity of hemolysis may depend on avidity and subtype of antibody, quantity of the complement bound, characteristics of RBC antigen, number of IgG Fc and complement receptor on macrophages, and functional status of mononuclear phagocytic system [[11], [12]]. Hepatosplenomegaly did not correlate with degree of anemia or jaundice.

One child had dark urine at presentation. Dark urine was reported in 4/8 children in one study [13]. One child had CMV infection, as reported earlier also [[l3]]. One girl had SLE at diagnosis and another developed SLE on follow-up after 3 years. In 8 (31%) patients reticulocyte counts were low due to hemolytic process affecting the reticulocytes circulating in peripheral blood also [8]. DAT was negative in 3 patients (2 M: 1 F), but peripheral blood smear showed a hemolytic picture. Reticulocyte count was raised in 2 and ICT was positive in 1 of these children. All had hepatosplenomegaly, and jaundice was present 2 of them. All these patients responded well to the steroid therapy without any relapse. Negative DAT in patients with clinical picture of AIHA could be due to a low level of antibodies on the red blood cells or lower sensitivity of DAT [14].

Eighty-one percent of our patients responded to oral corticosteroid therapy. The mechanism of action of steroids is probably downregulation of Fc receptors on phagocytes and reduced IL-2 production [14]. The most important early effect of steroids is to suppress sequestration of opsonized red cells by splenic macrophages. Another proposed early effect could be reduction in the binding affinity of autoantibodies for the patient's red cells [13].

Four children relapsed and all belonged to idiopathic group. Relapse correlated with increased duration between the onset of symptoms and treatment (p =. 0001). One child required the addition of cyclosporin A after a retrial of 2 weeks of steroid treatment failed to elicit a response. A 6-month-old boy with severe AIHA who initially responded to high-dose methylprednisolone and intravenous immunoglobulin G therapies but eventually became refractory was then treated with low-dose cyclosporine and prednisone successfully [15]. In one series of 164 adult cases the response rate of adrenocortical hormones and cyclosporin A (CsA) was 90.9% [16]. Another series found that patients treated with prednisolone and cyclosporin relapsed less than those treated with prednisolone alone [17]. Administration of cyclosporine in 2 of the 4 patients did not result in any amelioration of the symptoms in another series [10].

A series of 51 children (18 acute anemia: 33 chronic anemia) showed that corticosteroids were effective in all acute cases but the results were variable in the chronic cases. The acute form was more frequent in young children, while chronic AIHA occurred mainly among children at puberty. In chronic form, it was sometimes necessary to add immunosuppressive drugs and in 2 cases to perform a splenectomy [18].

In the present series transfusions were given in 6 (23%) patients who were symptomatically severely anemic. Transfusion of red cells in AIHA poses 2 difficulties. Owing to the presence of autoantibodies, it is nearly impossible to find truly serocompatible donor blood. In such circumstances it is best to use donor blood of the same ABO and Rh group as the patient, which is least incompatible, along with corticosteroids [19]. The second problem is the rapid in vivo destruction of transfused red cells. Once selected, 20–50 mL of packed RBCs (not whole blood) should be transfused very slowly while the child is closely monitored for signs of hemolytic reactions [13].

The response rates were similar between secondary and idiopathic AIHA, as evident from other studies [20].

Initial intensive inpatient monitoring may be required, followed by outpatient therapy. There is a high rate of remission with corticosteroids. In refractory cases cyclosporine can be tried before other options such as splenectomy, cyclophosphamide [2], and rituximab [[9], [21]] are pursued.