The moment Taeho took a close look at Minjun’s face, he sensed that something was wrong.
Minjun’s face was paler than usual, and his lips were dry.
“Minjun, could you open your mouth?”
“Doctor, please look at me first. I’m in more pain than my brother!”
Minseok raised his hand high.
Minjun, unwilling to lose, raised his hand as well.
“No. Please look at me first, Doctor.”
“They’re at it again. You’re both going to be examined, no matter who goes first, so just stay still.”
The children’s mother scolded them while glancing awkwardly at Taeho.
“Minjun is the older brother, right? Let’s have the older one go first this time, then the younger one.”
When Taeho spoke gently, Minseok merely stuck out his lower lip and stopped making a fuss.
“All right, Minjun. Say ‘ah.’”
When Minjun opened his mouth, Taeho’s eyes grew serious.
The aphthous ulcers were severe. This did not look like an ordinary cold.
When Taeho felt his neck with both hands, Minjun furrowed his brow.
Taeho confirmed that his lymph nodes were swollen, and his heart grew heavy.
“Minjun, have you been getting sick often lately? I mean, things like colds.”
“Yes. I think I get sick at least once a month.”
Taeho looked at Minseok.
“Minseok, have you been getting sick often too?”
“Of course! My head hurts a lot!”
“Minseok, could you show me the inside of your mouth?”
Minseok’s mouth was clean. There were no aphthous ulcers.
“You’re fine.”
“No, I’m in pain too.”
When Minseok answered defiantly, his mother tried to restrain him.
“Minseok! That’s enough. I’m sorry. Ever since he was little, he’s always tried to do exactly the same things as his brother…”
“It’s easy for siblings to be like that.”
Their temperatures, taken just before they entered the examination room, were 37.8 degrees Celsius for Minjun and 36.9 degrees for Minseok.
Taeho’s expression darkened. The symptoms looked mild, but he had a clear intuition that something was wrong.
“First, I’d like to run a blood test on Minjun.”
“A blood test?”
The children’s mother asked again, her face filled with surprise.
“Is it that serious?”
“We need to check in order to get an accurate picture. We have to determine whether it’s just a cold or a problem with his immune system. The results should be ready soon.”
The children’s mother wrapped an anxious arm around Minjun’s shoulders.
“Then we’ll have the test done.”
An hour later, Taeho received the printed results.
“Minjun’s neutrophil count is 480. It should normally be at least 1,500, so his level is quite low.”
“Then is it very serious?”
“At this level, it’s difficult for him to fight off even ordinary infections. It also explains the recurring infections he’s had recently.”
The children’s mother’s face turned deathly pale.
“In a case like this, there’s a strong possibility that it’s autoimmune neutropenia. However, we can’t say that for certain yet. A detailed examination will be necessary for a definitive diagnosis.”
“Autoimmune… But he’s been fine until now. How could this happen all of a sudden?”
The children’s mother looked bewildered.
“He must have been catching colds frequently and often developing ulcers in his mouth. He probably felt very tired as well.”
“That’s true, but is it a serious illness?”
“It’s rare, but it does occur in children from time to time. If it’s properly managed from an early stage, he can still lead a normal life. However, treatment may take two or three years or longer, and in some cases, immunosuppressants may be necessary.”
The children’s mother pressed her lips tightly together as she listened, and soon the corners of her eyes reddened.
“I thought he just caught colds often. I thought that was how all children grew up… I’ve been so busy with work that I don’t think I took proper care of them.”
“No, ma’am. This isn’t anyone’s fault. Autoimmune diseases usually have no obvious outward signs, so they’re very difficult to detect in the early stages. It’s not too late that we’ve found it now.”
Minseok glanced at Minjun and asked,
“Doctor, what about me? Aren’t you going to test me? I told you I’m sick too!”
“Minseok is fine.”
“No, I’m sick too. Doctor, test me as well.”
“Do you want to have your blood drawn too? Aren’t you afraid of needles?”
He flinched slightly at the word “needle,” but Minseok shouted again.
“I’m not afraid. Test me too!”
“Oh, you immature little rascal!”
Their mother scolded him while lightly smacking him on the back with her palm.
Seeing Minseok get scolded, Minjun struggled to hold back a laugh.
“I’m sorry, Doctor. So we have to go to another hospital, right?”
“Yes. I’ll write up a referral for you right away. It would be best to go to a large hospital with a pediatric immunology and hematology-oncology department.”
“I don’t know which hospital we should go to…”
“Then I’ll contact Gilcheon Medical Center and help you make an appointment.”
“Thank you, Doctor. Thank you so much.”
***
However, a week later, the children’s mother returned to Geumsan Clinic with Minjun and Minseok. Her face looked much more haggard than it had three days earlier.
“Doctor!”
The moment she saw Taeho, the children’s mother burst into tears.
“What happened? What did they say at Gilcheon Hospital?”
“The test results came back, just as you said. They confirmed that it was autoimmune neutropenia. But the doctor at Gilcheon Hospital said…”
The children’s mother pulled a crumpled sheet of paper from her pocket. It was the medical opinion she had received from Gilcheon Hospital.
“They said he’ll need continuous treatment for the next two or three years. They also said that because the treatment takes so long, he might not grow as tall due to the side effects. And apparently, it’s difficult to cure completely.”
Taeho took the medical opinion and skimmed through it.
Just as he had expected. The test results were clear, and the diagnosis was accurate.
One line caught his attention: “A 30–40% cure rate, with the possibility of growth hormone suppression.”
Even at a glance, Minjun appeared to be around 140 centimeters tall. He was on the shorter side compared to the average eleven-year-old boy.
Autoimmune neutropenia itself did not directly affect growth. However, long-term use of immunosuppressants could potentially suppress growth. Studies had shown that using oral steroids continuously for more than six months inhibited the division of cartilage cells in the growth plates.
Taeho looked at the twins sitting side by side. They looked so alike that it was difficult for anyone else to tell them apart. Even if the treatment went well, a clear difference in their heights might emerge after several years.
“Doctor…”
The children’s mother looked at Taeho imploringly.
“Please save our Minjun. I looked into you, and they said you’ve cured many rare diseases and are famous internationally as well. Please, help our Minjun.”
Taeho nodded.
“Then let’s treat him here at Geumsan. We may need to take a different approach from the standard treatment, so it could take some time.”
“Thank you. If you’ll accept him, we’ll wait as long as necessary. Should he be hospitalized?”
“Minjun doesn’t have a fever right now, and he isn’t showing any particular signs of infection. So for the time being, I’d like to monitor his progress through outpatient treatment rather than hospitalizing him.”
“Yes.”
The children’s mother answered with a much lighter expression.
“However, if his temperature rises above 38.5 degrees Celsius, or if he develops chills, vomiting, or diarrhea, you must contact us immediately. Even a minor cold can be dangerous for a child with a low neutrophil count.”
“I understand. Thank you, Doctor. Thank you so much.”
At that moment, Minseok suddenly stepped in front of Taeho.
“Doctor! Test my blood too!”
Minseok shouted at the top of his lungs.
His mother’s eyes widened as she pulled him toward her.
“What’s gotten into you again? Are you really going to act like this?”
“No! I was sick just like my brother! Test me too. Mom and Dad only treat my brother well because he’s sick… But I was sick too!”
Minseok stamped his feet and threw a tantrum.
His mother’s face turned bright red with embarrassment and anger.
“You little brat! Do you know where you are, throwing a tantrum like this?”
She gripped Minseok’s shoulder tightly to restrain him.
Minseok burst into tears and shouted,
“I was sick too! I was just as sick as my brother, so why won’t you test me too?”
At that moment, a thought flashed through Taeho’s mind like lightning.
He’d had the same symptoms?
“Minseok, when was that? Do you remember when you were sick like your brother?”
When Taeho asked seriously, Minseok abruptly stopped crying.
His mother also stared at Taeho in surprise.
Minseok wiped his tears with his sleeve and answered,
“Yes! It was after winter vacation ended. I was sick for a week before I went back to school!”
“What kind of symptoms did you have?”
“My throat hurt just like my brother’s, and I had sores in my mouth. I had a fever too.”
“And how did you get better?”
“I just got better on my own. I didn’t even take any medicine.”
Taeho nodded.
“Ma’am, then let’s test Minseok as well.”
“Really?”
Minseok’s eyes sparkled.
His mother looked bewildered.
“He’s only saying this because he’s jealous of his brother. Is that really necessary?”
“He wants to be tested so badly, so let’s do it once. Minseok, you’re really okay with getting a shot, right?”
“Yes! I’m not scared!”
Minseok answered energetically.
An hour later, Minseok’s test results came back.
Taeho slowly read through the results.
His neutrophil count was normal. A small amount of antibodies still remained, but his inflammatory markers were completely clear.
Something else stood out even more. Among his immune cells, those known as regulatory T cells were abnormally active.
“Minseok really was sick before.”
“What? You mean Minseok had the same illness as Minjun?”
“He had it once, but recovered.”
“Then does Minseok need treatment too?”
“No. In fact, it’s the opposite.”
Taeho explained as he looked over the test results.
“Minseok already has special immune cells in his body that overcame the autoimmune disease. They’re called regulatory T cells, and they’re suppressing the autoimmune response.”
Minseok tilted his head and asked,
“Doctor, what does that mean?”
“In simple terms, Minseok’s body has already fought the disease and won. That’s why he’s completely healthy now.”
Minseok looked proudly at his brother and mother, as if to say, “See?”
Taeho tapped the frame of his glasses and murmured as though speaking to himself,
“If things go well, we might be able to apply Minseok’s immune pattern to Minjun.”
-Analyzing…
-HLA compatibility between identical twins: 100%. Probability of immune cell transplant rejection: less than 0.1%.
-If Park Minseok’s regulatory T cells are transplanted into Park Minjun, the predicted success rate is 94.7%.
Just as expected.
“What about side effects…”
-In the case of an immune cell transplant between identical twins, the incidence of side effects is less than 3%.
-Major side effects: temporary fever and mild fatigue.
-Serious side effects are not expected.
The children’s mother looked at Taeho nervously.
“Ma’am, I think we may be able to use the immune cells Minseok has to treat Minjun.”
“What do you mean?”
“There are traces of having overcome the disease in Minseok’s blood. His autoantibodies haven’t disappeared completely, but his immune system has learned how to regulate them. We can use that information and apply it to Minjun.”
“Then Minjun can get better?”
“Yes. It should be much safer and more effective than standard treatment. Above all, there should be almost no side effects.”
Minseok’s eyes sparkled as he asked,
“Can I help my brother?”
“Of course, Minseok. I think you might be able to save your brother.”
Minseok suddenly stood up and said,
“Doctor, when do we do it? Can we do it right now?”
“Minseok, aren’t you scared?”
Minjun asked worriedly.
“Not at all! If I can help my brother, I’ll do anything!”
Minseok shouted.
“There’s no need to rush,” Taeho said. “We need about a week to prepare, and we’ll have to monitor Minjun’s condition during that time.”
“I understand. We’ll do whatever you say, Doctor.”
The children’s mother looked at the two boys with tears welling in her eyes.
She had thought that, despite being twins, they did nothing but fight every day. She had never imagined they could help each other like this… For the first time, she felt that having twins had been a blessing.
After the twins left, Taeho was in the examination room drawing up a treatment plan when he received a call from reporter Kim Jeonghun.
“Doctor, I arrived in Korea yesterday. When might you have some time? There’s something I’d like to discuss with you.”